What is the role of "Flatten" in Keras?
short read:
Flattening a tensor means to remove all of the dimensions except for one. This is exactly what the Flatten layer do.
long read:
If we take the original model (with the Flatten layer) created in consideration we can get the following model summary:
Layer (type) Output Shape Param #
=================================================================
D16 (Dense) (None, 3, 16) 48
_________________________________________________________________
A (Activation) (None, 3, 16) 0
_________________________________________________________________
F (Flatten) (None, 48) 0
_________________________________________________________________
D4 (Dense) (None, 4) 196
=================================================================
Total params: 244
Trainable params: 244
Non-trainable params: 0
For this summary the next image will hopefully provide little more sense on the input and output sizes for each layer.
The output shape for the Flatten layer as you can read is (None, 48). Here is the tip. You should read it (1, 48) or (2, 48) or ... or (16, 48) ... or (32, 48), ...
In fact, None on that position means any batch size. For the inputs to recall, the first dimension means the batch size and the second means the number of input features.
The role of the Flatten layer in Keras is super simple:
A flatten operation on a tensor reshapes the tensor to have the shape that is equal to the number of elements contained in tensor non including the batch dimension.
Note: I used the model.summary() method to provide the output shape and parameter details.
len() of a numpy array in python
You can transpose the array if you want to get the length of the other dimension.
len(np.array([[2,3,1,0], [2,3,1,0], [3,2,1,1]]).T)
Make the size of a heatmap bigger with seaborn
I do not know how to solve this using code, but I do manually adjust the control panel at the right bottom in the plot figure, and adjust the figure size like:
f, ax = plt.subplots(figsize=(16, 12))
at the meantime until you get a matched size colobar. This worked for me.
Tensorflow: Using Adam optimizer
The AdamOptimizer class creates additional variables, called "slots", to hold values for the "m" and "v" accumulators.
See the source here if you're curious, it's actually quite readable: https://github.com/tensorflow/tensorflow/blob/master/tensorflow/python/training/adam.py#L39 . Other optimizers, such as Momentum and Adagrad use slots too.
These variables must be initialized before you can train a model.
The normal way to initialize variables is to call tf.initialize_all_variables() which adds ops to initialize the variables present in the graph when it is called.
(Aside: unlike its name suggests, initialize_all_variables() does not initialize anything, it only add ops that will initialize the variables when run.)
What you must do is call initialize_all_variables() after you have added the optimizer:
...build your model...
# Add the optimizer
train_op = tf.train.AdamOptimizer(1e-4).minimize(cross_entropy)
# Add the ops to initialize variables. These will include
# the optimizer slots added by AdamOptimizer().
init_op = tf.initialize_all_variables()
# launch the graph in a session
sess = tf.Session()
# Actually intialize the variables
sess.run(init_op)
# now train your model
for ...:
sess.run(train_op)
Typescript - multidimensional array initialization
Beware of the use of push method, if you don't use indexes, it won't work!
var main2dArray: Things[][] = []
main2dArray.push(someTmp1dArray)
main2dArray.push(someOtherTmp1dArray)
gives only a 1 line array!
use
main2dArray[0] = someTmp1dArray
main2dArray[1] = someOtherTmp1dArray
to get your 2d array working!!!
Other beware! foreach doesn't seem to work with 2d arrays!
How to get every first element in 2 dimensional list
You can get the index [0] from each element in a list comprehension
>>> [i[0] for i in a]
[4.0, 3.0, 3.5]
Also just to be pedantic, you don't have a list of list, you have a tuple of tuple.
Using lodash to compare jagged arrays (items existence without order)
You can use lodashs xor for this
doArraysContainSameElements = _.xor(arr1, arr2).length === 0
If you consider array [1, 1] to be different than array [1] then you may improve performance a bit like so:
doArraysContainSameElements = arr1.length === arr2.length === 0 && _.xor(arr1, arr2).length === 0
VBA using ubound on a multidimensional array
You need to deal with the optional Rank parameter of UBound.
Dim arr(1 To 4, 1 To 3) As Variant
Debug.Print UBound(arr, 1) '? returns 4
Debug.Print UBound(arr, 2) '? returns 3
More at: UBound Function (Visual Basic)
Iterate through 2 dimensional array
Consider it as an array of arrays and this will work for sure.
int mat[][] = { {10, 20, 30, 40, 50, 60, 70, 80, 90},
{15, 25, 35, 45},
{27, 29, 37, 48},
{32, 33, 39, 50, 51, 89},
};
for(int i=0; i<mat.length; i++) {
for(int j=0; j<mat[i].length; j++) {
System.out.println("Values at arr["+i+"]["+j+"] is "+mat[i][j]);
}
}
Two-dimensional array in Swift
This can be done in one simple line.
Swift 5
var my2DArray = (0..<4).map { _ in Array(0..<) }
You could also map it to instances of any class or struct of your choice
struct MyStructCouldBeAClass {
var x: Int
var y: Int
}
var my2DArray: [[MyStructCouldBeAClass]] = (0..<2).map { x in
Array(0..<2).map { MyStructCouldBeAClass(x: x, y: $0)}
}
Multidimensional arrays in Swift
You are creating an array of three elements and assigning all three to the same thing, which is itself an array of three elements (three Doubles).
When you do the modifications you are modifying the floats in the internal array.
3-dimensional array in numpy
You are right, you are creating a matrix with 2 rows, 3 columns and 4 depth. Numpy prints matrixes different to Matlab:
Numpy:
>>> import numpy as np
>>> np.zeros((2,3,2))
array([[[ 0., 0.],
[ 0., 0.],
[ 0., 0.]],
[[ 0., 0.],
[ 0., 0.],
[ 0., 0.]]])
Matlab
>> zeros(2, 3, 2)
ans(:,:,1) =
0 0 0
0 0 0
ans(:,:,2) =
0 0 0
0 0 0
However you are calculating the same matrix. Take a look to Numpy for Matlab users, it will guide you converting Matlab code to Numpy.
For example if you are using OpenCV, you can build an image using numpy taking into account that OpenCV uses BGR representation:
import cv2
import numpy as np
a = np.zeros((100, 100,3))
a[:,:,0] = 255
b = np.zeros((100, 100,3))
b[:,:,1] = 255
c = np.zeros((100, 200,3))
c[:,:,2] = 255
img = np.vstack((c, np.hstack((a, b))))
cv2.imshow('image', img)
cv2.waitKey(0)
If you take a look to matrix c you will see it is a 100x200x3 matrix which is exactly what it is shown in the image (in red as we have set the R coordinate to 255 and the other two remain at 0).
Creating a Pandas DataFrame from a Numpy array: How do I specify the index column and column headers?
You need to specify data, index and columns to DataFrame constructor, as in:
>>> pd.DataFrame(data=data[1:,1:], # values
... index=data[1:,0], # 1st column as index
... columns=data[0,1:]) # 1st row as the column names
edit: as in the @joris comment, you may need to change above to np.int_(data[1:,1:]) to have correct data type.
How to sort multidimensional array by column?
You can use list.sort with its optional key parameter and a lambda expression:
>>> lst = [
... ['John',2],
... ['Jim',9],
... ['Jason',1]
... ]
>>> lst.sort(key=lambda x:x[1])
>>> lst
[['Jason', 1], ['John', 2], ['Jim', 9]]
>>>
This will sort the list in-place.
Note that for large lists, it will be faster to use operator.itemgetter instead of a lambda:
>>> from operator import itemgetter
>>> lst = [
... ['John',2],
... ['Jim',9],
... ['Jason',1]
... ]
>>> lst.sort(key=itemgetter(1))
>>> lst
[['Jason', 1], ['John', 2], ['Jim', 9]]
>>>
Fitting a Normal distribution to 1D data
Here you are not fitting a normal distribution. Replacing sns.distplot(data) by sns.distplot(data, fit=norm, kde=False) should do the trick.
Wait on the Database Engine recovery handle failed. Check the SQL server error log for potential causes
Simple Steps
- 1 Open SQL Server Configuration Manager
- Under SQL Server Services Select Your Server
- Right Click and Select Properties
- Log on Tab Change Built-in-account tick
- in the drop down list select Network Service
- Apply and start The service
Java - What does "\n" mean?
(as per http://java.sun.com/...ex/Pattern.html)
The backslash character ('\') serves to introduce escaped constructs, as defined in the table above, as well as to quote characters that otherwise would be interpreted as unescaped constructs. Thus the expression \\ matches a single backslash and { matches a left brace.
Other examples of usage :
\\ The backslash character<br>
\t The tab character ('\u0009')<br>
\n The newline (line feed) character ('\u000A')<br>
\r The carriage-return character ('\u000D')<br>
\f The form-feed character ('\u000C')<br>
\a The alert (bell) character ('\u0007')<br>
\e The escape character ('\u001B')<br>
\cx The control character corresponding to x <br>
Difference between "as $key => $value" and "as $value" in PHP foreach
Sample Array: Left ones are the keys, right one are my values
$array = array(
'key-1' => 'value-1',
'key-2' => 'value-2',
'key-3' => 'value-3',
);
Example A: I want only the values of $array
foreach($array as $value) {
echo $value; // Through $value I get first access to 'value-1' then 'value-2' and to 'value-3'
}
Example B: I want each value AND key of $array
foreach($array as $key => $value) {
echo $value; // Through $value I get first access to 'value-1' then 'value-2' and to 'value-3'
echo $key; // Through $key I get access to 'key-1' then 'key-2' and finally 'key-3'
echo $array[$key]; // Accessing the value through $key = Same output as echo $value;
$array[$key] = $value + 1; // Exmaple usage of $key: Change the value by increasing it by 1
}
How to Deserialize JSON data?
You can write your own JSON parser and make it more generic based on your requirement. Here is one which served my purpose nicely, hope will help you too.
class JsonParsor
{
public static DataTable JsonParse(String rawJson)
{
DataTable dataTable = new DataTable();
Dictionary<string, string> outdict = new Dictionary<string, string>();
StringBuilder keybufferbuilder = new StringBuilder();
StringBuilder valuebufferbuilder = new StringBuilder();
StringReader bufferreader = new StringReader(rawJson);
int s = 0;
bool reading = false;
bool inside_string = false;
bool reading_value = false;
bool reading_number = false;
while (s >= 0)
{
s = bufferreader.Read();
//open JSON
if (!reading)
{
if ((char)s == '{' && !inside_string && !reading)
{
reading = true;
continue;
}
if ((char)s == '}' && !inside_string && !reading)
break;
if ((char)s == ']' && !inside_string && !reading)
continue;
if ((char)s == ',')
continue;
}
else
{
if (reading_value)
{
if (!inside_string && (char)s >= '0' && (char)s <= '9')
{
reading_number = true;
valuebufferbuilder.Append((char)s);
continue;
}
}
//if we find a quote and we are not yet inside a string, advance and get inside
if (!inside_string)
{
if ((char)s == '\"' && !inside_string)
inside_string = true;
if ((char)s == '[' && !inside_string)
{
keybufferbuilder.Length = 0;
valuebufferbuilder.Length = 0;
reading = false;
inside_string = false;
reading_value = false;
}
if ((char)s == ',' && !inside_string && reading_number)
{
if (!dataTable.Columns.Contains(keybufferbuilder.ToString()))
dataTable.Columns.Add(keybufferbuilder.ToString(), typeof(string));
if (!outdict.ContainsKey(keybufferbuilder.ToString()))
outdict.Add(keybufferbuilder.ToString(), valuebufferbuilder.ToString());
keybufferbuilder.Length = 0;
valuebufferbuilder.Length = 0;
reading_value = false;
reading_number = false;
}
continue;
}
//if we reach end of the string
if (inside_string)
{
if ((char)s == '\"')
{
inside_string = false;
s = bufferreader.Read();
if ((char)s == ':')
{
reading_value = true;
continue;
}
if (reading_value && (char)s == ',')
{
//put the key-value pair into dictionary
if(!dataTable.Columns.Contains(keybufferbuilder.ToString()))
dataTable.Columns.Add(keybufferbuilder.ToString(),typeof(string));
if (!outdict.ContainsKey(keybufferbuilder.ToString()))
outdict.Add(keybufferbuilder.ToString(), valuebufferbuilder.ToString());
keybufferbuilder.Length = 0;
valuebufferbuilder.Length = 0;
reading_value = false;
}
if (reading_value && (char)s == '}')
{
if (!dataTable.Columns.Contains(keybufferbuilder.ToString()))
dataTable.Columns.Add(keybufferbuilder.ToString(), typeof(string));
if (!outdict.ContainsKey(keybufferbuilder.ToString()))
outdict.Add(keybufferbuilder.ToString(), valuebufferbuilder.ToString());
ICollection key = outdict.Keys;
DataRow newrow = dataTable.NewRow();
foreach (string k_loopVariable in key)
{
CommonModule.LogTheMessage(outdict[k_loopVariable],"","","");
newrow[k_loopVariable] = outdict[k_loopVariable];
}
dataTable.Rows.Add(newrow);
CommonModule.LogTheMessage(dataTable.Rows.Count.ToString(), "", "row_count", "");
outdict.Clear();
keybufferbuilder.Length=0;
valuebufferbuilder.Length=0;
reading_value = false;
reading = false;
continue;
}
}
else
{
if (reading_value)
{
valuebufferbuilder.Append((char)s);
continue;
}
else
{
keybufferbuilder.Append((char)s);
continue;
}
}
}
else
{
switch ((char)s)
{
case ':':
reading_value = true;
break;
default:
if (reading_value)
{
valuebufferbuilder.Append((char)s);
}
else
{
keybufferbuilder.Append((char)s);
}
break;
}
}
}
}
return dataTable;
}
}
Declare an empty two-dimensional array in Javascript?
An empty array is defined by omitting values, like so:
v=[[],[]]
a=[]
b=[1,2]
a.push(b)
b==a[0]
printing a two dimensional array in python
for i in A:
print('\t'.join(map(str, i)))
Initializing a two dimensional std::vector
Suppose you want to initialize a two dimensional integer vector with n rows and m column each having value 'VAL'
Write it as
std::vector<vector<int>> arr(n, vector<int>(m,VAL));
This VAL can be a integer type variable or constant such as 100
Matrix multiplication using arrays
The method mults is a procedure(Pascal) or subroutine(Fortran)
The method multMatrix is a function(Pascal,Fortran)
import java.util.*;
public class MatmultE
{
private static Scanner sc = new Scanner(System.in);
public static void main(String [] args)
{
double[][] A={{4.00,3.00},{2.00,1.00}};
double[][] B={{-0.500,1.500},{1.000,-2.0000}};
double[][] C=multMatrix(A,B);
printMatrix(A);
printMatrix(B);
printMatrix(C);
double a[][] = {{1, 2, -2, 0}, {-3, 4, 7, 2}, {6, 0, 3, 1}};
double b[][] = {{-1, 3}, {0, 9}, {1, -11}, {4, -5}};
double[][] c=multMatrix(a,b);
printMatrix(a);
printMatrix(b);
printMatrix(c);
double[][] a1 = readMatrix();
double[][] b1 = readMatrix();
double[][] c1 = new double[a1.length][b1[0].length];
mults(a1,b1,c1,a1.length,a1[0].length,b1.length,b1[0].length);
printMatrix(c1);
printMatrixE(c1);
}
public static double[][] readMatrix() {
int rows = sc.nextInt();
int cols = sc.nextInt();
double[][] result = new double[rows][cols];
for (int i = 0; i < rows; i++) {
for (int j = 0; j < cols; j++) {
result[i][j] = sc.nextDouble();
}
}
return result;
}
public static void printMatrix(double[][] mat) {
System.out.println("Matrix["+mat.length+"]["+mat[0].length+"]");
int rows = mat.length;
int columns = mat[0].length;
for (int i = 0; i < rows; i++) {
for (int j = 0; j < columns; j++) {
System.out.printf("%8.3f " , mat[i][j]);
}
System.out.println();
}
System.out.println();
}
public static void printMatrixE(double[][] mat) {
System.out.println("Matrix["+mat.length+"]["+mat[0].length+"]");
int rows = mat.length;
int columns = mat[0].length;
for (int i = 0; i < rows; i++) {
for (int j = 0; j < columns; j++) {
System.out.printf("%9.2e " , mat[i][j]);
}
System.out.println();
}
System.out.println();
}
public static double[][] multMatrix(double a[][], double b[][]){//a[m][n], b[n][p]
if(a.length == 0) return new double[0][0];
if(a[0].length != b.length) return null; //invalid dims
int n = a[0].length;
int m = a.length;
int p = b[0].length;
double ans[][] = new double[m][p];
for(int i = 0;i < m;i++){
for(int j = 0;j < p;j++){
ans[i][j]=0;
for(int k = 0;k < n;k++){
ans[i][j] += a[i][k] * b[k][j];
}
}
}
return ans;
}
public static void mults(double a[][], double b[][], double c[][], int r1,
int c1, int r2, int c2){
for(int i = 0;i < r1;i++){
for(int j = 0;j < c2;j++){
c[i][j]=0;
for(int k = 0;k < c1;k++){
c[i][j] += a[i][k] * b[k][j];
}
}
}
}
}
where as input matrix you can enter
inE.txt
4 4
1 1 1 1
2 4 8 16
3 9 27 81
4 16 64 256
4 3
4.0 -3.0 4.0
-13.0 19.0 -7.0
3.0 -2.0 7.0
-1.0 1.0 -1.0
in unix like cmmd line execute the command:
$ java MatmultE < inE.txt > outE.txt
and you get the output
outC.txt
Matrix[2][2]
4.000 3.000
2.000 1.000
Matrix[2][2]
-0.500 1.500
1.000 -2.000
Matrix[2][2]
1.000 0.000
0.000 1.000
Matrix[3][4]
1.000 2.000 -2.000 0.000
-3.000 4.000 7.000 2.000
6.000 0.000 3.000 1.000
Matrix[4][2]
-1.000 3.000
0.000 9.000
1.000 -11.000
4.000 -5.000
Matrix[3][2]
-3.000 43.000
18.000 -60.000
1.000 -20.000
Matrix[4][3]
-7.000 15.000 3.000
-36.000 70.000 20.000
-105.000 189.000 57.000
-256.000 420.000 96.000
Matrix[4][3]
-7.00e+00 1.50e+01 3.00e+00
-3.60e+01 7.00e+01 2.00e+01
-1.05e+02 1.89e+02 5.70e+01
-2.56e+02 4.20e+02 9.60e+01
Python: slicing a multi-dimensional array
If you use numpy, this is easy:
slice = arr[:2,:2]
or if you want the 0's,
slice = arr[0:2,0:2]
You'll get the same result.
*note that slice is actually the name of a builtin-type. Generally, I would advise giving your object a different "name".
Another way, if you're working with lists of lists*:
slice = [arr[i][0:2] for i in range(0,2)]
(Note that the 0's here are unnecessary: [arr[i][:2] for i in range(2)] would also work.).
What I did here is that I take each desired row 1 at a time (arr[i]). I then slice the columns I want out of that row and add it to the list that I'm building.
If you naively try: arr[0:2] You get the first 2 rows which if you then slice again arr[0:2][0:2], you're just slicing the first two rows over again.
*This actually works for numpy arrays too, but it will be slow compared to the "native" solution I posted above.
Transpose a matrix in Python
If we wanted to return the same matrix we would write:
return [[ m[row][col] for col in range(0,width) ] for row in range(0,height) ]
What this does is it iterates over a matrix m by going through each row and returning each element in each column. So the order would be like:
[[1,2,3],
[4,5,6],
[7,8,9]]
Now for question 3, we instead want to go column by column, returning each element in each row. So the order would be like:
[[1,4,7],
[2,5,8],
[3,6,9]]
Therefore just switch the order in which we iterate:
return [[ m[row][col] for row in range(0,height) ] for col in range(0,width) ]
Return single column from a multi-dimensional array
array_map is a call back function, where you can play with the passed array.
this should work.
$str = implode(',', array_map(function($el){ return $el['tag_id']; }, $arr));
Iterating over a 2 dimensional python list
same way you did the fill in, but reverse the indexes:
>>> for j in range(columns):
... for i in range(rows):
... print mylist[i][j],
...
0,0 1,0 2,0 0,1 1,1 2,1
>>>
How to convert comma separated string into numeric array in javascript
You can use the String split method to get the single numbers as an array of strings. Then convert them to numbers with the unary plus operator, the Number function or parseInt, and add them to your array:
var arr = [1,2,3],
strVale = "130,235,342,124 ";
var strings = strVale.split(",");
for (var i=0; i<strVale.length; i++)
arr.push( + strings[i] );
Or, in one step, using Array map to convert them and applying them to one single push:
arr.push.apply(arr, strVale.split(",").map(Number));
ReDim Preserve to a Multi-Dimensional Array in Visual Basic 6
Function Redim2d(ByRef Mtx As Variant, ByVal QtyColumnToAdd As Integer)
ReDim Preserve Mtx(LBound(Mtx, 1) To UBound(Mtx, 1), LBound(Mtx, 2) To UBound(Mtx, 2) + QtyColumnToAdd)
End Function
'Main Code
sub Main ()
Call Redim2d(MtxR8Strat, 1) 'Add one column
end sub
'OR
sub main2()
QtyColumnToAdd = 1 'Add one column
ReDim Preserve Mtx(LBound(Mtx, 1) To UBound(Mtx, 1), LBound(Mtx, 2) To UBound(Mtx, 2) + QtyColumnToAdd)
end sub
PHP add elements to multidimensional array with array_push
if you want to add the data in the increment order inside your associative array you can do this:
$newdata = array (
'wpseo_title' => 'test',
'wpseo_desc' => 'test',
'wpseo_metakey' => 'test'
);
// for recipe
$md_array["recipe_type"][] = $newdata;
//for cuisine
$md_array["cuisine"][] = $newdata;
this will get added to the recipe or cuisine depending on what was the last index.
Array push is usually used in the array when you have sequential index: $arr[0] , $ar[1].. you cannot use it in associative array directly. But since your sub array is had this kind of index you can still use it like this
array_push($md_array["cuisine"],$newdata);
How to sort 2 dimensional array by column value?
Standing on the shoulders of charles-clayton and @vikas-gautam, I added the string test which is needed if a column has strings as in OP.
return isNaN(a-b) ? (a === b) ? 0 : (a < b) ? -1 : 1 : a-b ;
The test isNaN(a-b) determines if the strings cannot be coerced to numbers. If they can then the a-b test is valid.
Note that sorting a column of mixed types will always give an entertaining result as the strict equality test (a === b) will always return false.
See MDN here
This is the full script with Logger test - using Google Apps Script.
function testSort(){
function sortByCol(arr, colIndex){
arr.sort(sortFunction);
function sortFunction(a, b) {
a = a[colIndex];
b = b[colIndex];
return isNaN(a-b) ? (a === b) ? 0 : (a < b) ? -1 : 1 : a-b ; // test if text string - ie cannot be coerced to numbers.
// Note that sorting a column of mixed types will always give an entertaining result as the strict equality test will always return false
// see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Equality_comparisons_and_sameness
}
}
// Usage
var a = [ [12,'12', 'AAA'],
[12,'11', 'AAB'],
[58,'120', 'CCC'],
[28,'08', 'BBB'],
[18,'80', 'DDD'],
]
var arr1 = a.map(function (i){return i;}).sort(); // use map to ensure tests are not corrupted by a sort in-place.
Logger.log("Original unsorted:\n " + JSON.stringify(a));
Logger.log("Vanilla sort:\n " + JSON.stringify(arr1));
sortByCol(a, 0);
Logger.log("By col 0:\n " + JSON.stringify(a));
sortByCol(a, 1);
Logger.log("By col 1:\n " + JSON.stringify(a));
sortByCol(a, 2);
Logger.log("By col 2:\n " + JSON.stringify(a));
/* vanilla sort returns " [
[12,"11","AAB"],
[12,"12","AAA"],
[18,"80","DDD"],
[28,"08","BBB"],
[58,"120","CCC"]
]
if col 0 then returns "[
[12,'12',"AAA"],
[12,'11', 'AAB'],
[18,'80',"DDD"],
[28,'08',"BBB"],
[58,'120',"CCC"]
]"
if col 1 then returns "[
[28,'08',"BBB"],
[12,'11', 'AAB'],
[12,'12',"AAA"],
[18,'80',"DDD"],
[58,'120',"CCC"],
]"
if col 2 then returns "[
[12,'12',"AAA"],
[12,'11', 'AAB'],
[28,'08',"BBB"],
[58,'120',"CCC"],
[18,'80',"DDD"],
]"
*/
}
Pointer-to-pointer dynamic two-dimensional array
In both cases your inner dimension may be dynamically specified (i.e. taken from a variable), but the difference is in the outer dimension.
This question is basically equivalent to the following:
Is
int* x = new int[4];"better" thanint x[4]?
The answer is: "no, unless you need to choose that array dimension dynamically."
how to use JSON.stringify and json_decode() properly
None of the other answers worked in my case, most likely because the JSON array contained special characters. What fixed it for me:
Javascript (added encodeURIComponent)
var JSONstr = encodeURIComponent(JSON.stringify(fullInfoArray));
document.getElementById('JSONfullInfoArray').value = JSONstr;
PHP (unchanged from the question)
$data = json_decode($_POST["JSONfullInfoArray"]);
var_dump($data);
echo($_POST["JSONfullInfoArray"]);
Both echo and var_dump have been verified to work fine on a sample of more than 2000 user-entered datasets that included a URL field and a long text field, and that were returning NULL on var_dump for a subset that included URLs with the characters ?&#.
How do I create ColorStateList programmatically?
See http://developer.android.com/reference/android/R.attr.html#state_above_anchor for a list of available states.
If you want to set colors for disabled, unfocused, unchecked states etc. just negate the states:
int[][] states = new int[][] {
new int[] { android.R.attr.state_enabled}, // enabled
new int[] {-android.R.attr.state_enabled}, // disabled
new int[] {-android.R.attr.state_checked}, // unchecked
new int[] { android.R.attr.state_pressed} // pressed
};
int[] colors = new int[] {
Color.BLACK,
Color.RED,
Color.GREEN,
Color.BLUE
};
ColorStateList myList = new ColorStateList(states, colors);
PHP foreach change original array values
function checkForm(& $fields){
foreach($fields as $field){
if($field['required'] && strlen($_POST[$field['name']]) <= 0){
$fields[$field]['value'] = "Some error";
}
}
return $fields;
}
This is what I would Suggest pass by reference
Plotting of 1-dimensional Gaussian distribution function
In addition to previous answers, I recommend to first calculate the ratio in the exponent, then taking the square:
def gaussian(x,x0,sigma):
return np.exp(-np.power((x - x0)/sigma, 2.)/2.)
That way, you can also calculate the gaussian of very small or very large numbers:
In: gaussian(1e-12,5e-12,3e-12)
Out: 0.64118038842995462
Excel VBA - How to Redim a 2D array?
i solved this in a shorter fashion.
Dim marray() as variant, array2() as variant, YY ,ZZ as integer
YY=1
ZZ=1
Redim marray(1 to 1000, 1 to 10)
Do while ZZ<100 ' this is populating the first array
marray(ZZ,YY)= "something"
ZZ=ZZ+1
YY=YY+1
Loop
'this part is where you store your array in another then resize and restore to original
array2= marray
Redim marray(1 to ZZ-1, 1 to YY)
marray = array2
How to print Two-Dimensional Array like table
public static void main(String[] args) {
int[][] matrix = {
{ 1, 2, 5 },
{ 3, 4, 6 },
{ 7, 8, 9 }
};
System.out.println(" ** Matrix ** ");
for (int rows = 0; rows < 3; rows++) {
System.out.println("\n");
for (int columns = 0; columns < matrix[rows].length; columns++) {
System.out.print(matrix[rows][columns] + "\t");
}
}
}
This works,add a new line in for loop of the row. When the first row will be done printing the code will jump in new line.
Convert a 1D array to a 2D array in numpy
Change 1D array into 2D array without using Numpy.
l = [i for i in range(1,21)]
part = 3
new = []
start, end = 0, part
while end <= len(l):
temp = []
for i in range(start, end):
temp.append(l[i])
new.append(temp)
start += part
end += part
print("new values: ", new)
# for uneven cases
temp = []
while start < len(l):
temp.append(l[start])
start += 1
new.append(temp)
print("new values for uneven cases: ", new)
Multidimensional Array [][] vs [,]
double[][] are called jagged arrays , The inner dimensions aren’t specified in the declaration. Unlike a rectangular array, each inner array can be an arbitrary length. Each inner array is implicitly initialized to null rather than an empty array. Each inner array must be created manually: Reference [C# 4.0 in nutshell The definitive Reference]
for (int i = 0; i < matrix.Length; i++)
{
matrix[i] = new int [3]; // Create inner array
for (int j = 0; j < matrix[i].Length; j++)
matrix[i][j] = i * 3 + j;
}
double[,] are called rectangular arrays, which are declared using commas to separate each dimension. The following piece of code declares a rectangular 3-by-3 two-dimensional array, initializing it with numbers from 0 to 8:
int [,] matrix = new int [3, 3];
for (int i = 0; i < matrix.GetLength(0); i++)
for (int j = 0; j < matrix.GetLength(1); j++)
matrix [i, j] = i * 3 + j;
Syntax for creating a two-dimensional array in Java
Try the following:
int[][] multi = new int[5][10];
... which is a short hand for something like this:
int[][] multi = new int[5][];
multi[0] = new int[10];
multi[1] = new int[10];
multi[2] = new int[10];
multi[3] = new int[10];
multi[4] = new int[10];
Note that every element will be initialized to the default value for int, 0, so the above are also equivalent to:
int[][] multi = new int[][]{
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }
};
How to unnest a nested list
Use itertools.chain:
itertools.chain(*iterables):Make an iterator that returns elements from the first iterable until it is exhausted, then proceeds to the next iterable, until all of the iterables are exhausted. Used for treating consecutive sequences as a single sequence.
from itertools import chain
A = [[1,2], [3,4]]
print list(chain(*A))
# or better: (available since Python 2.6)
print list(chain.from_iterable(A))
The output is:
[1, 2, 3, 4]
[1, 2, 3, 4]
push() a two-dimensional array
Iterating over two dimensions means you'll need to check over two dimensions.
assuming you're starting with:
var myArray = [
[1,1,1,1,1],
[1,1,1,1,1],
[1,1,1,1,1]
]; //don't forget your semi-colons
You want to expand this two-dimensional array to become:
var myArray = [
[1,1,1,1,1,0,0],
[1,1,1,1,1,0,0],
[1,1,1,1,1,0,0],
[0,0,0,0,0,0,0],
[0,0,0,0,0,0,0],
[0,0,0,0,0,0,0],
];
Which means you need to understand what the difference is.
Start with the outer array:
var myArray = [
[...],
[...],
[...]
];
If you want to make this array longer, you need to check that it's the correct length, and add more inner arrays to make up the difference:
var i,
rows,
myArray;
rows = 8;
myArray = [...]; //see first example above
for (i = 0; i < rows; i += 1) {
//check if the index exists in the outer array
if (!(i in myArray)) {
//if it doesn't exist, we need another array to fill
myArray.push([]);
}
}
The next step requires iterating over every column in every array, we'll build on the original code:
var i,
j,
row,
rows,
cols,
myArray;
rows = 8;
cols = 7; //adding columns in this time
myArray = [...]; //see first example above
for (i = 0; i < rows; i += 1) {
//check if the index exists in the outer array (row)
if (!(i in myArray)) {
//if it doesn't exist, we need another array to fill
myArray[i] = [];
}
row = myArray[i];
for (j = 0; j < cols; j += 1) {
//check if the index exists in the inner array (column)
if (!(i in row)) {
//if it doesn't exist, we need to fill it with `0`
row[j] = 0;
}
}
}
Multi-dimensional arrays in Bash
I am posting the following because it is a very simple and clear way to mimic (at least to some extent) the behavior of a two-dimensional array in Bash. It uses a here-file (see the Bash manual) and read (a Bash builtin command):
## Store the "two-dimensional data" in a file ($$ is just the process ID of the shell, to make sure the filename is unique)
cat > physicists.$$ <<EOF
Wolfgang Pauli 1900
Werner Heisenberg 1901
Albert Einstein 1879
Niels Bohr 1885
EOF
nbPhysicists=$(wc -l physicists.$$ | cut -sf 1 -d ' ') # Number of lines of the here-file specifying the physicists.
## Extract the needed data
declare -a person # Create an indexed array (necessary for the read command).
while read -ra person; do
firstName=${person[0]}
familyName=${person[1]}
birthYear=${person[2]}
echo "Physicist ${firstName} ${familyName} was born in ${birthYear}"
# Do whatever you need with data
done < physicists.$$
## Remove the temporary file
rm physicists.$$
Output:
Physicist Wolfgang Pauli was born in 1900 Physicist Werner Heisenberg was born in 1901 Physicist Albert Einstein was born in 1879 Physicist Niels Bohr was born in 1885
The way it works:
- The lines in the temporary file created play the role of one-dimensional vectors, where the blank spaces (or whatever separation character you choose; see the description of the
readcommand in the Bash manual) separate the elements of these vectors. - Then, using the
readcommand with its-aoption, we loop over each line of the file (until we reach end of file). For each line, we can assign the desired fields (= words) to an array, which we declared just before the loop. The-roption to thereadcommand prevents backslashes from acting as escape characters, in case we typed backslashes in the here-documentphysicists.$$.
In conclusion a file is created as a 2D-array, and its elements are extracted using a loop over each line, and using the ability of the read command to assign words to the elements of an (indexed) array.
Slight improvement:
In the above code, the file physicists.$$ is given as input to the while loop, so that it is in fact passed to the read command. However, I found that this causes problems when I have another command asking for input inside the while loop. For example, the select command waits for standard input, and if placed inside the while loop, it will take input from physicists.$$, instead of prompting in the command-line for user input.
To correct this, I use the -u option of read, which allows to read from a file descriptor. We only have to create a file descriptor (with the exec command) corresponding to physicists.$$ and to give it to the -u option of read, as in the following code:
## Store the "two-dimensional data" in a file ($$ is just the process ID of the shell, to make sure the filename is unique)
cat > physicists.$$ <<EOF
Wolfgang Pauli 1900
Werner Heisenberg 1901
Albert Einstein 1879
Niels Bohr 1885
EOF
nbPhysicists=$(wc -l physicists.$$ | cut -sf 1 -d ' ') # Number of lines of the here-file specifying the physicists.
exec {id_file}<./physicists.$$ # Create a file descriptor stored in 'id_file'.
## Extract the needed data
declare -a person # Create an indexed array (necessary for the read command).
while read -ra person -u "${id_file}"; do
firstName=${person[0]}
familyName=${person[1]}
birthYear=${person[2]}
echo "Physicist ${firstName} ${familyName} was born in ${birthYear}"
# Do whatever you need with data
done
## Close the file descriptor
exec {id_file}<&-
## Remove the temporary file
rm physicists.$$
Notice that the file descriptor is closed at the end.
How to search for string in an array
more simple Function whichs works on Apple OS too:
Function isInArray(ByVal stringToBeFound As String, ByVal arr As Variant) As Boolean
Dim element
For Each element In arr
If element = stringToBeFound Then
isInArray = True
Exit Function
End If
Next element
End Function
Two dimensional array list
I know that's an old question with good answers, but I believe I can add my 2 cents.
The simplest and most flexible way which works for me is just using an almost "Plain and Old Java Object" class2D to create each "row" of your array.
The below example has some explanations and is executable (you can copy and paste it, but remember to check the package name):
package my2darraylist;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JPanel;
public class My2DArrayList
{
public static void main(String[] args)
{
// This is your "2D" ArrayList
//
List<Box> boxes = new ArrayList<>();
// Add your stuff
//
Box stuff = new Box();
stuff.setAString( "This is my stuff");
stuff.addString("My Stuff 01");
stuff.addInteger( 1 );
boxes.add( stuff );
// Add other stuff
//
Box otherStuff = new Box();
otherStuff.setAString( "This is my other stuff");
otherStuff.addString("My Other Stuff 01");
otherStuff.addInteger( 1 );
otherStuff.addString("My Other Stuff 02");
otherStuff.addInteger( 2 );
boxes.add( otherStuff );
// List the whole thing
for ( Box box : boxes)
{
System.out.println( box.getAString() );
System.out.println( box.getMyStrings().size() );
System.out.println( box.getMyIntegers().size() );
}
}
}
class Box
{
// Each attribute is a "Column" in you array
//
private String aString;
private List<String> myStrings = new ArrayList<>() ;
private List<Integer> myIntegers = new ArrayList<>();
// Use your imagination...
//
private JPanel jpanel;
public void addString( String s )
{
myStrings.add( s );
}
public void addInteger( int i )
{
myIntegers.add( i );
}
// Getters & Setters
public String getAString()
{
return aString;
}
public void setAString(String aString)
{
this.aString = aString;
}
public List<String> getMyStrings()
{
return myStrings;
}
public void setMyStrings(List<String> myStrings)
{
this.myStrings = myStrings;
}
public List<Integer> getMyIntegers()
{
return myIntegers;
}
public void setMyIntegers(List<Integer> myIntegers)
{
this.myIntegers = myIntegers;
}
public JPanel getJpanel()
{
return jpanel;
}
public void setJpanel(JPanel jpanel)
{
this.jpanel = jpanel;
}
}
UPDATE - To answer the question from @Mohammed Akhtar Zuberi, I've created the simplified version of the program, to make it easier to show the results.
import java.util.ArrayList;
public class My2DArrayListSimplified
{
public static void main(String[] args)
{
ArrayList<Row> rows = new ArrayList<>();
Row row;
// Insert the columns for each row
// First Name, Last Name, Age
row = new Row("John", "Doe", 30);
rows.add(row);
row = new Row("Jane", "Doe", 29);
rows.add(row);
row = new Row("Mary", "Doe", 1);
rows.add(row);
// Show the Array
//
System.out.println("First\t Last\tAge");
System.out.println("----------------------");
for (Row printRow : rows)
{
System.out.println(
printRow.getFirstName() + "\t " +
printRow.getLastName() + "\t" +
printRow.getAge());
}
}
}
class Row
{
// REMEMBER: each attribute is a column
//
private final String firstName;
private final String lastName;
private final int age;
public Row(String firstName, String lastName, int age)
{
this.firstName = firstName;
this.lastName = lastName;
this.age = age;
}
public String getFirstName()
{
return firstName;
}
public String getLastName()
{
return lastName;
}
public int getAge()
{
return age;
}
}
The code above produces the following result (I ran it on NetBeans):
run:
First Last Age
----------------------
John Doe 30
Jane Doe 29
Mary Doe 1
BUILD SUCCESSFUL (total time: 0 seconds)
How to insert values in two dimensional array programmatically?
Think about it as array of array.
If you do this str[x][y], then there is array of length x where each element in turn contains array of length y. In java its not necessary for second dimension to have same length. So for x=i you can have y=m and x=j you can have y=n
For this your declaration looks like
String[][] test = new String[4][]; test[0] = new String[3]; test[1] = new String[2];
etc..
How to re-index all subarray elements of a multidimensional array?
Here you can see the difference between the way that deceze offered comparing to the simple array_values approach:
The Array:
$array['a'][0] = array('x' => 1, 'y' => 2, 'z' => 3);
$array['a'][5] = array('x' => 4, 'y' => 5, 'z' => 6);
$array['b'][1] = array('x' => 7, 'y' => 8, 'z' => 9);
$array['b'][7] = array('x' => 10, 'y' => 11, 'z' => 12);
In deceze way, here is your output:
$array = array_map('array_values', $array);
print_r($array);
/* Output */
Array
(
[a] => Array
(
[0] => Array
(
[x] => 1
[y] => 2
[z] => 3
)
[1] => Array
(
[x] => 4
[y] => 5
[z] => 6
)
)
[b] => Array
(
[0] => Array
(
[x] => 7
[y] => 8
[z] => 9
)
[1] => Array
(
[x] => 10
[y] => 11
[z] => 12
)
)
)
And here is your output if you only use array_values function:
$array = array_values($array);
print_r($array);
/* Output */
Array
(
[0] => Array
(
[0] => Array
(
[x] => 1
[y] => 2
[z] => 3
)
[5] => Array
(
[x] => 4
[y] => 5
[z] => 6
)
)
[1] => Array
(
[1] => Array
(
[x] => 7
[y] => 8
[z] => 9
)
[7] => Array
(
[x] => 10
[y] => 11
[z] => 12
)
)
)
php multidimensional array get values
This is the way to iterate on this array:
foreach($hotels as $row) {
foreach($row['rooms'] as $k) {
echo $k['boards']['board_id'];
echo $k['boards']['price'];
}
}
You want to iterate on the hotels and the rooms (the ones with numeric indexes), because those seem to be the "collections" in this case. The other arrays only hold and group properties.
For loop in multidimensional javascript array
Try this:
var i, j;
for (i = 0; i < cubes.length; i++) {
for (j = 0; j < cubes[i].length; j++) {
do whatever with cubes[i][j];
}
}
How to rename array keys in PHP?
Very simple approach to replace keys in a multidimensional array, and maybe even a bit dangerous, but should work fine if you have some kind of control over the source array:
$array = [ 'oldkey' => [ 'oldkey' => 'wow'] ];
$new_array = json_decode(str_replace('"oldkey":', '"newkey":', json_encode($array)));
print_r($new_array); // [ 'newkey' => [ 'newkey' => 'wow'] ]
Concatenating two one-dimensional NumPy arrays
The line should be:
numpy.concatenate([a,b])
The arrays you want to concatenate need to be passed in as a sequence, not as separate arguments.
From the NumPy documentation:
numpy.concatenate((a1, a2, ...), axis=0)Join a sequence of arrays together.
It was trying to interpret your b as the axis parameter, which is why it complained it couldn't convert it into a scalar.
How do I free memory in C?
You actually can't manually "free" memory in C, in the sense that the memory is released from the process back to the OS ... when you call malloc(), the underlying libc-runtime will request from the OS a memory region. On Linux, this may be done though a relatively "heavy" call like mmap(). Once this memory region is mapped to your program, there is a linked-list setup called the "free store" that manages this allocated memory region. When you call malloc(), it quickly looks though the free-store for a free block of memory at the size requested. It then adjusts the linked list to reflect that there has been a chunk of memory taken out of the originally allocated memory pool. When you call free() the memory block is placed back in the free-store as a linked-list node that indicates its an available chunk of memory.
If you request more memory than what is located in the free-store, the libc-runtime will again request more memory from the OS up to the limit of the OS's ability to allocate memory for running processes. When you free memory though, it's not returned back to the OS ... it's typically recycled back into the free-store where it can be used again by another call to malloc(). Thus, if you make a lot of calls to malloc() and free() with varying memory size requests, it could, in theory, cause a condition called "memory fragmentation", where there is enough space in the free-store to allocate your requested memory block, but not enough contiguous space for the size of the block you've requested. Thus the call to malloc() fails, and you're effectively "out-of-memory" even though there may be plenty of memory available as a total amount of bytes in the free-store.
How to normalize a 2-dimensional numpy array in python less verbose?
it appears that this also works
def normalizeRows(M):
row_sums = M.sum(axis=1)
return M / row_sums
Rotating a two-dimensional array in Python
Consider the following two-dimensional list:
original = [[1, 2],
[3, 4]]
Lets break it down step by step:
>>> original[::-1] # elements of original are reversed
[[3, 4], [1, 2]]
This list is passed into zip() using argument unpacking, so the zip call ends up being the equivalent of this:
zip([3, 4],
[1, 2])
# ^ ^----column 2
# |-------column 1
# returns [(3, 1), (4, 2)], which is a original rotated clockwise
Hopefully the comments make it clear what zip does, it will group elements from each input iterable based on index, or in other words it groups the columns.
Two dimensional array in python
There aren't multidimensional arrays as such in Python, what you have is a list containing other lists.
>>> arr = [[]]
>>> len(arr)
1
What you have done is declare a list containing a single list. So arr[0] contains a list but arr[1] is not defined.
You can define a list containing two lists as follows:
arr = [[],[]]
Or to define a longer list you could use:
>>> arr = [[] for _ in range(5)]
>>> arr
[[], [], [], [], []]
What you shouldn't do is this:
arr = [[]] * 3
As this puts the same list in all three places in the container list:
>>> arr[0].append('test')
>>> arr
[['test'], ['test'], ['test']]
PHP Multidimensional Array Searching (Find key by specific value)
I would do like below, where $products is the actual array given in the problem at the very beginning.
print_r(
array_search("breville-variable-temperature-kettle-BKE820XL",
array_map(function($product){return $product["slug"];},$products))
);
How to get an array of specific "key" in multidimensional array without looping
PHP 5.5+
Starting PHP5.5+ you have array_column() available to you, which makes all of the below obsolete.
PHP 5.3+
$ids = array_map(function ($ar) {return $ar['id'];}, $users);
Solution by @phihag will work flawlessly in PHP starting from PHP 5.3.0, if you need support before that, you will need to copy that wp_list_pluck.
PHP < 5.3
Wordpress 3.1+In Wordpress there is a function called wp_list_pluck If you're using Wordpress that solves your problem.
PHP < 5.3If you're not using Wordpress, since the code is open source you can copy paste the code in your project (and rename the function to something you prefer, like array_pick). View source here
javascript push multidimensional array
Arrays must have zero based integer indexes in JavaScript. So:
var valueToPush = new Array();
valueToPush[0] = productID;
valueToPush[1] = itemColorTitle;
valueToPush[2] = itemColorPath;
cookie_value_add.push(valueToPush);
Or maybe you want to use objects (which are associative arrays):
var valueToPush = { }; // or "var valueToPush = new Object();" which is the same
valueToPush["productID"] = productID;
valueToPush["itemColorTitle"] = itemColorTitle;
valueToPush["itemColorPath"] = itemColorPath;
cookie_value_add.push(valueToPush);
which is equivalent to:
var valueToPush = { };
valueToPush.productID = productID;
valueToPush.itemColorTitle = itemColorTitle;
valueToPush.itemColorPath = itemColorPath;
cookie_value_add.push(valueToPush);
It's a really fundamental and crucial difference between JavaScript arrays and JavaScript objects (which are associative arrays) that every JavaScript developer must understand.
Get column from a two dimensional array
Taking a column is easy with the map function.
// a two-dimensional array
var two_d = [[1,2,3],[4,5,6],[7,8,9]];
// take the third column
var col3 = two_d.map(function(value,index) { return value[2]; });
Why bother with the slice at all? Just filter the matrix to find the rows of interest.
var interesting = two_d.filter(function(value,index) {return value[1]==5;});
// interesting is now [[4,5,6]]
Sadly, filter and map are not natively available on IE9 and lower. The MDN documentation provides implementations for browsers without native support.
How to print a two dimensional array?
How about trying this?
public static void main (String [] args)
{
int [] [] listTwo = new int [5][5];
// 2 Dimensional array
int x = 0;
int y = 0;
while (x < 5) {
listTwo[x][y] = (int)(Math.random()*10);
while (y <5){
listTwo [x] [y] = (int)(Math.random()*10);
System.out.print(listTwo[x][y]+" | ");
y++;
}
System.out.println("");
y=0;
x++;
}
}
Getting and removing the first character of a string
See ?substring.
x <- 'hello stackoverflow'
substring(x, 1, 1)
## [1] "h"
substring(x, 2)
## [1] "ello stackoverflow"
The idea of having a pop method that both returns a value and has a side effect of updating the data stored in x is very much a concept from object-oriented programming. So rather than defining a pop function to operate on character vectors, we can make a reference class with a pop method.
PopStringFactory <- setRefClass(
"PopString",
fields = list(
x = "character"
),
methods = list(
initialize = function(x)
{
x <<- x
},
pop = function(n = 1)
{
if(nchar(x) == 0)
{
warning("Nothing to pop.")
return("")
}
first <- substring(x, 1, n)
x <<- substring(x, n + 1)
first
}
)
)
x <- PopStringFactory$new("hello stackoverflow")
x
## Reference class object of class "PopString"
## Field "x":
## [1] "hello stackoverflow"
replicate(nchar(x$x), x$pop())
## [1] "h" "e" "l" "l" "o" " " "s" "t" "a" "c" "k" "o" "v" "e" "r" "f" "l" "o" "w"
How to create multidimensional array
very simple
var states = [,];
states[0,0] = tName;
states[0,1] = '1';
states[1,0] = tName;
states[2,1] = '1';
. . .
states[n,0] = tName;
states[n,1] = '1';
Getting the length of two-dimensional array
//initializing few values
int[][] tab = new int[][]{
{1,0,1,0,1,0,1,0},
{0,1,0,1,0,1,0,1},
{1,0,1,0,1,0,1,0},
{0,1,0,1,0,1,0,1},
{1,0,1,0,1,0,1,0},
{0,1,0,1,0,1,0,1},
{1,0,1,0,1,0,1,0},
{0,1,0,1,0,1,0,1}
};
//tab.length in first loop
for (int row = 0; row < tab.length; row++)
{
//tab[0].length in second loop
for (int column = 0; column < tab[0].length; column++)
{
//printing one value from array with space
System.out.print(tab[row][column]+ " ");
}
System.out.println(); // new row = new enter
}
Arrays.fill with multidimensional array in Java
Using Java 8, you can declare and initialize a two-dimensional array without using a (explicit) loop as follows:
int x = 20; // first dimension
int y = 4; // second dimension
double[][] a = IntStream.range(0, x)
.mapToObj(i -> new double[y])
.toArray(i -> new double[x][]);
This will initialize the arrays with default values (0.0 in the case of double).
In case you want to explicitly define the fill value to be used, You can add in a DoubleStream:
int x = 20; // first dimension
int y = 4; // second dimension
double v = 5.0; // fill value
double[][] a = IntStream
.range(0, x)
.mapToObj(i -> DoubleStream.generate(() -> v).limit(y).toArray())
.toArray(i -> new double[x][]);
Check if a specific value exists at a specific key in any subarray of a multidimensional array
If you have to make a lot of "id" lookups and it should be really fast you should use a second array containing all the "ids" as keys:
$lookup_array=array();
foreach($my_array as $arr){
$lookup_array[$arr['id']]=1;
}
Now you can check for an existing id very fast, for example:
echo (isset($lookup_array[152]))?'yes':'no';
Convert multidimensional array into single array
I have done this with OOP style
$res=[1=>[2,3,7,8,19],3=>[4,12],2=>[5,9],5=>6,7=>[10,13],10=>[11,18],8=>[14,20],12=>15,6=>[16,17]];
class MultiToSingle{
public $result=[];
public function __construct($array){
if(!is_array($array)){
echo "Give a array";
}
foreach($array as $key => $value){
if(is_array($value)){
for($i=0;$i<count($value);$i++){
$this->result[]=$value[$i];
}
}else{
$this->result[]=$value;
}
}
}
}
$obj= new MultiToSingle($res);
$array=$obj->result;
print_r($array);
How to define a two-dimensional array?
The accepted answer is good and correct, but it took me a while to understand that I could also use it to create a completely empty array.
l = [[] for _ in range(3)]
results in
[[], [], []]
PHP multidimensional array search by value
Here is one liner for the same,
$pic_square = $userdb[array_search($uid,array_column($userdb, 'uid'))]['pic_square'];
How to read numbers from file in Python?
To me this kind of seemingly simple problem is what Python is all about. Especially if you're coming from a language like C++, where simple text parsing can be a pain in the butt, you'll really appreciate the functionally unit-wise solution that python can give you. I'd keep it really simple with a couple of built-in functions and some generator expressions.
You'll need open(name, mode), myfile.readlines(), mystring.split(), int(myval), and then you'll probably want to use a couple of generators to put them all together in a pythonic way.
# This opens a handle to your file, in 'r' read mode
file_handle = open('mynumbers.txt', 'r')
# Read in all the lines of your file into a list of lines
lines_list = file_handle.readlines()
# Extract dimensions from first line. Cast values to integers from strings.
cols, rows = (int(val) for val in lines_list[0].split())
# Do a double-nested list comprehension to get the rest of the data into your matrix
my_data = [[int(val) for val in line.split()] for line in lines_list[1:]]
Look up generator expressions here. They can really simplify your code into discrete functional units! Imagine doing the same thing in 4 lines in C++... It would be a monster. Especially the list generators, when I was I C++ guy I always wished I had something like that, and I'd often end up building custom functions to construct each kind of array I wanted.
php foreach with multidimensional array
This would have been a comment under Brad's answer, but I don't have a high enough reputation.
Recently I found that I needed the key of the multidimensional array too, i.e., it wasn't just an index for the array, in the foreach loop.
In order to achieve that, you could use something very similar to the accepted answer, but instead split the key and value as follows
foreach ($mda as $mdaKey => $mdaData) {
echo $mdaKey . ": " . $mdaData["value"];
}
Hope that helps someone.
PHP order array by date?
Use usort:
usort($array, function($a1, $a2) {
$v1 = strtotime($a1['date']);
$v2 = strtotime($a2['date']);
return $v1 - $v2; // $v2 - $v1 to reverse direction
});
Converting a SimpleXML Object to an Array
I found this in the PHP manual comments:
/**
* function xml2array
*
* This function is part of the PHP manual.
*
* The PHP manual text and comments are covered by the Creative Commons
* Attribution 3.0 License, copyright (c) the PHP Documentation Group
*
* @author k dot antczak at livedata dot pl
* @date 2011-04-22 06:08 UTC
* @link http://www.php.net/manual/en/ref.simplexml.php#103617
* @license http://www.php.net/license/index.php#doc-lic
* @license http://creativecommons.org/licenses/by/3.0/
* @license CC-BY-3.0 <http://spdx.org/licenses/CC-BY-3.0>
*/
function xml2array ( $xmlObject, $out = array () )
{
foreach ( (array) $xmlObject as $index => $node )
$out[$index] = ( is_object ( $node ) ) ? xml2array ( $node ) : $node;
return $out;
}
It could help you. However, if you convert XML to an array you will loose all attributes that might be present, so you cannot go back to XML and get the same XML.
Excel VBA function to print an array to the workbook
You can define a Range, the size of your array and use it's value property:
Sub PrintArray(Data, SheetName As String, intStartRow As Integer, intStartCol As Integer)
Dim oWorksheet As Worksheet
Dim rngCopyTo As Range
Set oWorksheet = ActiveWorkbook.Worksheets(SheetName)
' size of array
Dim intEndRow As Integer
Dim intEndCol As Integer
intEndRow = UBound(Data, 1)
intEndCol = UBound(Data, 2)
Set rngCopyTo = oWorksheet.Range(oWorksheet.Cells(intStartRow, intStartCol), oWorksheet.Cells(intEndRow, intEndCol))
rngCopyTo.Value = Data
End Sub
How do I copy a 2 Dimensional array in Java?
Arrays in java are objects, and all objects are passed by reference. In order to really "copy" an array, instead of creating another name for an array, you have to go and create a new array and copy over all the values. Note that System.arrayCopy will copy 1-dimensional arrays fully, but NOT 2-dimensional arrays. The reason is that a 2D array is in fact a 1D array of 1D arrays, and arrayCopy copies over pointers to the same internal 1D arrays.
How to get the index of a maximum element in a NumPy array along one axis
argmax() will only return the first occurrence for each row.
http://docs.scipy.org/doc/numpy/reference/generated/numpy.argmax.html
If you ever need to do this for a shaped array, this works better than unravel:
import numpy as np
a = np.array([[1,2,3], [4,3,1]]) # Can be of any shape
indices = np.where(a == a.max())
You can also change your conditions:
indices = np.where(a >= 1.5)
The above gives you results in the form that you asked for. Alternatively, you can convert to a list of x,y coordinates by:
x_y_coords = zip(indices[0], indices[1])
Java Comparator class to sort arrays
Just tried this solution, we don't have to even write int.
int[][] twoDim = { { 1, 2 }, { 3, 7 }, { 8, 9 }, { 4, 2 }, { 5, 3 } };
Arrays.sort(twoDim, (a1,a2) -> a2[0] - a1[0]);
This thing will also work, it automatically detects the type of string.
VBA Excel 2-Dimensional Arrays
Here's A generic VBA Array To Range function that writes an array to the sheet in a single 'hit' to the sheet. This is much faster than writing the data into the sheet one cell at a time in loops for the rows and columns... However, there's some housekeeping to do, as you must specify the size of the target range correctly.
This 'housekeeping' looks like a lot of work and it's probably rather slow: but this is 'last mile' code to write to the sheet, and everything is faster than writing to the worksheet. Or at least, so much faster that it's effectively instantaneous, compared with a read or write to the worksheet, even in VBA, and you should do everything you possibly can in code before you hit the sheet.
A major component of this is error-trapping that I used to see turning up everywhere . I hate repetitive coding: I've coded it all here, and - hopefully - you'll never have to write it again.
A VBA 'Array to Range' function
Public Sub ArrayToRange(rngTarget As Excel.Range, InputArray As Variant)
' Write an array to an Excel range in a single 'hit' to the sheet
' InputArray must be a 2-Dimensional structure of the form Variant(Rows, Columns)
' The target range is resized automatically to the dimensions of the array, with
' the top left cell used as the start point.
' This subroutine saves repetitive coding for a common VBA and Excel task.
' If you think you won't need the code that works around common errors (long strings
' and objects in the array, etc) then feel free to comment them out.
On Error Resume Next
'
' Author: Nigel Heffernan
' HTTP://Excellerando.blogspot.com
'
' This code is in te public domain: take care to mark it clearly, and segregate
' it from proprietary code if you intend to assert intellectual property rights
' or impose commercial confidentiality restrictions on that proprietary code
Dim rngOutput As Excel.Range
Dim iRowCount As Long
Dim iColCount As Long
Dim iRow As Long
Dim iCol As Long
Dim arrTemp As Variant
Dim iDimensions As Integer
Dim iRowOffset As Long
Dim iColOffset As Long
Dim iStart As Long
Application.EnableEvents = False
If rngTarget.Cells.Count > 1 Then
rngTarget.ClearContents
End If
Application.EnableEvents = True
If IsEmpty(InputArray) Then
Exit Sub
End If
If TypeName(InputArray) = "Range" Then
InputArray = InputArray.Value
End If
' Is it actually an array? IsArray is sadly broken so...
If Not InStr(TypeName(InputArray), "(") Then
rngTarget.Cells(1, 1).Value2 = InputArray
Exit Sub
End If
iDimensions = ArrayDimensions(InputArray)
If iDimensions < 1 Then
rngTarget.Value = CStr(InputArray)
ElseIf iDimensions = 1 Then
iRowCount = UBound(InputArray) - LBound(InputArray)
iStart = LBound(InputArray)
iColCount = 1
If iRowCount > (655354 - rngTarget.Row) Then
iRowCount = 655354 + iStart - rngTarget.Row
ReDim Preserve InputArray(iStart To iRowCount)
End If
iRowCount = UBound(InputArray) - LBound(InputArray)
iColCount = 1
' It's a vector. Yes, I asked for a 2-Dimensional array. But I'm feeling generous.
' By convention, a vector is presented in Excel as an arry of 1 to n rows and 1 column.
ReDim arrTemp(LBound(InputArray, 1) To UBound(InputArray, 1), 1 To 1)
For iRow = LBound(InputArray, 1) To UBound(InputArray, 1)
arrTemp(iRow, 1) = InputArray(iRow)
Next
With rngTarget.Worksheet
Set rngOutput = .Range(rngTarget.Cells(1, 1), rngTarget.Cells(iRowCount + 1, iColCount))
rngOutput.Value2 = arrTemp
Set rngTarget = rngOutput
End With
Erase arrTemp
ElseIf iDimensions = 2 Then
iRowCount = UBound(InputArray, 1) - LBound(InputArray, 1)
iColCount = UBound(InputArray, 2) - LBound(InputArray, 2)
iStart = LBound(InputArray, 1)
If iRowCount > (65534 - rngTarget.Row) Then
iRowCount = 65534 - rngTarget.Row
InputArray = ArrayTranspose(InputArray)
ReDim Preserve InputArray(LBound(InputArray, 1) To UBound(InputArray, 1), iStart To iRowCount)
InputArray = ArrayTranspose(InputArray)
End If
iStart = LBound(InputArray, 2)
If iColCount > (254 - rngTarget.Column) Then
ReDim Preserve InputArray(LBound(InputArray, 1) To UBound(InputArray, 1), iStart To iColCount)
End If
With rngTarget.Worksheet
Set rngOutput = .Range(rngTarget.Cells(1, 1), rngTarget.Cells(iRowCount + 1, iColCount + 1))
Err.Clear
Application.EnableEvents = False
rngOutput.Value2 = InputArray
Application.EnableEvents = True
If Err.Number <> 0 Then
For iRow = LBound(InputArray, 1) To UBound(InputArray, 1)
For iCol = LBound(InputArray, 2) To UBound(InputArray, 2)
If IsNumeric(InputArray(iRow, iCol)) Then
' no action
Else
InputArray(iRow, iCol) = "" & InputArray(iRow, iCol)
InputArray(iRow, iCol) = Trim(InputArray(iRow, iCol))
End If
Next iCol
Next iRow
Err.Clear
rngOutput.Formula = InputArray
End If 'err<>0
If Err <> 0 Then
For iRow = LBound(InputArray, 1) To UBound(InputArray, 1)
For iCol = LBound(InputArray, 2) To UBound(InputArray, 2)
If IsNumeric(InputArray(iRow, iCol)) Then
' no action
Else
If Left(InputArray(iRow, iCol), 1) = "=" Then
InputArray(iRow, iCol) = "'" & InputArray(iRow, iCol)
End If
If Left(InputArray(iRow, iCol), 1) = "+" Then
InputArray(iRow, iCol) = "'" & InputArray(iRow, iCol)
End If
If Left(InputArray(iRow, iCol), 1) = "*" Then
InputArray(iRow, iCol) = "'" & InputArray(iRow, iCol)
End If
End If
Next iCol
Next iRow
Err.Clear
rngOutput.Value2 = InputArray
End If 'err<>0
If Err <> 0 Then
For iRow = LBound(InputArray, 1) To UBound(InputArray, 1)
For iCol = LBound(InputArray, 2) To UBound(InputArray, 2)
If IsObject(InputArray(iRow, iCol)) Then
InputArray(iRow, iCol) = "[OBJECT] " & TypeName(InputArray(iRow, iCol))
ElseIf IsArray(InputArray(iRow, iCol)) Then
InputArray(iRow, iCol) = Split(InputArray(iRow, iCol), ",")
ElseIf IsNumeric(InputArray(iRow, iCol)) Then
' no action
Else
InputArray(iRow, iCol) = "" & InputArray(iRow, iCol)
If Len(InputArray(iRow, iCol)) > 255 Then
' Block-write operations fail on strings exceeding 255 chars. You *have*
' to go back and check, and write this masterpiece one cell at a time...
InputArray(iRow, iCol) = Left(Trim(InputArray(iRow, iCol)), 255)
End If
End If
Next iCol
Next iRow
Err.Clear
rngOutput.Text = InputArray
End If 'err<>0
If Err <> 0 Then
Application.ScreenUpdating = False
Application.Calculation = xlCalculationManual
iRowOffset = LBound(InputArray, 1) - 1
iColOffset = LBound(InputArray, 2) - 1
For iRow = 1 To iRowCount
If iRow Mod 100 = 0 Then
Application.StatusBar = "Filling range... " & CInt(100# * iRow / iRowCount) & "%"
End If
For iCol = 1 To iColCount
rngOutput.Cells(iRow, iCol) = InputArray(iRow + iRowOffset, iCol + iColOffset)
Next iCol
Next iRow
Application.StatusBar = False
Application.ScreenUpdating = True
End If 'err<>0
Set rngTarget = rngOutput ' resizes the range This is useful, *most* of the time
End With
End If
End Sub
You will need the source for ArrayDimensions:
This API declaration is required in the module header:
Private Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" _
(Destination As Any, _
Source As Any, _
ByVal Length As Long)
...And here's the function itself:
Private Function ArrayDimensions(arr As Variant) As Integer
'-----------------------------------------------------------------
' will return:
' -1 if not an array
' 0 if an un-dimmed array
' 1 or more indicating the number of dimensions of a dimmed array
'-----------------------------------------------------------------
' Retrieved from Chris Rae's VBA Code Archive - http://chrisrae.com/vba
' Code written by Chris Rae, 25/5/00
' Originally published by R. B. Smissaert.
' Additional credits to Bob Phillips, Rick Rothstein, and Thomas Eyde on VB2TheMax
Dim ptr As Long
Dim vType As Integer
Const VT_BYREF = &H4000&
'get the real VarType of the argument
'this is similar to VarType(), but returns also the VT_BYREF bit
CopyMemory vType, arr, 2
'exit if not an array
If (vType And vbArray) = 0 Then
ArrayDimensions = -1
Exit Function
End If
'get the address of the SAFEARRAY descriptor
'this is stored in the second half of the
'Variant parameter that has received the array
CopyMemory ptr, ByVal VarPtr(arr) + 8, 4
'see whether the routine was passed a Variant
'that contains an array, rather than directly an array
'in the former case ptr already points to the SA structure.
'Thanks to Monte Hansen for this fix
If (vType And VT_BYREF) Then
' ptr is a pointer to a pointer
CopyMemory ptr, ByVal ptr, 4
End If
'get the address of the SAFEARRAY structure
'this is stored in the descriptor
'get the first word of the SAFEARRAY structure
'which holds the number of dimensions
'...but first check that saAddr is non-zero, otherwise
'this routine bombs when the array is uninitialized
If ptr Then
CopyMemory ArrayDimensions, ByVal ptr, 2
End If
End Function
Also: I would advise you to keep that declaration private. If you must make it a public Sub in another module, insert the Option Private Module statement in the module header. You really don't want your users calling any function with CopyMemoryoperations and pointer arithmetic.
Sort a two dimensional array based on one column
Check out the ColumnComparator. It is basically the same solution as proposed by Costi, but it also supports sorting on columns in a List and has a few more sort properties.
jQuery UI autocomplete with item and id
Just want to share what worked on my end, in case it would be able to help someone else too. Alternatively based on Paty Lustosa's answer above, please allow me to add another approach derived from this site where he used an ajax approach for the source method
http://salman-w.blogspot.ca/2013/12/jquery-ui-autocomplete-examples.html#example-3
The kicker is the resulting "string" or json format from your php script (listing.php below) that derives the result set to be shown in the autocomplete field should follow something like this:
{"list":[
{"value": 1, "label": "abc"},
{"value": 2, "label": "def"},
{"value": 3, "label": "ghi"}
]}
Then on the source portion of the autocomplete method:
source: function(request, response) {
$.getJSON("listing.php", {
term: request.term
}, function(data) {
var array = data.error ? [] : $.map(data.list, function(m) {
return {
label: m.label,
value: m.value
};
});
response(array);
});
},
select: function (event, ui) {
$("#autocomplete_field").val(ui.item.label); // display the selected text
$("#field_id").val(ui.item.value); // save selected id to hidden input
return false;
}
Hope this helps... all the best!
How do I use arrays in C++?
Assignment
For no particular reason, arrays cannot be assigned to one another. Use std::copy instead:
#include <algorithm>
// ...
int a[8] = {2, 3, 5, 7, 11, 13, 17, 19};
int b[8];
std::copy(a + 0, a + 8, b);
This is more flexible than what true array assignment could provide because it is possible to copy slices of larger arrays into smaller arrays.
std::copy is usually specialized for primitive types to give maximum performance. It is unlikely that std::memcpy performs better. If in doubt, measure.
Although you cannot assign arrays directly, you can assign structs and classes which contain array members. That is because array members are copied memberwise by the assignment operator which is provided as a default by the compiler. If you define the assignment operator manually for your own struct or class types, you must fall back to manual copying for the array members.
Parameter passing
Arrays cannot be passed by value. You can either pass them by pointer or by reference.
Pass by pointer
Since arrays themselves cannot be passed by value, usually a pointer to their first element is passed by value instead. This is often called "pass by pointer". Since the size of the array is not retrievable via that pointer, you have to pass a second parameter indicating the size of the array (the classic C solution) or a second pointer pointing after the last element of the array (the C++ iterator solution):
#include <numeric>
#include <cstddef>
int sum(const int* p, std::size_t n)
{
return std::accumulate(p, p + n, 0);
}
int sum(const int* p, const int* q)
{
return std::accumulate(p, q, 0);
}
As a syntactic alternative, you can also declare parameters as T p[], and it means the exact same thing as T* p in the context of parameter lists only:
int sum(const int p[], std::size_t n)
{
return std::accumulate(p, p + n, 0);
}
You can think of the compiler as rewriting T p[] to T *p in the context of parameter lists only. This special rule is partly responsible for the whole confusion about arrays and pointers. In every other context, declaring something as an array or as a pointer makes a huge difference.
Unfortunately, you can also provide a size in an array parameter which is silently ignored by the compiler. That is, the following three signatures are exactly equivalent, as indicated by the compiler errors:
int sum(const int* p, std::size_t n)
// error: redefinition of 'int sum(const int*, size_t)'
int sum(const int p[], std::size_t n)
// error: redefinition of 'int sum(const int*, size_t)'
int sum(const int p[8], std::size_t n) // the 8 has no meaning here
Pass by reference
Arrays can also be passed by reference:
int sum(const int (&a)[8])
{
return std::accumulate(a + 0, a + 8, 0);
}
In this case, the array size is significant. Since writing a function that only accepts arrays of exactly 8 elements is of little use, programmers usually write such functions as templates:
template <std::size_t n>
int sum(const int (&a)[n])
{
return std::accumulate(a + 0, a + n, 0);
}
Note that you can only call such a function template with an actual array of integers, not with a pointer to an integer. The size of the array is automatically inferred, and for every size n, a different function is instantiated from the template. You can also write quite useful function templates that abstract from both the element type and from the size.
Import CSV file with mixed data types
I recommend looking at the dataset array.
The dataset array is a data type that ships with Statistics Toolbox. It is specifically designed to store hetrogeneous data in a single container.
The Statistics Toolbox demo page contains a couple vidoes that show some of the dataset array features. The first is titled "An Introduction to Dataset Arrays". The second is titled "An Introduction to Joins".
How to access the ith column of a NumPy multidimensional array?
And if you want to access more than one column at a time you could do:
>>> test = np.arange(9).reshape((3,3))
>>> test
array([[0, 1, 2],
[3, 4, 5],
[6, 7, 8]])
>>> test[:,[0,2]]
array([[0, 2],
[3, 5],
[6, 8]])
How to create a Multidimensional ArrayList in Java?
Credit goes for JAcob Tomao for the code. I only added some comments to help beginners like me understand it. I hope it helps.
// read about Generic Types In Java & the use of class<T,...> syntax
// This class will Allow me to create 2D Arrays that do not have fixed sizes
class TwoDimArrayList<T> extends ArrayList<ArrayList<T>> {
public void addToInnerArray(int index, T element) {
while (index >= this.size()) {
// Create enough Arrays to get to position = index
this.add(new ArrayList<T>()); // (as if going along Vertical axis)
}
// this.get(index) returns the Arraylist instance at the "index" position
this.get(index).add(element); // (as if going along Horizontal axis)
}
public void addToInnerArray(int index, int index2, T element) {
while (index >= this.size()) {
this.add(new ArrayList<T>());// (as if going along Vertical
}
//access the inner ArrayList at the "index" position.
ArrayList<T> inner = this.get(index);
while (index2 >= inner.size()) {
//add enough positions containing "null" to get to the position index 2 ..
//.. within the inner array. (if the requested position is too far)
inner.add(null); // (as if going along Horizontal axis)
}
//Overwrite "null" or "old_element" with the new "element" at the "index 2" ..
//.. position of the chosen(index) inner ArrayList
inner.set(index2, element); // (as if going along Horizontal axis)
}
}
Find the index of a dict within a list, by matching the dict's value
Answer offered by @faham is a nice one-liner, but it doesn't return the index to the dictionary containing the value. Instead it returns the dictionary itself. Here is a simple way to get: A list of indexes one or more if there are more than one, or an empty list if there are none:
list = [{'id':'1234','name':'Jason'},
{'id':'2345','name':'Tom'},
{'id':'3456','name':'Art'}]
[i for i, d in enumerate(list) if 'Tom' in d.values()]
Output:
>>> [1]
What I like about this approach is that with a simple edit you can get a list of both the indexes and the dictionaries as tuples. This is the problem I needed to solve and found these answers. In the following, I added a duplicate value in a different dictionary to show how it works:
list = [{'id':'1234','name':'Jason'},
{'id':'2345','name':'Tom'},
{'id':'3456','name':'Art'},
{'id':'4567','name':'Tom'}]
[(i, d) for i, d in enumerate(list) if 'Tom' in d.values()]
Output:
>>> [(1, {'id': '2345', 'name': 'Tom'}), (3, {'id': '4567', 'name': 'Tom'})]
This solution finds all dictionaries containing 'Tom' in any of their values.
How to get single value from this multi-dimensional PHP array
echo $myarray[0]->['email'];
Try this only if it you are passing the stdclass object
Multi-dimensional associative arrays in JavaScript
Javascript is flexible:
var arr = {
"fred": {"apple": 2, "orange": 4},
"mary": {}
//etc, etc
};
alert(arr.fred.orange);
alert(arr["fred"]["orange"]);
for (key in arr.fred)
alert(key + ": " + arr.fred[key]);
How do you get the width and height of a multi-dimensional array?
You could also consider using getting the indexes of last elements in each specified dimensions using this as following;
int x = ary.GetUpperBound(0);
int y = ary.GetUpperBound(1);
Keep in mind that this gets the value of index as 0-based.
Random / noise functions for GLSL
After the initial posting of this question in 2010, a lot has changed in the realm of good random functions and hardware support for them.
Looking at the accepted answer from today's perspective, this algorithm is very bad in uniformity of the random numbers drawn from it. And the uniformity suffers a lot depending on the magnitude of the input values and visible artifacts/patterns will become apparent when sampling from it for e.g. ray/path tracing applications.
There have been many different functions (most of them integer hashing) being devised for this task, for different input and output dimensionality, most of which are being evaluated in the 2020 JCGT paper Hash Functions for GPU Rendering. Depending on your needs you could select a function from the list of proposed functions in that paper and simply from the accompanying Shadertoy. One that isn't covered in this paper but that has served me very well without any noticeably patterns on any input magnitude values is also one that I want to highlight.
Other classes of algorithms use low-discrepancy sequences to draw pseudo-random numbers from, such as the Sobol squence with Owen-Nayar scrambling. Eric Heitz has done some amazing research in this area, as well with his A Low-Discrepancy Sampler that Distributes Monte Carlo Errors as a Blue Noise in Screen Space paper. Another example of this is the (so far latest) JCGT paper Practical Hash-based Owen Scrambling, which applies Owen scrambling to a different hash function (namely Laine-Karras).
Yet other classes use algorithms that produce noise patterns with desirable frequency spectrums, such as blue noise, that is particularly "pleasing" to the eyes.
(I realize that good StackOverflow answers should provide the algorithms as source code and not as links because those can break, but there are way too many different algorithms nowadays and I intend for this answer to be a summary of known-good algorithms today)
in_array() and multidimensional array
This will work too.
function in_array_r($item , $array){
return preg_match('/"'.preg_quote($item, '/').'"/i' , json_encode($array));
}
Usage:
if(in_array_r($item , $array)){
// found!
}
Convert a matrix to a 1 dimensional array
array(A) or array(t(A)) will give you a 1-d array.
How can I declare a two dimensional string array?
string[,] Tablero = new string[3,3];
You can also instantiate it in the same line with array initializer syntax as follows:
string[,] Tablero = new string[3, 3] {{"a","b","c"},
{"d","e","f"},
{"g","h","i"} };
How to write a multidimensional array to a text file?
Write to a file with Python's print():
import numpy as np
import sys
stdout_sys = sys.stdout
np.set_printoptions(precision=8) # Sets number of digits of precision.
np.set_printoptions(suppress=True) # Suppress scientific notations.
np.set_printoptions(threshold=sys.maxsize) # Prints the whole arrays.
with open('myfile.txt', 'w') as f:
sys.stdout = f
print(nparr)
sys.stdout = stdout_sys
Use set_printoptions() to customize how the objects are displayed.
Java ArrayList of Arrays?
This works very well.
ArrayList<String[]> a = new ArrayList<String[]>();
a.add(new String[3]);
a.get(0)[0] = "Zubair";
a.get(0)[1] = "Borkala";
a.get(0)[2] = "Kerala";
System.out.println(a.get(0)[1]);
Result will be
Borkala
How to iterate over a column vector in Matlab?
for i=1:length(list)
elm = list(i);
//do something with elm.
Populate dropdown select with array using jQuery
var qty = 5;
var option = '';
for (var i=1;i <= qty;i++){
option += '<option value="'+ i + '">' + i + '</option>';
}
$('#items').append(option);
vba: get unique values from array
I don't know of any built-in functionality in VBA. The best would be to use a collection using the value as key and only add to it if a value doesn't exist.
PHP Sort a multidimensional array by element containing date
Use usort() and a custom comparison function:
function date_compare($a, $b)
{
$t1 = strtotime($a['datetime']);
$t2 = strtotime($b['datetime']);
return $t1 - $t2;
}
usort($array, 'date_compare');
EDIT: Your data is organized in an array of arrays. To better distinguish those, let's call the inner arrays (data) records, so that your data really is an array of records.
usort will pass two of these records to the given comparison function date_compare() at a a time. date_compare then extracts the "datetime" field of each record as a UNIX timestamp (an integer), and returns the difference, so that the result will be 0 if both dates are equal, a positive number if the first one ($a) is larger or a negative value if the second argument ($b) is larger. usort() uses this information to sort the array.
Iterate Multi-Dimensional Array with Nested Foreach Statement
As mentioned elsewhere, you can just iterate over the array and it will produce all results in order across all dimensions. However, if you want to know the indices as well, then how about using this - http://blogs.msdn.com/b/ericlippert/archive/2010/06/28/computing-a-cartesian-product-with-linq.aspx
then doing something like:
var dimensionLengthRanges = Enumerable.Range(0, myArray.Rank).Select(x => Enumerable.Range(0, myArray.GetLength(x)));
var indicesCombinations = dimensionLengthRanges.CartesianProduct();
foreach (var indices in indicesCombinations)
{
Console.WriteLine("[{0}] = {1}", string.Join(",", indices), myArray.GetValue(indices.ToArray()));
}
How to pretty-print a numpy.array without scientific notation and with given precision?
Years later, another one is below. But for everyday use I just
np.set_printoptions( threshold=20, edgeitems=10, linewidth=140,
formatter = dict( float = lambda x: "%.3g" % x )) # float arrays %.3g
''' printf( "... %.3g ... %.1f ...", arg, arg ... ) for numpy arrays too
Example:
printf( """ x: %.3g A: %.1f s: %s B: %s """,
x, A, "str", B )
If `x` and `A` are numbers, this is like `"format" % (x, A, "str", B)` in python.
If they're numpy arrays, each element is printed in its own format:
`x`: e.g. [ 1.23 1.23e-6 ... ] 3 digits
`A`: [ [ 1 digit after the decimal point ... ] ... ]
with the current `np.set_printoptions()`. For example, with
np.set_printoptions( threshold=100, edgeitems=3, suppress=True )
only the edges of big `x` and `A` are printed.
`B` is printed as `str(B)`, for any `B` -- a number, a list, a numpy object ...
`printf()` tries to handle too few or too many arguments sensibly,
but this is iffy and subject to change.
How it works:
numpy has a function `np.array2string( A, "%.3g" )` (simplifying a bit).
`printf()` splits the format string, and for format / arg pairs
format: % d e f g
arg: try `np.asanyarray()`
--> %s np.array2string( arg, format )
Other formats and non-ndarray args are left alone, formatted as usual.
Notes:
`printf( ... end= file= )` are passed on to the python `print()` function.
Only formats `% [optional width . precision] d e f g` are implemented,
not `%(varname)format` .
%d truncates floats, e.g. 0.9 and -0.9 to 0; %.0f rounds, 0.9 to 1 .
%g is the same as %.6g, 6 digits.
%% is a single "%" character.
The function `sprintf()` returns a long string. For example,
title = sprintf( "%s m %g n %g X %.3g",
__file__, m, n, X )
print( title )
...
pl.title( title )
Module globals:
_fmt = "%.3g" # default for extra args
_squeeze = np.squeeze # (n,1) (1,n) -> (n,) print in 1 line not n
See also:
http://docs.scipy.org/doc/numpy/reference/generated/numpy.set_printoptions.html
http://docs.python.org/2.7/library/stdtypes.html#string-formatting
'''
# http://stackoverflow.com/questions/2891790/pretty-printing-of-numpy-array
#...............................................................................
from __future__ import division, print_function
import re
import numpy as np
__version__ = "2014-02-03 feb denis"
_splitformat = re.compile( r'''(
%
(?<! %% ) # not %%
-? [ \d . ]* # optional width.precision
\w
)''', re.X )
# ... %3.0f ... %g ... %-10s ...
# -> ['...' '%3.0f' '...' '%g' '...' '%-10s' '...']
# odd len, first or last may be ""
_fmt = "%.3g" # default for extra args
_squeeze = np.squeeze # (n,1) (1,n) -> (n,) print in 1 line not n
#...............................................................................
def printf( format, *args, **kwargs ):
print( sprintf( format, *args ), **kwargs ) # end= file=
printf.__doc__ = __doc__
def sprintf( format, *args ):
""" sprintf( "text %.3g text %4.1f ... %s ... ", numpy arrays or ... )
%[defg] array -> np.array2string( formatter= )
"""
args = list(args)
if not isinstance( format, basestring ):
args = [format] + args
format = ""
tf = _splitformat.split( format ) # [ text %e text %f ... ]
nfmt = len(tf) // 2
nargs = len(args)
if nargs < nfmt:
args += (nfmt - nargs) * ["?arg?"]
elif nargs > nfmt:
tf += (nargs - nfmt) * [_fmt, " "] # default _fmt
for j, arg in enumerate( args ):
fmt = tf[ 2*j + 1 ]
if arg is None \
or isinstance( arg, basestring ) \
or (hasattr( arg, "__iter__" ) and len(arg) == 0):
tf[ 2*j + 1 ] = "%s" # %f -> %s, not error
continue
args[j], isarray = _tonumpyarray(arg)
if isarray and fmt[-1] in "defgEFG":
tf[ 2*j + 1 ] = "%s"
fmtfunc = (lambda x: fmt % x)
formatter = dict( float_kind=fmtfunc, int=fmtfunc )
args[j] = np.array2string( args[j], formatter=formatter )
try:
return "".join(tf) % tuple(args)
except TypeError: # shouldn't happen
print( "error: tf %s types %s" % (tf, map( type, args )))
raise
def _tonumpyarray( a ):
""" a, isarray = _tonumpyarray( a )
-> scalar, False
np.asanyarray(a), float or int
a, False
"""
a = getattr( a, "value", a ) # cvxpy
if np.isscalar(a):
return a, False
if hasattr( a, "__iter__" ) and len(a) == 0:
return a, False
try:
# map .value ?
a = np.asanyarray( a )
except ValueError:
return a, False
if hasattr( a, "dtype" ) and a.dtype.kind in "fi": # complex ?
if callable( _squeeze ):
a = _squeeze( a ) # np.squeeze
return a, True
else:
return a, False
#...............................................................................
if __name__ == "__main__":
import sys
n = 5
seed = 0
# run this.py n= ... in sh or ipython
for arg in sys.argv[1:]:
exec( arg )
np.set_printoptions( 1, threshold=4, edgeitems=2, linewidth=80, suppress=True )
np.random.seed(seed)
A = np.random.exponential( size=(n,n) ) ** 10
x = A[0]
printf( "x: %.3g \nA: %.1f \ns: %s \nB: %s ",
x, A, "str", A )
printf( "x %%d: %d", x )
printf( "x %%.0f: %.0f", x )
printf( "x %%.1e: %.1e", x )
printf( "x %%g: %g", x )
printf( "x %%s uses np printoptions: %s", x )
printf( "x with default _fmt: ", x )
printf( "no args" )
printf( "too few args: %g %g", x )
printf( x )
printf( x, x )
printf( None )
printf( "[]:", [] )
printf( "[3]:", [3] )
printf( np.array( [] ))
printf( [[]] ) # squeeze
How do I 'foreach' through a two-dimensional array?
string[][] table = { ... };
Angles between two n-dimensional vectors in Python
Using numpy (highly recommended), you would do:
from numpy import (array, dot, arccos, clip)
from numpy.linalg import norm
u = array([1.,2,3,4])
v = ...
c = dot(u,v)/norm(u)/norm(v) # -> cosine of the angle
angle = arccos(clip(c, -1, 1)) # if you really want the angle
How do you sort an array on multiple columns?
I suggest to use a built in comparer and chain the wanted sort order with logical or ||.
function customSort(a, b) {
return a[3].localeCompare(b[3]) || a[1].localeCompare(b[1]);
}
Working example:
var array = [_x000D_
[0, 'Aluminium', 0, 'Francis'],_x000D_
[1, 'Argon', 1, 'Ada'],_x000D_
[2, 'Brom', 2, 'John'],_x000D_
[3, 'Cadmium', 3, 'Marie'],_x000D_
[4, 'Fluor', 3, 'Marie'],_x000D_
[5, 'Gold', 1, 'Ada'],_x000D_
[6, 'Kupfer', 4, 'Ines'],_x000D_
[7, 'Krypton', 4, 'Joe'],_x000D_
[8, 'Sauerstoff', 3, 'Marie'],_x000D_
[9, 'Zink', 5, 'Max']_x000D_
];_x000D_
_x000D_
array.sort(function (a, b) {_x000D_
return a[3].localeCompare(b[3]) || a[1].localeCompare(b[1]);_x000D_
});_x000D_
_x000D_
document.write('<pre>');_x000D_
array.forEach(function (a) {_x000D_
document.write(JSON.stringify(a) + '<br>');_x000D_
});how to create dynamic two dimensional array in java?
simple you want to inialize a 2d array and assign a size of array then a example is
public static void main(String args[])
{
char arr[][]; //arr is 2d array name
arr = new char[3][3];
}
//this is a way to inialize a 2d array in java....
How to Sort Multi-dimensional Array by Value?
I use this function :
function array_sort_by_column(&$arr, $col, $dir = SORT_ASC) {
$sort_col = array();
foreach ($arr as $key=> $row) {
$sort_col[$key] = $row[$col];
}
array_multisort($sort_col, $dir, $arr);
}
array_sort_by_column($array, 'order');
Submitting a multidimensional array via POST with php
I made a function which handles arrays as well as single GET or POST values
function subVal($varName, $default=NULL,$isArray=FALSE ){ // $isArray toggles between (multi)array or single mode
$retVal = "";
$retArray = array();
if($isArray) {
if(isset($_POST[$varName])) {
foreach ( $_POST[$varName] as $var ) { // multidimensional POST array elements
$retArray[]=$var;
}
}
$retVal=$retArray;
}
elseif (isset($_POST[$varName]) ) { // simple POST array element
$retVal = $_POST[$varName];
}
else {
if (isset($_GET[$varName]) ) {
$retVal = $_GET[$varName]; // simple GET array element
}
else {
$retVal = $default;
}
}
return $retVal;
}
Examples:
$curr_topdiameter = subVal("topdiameter","",TRUE)[3];
$user_name = subVal("user_name","");
How to initialize a two-dimensional array in Python?
You can try this [[0]*10]*10. This will return the 2d array of 10 rows and 10 columns with value 0 for each cell.
How do I calculate percentiles with python/numpy?
In case you need the answer to be a member of the input numpy array:
Just to add that the percentile function in numpy by default calculates the output as a linear weighted average of the two neighboring entries in the input vector. In some cases people may want the returned percentile to be an actual element of the vector, in this case, from v1.9.0 onwards you can use the "interpolation" option, with either "lower", "higher" or "nearest".
import numpy as np
x=np.random.uniform(10,size=(1000))-5.0
np.percentile(x,70) # 70th percentile
2.075966046220879
np.percentile(x,70,interpolation="nearest")
2.0729677997904314
The latter is an actual entry in the vector, while the former is a linear interpolation of two vector entries that border the percentile
Passing JavaScript array to PHP through jQuery $.ajax
This worked for me:
$.ajax({
url:"../messaging/delete.php",
type:"POST",
data:{messages:selected},
success:function(data){
if(data === "done"){
}
info($("#notification"), data);
},
beforeSend:function(){
info($("#notification"),"Deleting "+count+" messages");
},
error:function(jqXHR, textStatus, errorMessage){
error($("#notification"),errorMessage);
}
});
And this for your PHP:
$messages = $_POST['messages']
foreach($messages as $msg){
echo $msg;
}
Unsetting array values in a foreach loop
You would also need a
$i--;
after each unset to not skip an element/
Because when you unset $item[45], the next element in the for-loop should be $item[45] - which was [46] before unsetting. If you would not do this, you'd always skip an element after unsetting.
Using malloc for allocation of multi-dimensional arrays with different row lengths
Equivalent memory allocation for char a[10][20] would be as follows.
char **a;
a=(char **) malloc(10*sizeof(char *));
for(i=0;i<10;i++)
a[i]=(char *) malloc(20*sizeof(char));
I hope this looks simple to understand.
Why aren't variable-length arrays part of the C++ standard?
There are situations where allocating heap memory is very expensive compared to the operations performed. An example is matrix math. If you work with smallish matrices say 5 to 10 elements and do a lot of arithmetics the malloc overhead will be really significant. At the same time making the size a compile time constant does seem very wasteful and inflexible.
I think that C++ is so unsafe in itself that the argument to "try to not add more unsafe features" is not very strong. On the other hand, as C++ is arguably the most runtime efficient programming language features which makes it more so are always useful: People who write performance critical programs will to a large extent use C++, and they need as much performance as possible. Moving stuff from heap to stack is one such possibility. Reducing the number of heap blocks is another. Allowing VLAs as object members would one way to achieve this. I'm working on such a suggestion. It is a bit complicated to implement, admittedly, but it seems quite doable.
PHP foreach loop key value
You can access your array keys like so:
foreach ($array as $key => $value)
How do I declare a two dimensional array?
Just declare? You don't have to. Just make sure variable exists:
$d = array();
Arrays are resized dynamically, and attempt to write anything to non-exsistant element creates it (and creates entire array if needed)
$d[1][2] = 3;
This is valid for any number of dimensions without prior declarations.
How do you add an array to another array in Ruby and not end up with a multi-dimensional result?
["some", "thing"] + ["another", "thing"]
Create two-dimensional arrays and access sub-arrays in Ruby
rows, cols = x,y # your values
grid = Array.new(rows) { Array.new(cols) }
As for accessing elements, this article is pretty good for step by step way to encapsulate an array in the way you want:
Peak-finding algorithm for Python/SciPy
Detecting peaks in a spectrum in a reliable way has been studied quite a bit, for example all the work on sinusoidal modelling for music/audio signals in the 80ies. Look for "Sinusoidal Modeling" in the literature.
If your signals are as clean as the example, a simple "give me something with an amplitude higher than N neighbours" should work reasonably well. If you have noisy signals, a simple but effective way is to look at your peaks in time, to track them: you then detect spectral lines instead of spectral peaks. IOW, you compute the FFT on a sliding window of your signal, to get a set of spectrum in time (also called spectrogram). You then look at the evolution of the spectral peak in time (i.e. in consecutive windows).
Multi-dimensional arraylist or list in C#?
If you want to modify this I'd go with either of the following:
List<string[]> results;
-- or --
List<List<string>> results;
depending on your needs...
How to sum all column values in multi-dimensional array?
You can use array_walk_recursive() to get a general-case solution for your problem (the one when each inner array can possibly have unique keys).
$final = array();
array_walk_recursive($input, function($item, $key) use (&$final){
$final[$key] = isset($final[$key]) ? $item + $final[$key] : $item;
});
Example with array_walk_recursive() for the general case
Also, since PHP 5.5 you can use the array_column() function to achieve the result you want for the exact key, [gozhi], for example :
array_sum(array_column($input, 'gozhi'));
Example with array_column() for the specified key
If you want to get the total sum of all inner arrays with the same keys (the desired result that you've posted), you can do something like this (bearing in mind that the first inner array must have the same structure as the others) :
$final = array_shift($input);
foreach ($final as $key => &$value){
$value += array_sum(array_column($input, $key));
}
unset($value);
Example with array_column() in case all inner arrays have the same keys
If you want a general-case solution using array_column() then at first you may consider to get all unique keys , and then get the sum for each key :
$final = array();
foreach($input as $value)
$final = array_merge($final, $value);
foreach($final as $key => &$value)
$value = array_sum(array_column($input, $key));
unset($value);
Working with a List of Lists in Java
Here's an example that reads a list of CSV strings into a list of lists and then loops through that list of lists and prints the CSV strings back out to the console.
import java.util.ArrayList;
import java.util.List;
public class ListExample
{
public static void main(final String[] args)
{
//sample CSV strings...pretend they came from a file
String[] csvStrings = new String[] {
"abc,def,ghi,jkl,mno",
"pqr,stu,vwx,yz",
"123,345,678,90"
};
List<List<String>> csvList = new ArrayList<List<String>>();
//pretend you're looping through lines in a file here
for(String line : csvStrings)
{
String[] linePieces = line.split(",");
List<String> csvPieces = new ArrayList<String>(linePieces.length);
for(String piece : linePieces)
{
csvPieces.add(piece);
}
csvList.add(csvPieces);
}
//write the CSV back out to the console
for(List<String> csv : csvList)
{
//dumb logic to place the commas correctly
if(!csv.isEmpty())
{
System.out.print(csv.get(0));
for(int i=1; i < csv.size(); i++)
{
System.out.print("," + csv.get(i));
}
}
System.out.print("\n");
}
}
}
Pretty straightforward I think. Just a couple points to notice:
I recommend using "List" instead of "ArrayList" on the left side when creating list objects. It's better to pass around the interface "List" because then if later you need to change to using something like Vector (e.g. you now need synchronized lists), you only need to change the line with the "new" statement. No matter what implementation of list you use, e.g. Vector or ArrayList, you still always just pass around
List<String>.In the ArrayList constructor, you can leave the list empty and it will default to a certain size and then grow dynamically as needed. But if you know how big your list might be, you can sometimes save some performance. For instance, if you knew there were always going to be 500 lines in your file, then you could do:
List<List<String>> csvList = new ArrayList<List<String>>(500);
That way you would never waste processing time waiting for your list to grow dynamically grow. This is why I pass "linePieces.length" to the constructor. Not usually a big deal, but helpful sometimes.
Hope that helps!
Loop through each row of a range in Excel
Just stumbled upon this and thought I would suggest my solution. I typically like to use the built in functionality of assigning a range to an multi-dim array (I guess it's also the JS Programmer in me).
I frequently write code like this:
Sub arrayBuilder()
myarray = Range("A1:D4")
'unlike most VBA Arrays, this array doesn't need to be declared and will be automatically dimensioned
For i = 1 To UBound(myarray)
For j = 1 To UBound(myarray, 2)
Debug.Print (myarray(i, j))
Next j
Next i
End Sub
Assigning ranges to variables is a very powerful way to manipulate data in VBA.
How to get number of rows using SqlDataReader in C#
If you do not need to retrieve all the row and want to avoid to make a double query, you can probably try something like that:
using (var sqlCon = new SqlConnection("Server=127.0.0.1;Database=MyDb;User Id=Me;Password=glop;"))
{
sqlCon.Open();
var com = sqlCon.CreateCommand();
com.CommandText = "select * from BigTable";
using (var reader = com.ExecuteReader())
{
//here you retrieve what you need
}
com.CommandText = "select @@ROWCOUNT";
var totalRow = com.ExecuteScalar();
sqlCon.Close();
}
You may have to add a transaction not sure if reusing the same command will automatically add a transaction on it...
What are the most widely used C++ vector/matrix math/linear algebra libraries, and their cost and benefit tradeoffs?
I've heard good things about Eigen and NT2, but haven't personally used either. There's also Boost.UBLAS, which I believe is getting a bit long in the tooth. The developers of NT2 are building the next version with the intention of getting it into Boost, so that might count for somthing.
My lin. alg. needs don't exteed beyond the 4x4 matrix case, so I can't comment on advanced functionality; I'm just pointing out some options.
Very simple C# CSV reader
First of all need to understand what is CSV and how to write it.
(Most of answers (all of them at the moment) do not use this requirements, that's why they all is wrong!)
- Every next string (
/r/n) is next "table" row. - "Table" cells is separated by some delimiter symbol.
- As delimiter can be used ANY symbol. Often this is
\tor,. - Each cell possibly can contain this delimiter symbol inside of the cell (cell must to start with double quotes symbol and to have double quote in the end in this case)
- Each cell possibly can contains
/r/nsymbols inside of the cell (cell must to start with double quotes symbol and to have double quote in the end in this case)
Some time ago I had wrote simple class for CSV read/write based on standard Microsoft.VisualBasic.FileIO library. Using this simple class you will be able to work with CSV like with 2 dimensions array.
Simple example of using my library:
Csv csv = new Csv("\t");//delimiter symbol
csv.FileOpen("c:\\file1.csv");
var row1Cell6Value = csv.Rows[0][5];
csv.AddRow("asdf","asdffffff","5")
csv.FileSave("c:\\file2.csv");
You can find my class by the following link and investigate how it's written: https://github.com/ukushu/DataExporter
This library code is really fast in work and source code is really short.
PS: In the same time this solution will not work for unity.
PS2: Another solution is to work with library "LINQ-to-CSV". It must also work well. But it's will be bigger.
How to Flatten a Multidimensional Array?
Straightforward and One-liner answer.
function flatten_array(array $array)
{
return iterator_to_array(
new \RecursiveIteratorIterator(new \RecursiveArrayIterator($array)));
}
Usage:
$array = [
'name' => 'Allen Linatoc',
'profile' => [
'age' => 21,
'favourite_games' => [ 'Call of Duty', 'Titanfall', 'Far Cry' ]
]
];
print_r( flatten_array($array) );
Output (in PsySH):
Array
(
[name] => Allen Linatoc
[age] => 21
[0] => Call of Duty
[1] => Titanfall
[2] => Far Cry
)
Now it's pretty up to you now how you'll handle the keys. Cheers
EDIT (2017-03-01)
Quoting Nigel Alderton's concern/issue:
Just to clarify, this preserves keys (even numeric ones) so values that have the same key are lost. For example
$array = ['a',['b','c']]becomesArray ([0] => b, [1] => c ). The'a'is lost because'b'also has a key of0
Quoting Svish's answer:
Just add false as second parameter
($use_keys)to the iterator_to_array call
Multidimensional Lists in C#
Please show more of your code.
If that last piece of code declares and initializes the list variable outside the loop you're basically reusing the same list object, thus adding everything into one list.
Also show where .Capacity and .Count comes into play, how did you get those values?
How to detect duplicate values in PHP array?
Perhaps something like this (untested code but should give you an idea)?
$new = array();
foreach ($array as $value)
{
if (isset($new[$value]))
$new[$value]++;
else
$new[$value] = 1;
}
Then you'll get a new array with the values as keys and their value is the number of times they existed in the original array.
Initialising a multidimensional array in Java
Try replacing the appropriate lines with:
myStringArray[0][x-1] = "a string";
myStringArray[0][y-1] = "another string";
Your code is incorrect because the sub-arrays have a length of y, and indexing starts at 0. So setting to myStringArray[0][y] or myStringArray[0][x] will fail because the indices x and y are out of bounds.
String[][] myStringArray = new String [x][y]; is the correct way to initialise a rectangular multidimensional array. If you want it to be jagged (each sub-array potentially has a different length) then you can use code similar to this answer. Note however that John's assertion that you have to create the sub-arrays manually is incorrect in the case where you want a perfectly rectangular multidimensional array.
Create a pointer to two-dimensional array
Here you wanna make a pointer to the first element of the array
uint8_t (*matrix_ptr)[20] = l_matrix;
With typedef, this looks cleaner
typedef uint8_t array_of_20_uint8_t[20];
array_of_20_uint8_t *matrix_ptr = l_matrix;
Then you can enjoy life again :)
matrix_ptr[0][1] = ...;
Beware of the pointer/array world in C, much confusion is around this.
Edit
Reviewing some of the other answers here, because the comment fields are too short to do there. Multiple alternatives were proposed, but it wasn't shown how they behave. Here is how they do
uint8_t (*matrix_ptr)[][20] = l_matrix;
If you fix the error and add the address-of operator & like in the following snippet
uint8_t (*matrix_ptr)[][20] = &l_matrix;
Then that one creates a pointer to an incomplete array type of elements of type array of 20 uint8_t. Because the pointer is to an array of arrays, you have to access it with
(*matrix_ptr)[0][1] = ...;
And because it's a pointer to an incomplete array, you cannot do as a shortcut
matrix_ptr[0][0][1] = ...;
Because indexing requires the element type's size to be known (indexing implies an addition of an integer to the pointer, so it won't work with incomplete types). Note that this only works in C, because T[] and T[N] are compatible types. C++ does not have a concept of compatible types, and so it will reject that code, because T[] and T[10] are different types.
The following alternative doesn't work at all, because the element type of the array, when you view it as a one-dimensional array, is not uint8_t, but uint8_t[20]
uint8_t *matrix_ptr = l_matrix; // fail
The following is a good alternative
uint8_t (*matrix_ptr)[10][20] = &l_matrix;
You access it with
(*matrix_ptr)[0][1] = ...;
matrix_ptr[0][0][1] = ...; // also possible now
It has the benefit that it preserves the outer dimension's size. So you can apply sizeof on it
sizeof (*matrix_ptr) == sizeof(uint8_t) * 10 * 20
There is one other answer that makes use of the fact that items in an array are contiguously stored
uint8_t *matrix_ptr = l_matrix[0];
Now, that formally only allows you to access the elements of the first element of the two dimensional array. That is, the following condition hold
matrix_ptr[0] = ...; // valid
matrix_ptr[19] = ...; // valid
matrix_ptr[20] = ...; // undefined behavior
matrix_ptr[10*20-1] = ...; // undefined behavior
You will notice it probably works up to 10*20-1, but if you throw on alias analysis and other aggressive optimizations, some compiler could make an assumption that may break that code. Having said that, i've never encountered a compiler that fails on it (but then again, i've not used that technique in real code), and even the C FAQ has that technique contained (with a warning about its UB'ness), and if you cannot change the array type, this is a last option to save you :)
How to search by key=>value in a multidimensional array in PHP
function in_multi_array($needle, $key, $haystack)
{
$in_multi_array = false;
if (in_array($needle, $haystack))
{
$in_multi_array = true;
}else
{
foreach( $haystack as $key1 => $val )
{
if(is_array($val))
{
if($this->in_multi_array($needle, $key, $val))
{
$in_multi_array = true;
break;
}
}
}
}
return $in_multi_array;
}
How can I create a two dimensional array in JavaScript?
Here's a quick way I've found to make a two dimensional array.
function createArray(x, y) {
return Array.apply(null, Array(x)).map(e => Array(y));
}
You can easily turn this function into an ES5 function as well.
function createArray(x, y) {
return Array.apply(null, Array(x)).map(function(e) {
return Array(y);
});
}
Why this works: the new Array(n) constructor creates an object with a prototype of Array.prototype and then assigns the object's length, resulting in an unpopulated array. Due to its lack of actual members we can't run the Array.prototype.map function on it.
However, when you provide more than one argument to the constructor, such as when you do Array(1, 2, 3, 4), the constructor will use the arguments object to instantiate and populate an Array object correctly.
For this reason, we can use Array.apply(null, Array(x)), because the apply function will spread the arguments into the constructor. For clarification, doing Array.apply(null, Array(3)) is equivalent to doing Array(null, null, null).
Now that we've created an actual populated array, all we need to do is call map and create the second layer (y).
How do I work with dynamic multi-dimensional arrays in C?
int rows, columns;
/* initialize rows and columns to the desired value */
arr = (int**)malloc(rows*sizeof(int*));
for(i=0;i<rows;i++)
{
arr[i] = (int*)malloc(cols*sizeof(int));
}
Detect if a NumPy array contains at least one non-numeric value?
With numpy 1.3 or svn you can do this
In [1]: a = arange(10000.).reshape(100,100)
In [3]: isnan(a.max())
Out[3]: False
In [4]: a[50,50] = nan
In [5]: isnan(a.max())
Out[5]: True
In [6]: timeit isnan(a.max())
10000 loops, best of 3: 66.3 µs per loop
The treatment of nans in comparisons was not consistent in earlier versions.
How do you extract a column from a multi-dimensional array?
If you want to grab more than just one column just use slice:
a = np.array([[1, 2, 3],[4, 5, 6],[7, 8, 9]])
print(a[:, [1, 2]])
[[2 3]
[5 6]
[8 9]]
PHP foreach loop through multidimensional array
<?php
$first = reset($arr_nav); // Get the first element
$last = end($arr_nav); // Get the last element
// Ensure that we have a first element and that it's an array
if(is_array($first)) {
$first['class'] = 'first';
}
// Ensure we have a last element and that it differs from the first
if(is_array($last) && $last !== $first) {
$last['class'] = 'last';
}
Now you could just echo the class inside you html-generator. Would probably need some kind of check to ensure that the class is set, or provide a default empty class to the array.
Preferred method to store PHP arrays (json_encode vs serialize)
Check out the results here (sorry for the hack putting the PHP code in the JS code box):
http://jsfiddle.net/newms87/h3b0a0ha/embedded/result/
RESULTS: serialize() and unserialize() are both significantly faster in PHP 5.4 on arrays of varying size.
I made a test script on real world data for comparing json_encode vs serialize and json_decode vs unserialize. The test was run on the caching system of an in production e-commerce site. It simply takes the data already in the cache, and tests the times to encode / decode (or serialize / unserialize) all the data and I put it in an easy to see table.
I ran this on PHP 5.4 shared hosting server.
The results were very conclusive that for these large to small data sets serialize and unserialize were the clear winners. In particular for my use case, the json_decode and unserialize are the most important for the caching system. Unserialize was almost an ubiquitous winner here. It was typically 2 to 4 times (sometimes 6 or 7 times) as fast as json_decode.
It is interesting to note the difference in results from @peter-bailey.
Here is the PHP code used to generate the results:
<?php
ini_set('display_errors', 1);
error_reporting(E_ALL);
function _count_depth($array)
{
$count = 0;
$max_depth = 0;
foreach ($array as $a) {
if (is_array($a)) {
list($cnt, $depth) = _count_depth($a);
$count += $cnt;
$max_depth = max($max_depth, $depth);
} else {
$count++;
}
}
return array(
$count,
$max_depth + 1,
);
}
function run_test($file)
{
$memory = memory_get_usage();
$test_array = unserialize(file_get_contents($file));
$memory = round((memory_get_usage() - $memory) / 1024, 2);
if (empty($test_array) || !is_array($test_array)) {
return;
}
list($count, $depth) = _count_depth($test_array);
//JSON encode test
$start = microtime(true);
$json_encoded = json_encode($test_array);
$json_encode_time = microtime(true) - $start;
//JSON decode test
$start = microtime(true);
json_decode($json_encoded);
$json_decode_time = microtime(true) - $start;
//serialize test
$start = microtime(true);
$serialized = serialize($test_array);
$serialize_time = microtime(true) - $start;
//unserialize test
$start = microtime(true);
unserialize($serialized);
$unserialize_time = microtime(true) - $start;
return array(
'Name' => basename($file),
'json_encode() Time (s)' => $json_encode_time,
'json_decode() Time (s)' => $json_decode_time,
'serialize() Time (s)' => $serialize_time,
'unserialize() Time (s)' => $unserialize_time,
'Elements' => $count,
'Memory (KB)' => $memory,
'Max Depth' => $depth,
'json_encode() Win' => ($json_encode_time > 0 && $json_encode_time < $serialize_time) ? number_format(($serialize_time / $json_encode_time - 1) * 100, 2) : '',
'serialize() Win' => ($serialize_time > 0 && $serialize_time < $json_encode_time) ? number_format(($json_encode_time / $serialize_time - 1) * 100, 2) : '',
'json_decode() Win' => ($json_decode_time > 0 && $json_decode_time < $serialize_time) ? number_format(($serialize_time / $json_decode_time - 1) * 100, 2) : '',
'unserialize() Win' => ($unserialize_time > 0 && $unserialize_time < $json_decode_time) ? number_format(($json_decode_time / $unserialize_time - 1) * 100, 2) : '',
);
}
$files = glob(dirname(__FILE__) . '/system/cache/*');
$data = array();
foreach ($files as $file) {
if (is_file($file)) {
$result = run_test($file);
if ($result) {
$data[] = $result;
}
}
}
uasort($data, function ($a, $b) {
return $a['Memory (KB)'] < $b['Memory (KB)'];
});
$fields = array_keys($data[0]);
?>
<table>
<thead>
<tr>
<?php foreach ($fields as $f) { ?>
<td style="text-align: center; border:1px solid black;padding: 4px 8px;font-weight:bold;font-size:1.1em"><?= $f; ?></td>
<?php } ?>
</tr>
</thead>
<tbody>
<?php foreach ($data as $d) { ?>
<tr>
<?php foreach ($d as $key => $value) { ?>
<?php $is_win = strpos($key, 'Win'); ?>
<?php $color = ($is_win && $value) ? 'color: green;font-weight:bold;' : ''; ?>
<td style="text-align: center; vertical-align: middle; padding: 3px 6px; border: 1px solid gray; <?= $color; ?>"><?= $value . (($is_win && $value) ? '%' : ''); ?></td>
<?php } ?>
</tr>
<?php } ?>
</tbody>
</table>
How do I iterate through each element in an n-dimensional matrix in MATLAB?
You want to simulate n-nested for loops.
Iterating through n-dimmensional array can be seen as increasing the n-digit number.
At each dimmension we have as many digits as the lenght of the dimmension.
Example:
Suppose we had array(matrix)
int[][][] T=new int[3][4][5];
in "for notation" we have:
for(int x=0;x<3;x++)
for(int y=0;y<4;y++)
for(int z=0;z<5;z++)
T[x][y][z]=...
to simulate this you would have to use the "n-digit number notation"
We have 3 digit number, with 3 digits for first, 4 for second and five for third digit
We have to increase the number, so we would get the sequence
0 0 0
0 0 1
0 0 2
0 0 3
0 0 4
0 1 0
0 1 1
0 1 2
0 1 3
0 1 4
0 2 0
0 2 1
0 2 2
0 2 3
0 2 4
0 3 0
0 3 1
0 3 2
0 3 3
0 3 4
and so on
So you can write the code for increasing such n-digit number. You can do it in such way that you can start with any value of the number and increase/decrease the digits by any numbers. That way you can simulate nested for loops that begin somewhere in the table and finish not at the end.
This is not an easy task though. I can't help with the matlab notation unfortunaly.
Are 2 dimensional Lists possible in c#?
Here's a little something that I made a while ago for a game engine I was working on. It was used as a local object variable holder. Basically, you use it as a normal list, but it holds the value at the position of what ever the string name is(or ID). A bit of modification, and you will have your 2D list.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace GameEngineInterpreter
{
public class VariableList<T>
{
private List<string> list1;
private List<T> list2;
/// <summary>
/// Initialize a new Variable List
/// </summary>
public VariableList()
{
list1 = new List<string>();
list2 = new List<T>();
}
/// <summary>
/// Set the value of a variable. If the variable does not exist, then it is created
/// </summary>
/// <param name="variable">Name or ID of the variable</param>
/// <param name="value">The value of the variable</param>
public void Set(string variable, T value)
{
if (!list1.Contains(variable))
{
list1.Add(variable);
list2.Add(value);
}
else
{
list2[list1.IndexOf(variable)] = value;
}
}
/// <summary>
/// Remove the variable if it exists
/// </summary>
/// <param name="variable">Name or ID of the variable</param>
public void Remove(string variable)
{
if (list1.Contains(variable))
{
list2.RemoveAt(list1.IndexOf(variable));
list1.RemoveAt(list1.IndexOf(variable));
}
}
/// <summary>
/// Clears the variable list
/// </summary>
public void Clear()
{
list1.Clear();
list2.Clear();
}
/// <summary>
/// Get the value of the variable if it exists
/// </summary>
/// <param name="variable">Name or ID of the variable</param>
/// <returns>Value</returns>
public T Get(string variable)
{
if (list1.Contains(variable))
{
return (list2[list1.IndexOf(variable)]);
}
else
{
return default(T);
}
}
/// <summary>
/// Get a string list of all the variables
/// </summary>
/// <returns>List string</string></returns>
public List<string> GetList()
{
return (list1);
}
}
}
What are the differences between a multidimensional array and an array of arrays in C#?
This might have been mentioned in the above answers but not explicitly: with jagged array you can use array[row] to refer a whole row of data, but this is not allowed for multi-d arrays.
How to "flatten" a multi-dimensional array to simple one in PHP?
/*consider $mArray as multidimensional array and $sArray as single dimensional array
this code will ignore the parent array
*/
function flatten_array2($mArray) {
$sArray = array();
foreach ($mArray as $row) {
if ( !(is_array($row)) ) {
if($sArray[] = $row){
}
} else {
$sArray = array_merge($sArray,flatten_array2($row));
}
}
return $sArray;
}
Array of Matrices in MATLAB
Use cell arrays. This has an advantage over 3D arrays in that it does not require a contiguous memory space to store all the matrices. In fact, each matrix can be stored in a different space in memory, which will save you from Out-of-Memory errors if your free memory is fragmented. Here is a sample function to create your matrices in a cell array:
function result = createArrays(nArrays, arraySize)
result = cell(1, nArrays);
for i = 1 : nArrays
result{i} = zeros(arraySize);
end
end
To use it:
myArray = createArrays(requiredNumberOfArrays, [500 800]);
And to access your elements:
myArray{1}(2,3) = 10;
If you can't know the number of matrices in advance, you could simply use MATLAB's dynamic indexing to make the array as large as you need. The performance overhead will be proportional to the size of the cell array, and is not affected by the size of the matrices themselves. For example:
myArray{1} = zeros(500, 800);
if twoRequired, myArray{2} = zeros(500, 800); end
Ball to Ball Collision - Detection and Handling
I found an excellent page with information on collision detection and response in 2D.
http://www.metanetsoftware.com/technique.html (web.archive.org)
They try to explain how it's done from an academic point of view. They start with the simple object-to-object collision detection, and move on to collision response and how to scale it up.
Edit: Updated link
How can you determine a point is between two other points on a line segment?
Here's how I did it at school. I forgot why it is not a good idea.
EDIT:
@Darius Bacon: cites a "Beautiful Code" book which contains an explanation why the belowed code is not a good idea.
#!/usr/bin/env python
from __future__ import division
epsilon = 1e-6
class Point:
def __init__(self, x, y):
self.x, self.y = x, y
class LineSegment:
"""
>>> ls = LineSegment(Point(0,0), Point(2,4))
>>> Point(1, 2) in ls
True
>>> Point(.5, 1) in ls
True
>>> Point(.5, 1.1) in ls
False
>>> Point(-1, -2) in ls
False
>>> Point(.1, 0.20000001) in ls
True
>>> Point(.1, 0.2001) in ls
False
>>> ls = LineSegment(Point(1, 1), Point(3, 5))
>>> Point(2, 3) in ls
True
>>> Point(1.5, 2) in ls
True
>>> Point(0, -1) in ls
False
>>> ls = LineSegment(Point(1, 2), Point(1, 10))
>>> Point(1, 6) in ls
True
>>> Point(1, 1) in ls
False
>>> Point(2, 6) in ls
False
>>> ls = LineSegment(Point(-1, 10), Point(5, 10))
>>> Point(3, 10) in ls
True
>>> Point(6, 10) in ls
False
>>> Point(5, 10) in ls
True
>>> Point(3, 11) in ls
False
"""
def __init__(self, a, b):
if a.x > b.x:
a, b = b, a
(self.x0, self.y0, self.x1, self.y1) = (a.x, a.y, b.x, b.y)
self.slope = (self.y1 - self.y0) / (self.x1 - self.x0) if self.x1 != self.x0 else None
def __contains__(self, c):
return (self.x0 <= c.x <= self.x1 and
min(self.y0, self.y1) <= c.y <= max(self.y0, self.y1) and
(not self.slope or -epsilon < (c.y - self.y(c.x)) < epsilon))
def y(self, x):
return self.slope * (x - self.x0) + self.y0
if __name__ == '__main__':
import doctest
doctest.testmod()
How to remove duplicate values from a multi-dimensional array in PHP
Since 5.2.9 you can use array_unique() if you use the SORT_REGULAR flag like so:
array_unique($array, SORT_REGULAR);
This makes the function compare elements for equality as if $a == $b were being used, which is perfect for your case.
Output
Array
(
[0] => Array
(
[0] => abc
[1] => def
)
[1] => Array
(
[0] => ghi
[1] => jkl
)
[2] => Array
(
[0] => mno
[1] => pql
)
)
Keep in mind, though, that the documentation states:
array_unique()is not intended to work on multi dimensional arrays.
Java: Reading a file into an array
import java.io.File;
import java.nio.charset.Charset;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.List;
// ...
Path filePath = new File("fileName").toPath();
Charset charset = Charset.defaultCharset();
List<String> stringList = Files.readAllLines(filePath, charset);
String[] stringArray = stringList.toArray(new String[]{});
Calculating a 2D Vector's Cross Product
Another useful property of the cross product is that its magnitude is related to the sine of the angle between the two vectors:
| a x b | = |a| . |b| . sine(theta)
or
sine(theta) = | a x b | / (|a| . |b|)
So, in implementation 1 above, if a and b are known in advance to be unit vectors then the result of that function is exactly that sine() value.
How do I sort a two-dimensional (rectangular) array in C#?
Try this out. The basic strategy is to sort the particular column independently and remember the original row of the entry. The rest of the code will cycle through the sorted column data and swap out the rows in the array. The tricky part is remembing to update the original column as the swap portion will effectively alter the original column.
public class Pair<T> {
public int Index;
public T Value;
public Pair(int i, T v) {
Index = i;
Value = v;
}
}
static IEnumerable<Pair<T>> Iterate<T>(this IEnumerable<T> source) {
int index = 0;
foreach ( var cur in source) {
yield return new Pair<T>(index,cur);
index++;
}
}
static void Sort2d(string[][] source, IComparer comp, int col) {
var colValues = source.Iterate()
.Select(x => new Pair<string>(x.Index,source[x.Index][col])).ToList();
colValues.Sort((l,r) => comp.Compare(l.Value, r.Value));
var temp = new string[source[0].Length];
var rest = colValues.Iterate();
while ( rest.Any() ) {
var pair = rest.First();
var cur = pair.Value;
var i = pair.Index;
if (i == cur.Index ) {
rest = rest.Skip(1);
continue;
}
Array.Copy(source[i], temp, temp.Length);
Array.Copy(source[cur.Index], source[i], temp.Length);
Array.Copy(temp, source[cur.Index], temp.Length);
rest = rest.Skip(1);
rest.Where(x => x.Value.Index == i).First().Value.Index = cur.Index;
}
}
public static void Test1() {
var source = new string[][]
{
new string[]{ "foo", "bar", "4" },
new string[] { "jack", "dog", "1" },
new string[]{ "boy", "ball", "2" },
new string[]{ "yellow", "green", "3" }
};
Sort2d(source, StringComparer.Ordinal, 2);
}
Easy way to turn JavaScript array into comma-separated list?
Here's an implementation that converts a two-dimensional array or an array of columns into a properly escaped CSV string. The functions do not check for valid string/number input or column counts (ensure your array is valid to begin with). The cells can contain commas and quotes!
Here's a script for decoding CSV strings.
Here's my script for encoding CSV strings:
// Example
var csv = new csvWriter();
csv.del = '\t';
csv.enc = "'";
var nullVar;
var testStr = "The comma (,) pipe (|) single quote (') double quote (\") and tab (\t) are commonly used to tabulate data in plain-text formats.";
var testArr = [
false,
0,
nullVar,
// undefinedVar,
'',
{key:'value'},
];
console.log(csv.escapeCol(testStr));
console.log(csv.arrayToRow(testArr));
console.log(csv.arrayToCSV([testArr, testArr, testArr]));
/**
* Class for creating csv strings
* Handles multiple data types
* Objects are cast to Strings
**/
function csvWriter(del, enc) {
this.del = del || ','; // CSV Delimiter
this.enc = enc || '"'; // CSV Enclosure
// Convert Object to CSV column
this.escapeCol = function (col) {
if(isNaN(col)) {
// is not boolean or numeric
if (!col) {
// is null or undefined
col = '';
} else {
// is string or object
col = String(col);
if (col.length > 0) {
// use regex to test for del, enc, \r or \n
// if(new RegExp( '[' + this.del + this.enc + '\r\n]' ).test(col)) {
// escape inline enclosure
col = col.split( this.enc ).join( this.enc + this.enc );
// wrap with enclosure
col = this.enc + col + this.enc;
}
}
}
return col;
};
// Convert an Array of columns into an escaped CSV row
this.arrayToRow = function (arr) {
var arr2 = arr.slice(0);
var i, ii = arr2.length;
for(i = 0; i < ii; i++) {
arr2[i] = this.escapeCol(arr2[i]);
}
return arr2.join(this.del);
};
// Convert a two-dimensional Array into an escaped multi-row CSV
this.arrayToCSV = function (arr) {
var arr2 = arr.slice(0);
var i, ii = arr2.length;
for(i = 0; i < ii; i++) {
arr2[i] = this.arrayToRow(arr2[i]);
}
return arr2.join("\r\n");
};
}
How do I Sort a Multidimensional Array in PHP
You can use array_multisort()
Try something like this:
foreach ($mdarray as $key => $row) {
// replace 0 with the field's index/key
$dates[$key] = $row[0];
}
array_multisort($dates, SORT_DESC, $mdarray);
For PHP >= 5.5.0 just extract the column to sort by. No need for the loop:
array_multisort(array_column($mdarray, 0), SORT_DESC, $mdarray);
VB.NET Empty String Array
A little verbose, but self documenting...
Dim strEmpty() As String = Enumerable.Empty(Of String).ToArray
How do you rotate a two dimensional array?
There are tons of good code here but I just want to show what's going on geometrically so you can understand the code logic a little better. Here is how I would approach this.
first of all, do not confuse this with transposition which is very easy..
the basica idea is to treat it as layers and we rotate one layer at a time..
say we have a 4x4
1 2 3 4
5 6 7 8
9 10 11 12
13 14 15 16
after we rotate it clockwise by 90 we get
13 9 5 1
14 10 6 2
15 11 7 3
16 12 8 4
so let's decompose this, first we rotate the 4 corners essentially
1 4
13 16
then we rotate the following diamond which is sort of askew
2
8
9
15
and then the 2nd skewed diamond
3
5
12
14
so that takes care of the outer edge so essentially we do that one shell at a time until
finally the middle square (or if it's odd just the final element which does not move)
6 7
10 11
so now let's figure out the indices of each layer, assume we always work with the outermost layer, we are doing
[0,0] -> [0,n-1], [0,n-1] -> [n-1,n-1], [n-1,n-1] -> [n-1,0], and [n-1,0] -> [0,0]
[0,1] -> [1,n-1], [1,n-2] -> [n-1,n-2], [n-1,n-2] -> [n-2,0], and [n-2,0] -> [0,1]
[0,2] -> [2,n-2], [2,n-2] -> [n-1,n-3], [n-1,n-3] -> [n-3,0], and [n-3,0] -> [0,2]
so on and so on until we are halfway through the edge
so in general the pattern is
[0,i] -> [i,n-i], [i,n-i] -> [n-1,n-(i+1)], [n-1,n-(i+1)] -> [n-(i+1),0], and [n-(i+1),0] to [0,i]
How to add "class" to host element?
Günter's answer is great (question is asking for dynamic class attribute) but I thought I would add just for completeness...
If you're looking for a quick and clean way to add one or more static classes to the host element of your component (i.e., for theme-styling purposes) you can just do:
@Component({
selector: 'my-component',
template: 'app-element',
host: {'class': 'someClass1'}
})
export class App implements OnInit {
...
}
And if you use a class on the entry tag, Angular will merge the classes, i.e.,
<my-component class="someClass2">
I have both someClass1 & someClass2 applied to me
</my-component>
Use of REPLACE in SQL Query for newline/ carriage return characters
There are probably embedded tabs (CHAR(9)) etc. as well. You can find out what other characters you need to replace (we have no idea what your goal is) with something like this:
DECLARE @var NVARCHAR(255), @i INT;
SET @i = 1;
SELECT @var = AccountType FROM dbo.Account
WHERE AccountNumber = 200
AND AccountType LIKE '%Daily%';
CREATE TABLE #x(i INT PRIMARY KEY, c NCHAR(1), a NCHAR(1));
WHILE @i <= LEN(@var)
BEGIN
INSERT #x
SELECT SUBSTRING(@var, @i, 1), ASCII(SUBSTRING(@var, @i, 1));
SET @i = @i + 1;
END
SELECT i,c,a FROM #x ORDER BY i;
You might also consider doing better cleansing of this data before it gets into your database. Cleaning it every time you need to search or display is not the best approach.
How to modify WooCommerce cart, checkout pages (main theme portion)
You can use the is_cart() conditional tag:
if (! is_cart() ) {
// Do something.
}
AngularJS - Does $destroy remove event listeners?
Event listeners
First off it's important to understand that there are two kinds of "event listeners":
Scope event listeners registered via
$on:$scope.$on('anEvent', function (event, data) { ... });Event handlers attached to elements via for example
onorbind:element.on('click', function (event) { ... });
$scope.$destroy()
When $scope.$destroy() is executed it will remove all listeners registered via $on on that $scope.
It will not remove DOM elements or any attached event handlers of the second kind.
This means that calling $scope.$destroy() manually from example within a directive's link function will not remove a handler attached via for example element.on, nor the DOM element itself.
element.remove()
Note that remove is a jqLite method (or a jQuery method if jQuery is loaded before AngularjS) and is not available on a standard DOM Element Object.
When element.remove() is executed that element and all of its children will be removed from the DOM together will all event handlers attached via for example element.on.
It will not destroy the $scope associated with the element.
To make it more confusing there is also a jQuery event called $destroy. Sometimes when working with third-party jQuery libraries that remove elements, or if you remove them manually, you might need to perform clean up when that happens:
element.on('$destroy', function () {
scope.$destroy();
});
What to do when a directive is "destroyed"
This depends on how the directive is "destroyed".
A normal case is that a directive is destroyed because ng-view changes the current view. When this happens the ng-view directive will destroy the associated $scope, sever all the references to its parent scope and call remove() on the element.
This means that if that view contains a directive with this in its link function when it's destroyed by ng-view:
scope.$on('anEvent', function () {
...
});
element.on('click', function () {
...
});
Both event listeners will be removed automatically.
However, it's important to note that the code inside these listeners can still cause memory leaks, for example if you have achieved the common JS memory leak pattern circular references.
Even in this normal case of a directive getting destroyed due to a view changing there are things you might need to manually clean up.
For example if you have registered a listener on $rootScope:
var unregisterFn = $rootScope.$on('anEvent', function () {});
scope.$on('$destroy', unregisterFn);
This is needed since $rootScope is never destroyed during the lifetime of the application.
The same goes if you are using another pub/sub implementation that doesn't automatically perform the necessary cleanup when the $scope is destroyed, or if your directive passes callbacks to services.
Another situation would be to cancel $interval/$timeout:
var promise = $interval(function () {}, 1000);
scope.$on('$destroy', function () {
$interval.cancel(promise);
});
If your directive attaches event handlers to elements for example outside the current view, you need to manually clean those up as well:
var windowClick = function () {
...
};
angular.element(window).on('click', windowClick);
scope.$on('$destroy', function () {
angular.element(window).off('click', windowClick);
});
These were some examples of what to do when directives are "destroyed" by Angular, for example by ng-view or ng-if.
If you have custom directives that manage the lifecycle of DOM elements etc. it will of course get more complex.
How can I use the python HTMLParser library to extract data from a specific div tag?
Have You tried BeautifulSoup ?
from bs4 import BeautifulSoup
soup = BeautifulSoup('<div id="remository">20</div>')
tag=soup.div
print(tag.string)
This gives You 20 on output.
Java JTable setting Column Width
JTable.AUTO_RESIZE_LAST_COLUMN is defined as "During all resize operations, apply adjustments to the last column only" which means you have to set the autoresizemode at the end of your code, otherwise setPreferredWidth() won't affect anything!
So in your case this would be the correct way:
table.getColumnModel().getColumn(0).setPreferredWidth(27);
table.getColumnModel().getColumn(1).setPreferredWidth(120);
table.getColumnModel().getColumn(2).setPreferredWidth(100);
table.getColumnModel().getColumn(3).setPreferredWidth(90);
table.getColumnModel().getColumn(4).setPreferredWidth(90);
table.getColumnModel().getColumn(6).setPreferredWidth(120);
table.getColumnModel().getColumn(7).setPreferredWidth(100);
table.getColumnModel().getColumn(8).setPreferredWidth(95);
table.getColumnModel().getColumn(9).setPreferredWidth(40);
table.getColumnModel().getColumn(10).setPreferredWidth(400);
table.setAutoResizeMode(JTable.AUTO_RESIZE_LAST_COLUMN);
How can I get the DateTime for the start of the week?
Putting it all together, with Globalization and allowing for specifying the first day of the week as part of the call we have
public static DateTime StartOfWeek ( this DateTime dt, DayOfWeek? firstDayOfWeek )
{
DayOfWeek fdow;
if ( firstDayOfWeek.HasValue )
{
fdow = firstDayOfWeek.Value;
}
else
{
System.Globalization.CultureInfo ci = System.Threading.Thread.CurrentThread.CurrentCulture;
fdow = ci.DateTimeFormat.FirstDayOfWeek;
}
int diff = dt.DayOfWeek - fdow;
if ( diff < 0 )
{
diff += 7;
}
return dt.AddDays( -1 * diff ).Date;
}
How do I use cascade delete with SQL Server?
ON DELETE CASCADE
It specifies that the child data is deleted when the parent data is deleted.
CREATE TABLE products
( product_id INT PRIMARY KEY,
product_name VARCHAR(50) NOT NULL,
category VARCHAR(25)
);
CREATE TABLE inventory
( inventory_id INT PRIMARY KEY,
product_id INT NOT NULL,
quantity INT,
min_level INT,
max_level INT,
CONSTRAINT fk_inv_product_id
FOREIGN KEY (product_id)
REFERENCES products (product_id)
ON DELETE CASCADE
);
For this foreign key, we have specified the ON DELETE CASCADE clause which tells SQL Server to delete the corresponding records in the child table when the data in the parent table is deleted. So in this example, if a product_id value is deleted from the products table, the corresponding records in the inventory table that use this product_id will also be deleted.
Automatically start forever (node) on system restart
Use the PM2
Which is the best option to run the server production server
What are the advantages of running your application this way?
PM2 will automatically restart your application if it crashes.
PM2 will keep a log of your unhandled exceptions - in this case, in a file at /home/safeuser/.pm2/logs/app-err.log.
With one command, PM2 can ensure that any applications it manages restart when the server reboots. Basically, your node application will start as a service.
How to apply font anti-alias effects in CSS?
Works the best. If you want to use it sitewide, without having to add this syntax to every class or ID, add the following CSS to your css body:
body {
-webkit-font-smoothing: antialiased;
text-shadow: 1px 1px 1px rgba(0,0,0,0.004);
background: url('./images/background.png');
text-align: left;
margin: auto;
}
Android - java.lang.SecurityException: Permission Denial: starting Intent
Similar to Olayinka's answer about the configuration file for ADT: I just had the same issue on IntelliJ's IdeaU v14.
I'm working through a tutorial that had me change the starting activity from MyActivity to MyListActivity (Which is a list of MyActivity). I started getting Permissions Denial.
After much trial, toil and pain: In .idea\workspace.xml:
...
<configuration default="false" name="MyApp" type="AndroidRunConfigurationType" factoryName="Android Application">
<module name="MyApp" />
<option name="ACTIVITY_CLASS" value="com.domain.MyApp.MyActivity" />
...
</configuration>
...
I changed the MyActivity to MyListActivity, reloaded the project and I'm off to a rolling start again.
Not sure which IDE you are using, but maybe your IDE is overriding or forcing a specific starting activity?
/etc/apt/sources.list" E212: Can't open file for writing
change user to root
sodu su -
browse to etc
vi sudoers
look for root user in user priviledge section. you will get it like
root ALL=(ALL:ALL) ALL
make same entry for your user name. if you username is 'myuser' then add
myuser ALL=(ALL:ALL) ALL
it will look like
root ALL=(ALL:ALL) ALL
myuser ALL=(ALL:ALL) ALL
save it. change root user to your user. now try the same where you were getting the sudoers issue
Cron and virtualenv
If you're on python and using a Conda Virtual Environment where your python script contains the shebang #!/usr/bin/env python the following works:
* * * * * cd /home/user/project && /home/user/anaconda3/envs/envname/bin/python script.py 2>&1
Additionally, if you want to capture any outputs in your script (e.g. print, errors, etc) you can use the following:
* * * * * cd /home/user/project && /home/user/anaconda3/envs/envname/bin/python script.py >> /home/user/folder/script_name.log 2>&1
Adding a y-axis label to secondary y-axis in matplotlib
For everyone stumbling upon this post because pandas gets mentioned,
you now have the very elegant and straighforward option of directly accessing the
secondary_y axis in pandas with ax.right_ax
So paraphrasing the example initially posted, you would write:
table = sql.read_frame(query,connection)
ax = table[[0, 1]].plot(ylim=(0,100), secondary_y=table[1])
ax.set_ylabel('$')
ax.right_ax.set_ylabel('Your second Y-Axis Label goes here!')
Property 'value' does not exist on type 'EventTarget'
Use currentValue instead, as the type of currentValue is EventTarget & HTMLInputElement.
How can I create an editable combo box in HTML/Javascript?
Was looking for an Answer as well, but all I could find was outdated.
This Issue is solved since HTML5: https://developer.mozilla.org/en-US/docs/Web/HTML/Element/datalist
<label>Choose a browser from this list:
<input list="browsers" name="myBrowser" /></label>
<datalist id="browsers">
<option value="Chrome">
<option value="Firefox">
<option value="Internet Explorer">
<option value="Opera">
<option value="Safari">
<option value="Microsoft Edge">
</datalist>
If I had not found that, I would have gone with this approach:
http://www.dhtmlgoodies.com/scripts/form_widget_editable_select/form_widget_editable_select.html
What is the size of a boolean variable in Java?
It's virtual machine dependent.
Printing PDFs from Windows Command Line
I had the similar problem with printing multiple PDF files in a row and found only workaround by using 2Printer software. Command line example to print PDF files:
2Printer.exe -s "C:\In\*.PDF" -prn "HP LasetJet 1100"
It is free for non-commercial use at http://doc2prn.com/
Google Maps API Multiple Markers with Infowindows
function setMarkers(map,locations){
for (var i = 0; i < locations.length; i++)
{
var loan = locations[i][0];
var lat = locations[i][1];
var long = locations[i][2];
var add = locations[i][3];
latlngset = new google.maps.LatLng(lat, long);
var marker = new google.maps.Marker({
map: map, title: loan , position: latlngset
});
map.setCenter(marker.getPosition());
marker.content = "<h3>Loan Number: " + loan + '</h3>' + "Address: " + add;
google.maps.events.addListener(marker,'click', function(map,marker){
map.infowindow.setContent(marker.content);
map.infowindow.open(map,marker);
});
}
}
Then move var infowindow = new google.maps.InfoWindow() to the initialize() function:
function initialize() {
var myOptions = {
center: new google.maps.LatLng(33.890542, 151.274856),
zoom: 8,
mapTypeId: google.maps.MapTypeId.ROADMAP
};
var map = new google.maps.Map(document.getElementById("default"),
myOptions);
map.infowindow = new google.maps.InfoWindow();
setMarkers(map,locations)
}
Removing spaces from a variable input using PowerShell 4.0
The Replace operator means Replace something with something else; do not be confused with removal functionality.
Also you should send the result processed by the operator to a variable or to another operator. Neither .Replace(), nor -replace modifies the original variable.
To remove all spaces, use 'Replace any space symbol with empty string'
$string = $string -replace '\s',''
To remove all spaces at the beginning and end of the line, and replace all double-and-more-spaces or tab symbols to spacebar symbol, use
$string = $string -replace '(^\s+|\s+$)','' -replace '\s+',' '
or the more native System.String method
$string = $string.Trim()
Regexp is preferred, because ' ' means only 'spacebar' symbol, and '\s' means 'spacebar, tab and other space symbols'. Note that $string.Replace() does 'Normal' replace, and $string -replace does RegEx replace, which is more heavy but more functional.
Note that RegEx have some special symbols like dot (.), braces ([]()), slashes (\), hats (^), mathematical signs (+-) or dollar signs ($) that need do be escaped. ( 'my.space.com' -replace '\.','-' => 'my-space-com'. A dollar sign with a number (ex $1) must be used on a right part with care
'2033' -replace '(\d+)',$( 'Data: $1')
Data: 2033
UPDATE: You can also use $str = $str.Trim(), along with TrimEnd() and TrimStart(). Read more at System.String MSDN page.
How to get the selected value from RadioButtonList?
Technically speaking the answer is correct, but there is a potential problem remaining.
string test = rb.SelectedValue is an object and while this implicit cast works. It may not work correction if you were sending it to another method (and granted this may depend on the version of framework, I am unsure) it may not recognize the value.
string test = rb.SelectedValue; //May work fine
SomeMethod(rb.SelectedValue);
where SomeMethod is expecting a string may not.
Sadly the rb.SelectedValue.ToString(); can save a few unexpected issues.
What is __main__.py?
What is the __main__.py file for?
When creating a Python module, it is common to make the module execute some functionality (usually contained in a main function) when run as the entry point of the program. This is typically done with the following common idiom placed at the bottom of most Python files:
if __name__ == '__main__':
# execute only if run as the entry point into the program
main()
You can get the same semantics for a Python package with __main__.py, which might have the following structure:
.
+-- demo
+-- __init__.py
+-- __main__.py
To see this, paste the below into a Python 3 shell:
from pathlib import Path
demo = Path.cwd() / 'demo'
demo.mkdir()
(demo / '__init__.py').write_text("""
print('demo/__init__.py executed')
def main():
print('main() executed')
""")
(demo / '__main__.py').write_text("""
print('demo/__main__.py executed')
from demo import main
main()
""")
We can treat demo as a package and actually import it, which executes the top-level code in the __init__.py (but not the main function):
>>> import demo
demo/__init__.py executed
When we use the package as the entry point to the program, we perform the code in the __main__.py, which imports the __init__.py first:
$ python -m demo
demo/__init__.py executed
demo/__main__.py executed
main() executed
You can derive this from the documentation. The documentation says:
__main__— Top-level script environment
'__main__'is the name of the scope in which top-level code executes. A module’s__name__is set equal to'__main__'when read from standard input, a script, or from an interactive prompt.A module can discover whether or not it is running in the main scope by checking its own
__name__, which allows a common idiom for conditionally executing code in a module when it is run as a script or withpython -mbut not when it is imported:if __name__ == '__main__': # execute only if run as a script main()For a package, the same effect can be achieved by including a
__main__.pymodule, the contents of which will be executed when the module is run with-m.
Zipped
You can also zip up this directory, including the __main__.py, into a single file and run it from the command line like this - but note that zipped packages can't execute sub-packages or submodules as the entry point:
from pathlib import Path
demo = Path.cwd() / 'demo2'
demo.mkdir()
(demo / '__init__.py').write_text("""
print('demo2/__init__.py executed')
def main():
print('main() executed')
""")
(demo / '__main__.py').write_text("""
print('demo2/__main__.py executed')
from __init__ import main
main()
""")
Note the subtle change - we are importing main from __init__ instead of demo2 - this zipped directory is not being treated as a package, but as a directory of scripts. So it must be used without the -m flag.
Particularly relevant to the question - zipapp causes the zipped directory to execute the __main__.py by default - and it is executed first, before __init__.py:
$ python -m zipapp demo2 -o demo2zip
$ python demo2zip
demo2/__main__.py executed
demo2/__init__.py executed
main() executed
Note again, this zipped directory is not a package - you cannot import it either.
The Import android.support.v7 cannot be resolved
Go to your project in the navigator, right click on properties.
Go to the Java Build Path tab on the left.
Go to the libraries tab on top.
Click add external jars.
Go to your ADT Bundle folder, go to sdk/extras/android/support/v7/appcompat/libs.
Select the file android-support-v7-appcompat.jar
Go to order and export and check the box next to your new jar.
Click ok.
ipad safari: disable scrolling, and bounce effect?
Solution tested, works on iOS 12.x
This is problem I was encountering :
<body> <!-- the whole body can be scroll vertically -->
<article>
<my_gallery> <!-- some picture gallery, can be scroll horizontally -->
</my_gallery>
</article>
</body>
While I scrolling my gallery, the body always scrolling itself (human swipe aren't really horizontal), that makes my gallery useless.
Here's what I did while my gallery start scrolling
var html=jQuery('html');
html.css('overflow-y', 'hidden');
//above code works on mobile Chrome/Edge/Firefox
document.ontouchmove=function(e){e.preventDefault();} //Add this only for mobile Safari
And when my gallery end its scrolling...
var html=jQuery('html');
html.css('overflow-y', 'scroll');
document.ontouchmove=function(e){return true;}
Hope this helps~
Choosing a file in Python with simple Dialog
With EasyGui:
import easygui
print(easygui.fileopenbox())
To install:
pip install easygui
Demo:
import easygui
easygui.egdemo()
Android: findviewbyid: finding view by id when view is not on the same layout invoked by setContentView
try:
Activity parentActivity = this.getParent();
if (parentActivity != null)
{
View landmarkEditNameView = (EditText) parentActivity.findViewById(R.id. landmark_name_dialog_edit);
}
Python 'If not' syntax
Yes, if bar is not None is more explicit, and thus better, assuming it is indeed what you want. That's not always the case, there are subtle differences: if not bar: will execute if bar is any kind of zero or empty container, or False.
Many people do use not bar where they really do mean bar is not None.
How can I get Android Wifi Scan Results into a list?
Find a complete working example below:
The code by @Android is very good but has few issues, namely:
- Populating to ListView code needs to be moved to onReceive of BroadCastReceiver where only the result will be available. In the case result is obtained at 2nd attempt.
- BroadCastReceiver needs to be unregistered after the results are obtained.
size = size -1seems unnecessary.
Find below the modified code of @Android as a working example:
WifiScanner.java which is the Main Activity
package com.arjunandroid.wifiscanner;
import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.net.wifi.ScanResult;
import android.net.wifi.WifiManager;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.List;
public class WifiScanner extends Activity implements View.OnClickListener{
WifiManager wifi;
ListView lv;
Button buttonScan;
int size = 0;
List<ScanResult> results;
String ITEM_KEY = "key";
ArrayList<String> arraylist = new ArrayList<>();
ArrayAdapter adapter;
/* Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
getActionBar().setTitle("Widhwan Setup Wizard");
setContentView(R.layout.activity_wifi_scanner);
buttonScan = (Button) findViewById(R.id.scan);
buttonScan.setOnClickListener(this);
lv = (ListView)findViewById(R.id.wifilist);
wifi = (WifiManager) getApplicationContext().getSystemService(Context.WIFI_SERVICE);
if (wifi.isWifiEnabled() == false)
{
Toast.makeText(getApplicationContext(), "wifi is disabled..making it enabled", Toast.LENGTH_LONG).show();
wifi.setWifiEnabled(true);
}
this.adapter = new ArrayAdapter<>(this,android.R.layout.simple_list_item_1,arraylist);
lv.setAdapter(this.adapter);
scanWifiNetworks();
}
public void onClick(View view)
{
scanWifiNetworks();
}
private void scanWifiNetworks(){
arraylist.clear();
registerReceiver(wifi_receiver, new IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION));
wifi.startScan();
Log.d("WifScanner", "scanWifiNetworks");
Toast.makeText(this, "Scanning....", Toast.LENGTH_SHORT).show();
}
BroadcastReceiver wifi_receiver= new BroadcastReceiver()
{
@Override
public void onReceive(Context c, Intent intent)
{
Log.d("WifScanner", "onReceive");
results = wifi.getScanResults();
size = results.size();
unregisterReceiver(this);
try
{
while (size >= 0)
{
size--;
arraylist.add(results.get(size).SSID);
adapter.notifyDataSetChanged();
}
}
catch (Exception e)
{
Log.w("WifScanner", "Exception: "+e);
}
}
};
}
activity_wifi_scanner.xml which is the layout file for the Activity
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:padding="10dp"
android:layout_width="match_parent"
android:layout_height="match_parent">
<ListView
android:id="@+id/wifilist"
android:layout_width="match_parent"
android:layout_height="312dp"
android:layout_weight="0.97" />
<Button
android:id="@+id/scan"
android:layout_width="match_parent"
android:layout_height="50dp"
android:layout_gravity="bottom"
android:layout_margin="15dp"
android:background="@android:color/holo_green_light"
android:text="Scan Again" />
</LinearLayout>
Also as mentioned above, do not forget to add Wifi permissions in the AndroidManifest.xml
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />
What is a reasonable code coverage % for unit tests (and why)?
Code coverage is great, but functionality coverage is even better. I don't believe in covering every single line I write. But I do believe in writing 100% test coverage of all the functionality I want to provide (even for the extra cool features I came with myself and which were not discussed during the meetings).
I don't care if I would have code which is not covered in tests, but I would care if I would refactor my code and end up having a different behaviour. Therefore, 100% functionality coverage is my only target.
iCheck check if checkbox is checked
Use following code to check if iCheck is checked or not using single method.
$('Selector').on('ifChanged', function(event){
//Check if checkbox is checked or not
var checkboxChecked = $(this).is(':checked');
if(checkboxChecked) {
alert("checked");
}else{
alert("un-checked");
}
});
Best way to store passwords in MYSQL database
Passwords in the database should be stored encrypted. One way encryption (hashing) is recommended, such as SHA2, SHA2, WHIRLPOOL, bcrypt DELETED: MD5 or SHA1. (those are older, vulnerable
In addition to that you can use additional per-user generated random string - 'salt':
$salt = MD5($this->createSalt());
$Password = SHA2($postData['Password'] . $salt);
createSalt() in this case is a function that generates a string from random characters.
EDIT: or if you want more security, you can even add 2 salts: $salt1 . $pass . $salt2
Another security measure you can take is user inactivation: after 5 (or any other number) incorrect login attempts user is blocked for x minutes (15 mins lets say). It should minimize success of brute force attacks.
How to query data out of the box using Spring data JPA by both Sort and Pageable?
public List<Model> getAllData(Pageable pageable){
List<Model> models= new ArrayList<>();
modelRepository.findAllByOrderByIdDesc(pageable).forEach(models::add);
return models;
}
how do I create an infinite loop in JavaScript
By omitting all parts of the head, the loop can also become infinite:
for (;;) {}
Java Delegates?
Have you read this :
Delegates are a useful construct in event-based systems. Essentially Delegates are objects that encode a method dispatch on a specified object. This document shows how java inner classes provide a more generic solution to such problems.
What is a Delegate? Really it is very similar to a pointer to member function as used in C++. But a delegate contains the target object alongwith the method to be invoked. Ideally it would be nice to be able to say:
obj.registerHandler(ano.methodOne);
..and that the method methodOne would be called on ano when some specific event was received.
This is what the Delegate structure achieves.
Java Inner Classes
It has been argued that Java provides this functionality via anonymous inner classes and thus does not need the additional Delegate construct.
obj.registerHandler(new Handler() {
public void handleIt(Event ev) {
methodOne(ev);
}
} );
At first glance this seems correct but at the same time a nuisance. Because for many event processing examples the simplicity of the Delegates syntax is very attractive.
General Handler
However, if event-based programming is used in a more pervasive manner, say, for example, as a part of a general asynchronous programming environment, there is more at stake.
In such a general situation, it is not sufficient to include only the target method and target object instance. In general there may be other parameters required, that are determined within the context when the event handler is registered.
In this more general situation, the java approach can provide a very elegant solution, particularly when combined with use of final variables:
void processState(final T1 p1, final T2 dispatch) {
final int a1 = someCalculation();
m_obj.registerHandler(new Handler() {
public void handleIt(Event ev) {
dispatch.methodOne(a1, ev, p1);
}
} );
}
final * final * final
Got your attention?
Note that the final variables are accessible from within the anonymous class method definitions. Be sure to study this code carefully to understand the ramifications. This is potentially a very powerful technique. For example, it can be used to good effect when registering handlers in MiniDOM and in more general situations.
By contrast, the Delegate construct does not provide a solution for this more general requirement, and as such should be rejected as an idiom on which designs can be based.
Ant: How to execute a command for each file in directory?
Here is way to do this using javascript and the ant scriptdef task, you don't need ant-contrib for this code to work since scriptdef is a core ant task.
<scriptdef name="bzip2-files" language="javascript">
<element name="fileset" type="fileset"/>
<![CDATA[
importClass(java.io.File);
filesets = elements.get("fileset");
for (i = 0; i < filesets.size(); ++i) {
fileset = filesets.get(i);
scanner = fileset.getDirectoryScanner(project);
scanner.scan();
files = scanner.getIncludedFiles();
for( j=0; j < files.length; j++) {
var basedir = fileset.getDir(project);
var filename = files[j];
var src = new File(basedir, filename);
var dest= new File(basedir, filename + ".bz2");
bzip2 = self.project.createTask("bzip2");
bzip2.setSrc( src);
bzip2.setDestfile(dest );
bzip2.execute();
}
}
]]>
</scriptdef>
<bzip2-files>
<fileset id="test" dir="upstream/classpath/jars/development">
<include name="**/*.jar" />
</fileset>
</bzip2-files>
Why doesn't Dijkstra's algorithm work for negative weight edges?
The other answers so far demonstrate pretty well why Dijkstra's algorithm cannot handle negative weights on paths.
But the question itself is maybe based on a wrong understanding of the weight of paths. If negative weights on paths would be allowed in pathfinding algorithms in general, then you would get permanent loops that would not stop.
Consider this:
A <- 5 -> B <- (-1) -> C <- 5 -> D
What is the optimal path between A and D?
Any pathfinding algorithm would have to continuously loop between B and C because doing so would reduce the weight of the total path. So allowing negative weights for a connection would render any pathfindig algorithm moot, maybe except if you limit each connection to be used only once.
So, to explain this in more detail, consider the following paths and weights:
Path | Total weight
ABCD | 9
ABCBCD | 7
ABCBCBCD | 5
ABCBCBCBCD | 3
ABCBCBCBCBCD | 1
ABCBCBCBCBCBCD | -1
...
So, what's the perfect path? Any time the algorithm adds a BC step, it reduces the total weight by 2.
So the optimal path is A (BC) D with the BC part being looped forever.
Since Dijkstra's goal is to find the optimal path (not just any path), it, by definition, cannot work with negative weights, since it cannot find the optimal path.
Dijkstra will actually not loop, since it keeps a list of nodes that it has visited. But it will not find a perfect path, but instead just any path.
How to try convert a string to a Guid
use code like this:
new Guid("9D2B0228-4D0D-4C23-8B49-01A698857709")
instead of "9D2B0228-4D0D-4C23-8B49-01A698857709" you can set your string value
Image re-size to 50% of original size in HTML
The percentage setting does not take into account the original image size. From w3schools :
In HTML 4.01, the width could be defined in pixels or in % of the containing element. In HTML5, the value must be in pixels.
Also, good practice advice from the same source :
Tip: Downsizing a large image with the height and width attributes forces a user to download the large image (even if it looks small on the page). To avoid this, rescale the image with a program before using it on a page.
Convert to absolute value in Objective-C
Depending on the type of your variable, one of abs(int), labs(long), llabs(long long), imaxabs(intmax_t), fabsf(float), fabs(double), or fabsl(long double).
Those functions are all part of the C standard library, and so are present both in Objective-C and plain C (and are generally available in C++ programs too.)
(Alas, there is no habs(short) function. Or scabs(signed char) for that matter...)
Apple's and GNU's Objective-C headers also include an ABS() macro which is type-agnostic. I don't recommend using ABS() however as it is not guaranteed to be side-effect-safe. For instance, ABS(a++) will have an undefined result.
If you're using C++ or Objective-C++, you can bring in the <cmath> header and use std::abs(), which is templated for all the standard integer and floating-point types.
How to get form input array into PHP array
They are already in arrays: $name is an array, as is $email
So all you need to do is add a bit of processing to attack both arrays:
$name = $_POST['name'];
$email = $_POST['account'];
foreach( $name as $key => $n ) {
print "The name is ".$n." and email is ".$email[$key].", thank you\n";
}
To handle more inputs, just extend the pattern:
$name = $_POST['name'];
$email = $_POST['account'];
$location = $_POST['location'];
foreach( $name as $key => $n ) {
print "The name is ".$n.", email is ".$email[$key].
", and location is ".$location[$key].". Thank you\n";
}
Spark - repartition() vs coalesce()
Repartition: Shuffle the data into a NEW number of partitions.
Eg. Initial data frame is partitioned in 200 partitions.
df.repartition(500): Data will be shuffled from 200 partitions to new 500 partitions.
Coalesce: Shuffle the data into existing number of partitions.
df.coalesce(5): Data will be shuffled from remaining 195 partitions to 5 existing partitions.
How to return a specific status code and no contents from Controller?
The best way to do it is:
return this.StatusCode(StatusCodes.Status418ImATeapot, "Error message");
'StatusCodes' has every kind of return status and you can see all of them in this link https://httpstatuses.com/
Once you choose your StatusCode, return it with a message.
How do I select which GPU to run a job on?
You can also set the GPU in the command line so that you don't need to hard-code the device into your script (which may fail on systems without multiple GPUs). Say you want to run your script on GPU number 5, you can type the following on the command line and it will run your script just this once on GPU#5:
CUDA_VISIBLE_DEVICES=5, python test_script.py
How print out the contents of a HashMap<String, String> in ascending order based on its values?
the for loop of for(Map.Entry entry: codes.entrySet()) didn't work for me. Used Iterator instead.
Iterator<Map.Entry<String, String>> i = codes.entrySet().iterator();
while(i.hasNext()){
String key = i.next().getKey();
System.out.println(key+", "+codes.get(key));
}
How to extract img src, title and alt from html using php?
Here is THE solution, in PHP:
Just download QueryPath, and then do as follows:
$doc= qp($myHtmlDoc);
foreach($doc->xpath('//img') as $img) {
$src= $img->attr('src');
$title= $img->attr('title');
$alt= $img->attr('alt');
}
That's it, you're done !
What do these operators mean (** , ^ , %, //)?
You are correct that ** is the power function.
^ is bitwise XOR.
% is indeed the modulus operation, but note that for positive numbers, x % m = x whenever m > x. This follows from the definition of modulus. (Additionally, Python specifies x % m to have the sign of m.)
// is a division operation that returns an integer by discarding the remainder. This is the standard form of division using the / in most programming languages. However, Python 3 changed the behavior of / to perform floating-point division even if the arguments are integers. The // operator was introduced in Python 2.6 and Python 3 to provide an integer-division operator that would behave consistently between Python 2 and Python 3. This means:
| context | `/` behavior | `//` behavior |
---------------------------------------------------------------------------
| floating-point arguments, Python 2 & 3 | float division | int divison |
---------------------------------------------------------------------------
| integer arguments, python 2 | int division | int division |
---------------------------------------------------------------------------
| integer arguments, python 3 | float division | int division |
For more details, see this question: Division in Python 2.7. and 3.3
how to import csv data into django models
You want to use the csv module that is part of the python language and you should use Django's get_or_create method
with open(path) as f:
reader = csv.reader(f)
for row in reader:
_, created = Teacher.objects.get_or_create(
first_name=row[0],
last_name=row[1],
middle_name=row[2],
)
# creates a tuple of the new object or
# current object and a boolean of if it was created
In my example the model teacher has three attributes first_name, last_name and middle_name.
Django documentation of get_or_create method
Invariant Violation: Could not find "store" in either the context or props of "Connect(SportsDatabase)"
Possible solution that worked for me with jest
import React from "react";
import { shallow } from "enzyme";
import { Provider } from "react-redux";
import configureMockStore from "redux-mock-store";
import TestPage from "../TestPage";
const mockStore = configureMockStore();
const store = mockStore({});
describe("Testpage Component", () => {
it("should render without throwing an error", () => {
expect(
shallow(
<Provider store={store}>
<TestPage />
</Provider>
).exists(<h1>Test page</h1>)
).toBe(true);
});
});
Batch files : How to leave the console window open
I just written last line as Pause it worked fine with both .bat and .cmd. It will display message also as 'Press any key to continue'.
Angular - Use pipes in services and components
This answer is now outdated
recommend using DI approach from other answers instead of this approach
Original answer:
You should be able to use the class directly
new DatePipe().transform(myDate, 'yyyy-MM-dd');
For instance
var raw = new Date(2015, 1, 12);
var formatted = new DatePipe().transform(raw, 'yyyy-MM-dd');
expect(formatted).toEqual('2015-02-12');
Is it possible to create static classes in PHP (like in C#)?
you can have those "static"-like classes. but i suppose, that something really important is missing: in php you don't have an app-cycle, so you won't get a real static (or singleton) in your whole application...
see Singleton in PHP
"Gradle Version 2.10 is required." Error
For Android studio v2.1
Follow these easy steps from images.
Go "File" and click "Project structure".
Then select "Project" from left menu and then change "Gradle version" to the version your sdk manager has installed. In my case it is 2.10 so i change version to 2.10 and then click on "Ok". And then android studio automatically do gradle sync again and error was fixed.
How to store images in mysql database using php
I found the answer, For those who are looking for the same thing here is how I did it. You should not consider uploading images to the database instead you can store the name of the uploaded file in your database and then retrieve the file name and use it where ever you want to display the image.
HTML CODE
<input type="file" name="imageUpload" id="imageUpload">
PHP CODE
if(isset($_POST['submit'])) {
//Process the image that is uploaded by the user
$target_dir = "uploads/";
$target_file = $target_dir . basename($_FILES["imageUpload"]["name"]);
$uploadOk = 1;
$imageFileType = pathinfo($target_file,PATHINFO_EXTENSION);
if (move_uploaded_file($_FILES["imageUpload"]["tmp_name"], $target_file)) {
echo "The file ". basename( $_FILES["imageUpload"]["name"]). " has been uploaded.";
} else {
echo "Sorry, there was an error uploading your file.";
}
$image=basename( $_FILES["imageUpload"]["name"],".jpg"); // used to store the filename in a variable
//storind the data in your database
$query= "INSERT INTO items VALUES ('$id','$title','$description','$price','$value','$contact','$image')";
mysql_query($query);
require('heading.php');
echo "Your add has been submited, you will be redirected to your account page in 3 seconds....";
header( "Refresh:3; url=account.php", true, 303);
}
CODE TO DISPLAY THE IMAGE
while($row = mysql_fetch_row($result)) {
echo "<tr>";
echo "<td><img src='uploads/$row[6].jpg' height='150px' width='300px'></td>";
echo "</tr>\n";
}
how do I query sql for a latest record date for each user
I used this way to take the last record for each user that I have on my table. It was a query to get last location for salesman as per recent time detected on PDA devices.
CREATE FUNCTION dbo.UsersLocation()
RETURNS TABLE
AS
RETURN
Select GS.UserID, MAX(GS.UTCDateTime) 'LastDate'
From USERGPS GS
where year(GS.UTCDateTime) = YEAR(GETDATE())
Group By GS.UserID
GO
select gs.UserID, sl.LastDate, gs.Latitude , gs.Longitude
from USERGPS gs
inner join USER s on gs.SalesManNo = s.SalesmanNo
inner join dbo.UsersLocation() sl on gs.UserID= sl.UserID and gs.UTCDateTime = sl.LastDate
order by LastDate desc
Remove URL parameters without refreshing page
Better solution :
window.history.pushState(null, null, window.location.pathname);
Twitter bootstrap collapse: change display of toggle button
Some may take issue with changing the Bootstrap js (and perhaps validly so) but here is a two line approach to achieving this.
In bootstrap.js, look for the Collapse.prototype.show function and modify the this.$trigger call to add the html change as follows:
this.$trigger
.removeClass('collapsed')
.attr('aria-expanded', true)
.html('Collapse')
Likewise in the Collapse.prototype.hide function change it to
this.$trigger
.addClass('collapsed')
.attr('aria-expanded', false)
.html('Expand')
This will toggle the text between "Collapse" when everything is expanded and "Expand" when everything is collapsed.
Two lines. Done.
EDIT: longterm this won't work. bootstrap.js is part of a Nuget package so I don't think it was propogating my change to the server. As mentioned previously, not best practice anyway to edit bootstrap.js, so I implemented PSL's solution which worked great. Nonetheless, my solution will work locally if you need something quick just to try it out.
Java: how to convert HashMap<String, Object> to array
hashMap.keySet().toArray(); // returns an array of keys
hashMap.values().toArray(); // returns an array of values
Edit
It should be noted that the ordering of both arrays may not be the same, See oxbow_lakes answer for a better approach for iteration when the pair key/values are needed.
Conda command not found
I had the same issue. I just closed and reopened the terminal, and it worked. That was because I installed anaconda with the terminal open.
What is the __del__ method, How to call it?
I wrote up the answer for another question, though this is a more accurate question for it.
How do constructors and destructors work?
Here is a slightly opinionated answer.
Don't use __del__. This is not C++ or a language built for destructors. The __del__ method really should be gone in Python 3.x, though I'm sure someone will find a use case that makes sense. If you need to use __del__, be aware of the basic limitations per http://docs.python.org/reference/datamodel.html:
__del__is called when the garbage collector happens to be collecting the objects, not when you lose the last reference to an object and not when you executedel object.__del__is responsible for calling any__del__in a superclass, though it is not clear if this is in method resolution order (MRO) or just calling each superclass.- Having a
__del__means that the garbage collector gives up on detecting and cleaning any cyclic links, such as losing the last reference to a linked list. You can get a list of the objects ignored from gc.garbage. You can sometimes use weak references to avoid the cycle altogether. This gets debated now and then: see http://mail.python.org/pipermail/python-ideas/2009-October/006194.html. - The
__del__function can cheat, saving a reference to an object, and stopping the garbage collection. - Exceptions explicitly raised in
__del__are ignored. __del__complements__new__far more than__init__. This gets confusing. See http://www.algorithm.co.il/blogs/programming/python-gotchas-1-del-is-not-the-opposite-of-init/ for an explanation and gotchas.__del__is not a "well-loved" child in Python. You will notice that sys.exit() documentation does not specify if garbage is collected before exiting, and there are lots of odd issues. Calling the__del__on globals causes odd ordering issues, e.g., http://bugs.python.org/issue5099. Should__del__called even if the__init__fails? See http://mail.python.org/pipermail/python-dev/2000-March/thread.html#2423 for a long thread.
But, on the other hand:
__del__means you do not forget to call a close statement. See http://eli.thegreenplace.net/2009/06/12/safely-using-destructors-in-python/ for a pro__del__viewpoint. This is usually about freeing ctypes or some other special resource.
And my pesonal reason for not liking the __del__ function.
- Everytime someone brings up
__del__it devolves into thirty messages of confusion. - It breaks these items in the Zen of Python:
- Simple is better than complicated.
- Special cases aren't special enough to break the rules.
- Errors should never pass silently.
- In the face of ambiguity, refuse the temptation to guess.
- There should be one – and preferably only one – obvious way to do it.
- If the implementation is hard to explain, it's a bad idea.
So, find a reason not to use __del__.
How to install a specific JDK on Mac OS X?
Check this awesome tool sdkman to manage your jdk and other jdk related tools with great ease!
e.g.
$sdk list java
$sdk install java <VERSION>
Model summary in pytorch
While you will not get as detailed information about the model as in Keras' model.summary, simply printing the model will give you some idea about the different layers involved and their specifications.
For instance:
from torchvision import models
model = models.vgg16()
print(model)
The output in this case would be something as follows:
VGG (
(features): Sequential (
(0): Conv2d(3, 64, kernel_size=(3, 3), stride=(1, 1), padding=(1, 1))
(1): ReLU (inplace)
(2): Conv2d(64, 64, kernel_size=(3, 3), stride=(1, 1), padding=(1, 1))
(3): ReLU (inplace)
(4): MaxPool2d (size=(2, 2), stride=(2, 2), dilation=(1, 1))
(5): Conv2d(64, 128, kernel_size=(3, 3), stride=(1, 1), padding=(1, 1))
(6): ReLU (inplace)
(7): Conv2d(128, 128, kernel_size=(3, 3), stride=(1, 1), padding=(1, 1))
(8): ReLU (inplace)
(9): MaxPool2d (size=(2, 2), stride=(2, 2), dilation=(1, 1))
(10): Conv2d(128, 256, kernel_size=(3, 3), stride=(1, 1), padding=(1, 1))
(11): ReLU (inplace)
(12): Conv2d(256, 256, kernel_size=(3, 3), stride=(1, 1), padding=(1, 1))
(13): ReLU (inplace)
(14): Conv2d(256, 256, kernel_size=(3, 3), stride=(1, 1), padding=(1, 1))
(15): ReLU (inplace)
(16): MaxPool2d (size=(2, 2), stride=(2, 2), dilation=(1, 1))
(17): Conv2d(256, 512, kernel_size=(3, 3), stride=(1, 1), padding=(1, 1))
(18): ReLU (inplace)
(19): Conv2d(512, 512, kernel_size=(3, 3), stride=(1, 1), padding=(1, 1))
(20): ReLU (inplace)
(21): Conv2d(512, 512, kernel_size=(3, 3), stride=(1, 1), padding=(1, 1))
(22): ReLU (inplace)
(23): MaxPool2d (size=(2, 2), stride=(2, 2), dilation=(1, 1))
(24): Conv2d(512, 512, kernel_size=(3, 3), stride=(1, 1), padding=(1, 1))
(25): ReLU (inplace)
(26): Conv2d(512, 512, kernel_size=(3, 3), stride=(1, 1), padding=(1, 1))
(27): ReLU (inplace)
(28): Conv2d(512, 512, kernel_size=(3, 3), stride=(1, 1), padding=(1, 1))
(29): ReLU (inplace)
(30): MaxPool2d (size=(2, 2), stride=(2, 2), dilation=(1, 1))
)
(classifier): Sequential (
(0): Dropout (p = 0.5)
(1): Linear (25088 -> 4096)
(2): ReLU (inplace)
(3): Dropout (p = 0.5)
(4): Linear (4096 -> 4096)
(5): ReLU (inplace)
(6): Linear (4096 -> 1000)
)
)
Now you could, as mentioned by Kashyap, use the state_dict method to get the weights of the different layers. But using this listing of the layers would perhaps provide more direction is creating a helper function to get that Keras like model summary! Hope this helps!
Adding a directory to the PATH environment variable in Windows
Aside from all the answers, if you want a nice GUI tool to edit your Windows environment variables you can use Rapid Environment Editor.
Try it! It's safe to use and is awesome!
How to set JVM parameters for Junit Unit Tests?
Parameters can be set on the fly also.
mvn test -DargLine="-Dsystem.test.property=test"
See http://www.cowtowncoder.com/blog/archives/2010/04/entry_385.html
What is the C# version of VB.net's InputDialog?
Add reference to Microsoft.VisualBasic and use this function:
string response = Microsoft.VisualBasic.Interaction.InputBox("What's 1+1?", "Title", "2", 0, 0);
The last 2 number is an X/Y position to display the input dialog.
Use CSS to automatically add 'required field' asterisk to form inputs
A similar outcome could be achieved by using a background image of a picture of an asterisk and setting the background of the label/input/the outer div and a padding of the size of the asterisk image. Something like this:
.required input {
padding-right: 25px;
background-image: url(...);
background-position: right top;
}
This will put the asterisk INSIDE the text box, but putting the same on div.required instead of .required input will probably be more what you're looking for, if a little less elegant.
This method doesn't require an additional input.
Java List.add() UnsupportedOperationException
Many of the List implementation support limited support to add/remove, and Arrays.asList(membersArray) is one of that. You need to insert the record in java.util.ArrayList or use the below approach to convert into ArrayList.
With the minimal change in your code, you can do below to convert a list to ArrayList. The first solution is having a minimum change in your solution, but the second one is more optimized, I guess.
String[] membersArray = request.getParameterValues('members');
ArrayList<String> membersList = new ArrayList<>(Arrays.asList(membersArray));
OR
String[] membersArray = request.getParameterValues('members');
ArrayList<String> membersList = Stream.of(membersArray).collect(Collectors.toCollection(ArrayList::new));
Sending "User-agent" using Requests library in Python
The user-agent should be specified as a field in the header.
Here is a list of HTTP header fields, and you'd probably be interested in request-specific fields, which includes User-Agent.
If you're using requests v2.13 and newer
The simplest way to do what you want is to create a dictionary and specify your headers directly, like so:
import requests
url = 'SOME URL'
headers = {
'User-Agent': 'My User Agent 1.0',
'From': '[email protected]' # This is another valid field
}
response = requests.get(url, headers=headers)
If you're using requests v2.12.x and older
Older versions of requests clobbered default headers, so you'd want to do the following to preserve default headers and then add your own to them.
import requests
url = 'SOME URL'
# Get a copy of the default headers that requests would use
headers = requests.utils.default_headers()
# Update the headers with your custom ones
# You don't have to worry about case-sensitivity with
# the dictionary keys, because default_headers uses a custom
# CaseInsensitiveDict implementation within requests' source code.
headers.update(
{
'User-Agent': 'My User Agent 1.0',
}
)
response = requests.get(url, headers=headers)
Using Camera in the Android emulator
Does not seem like it, but android recognises a webcam as a device. Every time I run the emulator my webcam's active light comes on.
Can the Android layout folder contain subfolders?
Check Bash Flatten Folder script that converts folder hierarchy to a single folder
How to get a password from a shell script without echoing
You can also prompt for a password without setting a variable in the current shell by doing something like this:
$(read -s;echo $REPLY)
For instance:
my-command --set password=$(read -sp "Password: ";echo $REPLY)
You can add several of these prompted values with line break, doing this:
my-command --set user=$(read -sp "`echo $'\n '`User: ";echo $REPLY) --set password=$(read -sp "`echo $'\n '`Password: ";echo $REPLY)
Port 80 is being used by SYSTEM (PID 4), what is that?
None of these worked for me. I had to go to a SuperUser question.
If it is a System Process—PID 4—you need to disable the HTTP.sys driver which is started on demand by another service, such as Windows Remote Management or Print Spooler on Windows 7 or 2008.
There is two ways to disable it but the first one is safer:
Go to device manager, select “show hidden devices” from menu/view, go to “Non-Plug and Play Driver”/HTTP, double click it to disable it (or set it to manual, some services depended on it).
Reboot and use
netstat -nao | find ":80"to check if 80 is still used.
This is the one that worked for me!
Can't start Eclipse - Java was started but returned exit code=13
The solution is simple: Put the "eclipse" folder on "C:/Program Files". If it does not work, put it in "C:/Program Files (x86)".
Creating a div element inside a div element in javascript
'b' should be in capital letter in document.getElementById modified code jsfiddle
function test()
{
var element = document.createElement("div");
element.appendChild(document.createTextNode('The man who mistook his wife for a hat'));
document.getElementById('lc').appendChild(element);
//document.body.appendChild(element);
}
@angular/material/index.d.ts' is not a module
Do npm i -g @angular/material --save to solve the problem
Better way to set distance between flexbox items
Well, the simplest solution regarding to your CSS, imo, is to add spacers into HTML:
<div id='box'>
<div class='item'></div>
<div style='width: 5px;'></div>
<div class='item'></div>
<div class='item'></div>
<div class='item'></div>
</div>
so, you may control it with inline-style or class names.. sometimes, it's also possible to do spacing with padding.
Postgresql 9.2 pg_dump version mismatch
** after install postgres version is match(9.2) Create a symbolic link or new shortcut
**- on '/usr/bin'
syntag is = sudo ln -s [path for use] [new shortcut name]
example
sudo ln -s /usr/lib/postgresql/9.2/bin/pg_dump new_pg_dump
-- how to call : new_pg_dump -h 192.168.9.88 -U postgres database
Firebase (FCM) how to get token
If are using some auth function of firebase, you can take token using this:
//------GET USER TOKEN-------
FirebaseUser mUser = FirebaseAuth.getInstance().getCurrentUser();
mUser.getToken(true)
.addOnCompleteListener(new OnCompleteListener<GetTokenResult>() {
public void onComplete(@NonNull Task<GetTokenResult> task) {
if (task.isSuccessful()) {
String idToken = task.getResult().getToken();
// ...
}
}
});
Work well if user are logged. getCurrentUser()
How can I reconcile detached HEAD with master/origin?
If you did some commits on top of master and just want to "backwards merge" master there (i.e. you want master to point to HEAD), the one-liner would be:
git checkout -B master HEAD
- That creates a new branch named
master, even if it exists already (which is like movingmasterand that's what we want). - The newly created branch is set to point to
HEAD, which is where you are. - The new branch is checked out, so you are on
masterafterwards.
I found this especially useful in the case of sub-repositories, which also happen to be in a detached state rather often.
SQL Server 100% CPU Utilization - One database shows high CPU usage than others
You can see some reports in SSMS:
Right-click the instance name / reports / standard / top sessions
You can see top CPU consuming sessions. This may shed some light on what SQL processes are using resources. There are a few other CPU related reports if you look around. I was going to point to some more DMVs but if you've looked into that already I'll skip it.
You can use sp_BlitzCache to find the top CPU consuming queries. You can also sort by IO and other things as well. This is using DMV info which accumulates between restarts.
This article looks promising.
Some stackoverflow goodness from Mr. Ozar.
edit: A little more advice... A query running for 'only' 5 seconds can be a problem. It could be using all your cores and really running 8 cores times 5 seconds - 40 seconds of 'virtual' time. I like to use some DMVs to see how many executions have happened for that code to see what that 5 seconds adds up to.
What's the difference between interface and @interface in java?
The interface keyword indicates that you are declaring a traditional interface class in Java.
The @interface keyword is used to declare a new annotation type.
See docs.oracle tutorial on annotations for a description of the syntax.
See the JLS if you really want to get into the details of what @interface means.
How to find nth occurrence of character in a string?
public static int findNthOccurrence(String phrase, String str, int n)
{
int val = 0, loc = -1;
for(int i = 0; i <= phrase.length()-str.length() && val < n; i++)
{
if(str.equals(phrase.substring(i,i+str.length())))
{
val++;
loc = i;
}
}
if(val == n)
return loc;
else
return -1;
}
How to read xml file contents in jQuery and display in html elements?
$.get("/folder_name/filename.xml", function (xml) {_x000D_
var xmlInnerhtml = xml.documentElement.innerHTML;_x000D_
});How to troubleshoot an "AttributeError: __exit__" in multiproccesing in Python?
The problem is in this line:
with pattern.findall(row) as f:
You are using the with statement. It requires an object with __enter__ and __exit__ methods. But pattern.findall returns a list, with tries to store the __exit__ method, but it can't find it, and raises an error. Just use
f = pattern.findall(row)
instead.
Expression must be a modifiable lvalue
You test k = M instead of k == M.
Maybe it is what you want to do, in this case, write if (match == 0 && (k = M))
Select top 1 result using JPA
Use a native SQL query by specifying a @NamedNativeQuery annotation on the entity class, or by using the EntityManager.createNativeQuery method. You will need to specify the type of the ResultSet using an appropriate class, or use a ResultSet mapping.
Spring Boot @Value Properties
Your problem is that you need a static PropertySourcesPlaceholderConfigurer Bean definition in your configuration. I say static with emphasis, because I had a non-static one and it didn't work.
@Bean
public static PropertySourcesPlaceholderConfigurer propertySourcesPlaceholderConfigurer() {
return new PropertySourcesPlaceholderConfigurer();
}
angular2: Error: TypeError: Cannot read property '...' of undefined
Safe navigation operator or Existential Operator or Null Propagation Operator is supported in Angular Template. Suppose you have Component class
myObj:any = {
doSomething: function () { console.log('doing something'); return 'doing something'; },
};
myArray:any;
constructor() { }
ngOnInit() {
this.myArray = [this.myObj];
}
You can use it in template html file as following:
<div>test-1: {{ myObj?.doSomething()}}</div>
<div>test-2: {{ myArray[0].doSomething()}}</div>
<div>test-3: {{ myArray[2]?.doSomething()}}</div>
Simplest way to form a union of two lists
If it is a list, you can also use AddRange method.
var listB = new List<int>{3, 4, 5};
var listA = new List<int>{1, 2, 3, 4, 5};
listA.AddRange(listB); // listA now has elements of listB also.
If you need new list (and exclude the duplicate), you can use Union
var listB = new List<int>{3, 4, 5};
var listA = new List<int>{1, 2, 3, 4, 5};
var listFinal = listA.Union(listB);
If you need new list (and include the duplicate), you can use Concat
var listB = new List<int>{3, 4, 5};
var listA = new List<int>{1, 2, 3, 4, 5};
var listFinal = listA.Concat(listB);
If you need common items, you can use Intersect.
var listB = new List<int>{3, 4, 5};
var listA = new List<int>{1, 2, 3, 4};
var listFinal = listA.Intersect(listB); //3,4
Undefined symbols for architecture x86_64 on Xcode 6.1
I simply wasn't linking the libraries in the "Link Binary with Libraries" section.
What is callback in Android?
Here is a nice tutorial, which describes callbacks and the use-case well.
The concept of callbacks is to inform a class synchronous / asynchronous if some work in another class is done. Some call it the Hollywood principle: "Don't call us we call you".
Here's a example:
class A implements ICallback {
MyObject o;
B b = new B(this, someParameter);
@Override
public void callback(MyObject o){
this.o = o;
}
}
class B {
ICallback ic;
B(ICallback ic, someParameter){
this.ic = ic;
}
new Thread(new Runnable(){
public void run(){
// some calculation
ic.callback(myObject)
}
}).start();
}
interface ICallback{
public void callback(MyObject o);
}
Class A calls Class B to get some work done in a Thread. If the Thread finished the work, it will inform Class A over the callback and provide the results. So there is no need for polling or something. You will get the results as soon as they are available.
In Android Callbacks are used f.e. between Activities and Fragments. Because Fragments should be modular you can define a callback in the Fragment to call methods in the Activity.
Getting path of captured image in Android using camera intent
Here I updated the sample code in Kotlin. Please note on Nougat and above version Uri.fromFile(file) is not working and it crashes the app for that need to implement FileProvider which is safest way to send files from intent. For implementing this refer this answer or this article
private fun takePhotoFromCamera() {
val isDeviceSupportCamera: Boolean = this.packageManager.hasSystemFeature(PackageManager.FEATURE_CAMERA)
if (isDeviceSupportCamera) {
val takePictureIntent = Intent(MediaStore.ACTION_IMAGE_CAPTURE)
if (takePictureIntent.resolveActivity(getPackageManager()) != null) {
file = File(getExternalFilesDir(Environment.DIRECTORY_DOCUMENTS + "/attachments")!!.path,
System.currentTimeMillis().toString() + ".jpg")
// fileUri = Uri.fromFile(file)
fileUri = FileProvider.getUriForFile(this, this.applicationContext.packageName + ".provider", file!!)
takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT, fileUri)
if (Build.VERSION.SDK_INT <= Build.VERSION_CODES.LOLLIPOP) {
takePictureIntent.addFlags(Intent.FLAG_GRANT_WRITE_URI_PERMISSION)
}
startActivityForResult(takePictureIntent, Constants.REQUEST_CODE_IMAGE_CAPTURE)
}
} else {
Toast.makeText(this, this.getString(R.string.camera_not_supported), Toast.LENGTH_SHORT).show()
}
}
override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
super.onActivityResult(requestCode, resultCode, data)
if (resultCode == Activity.RESULT_OK) {
if(requestCode == Constants.REQUEST_CODE_IMAGE_CAPTURE) {
realPath = file?.path
//do what ever you want to do
}
}
}
Get day of week using NSDate
There is an easier way. Just pass your string date to the following function, it will give you the day name :)
func getDayNameBy(stringDate: String) -> String
{
let df = NSDateFormatter()
df.dateFormat = "YYYY-MM-dd"
let date = df.dateFromString(stringDate)!
df.dateFormat = "EEEE"
return df.stringFromDate(date);
}
Returning a promise in an async function in TypeScript
It's complicated.
First of all, in this code
const p = new Promise((resolve) => {
resolve(4);
});
the type of p is inferred as Promise<{}>. There is open issue about this on typescript github, so arguably this is a bug, because obviously (for a human), p should be Promise<number>.
Then, Promise<{}> is compatible with Promise<number>, because basically the only property a promise has is then method, and then is compatible in these two promise types in accordance with typescript rules for function types compatibility. That's why there is no error in whatever1.
But the purpose of async is to pretend that you are dealing with actual values, not promises, and then you get the error in whatever2 because {} is obvioulsy not compatible with number.
So the async behavior is the same, but currently some workaround is necessary to make typescript compile it. You could simply provide explicit generic argument when creating a promise like this:
const whatever2 = async (): Promise<number> => {
return new Promise<number>((resolve) => {
resolve(4);
});
};
Can a java file have more than one class?
Besides anonymous inner classes, another use is private inner classes that implement a public interface (see this article). The outer class can access all private fields and methods of the inner class.
This lets you create two tightly-coupled classes, such as a model and its view, without exposing the implementations of either. Another example is a collection and its iterators.
CSS: Center block, but align contents to the left
For those of us still working with older browsers, here's some extended backwards compatibility:
<div style="text-align: center;">
<div style="display:-moz-inline-stack; display:inline-block; zoom:1; *display:inline; text-align: left;">
Line 1: Testing<br>
Line 2: More testing<br>
Line 3: Even more testing<br>
</div>
</div>Partially inspired by this post: https://stackoverflow.com/a/12567422/14999964.
ASP.NET MVC Dropdown List From SelectList
Try this, just an example:
u.UserTypeOptions = new SelectList(new[]
{
new { ID="1", Name="name1" },
new { ID="2", Name="name2" },
new { ID="3", Name="name3" },
}, "ID", "Name", 1);
Or
u.UserTypeOptions = new SelectList(new List<SelectListItem>
{
new SelectListItem { Selected = true, Text = string.Empty, Value = "-1"},
new SelectListItem { Selected = false, Text = "Homeowner", Value = "2"},
new SelectListItem { Selected = false, Text = "Contractor", Value = "3"},
},"Value","Text");
DateTime.Today.ToString("dd/mm/yyyy") returns invalid DateTime Value
use MM(months) instead of mm(minutes) :
DateTime.Now.ToString("dd/MM/yyyy");
check here for more format options.
Location of sqlite database on the device
If your application creates a database, this database is by default saved in the directory DATA/data/APP_NAME/databases/FILENAME.
The parts of the above directory are constructed based on the following rules. DATA is the path which the Environment.getDataDirectory() method returns. APP_NAME is your application name. FILENAME is the name you specify in your application code for the database.
Implementing Singleton with an Enum (in Java)
This,
public enum MySingleton {
INSTANCE;
}
has an implicit empty constructor. Make it explicit instead,
public enum MySingleton {
INSTANCE;
private MySingleton() {
System.out.println("Here");
}
}
If you then added another class with a main() method like
public static void main(String[] args) {
System.out.println(MySingleton.INSTANCE);
}
You would see
Here
INSTANCE
enum fields are compile time constants, but they are instances of their enum type. And, they're constructed when the enum type is referenced for the first time.
Determine if two rectangles overlap each other?
struct rect
{
int x;
int y;
int width;
int height;
};
bool valueInRange(int value, int min, int max)
{ return (value >= min) && (value <= max); }
bool rectOverlap(rect A, rect B)
{
bool xOverlap = valueInRange(A.x, B.x, B.x + B.width) ||
valueInRange(B.x, A.x, A.x + A.width);
bool yOverlap = valueInRange(A.y, B.y, B.y + B.height) ||
valueInRange(B.y, A.y, A.y + A.height);
return xOverlap && yOverlap;
}How can I import Swift code to Objective-C?
You need to import ProductName-Swift.h. Note that it's the product name - the other answers make the mistake of using the class name.
This single file is an autogenerated header that defines Objective-C interfaces for all Swift classes in your project that are either annotated with @objc or inherit from NSObject.
Considerations:
If your product name contains spaces, replace them with underscores (e.g.
My ProjectbecomesMy_Project-Swift.h)If your target is a framework, you need to import
<ProductName/ProductName-Swift.h>Make sure your Swift file is member of the target
Python date string to date object
you have a date string like this, "24052010" and you want date object for this,
from datetime import datetime
cus_date = datetime.strptime("24052010", "%d%m%Y").date()
this cus_date will give you date object.
you can retrieve date string from your date object using this,
cus_date.strftime("%d%m%Y")
How can I shuffle an array?
Use the modern version of the Fisher–Yates shuffle algorithm:
/**
* Shuffles array in place.
* @param {Array} a items An array containing the items.
*/
function shuffle(a) {
var j, x, i;
for (i = a.length - 1; i > 0; i--) {
j = Math.floor(Math.random() * (i + 1));
x = a[i];
a[i] = a[j];
a[j] = x;
}
return a;
}
ES2015 (ES6) version
/**
* Shuffles array in place. ES6 version
* @param {Array} a items An array containing the items.
*/
function shuffle(a) {
for (let i = a.length - 1; i > 0; i--) {
const j = Math.floor(Math.random() * (i + 1));
[a[i], a[j]] = [a[j], a[i]];
}
return a;
}
Note however, that swapping variables with destructuring assignment causes significant performance loss, as of October 2017.
Use
var myArray = ['1','2','3','4','5','6','7','8','9'];
shuffle(myArray);
Implementing prototype
Using Object.defineProperty (method taken from this SO answer) we can also implement this function as a prototype method for arrays, without having it show up in loops such as for (i in arr). The following will allow you to call arr.shuffle() to shuffle the array arr:
Object.defineProperty(Array.prototype, 'shuffle', {
value: function() {
for (let i = this.length - 1; i > 0; i--) {
const j = Math.floor(Math.random() * (i + 1));
[this[i], this[j]] = [this[j], this[i]];
}
return this;
}
});
Downloading Java JDK on Linux via wget is shown license page instead
I know that Oracle made everything possible to make their Java Runtime and Java SDK as hard as possible.
Here are some guides for command line lovers.
For Debian like systems (tested on Debian squeeze and Ubuntu 12.x+)
su -
echo "deb http://ppa.launchpad.net/webupd8team/java/ubuntu precise main" | tee -a /etc/apt/sources.list
echo "deb-src http://ppa.launchpad.net/webupd8team/java/ubuntu precise main" | tee -a /etc/apt/sources.list
apt-key adv --keyserver keyserver.ubuntu.com --recv-keys EEA14886
apt-get update
apt-get install --yes oracle-java7-installer
exit
Note: if you know a better or easier way add a comment, I will update the guide.
NodeJs : TypeError: require(...) is not a function
I've faced to something like this too. in your routes file , export the function as an object like this :
module.exports = {
hbd: handlebar
}
and in your app file , you can have access to the function by .hbd and there is no ptoblem ....!
How do I replace whitespaces with underscore?
I'm using the following piece of code for my friendly urls:
from unicodedata import normalize
from re import sub
def slugify(title):
name = normalize('NFKD', title).encode('ascii', 'ignore').replace(' ', '-').lower()
#remove `other` characters
name = sub('[^a-zA-Z0-9_-]', '', name)
#nomalize dashes
name = sub('-+', '-', name)
return name
It works fine with unicode characters as well.
Max size of an iOS application
150MB is the constraint for over-the-air downloads via the cellular network. Anything above that and users will be suggested Wi-Fi or iTunes sync to actually get your app.
This will not prevent a purchase though, at point of sale.
How to get folder path from file path with CMD
In order to assign these to variables, be sure not to add spaces in front or after the equals sign:
set filepath=%~dp1
set filename=%~nx1
Then you should have no issues.
Change fill color on vector asset in Android Studio
To change vector image color you can directly use android:tint="@color/colorAccent"
<ImageView
android:id="@+id/ivVectorImage"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/ic_account_circle_black_24dp"
android:tint="@color/colorAccent" />
To change color programatically
ImageView ivVectorImage = (ImageView) findViewById(R.id.ivVectorImage);
ivVectorImage.setColorFilter(getResources().getColor(R.color.colorPrimary));
How to remove unused C/C++ symbols with GCC and ld?
For GCC, this is accomplished in two stages:
First compile the data but tell the compiler to separate the code into separate sections within the translation unit. This will be done for functions, classes, and external variables by using the following two compiler flags:
-fdata-sections -ffunction-sections
Link the translation units together using the linker optimization flag (this causes the linker to discard unreferenced sections):
-Wl,--gc-sections
So if you had one file called test.cpp that had two functions declared in it, but one of them was unused, you could omit the unused one with the following command to gcc(g++):
gcc -Os -fdata-sections -ffunction-sections test.cpp -o test -Wl,--gc-sections
(Note that -Os is an additional compiler flag that tells GCC to optimize for size)
Including all the jars in a directory within the Java classpath
Think of a jar file as the root of a directory structure. Yes, you need to add them all separately.
Difference between webdriver.Dispose(), .Close() and .Quit()
driver.close and driver.quit are two different methods for closing the browser session in Selenium WebDriver. Understanding both of them and knowing when to use each method is important in your test execution. Therefore, I have tried to shed some light on both of these methods.
driver.close - This method closes the browser window on which the focus is set. Despite the familiar name for this method, WebDriver does not implement the AutoCloseable interface.
driver.quit – This method basically calls driver.dispose a now internal method which in turn closes all of the browser windows and ends the WebDriver session gracefully.
driver.dispose - As mentioned previously, is an internal method of WebDriver which has been silently dropped according to another answer - Verification needed. This method really doesn't have a use-case in a normal test workflow as either of the previous methods should work for most use cases.
Explanation use case:
You should use driver.quit whenever you want to end the program. It will close all opened browser windows and terminates the WebDriver session. If you do not use driver.quit at the end of the program, the WebDriver session will not close properly and files would not be cleared from memory. This may result in memory leak errors.
The above explanation should explain the difference between driver.close and driver.quit methods in WebDriver. I hope you find it useful.
The following website has some good tips on selenium testing : Link
How to return result of a SELECT inside a function in PostgreSQL?
Use RETURN QUERY:
CREATE OR REPLACE FUNCTION word_frequency(_max_tokens int)
RETURNS TABLE (txt text -- also visible as OUT parameter inside function
, cnt bigint
, ratio bigint) AS
$func$
BEGIN
RETURN QUERY
SELECT t.txt
, count(*) AS cnt -- column alias only visible inside
, (count(*) * 100) / _max_tokens -- I added brackets
FROM (
SELECT t.txt
FROM token t
WHERE t.chartype = 'ALPHABETIC'
LIMIT _max_tokens
) t
GROUP BY t.txt
ORDER BY cnt DESC; -- potential ambiguity
END
$func$ LANGUAGE plpgsql;
Call:
SELECT * FROM word_frequency(123);
Explanation:
It is much more practical to explicitly define the return type than simply declaring it as record. This way you don't have to provide a column definition list with every function call.
RETURNS TABLEis one way to do that. There are others. Data types ofOUTparameters have to match exactly what is returned by the query.Choose names for
OUTparameters carefully. They are visible in the function body almost anywhere. Table-qualify columns of the same name to avoid conflicts or unexpected results. I did that for all columns in my example.But note the potential naming conflict between the
OUTparametercntand the column alias of the same name. In this particular case (RETURN QUERY SELECT ...) Postgres uses the column alias over theOUTparameter either way. This can be ambiguous in other contexts, though. There are various ways to avoid any confusion:- Use the ordinal position of the item in the SELECT list:
ORDER BY 2 DESC. Example: - Repeat the expression
ORDER BY count(*). - (Not applicable here.) Set the configuration parameter
plpgsql.variable_conflictor use the special command#variable_conflict error | use_variable | use_columnin the function. See:
- Use the ordinal position of the item in the SELECT list:
Don't use "text" or "count" as column names. Both are legal to use in Postgres, but "count" is a reserved word in standard SQL and a basic function name and "text" is a basic data type. Can lead to confusing errors. I use
txtandcntin my examples.Added a missing
;and corrected a syntax error in the header.(_max_tokens int), not(int maxTokens)- type after name.While working with integer division, it's better to multiply first and divide later, to minimize the rounding error. Even better: work with
numeric(or a floating point type). See below.
Alternative
This is what I think your query should actually look like (calculating a relative share per token):
CREATE OR REPLACE FUNCTION word_frequency(_max_tokens int)
RETURNS TABLE (txt text
, abs_cnt bigint
, relative_share numeric) AS
$func$
BEGIN
RETURN QUERY
SELECT t.txt, t.cnt
, round((t.cnt * 100) / (sum(t.cnt) OVER ()), 2) -- AS relative_share
FROM (
SELECT t.txt, count(*) AS cnt
FROM token t
WHERE t.chartype = 'ALPHABETIC'
GROUP BY t.txt
ORDER BY cnt DESC
LIMIT _max_tokens
) t
ORDER BY t.cnt DESC;
END
$func$ LANGUAGE plpgsql;
The expression sum(t.cnt) OVER () is a window function. You could use a CTE instead of the subquery - pretty, but a subquery is typically cheaper in simple cases like this one.
A final explicit RETURN statement is not required (but allowed) when working with OUT parameters or RETURNS TABLE (which makes implicit use of OUT parameters).
round() with two parameters only works for numeric types. count() in the subquery produces a bigint result and a sum() over this bigint produces a numeric result, thus we deal with a numeric number automatically and everything just falls into place.
How can I serve static html from spring boot?
Static files should be served from resources, not from controller.
Spring Boot will automatically add static web resources located within any of the following directories:
/META-INF/resources/ /resources/ /static/ /public/
refs:
https://spring.io/blog/2013/12/19/serving-static-web-content-with-spring-boot
https://spring.io/guides/gs/serving-web-content/
check all socket opened in linux OS
Also you can use ss utility to dump sockets statistics.
To dump summary:
ss -s
Total: 91 (kernel 0)
TCP: 18 (estab 11, closed 0, orphaned 0, synrecv 0, timewait 0/0), ports 0
Transport Total IP IPv6
* 0 - -
RAW 0 0 0
UDP 4 2 2
TCP 18 16 2
INET 22 18 4
FRAG 0 0 0
To display all sockets:
ss -a
To display UDP sockets:
ss -u -a
To display TCP sockets:
ss -t -a
Here you can read ss man: ss
T-SQL STOP or ABORT command in SQL Server
No, there isn't one - you have a couple of options:
Wrap the whole script in a big if/end block that is simply ensured to not be true (i.e. "if 1=2 begin" - this will only work however if the script doesn't include any GO statements (as those indicate a new batch)
Use the return statement at the top (again, limited by the batch separators)
Use a connection based approach, which will ensure non-execution for the entire script (entire connection to be more accurate) - use something like a 'SET PARSEONLY ON' or 'SET NOEXEC ON' at the top of the script. This will ensure all statements in the connection (or until said set statement is turned off) will not execute and will instead be parsed/compiled only.
Use a comment block to comment out the entire script (i.e. /* and */)
EDIT: Demonstration that the 'return' statement is batch specific - note that you will continue to see result-sets after the returns:
select 1
return
go
select 2
return
select 3
go
select 4
return
select 5
select 6
go
HTML entity for check mark
There is HTML entity ✓ but it doesn't work in some older browsers.
What is the difference between dim and set in vba
-
Dim r As Range Setsets the variable to an object reference.Set r = Range("A1")
However, I don't think this is what you're really asking.
Sometimes I use:
Dim r as Range r = Range("A1")
This will never work. Without Set you will receive runtime error #91 Object variable or With block variable not set. This is because you must use Set to assign a variables value to an object reference. Then the code above will work.
I think the code below illustrates what you're really asking about. Let's suppose we don't declare a type and let r be a Variant type instead.
Public Sub test()
Dim r
debug.print TypeName(r)
Set r = Range("A1")
debug.print TypeName(r)
r = Range("A1")
debug.print TypeName(r)
End Sub
So, let's break down what happens here.
ris declared as a Variant`Dim r` ' TypeName(r) returns "Empty", which is the value for an uninitialized variantris set to theRangecontaining cell "A1"Set r = Range("A1") ' TypeName(r) returns "Range"ris set to the value of the default property ofRange("A1").r = Range("A1") ' TypeName(r) returns "String"
In this case, the default property of a Range is .Value, so the following two lines of code are equivalent.
r = Range("A1")
r = Range("A1").Value
For more about default object properties, please see Chip Pearson's "Default Member of a Class".
As for your Set example:
Other times I use
Set r = Range("A1")
This wouldn't work without first declaring that r is a Range or Variant object... using the Dim statement - unless you don't have Option Explicit enabled, which you should. Always. Otherwise, you're using identifiers that you haven't declared and they are all implicitly declared as Variants.
What is the difference between the float and integer data type when the size is the same?
floatstores floating-point values, that is, values that have potential decimal placesintonly stores integral values, that is, whole numbers
So while both are 32 bits wide, their use (and representation) is quite different. You cannot store 3.141 in an integer, but you can in a float.
Dissecting them both a little further:
In an integer, all bits are used to store the number value. This is (in Java and many computers too) done in the so-called two's complement. This basically means that you can represent the values of −231 to 231 − 1.
In a float, those 32 bits are divided between three distinct parts: The sign bit, the exponent and the mantissa. They are laid out as follows:
S EEEEEEEE MMMMMMMMMMMMMMMMMMMMMMM
There is a single bit that determines whether the number is negative or non-negative (zero is neither positive nor negative, but has the sign bit set to zero). Then there are eight bits of an exponent and 23 bits of mantissa. To get a useful number from that, (roughly) the following calculation is performed:
M × 2E
(There is more to it, but this should suffice for the purpose of this discussion)
The mantissa is in essence not much more than a 24-bit integer number. This gets multiplied by 2 to the power of the exponent part, which, roughly, is a number between −128 and 127.
Therefore you can accurately represent all numbers that would fit in a 24-bit integer but the numeric range is also much greater as larger exponents allow for larger values. For example, the maximum value for a float is around 3.4 × 1038 whereas int only allows values up to 2.1 × 109.
But that also means, since 32 bits only have 4.2 × 109 different states (which are all used to represent the values int can store), that at the larger end of float's numeric range the numbers are spaced wider apart (since there cannot be more unique float numbers than there are unique int numbers). You cannot represent some numbers exactly, then. For example, the number 2 × 1012 has a representation in float of 1,999,999,991,808. That might be close to 2,000,000,000,000 but it's not exact. Likewise, adding 1 to that number does not change it because 1 is too small to make a difference in the larger scales float is using there.
Similarly, you can also represent very small numbers (between 0 and 1) in a float but regardless of whether the numbers are very large or very small, float only has a precision of around 6 or 7 decimal digits. If you have large numbers those digits are at the start of the number (e.g. 4.51534 × 1035, which is nothing more than 451534 follows by 30 zeroes – and float cannot tell anything useful about whether those 30 digits are actually zeroes or something else), for very small numbers (e.g. 3.14159 × 10−27) they are at the far end of the number, way beyond the starting digits of 0.0000...
Can't compare naive and aware datetime.now() <= challenge.datetime_end
It is working form me. Here I am geeting the table created datetime and adding 10 minutes on the datetime. later depending on the current time, Expiry Operations are done.
from datetime import datetime, time, timedelta
import pytz
Added 10 minutes on database datetime
table_datetime = '2019-06-13 07:49:02.832969' (example)
# Added 10 minutes on database datetime
# table_datetime = '2019-06-13 07:49:02.832969' (example)
table_expire_datetime = table_datetime + timedelta(minutes=10 )
# Current datetime
current_datetime = datetime.now()
# replace the timezone in both time
expired_on = table_expire_datetime.replace(tzinfo=utc)
checked_on = current_datetime.replace(tzinfo=utc)
if expired_on < checked_on:
print("Time Crossed)
else:
print("Time not crossed ")
It worked for me.
Portable way to get file size (in bytes) in shell?
Even though du usually prints disk usage and not actual data size, GNU coreutils du can print file's "apparent size" in bytes:
du -b FILE
But it won't work under BSD, Solaris, macOS, ...
How do I get list of methods in a Python class?
To produce a list of methods put the name of the method in a list without the usual parenthesis. Remove the name and attach the parenthesis and that calls the method.
def methodA():
print("@ MethodA")
def methodB():
print("@ methodB")
a = []
a.append(methodA)
a.append(methodB)
for item in a:
item()
My kubernetes pods keep crashing with "CrashLoopBackOff" but I can't find any log
As @Sukumar commented, you need to have your Dockerfile have a Command to run or have your ReplicationController specify a command.
The pod is crashing because it starts up then immediately exits, thus Kubernetes restarts and the cycle continues.
How to change root logging level programmatically for logback
using logback 1.1.3 I had to do the following (Scala code):
import ch.qos.logback.classic.Logger
import org.slf4j.LoggerFactory
...
val root: Logger = LoggerFactory.getLogger(org.slf4j.Logger.ROOT_LOGGER_NAME).asInstanceOf[Logger]
What is <=> (the 'Spaceship' Operator) in PHP 7?
According to the RFC that introduced the operator, $a <=> $b evaluates to:
- 0 if
$a == $b - -1 if
$a < $b - 1 if
$a > $b
which seems to be the case in practice in every scenario I've tried, although strictly the official docs only offer the slightly weaker guarantee that $a <=> $b will return
an integer less than, equal to, or greater than zero when
$ais respectively less than, equal to, or greater than$b
Regardless, why would you want such an operator? Again, the RFC addresses this - it's pretty much entirely to make it more convenient to write comparison functions for usort (and the similar uasort and uksort).
usort takes an array to sort as its first argument, and a user-defined comparison function as its second argument. It uses that comparison function to determine which of a pair of elements from the array is greater. The comparison function needs to return:
an integer less than, equal to, or greater than zero if the first argument is considered to be respectively less than, equal to, or greater than the second.
The spaceship operator makes this succinct and convenient:
$things = [
[
'foo' => 5.5,
'bar' => 'abc'
],
[
'foo' => 7.7,
'bar' => 'xyz'
],
[
'foo' => 2.2,
'bar' => 'efg'
]
];
// Sort $things by 'foo' property, ascending
usort($things, function ($a, $b) {
return $a['foo'] <=> $b['foo'];
});
// Sort $things by 'bar' property, descending
usort($things, function ($a, $b) {
return $b['bar'] <=> $a['bar'];
});
More examples of comparison functions written using the spaceship operator can be found in the Usefulness section of the RFC.
Console errors. Failed to load resource: net::ERR_INSECURE_RESPONSE
Encode and make it like this: $_GET[].
jQuery get input value after keypress
I think what you need is the below prototype
$(element).on('input',function(){code})
How do I shut down a python simpleHTTPserver?
Hitting ctrl + c once(wait for traceback), then hitting ctrl+c again did the trick for me :)
Increase max execution time for php
Well, since your on a shared server, you can't do anything about it. They usually set the max execution time so that you can't override it. I suggest you contact them.
"Post Image data using POSTMAN"
Now you can hover the key input and select "file", which will give you a file selector in the value column:
jQuery scroll to ID from different page
You basically need to do this:
- include the target hash into the link pointing to the other page (
href="other_page.html#section") - in your
readyhandler clear the hard jump scroll normally dictated by the hash and as soon as possible scroll the page back to the top and calljump()- you'll need to do this asynchronously - in
jump()if no event is given, makelocation.hashthe target - also this technique might not catch the jump in time, so you'll better hide the
html,bodyright away and show it back once you scrolled it back to zero
This is your code with the above added:
var jump=function(e)
{
if (e){
e.preventDefault();
var target = $(this).attr("href");
}else{
var target = location.hash;
}
$('html,body').animate(
{
scrollTop: $(target).offset().top
},2000,function()
{
location.hash = target;
});
}
$('html, body').hide();
$(document).ready(function()
{
$('a[href^=#]').bind("click", jump);
if (location.hash){
setTimeout(function(){
$('html, body').scrollTop(0).show();
jump();
}, 0);
}else{
$('html, body').show();
}
});
Verified working in Chrome/Safari, Firefox and Opera. I don't know about IE though.
how to check if item is selected from a comboBox in C#
Use:
if(comboBox.SelectedIndex > -1) //somthing was selected
To get the selected item you do:
Item m = comboBox.Items[comboBox.SelectedIndex];
As Matthew correctly states, to get the selected item you could also do
Item m = comboBox.SelectedItem;
How to convert a string to integer in C?
Robust C89 strtol-based solution
With:
- no undefined behavior (as could be had with the
atoifamily) - a stricter definition of integer than
strtol(e.g. no leading whitespace nor trailing trash chars) - classification of the error case (e.g. to give useful error messages to users)
- a "testsuite"
#include <assert.h>
#include <ctype.h>
#include <errno.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
typedef enum {
STR2INT_SUCCESS,
STR2INT_OVERFLOW,
STR2INT_UNDERFLOW,
STR2INT_INCONVERTIBLE
} str2int_errno;
/* Convert string s to int out.
*
* @param[out] out The converted int. Cannot be NULL.
*
* @param[in] s Input string to be converted.
*
* The format is the same as strtol,
* except that the following are inconvertible:
*
* - empty string
* - leading whitespace
* - any trailing characters that are not part of the number
*
* Cannot be NULL.
*
* @param[in] base Base to interpret string in. Same range as strtol (2 to 36).
*
* @return Indicates if the operation succeeded, or why it failed.
*/
str2int_errno str2int(int *out, char *s, int base) {
char *end;
if (s[0] == '\0' || isspace(s[0]))
return STR2INT_INCONVERTIBLE;
errno = 0;
long l = strtol(s, &end, base);
/* Both checks are needed because INT_MAX == LONG_MAX is possible. */
if (l > INT_MAX || (errno == ERANGE && l == LONG_MAX))
return STR2INT_OVERFLOW;
if (l < INT_MIN || (errno == ERANGE && l == LONG_MIN))
return STR2INT_UNDERFLOW;
if (*end != '\0')
return STR2INT_INCONVERTIBLE;
*out = l;
return STR2INT_SUCCESS;
}
int main(void) {
int i;
/* Lazy to calculate this size properly. */
char s[256];
/* Simple case. */
assert(str2int(&i, "11", 10) == STR2INT_SUCCESS);
assert(i == 11);
/* Negative number . */
assert(str2int(&i, "-11", 10) == STR2INT_SUCCESS);
assert(i == -11);
/* Different base. */
assert(str2int(&i, "11", 16) == STR2INT_SUCCESS);
assert(i == 17);
/* 0 */
assert(str2int(&i, "0", 10) == STR2INT_SUCCESS);
assert(i == 0);
/* INT_MAX. */
sprintf(s, "%d", INT_MAX);
assert(str2int(&i, s, 10) == STR2INT_SUCCESS);
assert(i == INT_MAX);
/* INT_MIN. */
sprintf(s, "%d", INT_MIN);
assert(str2int(&i, s, 10) == STR2INT_SUCCESS);
assert(i == INT_MIN);
/* Leading and trailing space. */
assert(str2int(&i, " 1", 10) == STR2INT_INCONVERTIBLE);
assert(str2int(&i, "1 ", 10) == STR2INT_INCONVERTIBLE);
/* Trash characters. */
assert(str2int(&i, "a10", 10) == STR2INT_INCONVERTIBLE);
assert(str2int(&i, "10a", 10) == STR2INT_INCONVERTIBLE);
/* int overflow.
*
* `if` needed to avoid undefined behaviour
* on `INT_MAX + 1` if INT_MAX == LONG_MAX.
*/
if (INT_MAX < LONG_MAX) {
sprintf(s, "%ld", (long int)INT_MAX + 1L);
assert(str2int(&i, s, 10) == STR2INT_OVERFLOW);
}
/* int underflow */
if (LONG_MIN < INT_MIN) {
sprintf(s, "%ld", (long int)INT_MIN - 1L);
assert(str2int(&i, s, 10) == STR2INT_UNDERFLOW);
}
/* long overflow */
sprintf(s, "%ld0", LONG_MAX);
assert(str2int(&i, s, 10) == STR2INT_OVERFLOW);
/* long underflow */
sprintf(s, "%ld0", LONG_MIN);
assert(str2int(&i, s, 10) == STR2INT_UNDERFLOW);
return EXIT_SUCCESS;
}
Git error when trying to push -- pre-receive hook declined
For me everything was working fine until Bitbucket automatically changed their policy today (April 21, 2020). This happens to align with a new feature recently introduced today called Workspaces, so I suspect it has something to do with that.
Workaround: I (as an Admin) followed the instructions to add the email address to Users in the UI (the email you are using can be found git config --list
Cut Corners using CSS
Here is another approach using CSS transform: skew(45deg) to produce the cut corner effect. The shape itself involves three elements (1 real and 2 pseudo-elements) as follows:
- The main container
divelement hasoverflow: hiddenand produces the left border. - The
:beforepseudo-element which is 20% the height of the parent container and has a skew transform applied to it. This element prodcues the border on the top and cut (slanted) border on the right side. - The
:afterpseudo-element which is 80% the height of the parent (basically, remaining height) and produces the bottom border, the remaining portion of the right border.
The output produced is responsive, produces a transparent cut at the top and supports transparent backgrounds.
div {_x000D_
position: relative;_x000D_
height: 100px;_x000D_
width: 200px;_x000D_
border-left: 2px solid beige;_x000D_
overflow: hidden;_x000D_
}_x000D_
div:after,_x000D_
div:before {_x000D_
position: absolute;_x000D_
content: '';_x000D_
width: calc(100% - 2px);_x000D_
left: 0px;_x000D_
z-index: -1;_x000D_
}_x000D_
div:before {_x000D_
height: 20%;_x000D_
top: 0px;_x000D_
border: 2px solid beige;_x000D_
border-width: 2px 3px 0px 0px;_x000D_
transform: skew(45deg);_x000D_
transform-origin: right bottom;_x000D_
}_x000D_
div:after {_x000D_
height: calc(80% - 4px);_x000D_
bottom: 0px;_x000D_
border: 2px solid beige;_x000D_
border-width: 0px 2px 2px 0px;_x000D_
}_x000D_
.filled:before, .filled:after {_x000D_
background-color: beige;_x000D_
}_x000D_
_x000D_
/* Just for demo */_x000D_
_x000D_
div {_x000D_
float: left;_x000D_
color: beige;_x000D_
padding: 10px;_x000D_
transition: all 1s;_x000D_
margin: 10px;_x000D_
}_x000D_
div:hover {_x000D_
height: 200px;_x000D_
width: 300px;_x000D_
}_x000D_
div.filled{_x000D_
color: black;_x000D_
}_x000D_
body{_x000D_
background-image: radial-gradient(circle, #3F9CBA 0%, #153346 100%);_x000D_
}<div class="cut-corner">Some content</div>_x000D_
<div class="cut-corner filled">Some content</div>
The below is another method to produce the cut corner effect by using linear-gradient background images. A combination of 3 gradient images (given below) is used:
- One linear gradient (angled towards bottom left) to produce the cut corner effect. This gradient has a fixed 25px x 25px size.
- One linear gradient to provide a solid color to the left of the triangle that causes the cut effect. A gradient is used even though it produces a solid color because we can control size, position of background only when images or gradients are used. This gradient is positioned at -25px on X-axis (basically meaning it would end before the place where the cut is present).
- Another gradient similar to the above which again produces a solid color but is positioned at 25px down on the Y-axis (again to leave out the cut area).
The output produced is responsive, produces transparent cut and doesn't require any extra elements (real or pseudo). The drawback is that this approach would work only when the background (fill) is a solid color and it is very difficult to produce borders (but still possible as seen in the snippet).
.cut-corner {_x000D_
height: 100px;_x000D_
width: 200px;_x000D_
background-image: linear-gradient(to bottom left, transparent 50%, beige 50%), linear-gradient(beige, beige), linear-gradient(beige, beige);_x000D_
background-size: 25px 25px, 100% 100%, 100% 100%;_x000D_
background-position: 100% 0%, -25px 0%, 100% 25px;_x000D_
background-repeat: no-repeat;_x000D_
}_x000D_
.filled {_x000D_
background-image: linear-gradient(black, black), linear-gradient(black, black), linear-gradient(black, black), linear-gradient(black, black), linear-gradient(to bottom left, transparent calc(50% - 1px), black calc(50% - 1px), black calc(50% + 1px), beige calc(50% + 1px)), linear-gradient(beige, beige), linear-gradient(beige, beige);_x000D_
background-size: 2px 100%, 2px 100%, 100% 2px, 100% 2px, 25px 25px, 100% 100%, 100% 100%;_x000D_
background-position: 0% 0%, 100% 25px, -25px 0%, 0px 100%, 100% 0%, -25px 0%, 100% 25px;_x000D_
}_x000D_
_x000D_
/* Just for demo */_x000D_
_x000D_
*{_x000D_
box-sizing: border-box;_x000D_
}_x000D_
div {_x000D_
float: left;_x000D_
color: black;_x000D_
padding: 10px;_x000D_
transition: all 1s;_x000D_
margin: 10px;_x000D_
}_x000D_
div:hover {_x000D_
height: 200px;_x000D_
width: 300px;_x000D_
}_x000D_
body{_x000D_
background-image: radial-gradient(circle, #3F9CBA 0%, #153346 100%);_x000D_
}<div class="cut-corner">Some content</div>_x000D_
<div class="cut-corner filled">Some content</div>
Best equivalent VisualStudio IDE for Mac to program .NET/C#
codeblocks.It seems to be good
python: creating list from string
If you need to convert some of them to numbers and don't know in advance which ones, some additional code will be needed. Try something like this:
b = []
for x in a:
temp = []
items = x.split(",")
for item in items:
try:
n = int(item)
except ValueError:
temp.append(item)
else:
temp.append(n)
b.append(temp)
This is longer than the other answers, but it's more versatile.
Encode/Decode URLs in C++
You can use "g_uri_escape_string()" function provided glib.h. https://developer.gnome.org/glib/stable/glib-URI-Functions.html
#include <stdio.h>
#include <stdlib.h>
#include <glib.h>
int main() {
char *uri = "http://www.example.com?hello world";
char *encoded_uri = NULL;
//as per wiki (https://en.wikipedia.org/wiki/Percent-encoding)
char *escape_char_str = "!*'();:@&=+$,/?#[]";
encoded_uri = g_uri_escape_string(uri, escape_char_str, TRUE);
printf("[%s]\n", encoded_uri);
free(encoded_uri);
return 0;
}
compile it with:
gcc encoding_URI.c `pkg-config --cflags --libs glib-2.0`
How to install JSON.NET using NuGet?
I have Had the same issue and the only Solution i found was open Package manager> Select Microsoft and .Net as Package Source and You will install it..
JavaScript inside an <img title="<a href='#' onClick='alert('Hello World!')>The Link</a>" /> possible?
Im my browser, this doesn't work at all. The tooltip field doesn't show a link, but <a href='#' onClick='alert('Hello World!')>The Link</a>.
I'm using FF 3.6.12.
You'll have to do this by hand with JS and CSS. Begin here
How to disable textbox from editing?
You can set the ReadOnly property to true.
Quoth the link:
When this property is set to true, the contents of the control cannot be changed by the user at runtime. With this property set to true, you can still set the value of the Text property in code. You can use this feature instead of disabling the control with the Enabled property to allow the contents to be copied and ToolTips to be shown.
How to create dynamic href in react render function?
You can use ES6 backtick syntax too
<a href={`/customer/${item._id}`} >{item.get('firstName')} {item.get('lastName')}</a>
How can I count the number of children?
Try to get using:
var count = $("ul > li").size();
alert(count);
Network usage top/htop on Linux
Another option you could try is iptstate.
How to write character & in android strings.xml
It is also possible put the contents of your string into a XML CDATA, like Android Studio does for you when you Extract string resource
<string name="game_settings_dragNDropMove_checkBox"><![CDATA[Move by Drag&Drop]]></string>
What is the difference between a candidate key and a primary key?
A table can have so many column which can uniquely identify a row. This columns are referred as candidate keys, but primary key should be one of them because one primary key is enough for a table. So selection of primary key is important among so many candidate key. Thats the main difference.
What does the Java assert keyword do, and when should it be used?
assert is a keyword. It was introduced in JDK 1.4. The are two types of asserts
- Very simple
assertstatements - Simple
assertstatements.
By default all assert statements will not be executed. If an assert statement receives false, then it will automatically raise an assertion error.
Java 'file.delete()' Is not Deleting Specified File
I suspect that the problem is that the path is incorrect. Try this:
UserInput.prompt("Enter name of file to delete");
String name = UserInput.readString();
File file = new File("\\Files\\" + name + ".txt");
if (file.exists()) {
file.delete();
} else {
System.err.println(
"I cannot find '" + file + "' ('" + file.getAbsolutePath() + "')");
}
How long do browsers cache HTTP 301s?
To solve the issue for a localhost address I changed the port number the site ran under. This worked on Chrome version 73.0.3683.86.
ADB Android Device Unauthorized
Check if you have kies installed. That is one possible solution
How can I prevent the backspace key from navigating back?
This code works on all browsers and swallows the backspace key when not on a form element, or if the form element is disabled|readOnly. It is also efficient, which is important when it is executing on every key typed in.
$(function(){
/*
* this swallows backspace keys on any non-input element.
* stops backspace -> back
*/
var rx = /INPUT|SELECT|TEXTAREA/i;
$(document).bind("keydown keypress", function(e){
if( e.which == 8 ){ // 8 == backspace
if(!rx.test(e.target.tagName) || e.target.disabled || e.target.readOnly ){
e.preventDefault();
}
}
});
});
Wait until an HTML5 video loads
you can use preload="none" in the attribute of video tag so the video will be displayed only when user clicks on play button.
<video preload="none">Histogram Matplotlib
I know this does not answer your question, but I always end up on this page, when I search for the matplotlib solution to histograms, because the simple histogram_demo was removed from the matplotlib example gallery page.
Here is a solution, which doesn't require numpy to be imported. I only import numpy to generate the data x to be plotted. It relies on the function hist instead of the function bar as in the answer by @unutbu.
import numpy as np
mu, sigma = 100, 15
x = mu + sigma * np.random.randn(10000)
import matplotlib.pyplot as plt
plt.hist(x, bins=50)
plt.savefig('hist.png')
Also check out the matplotlib gallery and the matplotlib examples.
Service vs IntentService in the Android platform
Android IntentService vs Service
1.Service
- A Service is invoked using startService().
- A Service can be invoked from any thread.
- A Service runs background operations on the Main Thread of the Application by default. Hence it can block your Application’s UI.
- A Service invoked multiple times would create multiple instances.
- A service needs to be stopped using stopSelf() or stopService().
- Android service can run parallel operations.
2. IntentService
- An IntentService is invoked using Intent.
- An IntentService can in invoked from the Main thread only.
- An IntentService creates a separate worker thread to run background operations.
- An IntentService invoked multiple times won’t create multiple instances.
- An IntentService automatically stops after the queue is completed. No need to trigger stopService() or stopSelf().
- In an IntentService, multiple intent calls are automatically Queued and they would be executed sequentially.
- An IntentService cannot run parallel operation like a Service.
Refer from Here
How to un-commit last un-pushed git commit without losing the changes
For the case: "This has not been pushed, only committed." - if you use IntelliJ (or another JetBrains IDE) and you haven't pushed changes yet you can do next.
- Go to Version control window (Alt + 9/Command + 9) - "Log" tab.
- Right-click on a commit before your last one.
- Reset current branch to here
- pick Soft (!!!)
- push the Reset button in the bottom of the dialog window.
Done.
This will "uncommit" your changes and return your git status to the point before your last local commit. You will not lose any changes you made.
MySQL - force not to use cache for testing speed of query
If you want to disable the Query cache set the 'query_cache_size' to 0 in your mysql configuration file . If its set 0 mysql wont use the query cache.
How to Convert datetime value to yyyymmddhhmmss in SQL server?
also this works too
SELECT replace(replace(replace(convert(varchar, getdate(), 120),':',''),'-',''),' ','')
comparing 2 strings alphabetically for sorting purposes
Lets look at some test cases - try running the following expressions in your JS console:
"a" < "b"
"aa" < "ab"
"aaa" < "aab"
All return true.
JavaScript compares strings character by character and "a" comes before "b" in the alphabet - hence less than.
In your case it works like so -
1 . "a?aaa" < "?a?b"
compares the first two "a" characters - all equal, lets move to the next character.
2 . "a?a??aa" < "a?b??"
compares the second characters "a" against "b" - whoop! "a" comes before "b". Returns true.
Scale Image to fill ImageView width and keep aspect ratio
To create an image with width equals screen width, and height proportionally set according to aspect ratio, do the following.
Glide.with(context).load(url).asBitmap().into(new SimpleTarget<Bitmap>() {
@Override
public void onResourceReady(Bitmap resource, GlideAnimation<? super Bitmap> glideAnimation) {
// creating the image that maintain aspect ratio with width of image is set to screenwidth.
int width = imageView.getMeasuredWidth();
int diw = resource.getWidth();
if (diw > 0) {
int height = 0;
height = width * resource.getHeight() / diw;
resource = Bitmap.createScaledBitmap(resource, width, height, false);
}
imageView.setImageBitmap(resource);
}
});
Hope this helps.
How to redirect to previous page in Ruby On Rails?
In your edit action, store the requesting url in the session hash, which is available across multiple requests:
session[:return_to] ||= request.referer
Then redirect to it in your update action, after a successful save:
redirect_to session.delete(:return_to)
How do you get assembler output from C/C++ source in gcc?
-save-temps
This was mentioned at https://stackoverflow.com/a/17083009/895245 but let me further exemplify it.
The big advantage of this option over -S is that it is very easy to add it to any build script, without interfering much in the build itself.
When you do:
gcc -save-temps -c -o main.o main.c
main.c
#define INC 1
int myfunc(int i) {
return i + INC;
}
and now, besides the normal output main.o, the current working directory also contains the following files:
main.iis a bonus and contains the preprossessed file:# 1 "main.c" # 1 "<built-in>" # 1 "<command-line>" # 31 "<command-line>" # 1 "/usr/include/stdc-predef.h" 1 3 4 # 32 "<command-line>" 2 # 1 "main.c" int myfunc(int i) { return i + 1; }main.scontains the desired generated assembly:.file "main.c" .text .globl myfunc .type myfunc, @function myfunc: .LFB0: .cfi_startproc pushq %rbp .cfi_def_cfa_offset 16 .cfi_offset 6, -16 movq %rsp, %rbp .cfi_def_cfa_register 6 movl %edi, -4(%rbp) movl -4(%rbp), %eax addl $1, %eax popq %rbp .cfi_def_cfa 7, 8 ret .cfi_endproc .LFE0: .size myfunc, .-myfunc .ident "GCC: (Ubuntu 8.3.0-6ubuntu1) 8.3.0" .section .note.GNU-stack,"",@progbits
If you want to do it for a large number of files, consider using instead:
-save-temps=obj
which saves the intermediate files to the same directory as the -o object output instead of the current working directory, thus avoiding potential basename conflicts.
Another cool thing about this option is if you add -v:
gcc -save-temps -c -o main.o -v main.c
it actually shows the explicit files being used instead of ugly temporaries under /tmp, so it is easy to know exactly what is going on, which includes the preprocessing / compilation / assembly steps:
/usr/lib/gcc/x86_64-linux-gnu/8/cc1 -E -quiet -v -imultiarch x86_64-linux-gnu main.c -mtune=generic -march=x86-64 -fpch-preprocess -fstack-protector-strong -Wformat -Wformat-security -o main.i
/usr/lib/gcc/x86_64-linux-gnu/8/cc1 -fpreprocessed main.i -quiet -dumpbase main.c -mtune=generic -march=x86-64 -auxbase-strip main.o -version -fstack-protector-strong -Wformat -Wformat-security -o main.s
as -v --64 -o main.o main.s
Tested in Ubuntu 19.04 amd64, GCC 8.3.0.
CMake predefined targets
CMake automatically provides a targets for the preprocessed file:
make help
shows us that we can do:
make main.s
and that target runs:
Compiling C source to assembly CMakeFiles/main.dir/main.c.s
/usr/bin/cc -S /home/ciro/hello/main.c -o CMakeFiles/main.dir/main.c.s
so the file can be seen at CMakeFiles/main.dir/main.c.s
Tested on cmake 3.16.1.
How to convert xml into array in php?
easy!
$xml = simplexml_load_string($xmlstring, "SimpleXMLElement", LIBXML_NOCDATA);
$json = json_encode($xml);
$array = json_decode($json,TRUE);
What is the id( ) function used for?
id() does return the address of the object being referenced (in CPython), but your confusion comes from the fact that python lists are very different from C arrays. In a python list, every element is a reference. So what you are doing is much more similar to this C code:
int *arr[3];
arr[0] = malloc(sizeof(int));
*arr[0] = 1;
arr[1] = malloc(sizeof(int));
*arr[1] = 2;
arr[2] = malloc(sizeof(int));
*arr[2] = 3;
printf("%p %p %p", arr[0], arr[1], arr[2]);
In other words, you are printing the address from the reference and not an address relative to where your list is stored.
In my case, I have found the id() function handy for creating opaque handles to return to C code when calling python from C. Doing that, you can easily use a dictionary to look up the object from its handle and it's guaranteed to be unique.
How to run python script with elevated privilege on windows
Make sure you have python in path,if not,win key + r, type in "%appdata%"(without the qotes) open local directory, then go to Programs directory ,open python and then select your python version directory. Click on file tab and select copy path and close file explorer.
Then do win key + r again, type control and hit enter. search for environment variables. click on the result, you will get a window. In the bottom right corner click on environmental variables. In the system side find path, select it and click on edit. In the new window, click on new and paste the path in there. Click ok and then apply in the first window. Restart your PC. Then do win + r for the last time, type cmd and do ctrl + shift + enter. Grant the previliges and open file explorer, goto your script and copy its path. Go back into cmd , type in "python" and paste the path and hit enter. Done
How do I get the time difference between two DateTime objects using C#?
The way I usually do it is subtracting the two DateTime and this gets me a TimeSpan that will tell me the diff.
Here's an example:
DateTime start = DateTime.Now;
// Do some work
TimeSpan timeDiff = DateTime.Now - start;
timeDiff.TotalMilliseconds;
Convert from java.util.date to JodaTime
http://joda-time.sourceforge.net/quickstart.html
Each datetime class provides a variety of constructors. These include the Object constructor. This allows you to construct, for example, DateTime from the following objects:
* Date - a JDK instant
* Calendar - a JDK calendar
* String - in ISO8601 format
* Long - in milliseconds
* any Joda-Time datetime class
Getting the IP Address of a Remote Socket Endpoint
RemoteEndPoint is a property, its type is System.Net.EndPoint which inherits from System.Net.IPEndPoint.
If you take a look at IPEndPoint's members, you'll see that there's an Address property.
How do I enumerate the properties of a JavaScript object?
Python's dict has 'keys' method, and that is really useful. I think in JavaScript we can have something this:
function keys(){
var k = [];
for(var p in this) {
if(this.hasOwnProperty(p))
k.push(p);
}
return k;
}
Object.defineProperty(Object.prototype, "keys", { value : keys, enumerable:false });
EDIT: But the answer of @carlos-ruana works very well. I tested Object.keys(window), and the result is what I expected.
EDIT after 5 years: it is not good idea to extend Object, because it can conflict with other libraries that may want to use keys on their objects and it will lead unpredictable behavior on your project. @carlos-ruana answer is the correct way to get keys of an object.
How to remove underline from a name on hover
To keep the color and prevent an underline on the link:
legend.green-color a{
color:green;
text-decoration: none;
}
Node Sass couldn't find a binding for your current environment
On linux ubuntu 20.04 I needed few steps,downgrade node first to apropriate version,remove node_modules,run yarn install and finally run sudo yarn add [email protected] --force.Node version 10.0.0.
Only working way for me.
How do I sort strings alphabetically while accounting for value when a string is numeric?
My preferred solution (if all strings are numeric only):
// Order by numerical order: (Assertion: all things are numeric strings only)
foreach (var thing in things.OrderBy(int.Parse))
{
Console.Writeline(thing);
}
Get current date in Swift 3?
You say in a comment you want to get "15.09.2016".
For this, use Date and DateFormatter:
let date = Date()
let formatter = DateFormatter()
Give the format you want to the formatter:
formatter.dateFormat = "dd.MM.yyyy"
Get the result string:
let result = formatter.string(from: date)
Set your label:
label.text = result
Result:
15.09.2016
Access-Control-Allow-Origin error sending a jQuery Post to Google API's
Yes, the moment jQuery sees the URL belongs to a different domain, it assumes that call as a cross domain call, thus crossdomain:true is not required here.
Also, important to note that you cannot make a synchronous call with $.ajax if your URL belongs to a different domain (cross domain) or you are using JSONP. Only async calls are allowed.
Note: you can call the service synchronously if you specify the async:false with your request.
unable to install pg gem
Regardless of what OS you are running, look at the logs file of the "Makefile" to see what is going on, instead of blindly installing stuff.
In my case, MAC OS, the log file is here:
/Users/za/.rbenv/versions/2.3.0/lib/ruby/gems/2.3.0/extensions/x86_64-darwin-15/2.3.0-static/pg-1.0.0/mkmf.log
The logs indicated that the make file could not be created because of the following:
Could not create Makefile due to some reason, probably lack of necessary
libraries and/or headers
Inside the mkmf.log, you will see that it could not find required libraries, to finish the build.
checking for pg_config... no
Can't find the 'libpq-fe.h header
blah blah
After running "brew install postgresql", I can see all required libraries being there:
za:myapp za$ cat /Users/za/.rbenv/versions/2.3.0/lib/ruby/gems/2.3.0/extensions/x86_64-darwin-15/2.3.0-static/pg-1.0.0/mkmf.log | grep yes
find_executable: checking for pg_config... -------------------- yes
find_header: checking for libpq-fe.h... -------------------- yes
find_header: checking for libpq/libpq-fs.h... -------------------- yes
find_header: checking for pg_config_manual.h... -------------------- yes
have_library: checking for PQconnectdb() in -lpq... -------------------- yes
have_func: checking for PQsetSingleRowMode()... -------------------- yes
have_func: checking for PQconninfo()... -------------------- yes
have_func: checking for PQsslAttribute()... -------------------- yes
have_func: checking for PQencryptPasswordConn()... -------------------- yes
have_const: checking for PG_DIAG_TABLE_NAME in libpq-fe.h... -------------------- yes
have_header: checking for unistd.h... -------------------- yes
have_header: checking for inttypes.h... -------------------- yes
checking for C99 variable length arrays... -------------------- yes
LinearLayout not expanding inside a ScrollView
I know this post is very old, For those who don't want to use android:fillViewport="true" because it sometimes doesn't bring up the edittext above keyboard.
Use Relative layout instead of LinearLayout it solves the purpose.
How to fully clean bin and obj folders within Visual Studio?
This is how I do with a batch file to delete all BIN and OBJ folders recursively.
- Create an empty file and name it DeleteBinObjFolders.bat
- Copy-paste code the below code into the DeleteBinObjFolders.bat
- Move the DeleteBinObjFolders.bat file in the same folder with your solution (*.sln) file.
@echo off
@echo Deleting all BIN and OBJ folders...
for /d /r . %%d in (bin,obj) do @if exist "%%d" rd /s/q "%%d"
@echo BIN and OBJ folders successfully deleted :) Close the window.
pause > nul
Can dplyr join on multiple columns or composite key?
Updating to use tibble()
You can pass a named vector of length greater than 1 to the by argument of left_join():
library(dplyr)
d1 <- tibble(
x = letters[1:3],
y = LETTERS[1:3],
a = rnorm(3)
)
d2 <- tibble(
x2 = letters[3:1],
y2 = LETTERS[3:1],
b = rnorm(3)
)
left_join(d1, d2, by = c("x" = "x2", "y" = "y2"))
The Controls collection cannot be modified because the control contains code blocks (i.e. <% ... %>)
Check out the solutions at "The Controls collection cannot be modified because the control contains code blocks"
The accepted solution on the other question worked for me -- change instances of <%= to <%#, which converts the code block from Response.Write to an evaluation block, which isn't restricted by the same limitations.
In this case though, like the accepted solution here suggests, you should add the controls to something other than a masterpage ContentPlaceHolder element, namely the asp:Placeholder control suggested.
Remove all git files from a directory?
How to remove all .git directories under a folder in Linux.
Run this find command, it will list all .git directories under the current folder:
find . -type d -name ".git" \
&& find . -name ".gitignore" \
&& find . -name ".gitmodules"
Prints:
./.git
./.gitmodules
./foobar/.git
./footbar2/.git
./footbar2/.gitignore
There should only be like 3 or 4 .git directories because git only has one .git folder for every project. You can rm -rf yourpath each of the above by hand.
If you feel like removing them all in one command and living dangerously:
//Retrieve all the files named ".git" and pump them into 'rm -rf'
//WARNING if you don't understand why/how this command works, DO NOT run it!
( find . -type d -name ".git" \
&& find . -name ".gitignore" \
&& find . -name ".gitmodules" ) | xargs rm -rf
//WARNING, if you accidentally pipe a `.` or `/` or other wildcard
//into xargs rm -rf, then the next question you will have is: "why is
//the bash ls command not found? Requiring an OS reinstall.
How to list the contents of a package using YUM?
There are several good answers here, so let me provide a terrible one:
: you can type in anything below, doesnt have to match anything
yum whatprovides "me with a life"
: result of the above (some liberties taken with spacing):
Loaded plugins: fastestmirror
base | 3.6 kB 00:00
extras | 3.4 kB 00:00
updates | 3.4 kB 00:00
(1/4): extras/7/x86_64/primary_db | 166 kB 00:00
(2/4): base/7/x86_64/group_gz | 155 kB 00:00
(3/4): updates/7/x86_64/primary_db | 9.1 MB 00:04
(4/4): base/7/x86_64/primary_db | 5.3 MB 00:05
Determining fastest mirrors
* base: mirrors.xmission.com
* extras: mirrors.xmission.com
* updates: mirrors.xmission.com
base/7/x86_64/filelists_db | 6.2 MB 00:02
extras/7/x86_64/filelists_db | 468 kB 00:00
updates/7/x86_64/filelists_db | 5.3 MB 00:01
No matches found
: the key result above is that "primary_db" files were downloaded
: filelists are downloaded EVEN IF you have keepcache=0 in your yum.conf
: note you can limit this to "primary_db.sqlite" if you really want
find /var/cache/yum -name '*.sqlite'
: if you download/install a new repo, run the exact same command again
: to get the databases for the new repo
: if you know sqlite you can stop reading here
: if not heres a sample command to dump the contents
echo 'SELECT packages.name, GROUP_CONCAT(files.name, ", ") AS files FROM files JOIN packages ON (files.pkgKey = packages.pkgKey) GROUP BY packages.name LIMIT 10;' | sqlite3 -line /var/cache/yum/x86_64/7/base/gen/primary_db.sqlite
: remove "LIMIT 10" above for the whole list
: format chosen for proof-of-concept purposes, probably can be improved a lotASP.NET MVC 3 - redirect to another action
Your method needs to return a ActionResult type:
public ActionResult Index()
{
//All we want to do is redirect to the class selection page
return RedirectToAction("SelectClasses", "Registration");
}
Invisible characters - ASCII
Other answers are correct -- whether a character is invisible or not depends on what font you use. This seems to be a pretty good list to me of characters that are truly invisible (not even space). It contains some chars that the other lists are missing.
'\u2060', // Word Joiner
'\u2061', // FUNCTION APPLICATION
'\u2062', // INVISIBLE TIMES
'\u2063', // INVISIBLE SEPARATOR
'\u2064', // INVISIBLE PLUS
'\u2066', // LEFT - TO - RIGHT ISOLATE
'\u2067', // RIGHT - TO - LEFT ISOLATE
'\u2068', // FIRST STRONG ISOLATE
'\u2069', // POP DIRECTIONAL ISOLATE
'\u206A', // INHIBIT SYMMETRIC SWAPPING
'\u206B', // ACTIVATE SYMMETRIC SWAPPING
'\u206C', // INHIBIT ARABIC FORM SHAPING
'\u206D', // ACTIVATE ARABIC FORM SHAPING
'\u206E', // NATIONAL DIGIT SHAPES
'\u206F', // NOMINAL DIGIT SHAPES
'\u200B', // Zero-Width Space
'\u200C', // Zero Width Non-Joiner
'\u200D', // Zero Width Joiner
'\u200E', // Left-To-Right Mark
'\u200F', // Right-To-Left Mark
'\u061C', // Arabic Letter Mark
'\uFEFF', // Byte Order Mark
'\u180E', // Mongolian Vowel Separator
'\u00AD' // soft-hyphen
How to add new elements to an array?
You need to use a Collection List. You cannot re-dimension an array.
How to colorize diff on the command line?
diff --color option was added to GNU diffutils 3.4 (2016-08-08)
This is the default diff implementation on most distros, which will soon be getting it.
Ubuntu 18.04 has diffutils 3.6 and therefore has it.
On 3.5 it looks like this:
Tested with:
diff --color -u \
<(seq 6 | sed 's/$/ a/') \
<(seq 8 | grep -Ev '^(2|3)$' | sed 's/$/ a/')
Apparently added in commit c0fa19fe92da71404f809aafb5f51cfd99b1bee2 (Mar 2015).
Word-level diff
Like diff-highlight. Not possible it seems, feature request: https://lists.gnu.org/archive/html/diffutils-devel/2017-01/msg00001.html
Related threads:
- Using 'diff' (or anything else) to get character-level diff between text files
- https://unix.stackexchange.com/questions/11128/diff-within-a-line
- https://superuser.com/questions/496415/using-diff-on-a-long-one-line-file
ydiff does it though, see below.
ydiff side-by-side word level diff
https://github.com/ymattw/ydiff
Is this Nirvana?
python3 -m pip install --user ydiff
diff -u a b | ydiff -s
Outcome:
If the lines are too narrow (default 80 columns), fit to screen with:
diff -u a b | ydiff -w 0 -s
Contents of the test files:
a
1
2
3
4
5 the original line the original line the original line the original line
6
7
8
9
10
11
12
13
14
15 the original line the original line the original line the original line
16
17
18
19
20
b
1
2
3
4
5 the original line teh original line the original line the original line
6
7
8
9
10
11
12
13
14
15 the original line the original line the original line the origlnal line
16
17
18
19
20
ydiff Git integration
ydiff integrates with Git without any configuration required.
From inside a git repository, instead of git diff, you can do just:
ydiff -s
and instead of git log:
ydiff -ls
See also: How can I get a side-by-side diff when I do "git diff"?
Tested on Ubuntu 16.04, git 2.18.0, ydiff 1.1.
Need table of key codes for android and presenter
I had to make my own JSON file to loop on the key codes for android devices
{
"UNKNOWN": "0",
"SOFT_LEFT": "1",
"SOFT_RIGHT": "2",
"HOME": "3",
"BACK": "4",
"CALL": "5",
"ENDCALL": "6",
"0": "7",
"1": "8",
"2": "9",
"3": "10",
"4": "11",
"5": "12",
"6": "13",
"7": "14",
"8": "15",
"9": "16",
"STAR": "17",
"POUND": "18",
"DPAD_UP": "19",
"DPAD_DOWN": "20",
"DPAD_LEFT": "21",
"DPAD_RIGHT": "22",
"DPAD_CENTER": "23",
"VOLUME_UP": "24",
"VOLUME_DOWN": "25",
"POWER": "26",
"CAMERA": "27",
"CLEAR": "28",
"A": "29",
"B": "30",
"C": "31",
"D": "32",
"E": "33",
"F": "34",
"G": "35",
"H": "36",
"I": "37",
"J": "38",
"K": "39",
"L": "40",
"M": "41",
"N": "42",
"O": "43",
"P": "44",
"Q": "45",
"R": "46",
"S": "47",
"T": "48",
"U": "49",
"V": "50",
"W": "51",
"X": "52",
"Y": "53",
"Z": "54",
"COMMA": "55",
"PERIOD": "56",
"ALT_LEFT": "57",
"ALT_RIGHT": "58",
"SHIFT_LEFT": "59",
"SHIFT_RIGHT": "60",
"TAB": "61",
"SPACE": "62",
"SYM": "63",
"EXPLORER": "64",
"ENVELOPE": "65",
"ENTER": "66",
"DEL": "67",
"GRAVE": "68",
"MINUS": "69",
"EQUALS": "70",
"LEFT_BRACKET": "71",
"RIGHT_BRACKET": "72",
"BACKSLASH": "73",
"SEMICOLON": "74",
"APOSTROPHE": "75",
"SLASH": "76",
"AT": "77",
"NUM": "78",
"HEADSETHOOK": "79",
"PLUS": "81",
"MENU": "82",
"NOTIFICATION": "83",
"SEARCH": "84",
"MEDIA_PLAY_PAUSE": "85",
"MEDIA_STOP": "86",
"MEDIA_NEXT": "87",
"MEDIA_PREVIOUS": "88",
"MEDIA_REWIND": "89",
"MEDIA_FAST_FORWARD": "90",
"MUTE": "91",
"PAGE_UP": "92",
"PAGE_DOWN": "93",
"BUTTON_A": "96",
"BUTTON_B": "97",
"BUTTON_C": "98",
"BUTTON_X": "99",
"BUTTON_Y": "100",
"BUTTON_Z": "101",
"BUTTON_L1": "102",
"BUTTON_R1": "103",
"BUTTON_L2": "104",
"BUTTON_R2": "105",
"BUTTON_THUMBL": "106",
"BUTTON_THUMBR": "107",
"BUTTON_START": "108",
"BUTTON_SELECT": "109",
"BUTTON_MODE": "110",
"ESCAPE": "111",
"FORWARD_DEL": "112",
"CTRL_LEFT": "113",
"CTRL_RIGHT": "114",
"CAPS_LOCK": "115",
"SCROLL_LOCK": "116",
"META_LEFT": "117",
"META_RIGHT": "118",
"FUNCTION": "119",
"SYSRQ": "120",
"BREAK": "121",
"MOVE_HOME": "122",
"MOVE_END": "123",
"INSERT": "124",
"FORWARD": "125",
"MEDIA_PLAY": "126",
"MEDIA_PAUSE": "127",
"MEDIA_CLOSE": "128",
"MEDIA_EJECT": "129",
"MEDIA_RECORD": "130",
"F1": "131",
"F2": "132",
"F3": "133",
"F4": "134",
"F5": "135",
"F6": "136",
"F7": "137",
"F8": "138",
"F9": "139",
"F10": "140",
"F11": "141",
"F12": "142",
"NUM_LOCK": "143",
"NUMPAD_0": "144",
"NUMPAD_1": "145",
"NUMPAD_2": "146",
"NUMPAD_3": "147",
"NUMPAD_4": "148",
"NUMPAD_5": "149",
"NUMPAD_6": "150",
"NUMPAD_7": "151",
"NUMPAD_8": "152",
"NUMPAD_9": "153",
"NUMPAD_DIVIDE": "154",
"NUMPAD_MULTIPLY": "155",
"NUMPAD_SUBTRACT": "156",
"NUMPAD_ADD": "157",
"NUMPAD_DOT": "158",
"NUMPAD_COMMA": "159",
"NUMPAD_ENTER": "160",
"NUMPAD_EQUALS": "161",
"NUMPAD_LEFT_PAREN": "162",
"NUMPAD_RIGHT_PAREN": "163",
"VOLUME_MUTE": "164",
"INFO": "165",
"CHANNEL_UP": "166",
"CHANNEL_DOWN": "167",
"ZOOM_IN": "168",
"ZOOM_OUT": "169",
"TV": "170",
"WINDOW": "171",
"GUIDE": "172",
"DVR": "173",
"BOOKMARK": "174",
"CAPTIONS": "175",
"SETTINGS": "176",
"TV_POWER": "177",
"TV_INPUT": "178",
"STB_POWER": "179",
"STB_INPUT": "180",
"AVR_POWER": "181",
"AVR_INPUT": "182",
"PROG_RED": "183",
"PROG_GREEN": "184",
"PROG_YELLOW": "185",
"PROG_BLUE": "186",
"APP_SWITCH": "187",
"BUTTON_1": "188",
"BUTTON_2": "189",
"BUTTON_3": "190",
"BUTTON_4": "191",
"BUTTON_5": "192",
"BUTTON_6": "193",
"BUTTON_7": "194",
"BUTTON_8": "195",
"BUTTON_9": "196",
"BUTTON_10": "197",
"BUTTON_11": "198",
"BUTTON_12": "199",
"BUTTON_13": "200",
"BUTTON_14": "201",
"BUTTON_15": "202",
"BUTTON_16": "203",
"LANGUAGE_SWITCH": "204",
"MANNER_MODE": "205",
"3D_MODE": "206",
"CONTACTS": "207",
"CALENDAR": "208",
"MUSIC": "209",
"CALCULATOR": "210",
"ZENKAKU_HANKAKU": "211",
"EISU": "212",
"MUHENKAN": "213",
"HENKAN": "214",
"KATAKANA_HIRAGANA": "215",
"YEN": "216",
"RO": "217",
"KANA": "218",
"ASSIST": "219",
"BRIGHTNESS_DOWN": "220",
"BRIGHTNESS_UP": "221",
"MEDIA_AUDIO_TRACK": "222",
"SLEEP": "223",
"WAKEUP": "224",
"PAIRING": "225",
"MEDIA_TOP_MENU": "226",
"11": "227",
"12": "228",
"LAST_CHANNEL": "229",
"TV_DATA_SERVICE": "230",
"VOICE_ASSIST": "231",
"TV_RADIO_SERVICE": "232",
"TV_TELETEXT": "233",
"TV_NUMBER_ENTRY": "234",
"TV_TERRESTRIAL_ANALOG": "235",
"TV_TERRESTRIAL_DIGITAL": "236",
"TV_SATELLITE": "237",
"TV_SATELLITE_BS": "238",
"TV_SATELLITE_CS": "239",
"TV_SATELLITE_SERVICE": "240",
"TV_NETWORK": "241",
"TV_ANTENNA_CABLE": "242",
"TV_INPUT_HDMI_1": "243",
"TV_INPUT_HDMI_2": "244",
"TV_INPUT_HDMI_3": "245",
"TV_INPUT_HDMI_4": "246",
"TV_INPUT_COMPOSITE_1": "247",
"TV_INPUT_COMPOSITE_2": "248",
"TV_INPUT_COMPONENT_1": "249",
"TV_INPUT_COMPONENT_2": "250",
"TV_INPUT_VGA_1": "251",
"TV_AUDIO_DESCRIPTION": "252",
"TV_AUDIO_DESCRIPTION_MIX_UP": "253",
"TV_AUDIO_DESCRIPTION_MIX_DOWN": "254",
"TV_ZOOM_MODE": "255",
"TV_CONTENTS_MENU": "256",
"TV_MEDIA_CONTEXT_MENU": "257",
"TV_TIMER_PROGRAMMING": "258",
"HELP": "259",
"NAVIGATE_PREVIOUS": "260",
"NAVIGATE_NEXT": "261",
"NAVIGATE_IN": "262",
"NAVIGATE_OUT": "263",
"STEM_PRIMARY": "264",
"STEM_1": "265",
"STEM_2": "266",
"STEM_3": "267",
"DPAD_UP_LEFT": "268",
"DPAD_DOWN_LEFT": "269",
"DPAD_UP_RIGHT": "270",
"DPAD_DOWN_RIGHT": "271",
"MEDIA_SKIP_FORWARD": "272",
"MEDIA_SKIP_BACKWARD": "273",
"MEDIA_STEP_FORWARD": "274",
"MEDIA_STEP_BACKWARD": "275",
"SOFT_SLEEP": "276",
"CUT": "277",
"COPY": "278",
"PASTE": "279",
"SYSTEM_NAVIGATION_UP": "280",
"SYSTEM_NAVIGATION_DOWN": "281",
"SYSTEM_NAVIGATION_LEFT": "282",
"SYSTEM_NAVIGATION_RIGHT": "283"
}
Android Whatsapp/Chat Examples
If you are looking to create an instant messenger for Android, this code should get you started somewhere.
Excerpt from the source :
This is a simple IM application runs on Android, application makes http request to a server, implemented in php and mysql, to authenticate, to register and to get the other friends' status and data, then it communicates with other applications in other devices by socket interface.
EDIT : Just found this! Maybe it's not related to WhatsApp. But you can use the source to understand how chat applications are programmed.
There is a website called Scringo. These awesome people provide their own SDK which you can integrate in your existing application to exploit cool features like radaring, chatting, feedback, etc. So if you are looking to integrate chat in application, you could just use their SDK. And did I say the best part? It's free!
*UPDATE : * Scringo services will be closed down on 15 February, 2015.
Conda update failed: SSL error: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed
For those of us on corporate networks using web filters that implement trusted man in the middle SSL solutions, it is necessary to add the web-filter certificate to the certifi cacert.pem.
A guide to doing this is here.
Main steps are:
- connect to https site with browser
- view and save root certificate
- convert cert to .pem
- copy and paste onto end of existing cacert.pem
- save
- SSL happiness
http://localhost:50070 does not work HADOOP
- step 1 : bin/stop-all.sh
- step 2 : bin/hadoop namenode -format
- step 3 : bin/start-all.sh
How to get the current time as datetime
Swift 5
func printTimestamp() {
let timestamp = DateFormatter.localizedString(from: NSDate() as Date, dateStyle: .medium, timeStyle: .short)
print(timestamp)
}
and Call function printTimestamp()
How to remove duplicates from a list?
I suspect you might not have Customer.equals() implemented properly (or at all).
List.contains() uses equals() to verify whether any of its elements is identical to the object passed as parameter. However, the default implementation of equals tests for physical identity, not value identity. So if you have not overwritten it in Customer, it will return false for two distinct Customer objects having identical state.
Here are the nitty-gritty details of how to implement equals (and hashCode, which is its pair - you must practically always implement both if you need to implement either of them). Since you haven't shown us the Customer class, it is difficult to give more concrete advice.
As others have noted, you are better off using a Set rather than doing the job by hand, but even for that, you still need to implement those methods.
Python - Get path of root project structure
Here's my take on this issue.
I have a simple use-case that bugged me for a while. Tried a few solutions, but I didn't like either of them flexible enough.
So here's what I figured out.
- create a blank python file in the root dir -> I call this
beacon.py
(assuming that the project root is in the PYTHONPATH so it can be imported) - add a few lines to my module/class which I call here
not_in_root.py.
This will import thebeacon.pymodule and get the path to that module
Here's an example project structure
this_project
+-- beacon.py
+-- lv1
¦ +-- __init__.py
¦ +-- lv2
¦ +-- __init__.py
¦ +-- not_in_root.py
...
The content of the not_in_root.py
import os
from pathlib import Path
class Config:
try:
import beacon
print(f"'import beacon' -> {os.path.dirname(os.path.abspath(beacon.__file__))}") # only for demo purposes
print(f"'import beacon' -> {Path(beacon.__file__).parent.resolve()}") # only for demo purposes
except ModuleNotFoundError as e:
print(f"ModuleNotFoundError: import beacon failed with {e}. "
f"Please. create a file called beacon.py and place it to the project root directory.")
project_root = Path(beacon.__file__).parent.resolve()
input_dir = project_root / 'input'
output_dir = project_root / 'output'
if __name__ == '__main__':
c = Config()
print(f"Config.project_root: {c.project_root}")
print(f"Config.input_dir: {c.input_dir}")
print(f"Config.output_dir: {c.output_dir}")
The output would be
/home/xyz/projects/this_project/venv/bin/python /home/xyz/projects/this_project/lv1/lv2/not_in_root.py
'import beacon' -> /home/xyz/projects/this_project
'import beacon' -> /home/xyz/projects/this_project
Config.project_root: /home/xyz/projects/this_project
Config.input_dir: /home/xyz/projects/this_project/input
Config.output_dir: /home/xyz/projects/this_project/output
Of course, it doesn't need to be called beacon.py nor need to be empty, essentially any python file (importable) file would do as long as it's in the root directory.
Using an empty .py file sort of guarantees that it will not be moved elsewhere due to some future refactoring.
Cheers
How to develop or migrate apps for iPhone 5 screen resolution?
According to me the best way of dealing with such problems and avoiding couple of condition required for checking the the height of device, is using the relative frame for views or any UI element which you are adding to you view for example: if you are adding some UI element which you want should at the bottom of view or just above tab bar then you should take the y origin with respect to your view's height or with respect to tab bar (if present) and we have auto resizing property as well. I hope this will work for you
Appending a line to a file only if it does not already exist
Using sed: It will insert at the end of line. You can also pass in variables as usual of course.
grep -qxF "port=9033" $light.conf
if [ $? -ne 0 ]; then
sed -i "$ a port=9033" $light.conf
else
echo "port=9033 already added"
fi
Using oneliner sed
grep -qxF "port=9033" $lightconf || sed -i "$ a port=9033" $lightconf
Using echo may not work under root, but will work like this. But it will not let you automate things if you are looking to do it since it might ask for password.
I had a problem when I was trying to edit from the root for a particular user. Just adding the $username before was a fix for me.
grep -qxF "port=9033" light.conf
if [ $? -ne 0 ]; then
sudo -u $user_name echo "port=9033" >> light.conf
else
echo "already there"
fi
Module not found: Error: Can't resolve 'core-js/es6'
I found possible answer. You have core-js version 3.0, and this version doesn't have separate folders for ES6 and ES7; that's why the application cannot find correct paths.
To resolve this error, you can downgrade the core-js version to 2.5.7. This version produces correct catalogs structure, with separate ES6 and ES7 folders.
To downgrade the version, simply run:
npm i -S [email protected]
In my case, with Angular, this works ok.
Git - fatal: Unable to create '/path/my_project/.git/index.lock': File exists
Use This:
rm -Force ./.git/index.lock
YAML: Do I need quotes for strings in YAML?
After a brief review of the YAML cookbook cited in the question and some testing, here's my interpretation:
- In general, you don't need quotes.
- Use quotes to force a string, e.g. if your key or value is
10but you want it to return a String and not a Fixnum, write'10'or"10". - Use quotes if your value includes special characters, (e.g.
:,{,},[,],,,&,*,#,?,|,-,<,>,=,!,%,@,\). - Single quotes let you put almost any character in your string, and won't try to parse escape codes.
'\n'would be returned as the string\n. - Double quotes parse escape codes.
"\n"would be returned as a line feed character. - The exclamation mark introduces a method, e.g.
!ruby/symto return a Ruby symbol.
Seems to me that the best approach would be to not use quotes unless you have to, and then to use single quotes unless you specifically want to process escape codes.
Update
"Yes" and "No" should be enclosed in quotes (single or double) or else they will be interpreted as TrueClass and FalseClass values:
en:
yesno:
'yes': 'Yes'
'no': 'No'
Using JsonConvert.DeserializeObject to deserialize Json to a C# POCO class
Here is a working example.
Keypoints are:
- Declaration of
Accounts - Use of
JsonPropertyattribute
.
using (WebClient wc = new WebClient())
{
var json = wc.DownloadString("http://coderwall.com/mdeiters.json");
var user = JsonConvert.DeserializeObject<User>(json);
}
-
public class User
{
/// <summary>
/// A User's username. eg: "sergiotapia, mrkibbles, matumbo"
/// </summary>
[JsonProperty("username")]
public string Username { get; set; }
/// <summary>
/// A User's name. eg: "Sergio Tapia, John Cosack, Lucy McMillan"
/// </summary>
[JsonProperty("name")]
public string Name { get; set; }
/// <summary>
/// A User's location. eh: "Bolivia, USA, France, Italy"
/// </summary>
[JsonProperty("location")]
public string Location { get; set; }
[JsonProperty("endorsements")]
public int Endorsements { get; set; } //Todo.
[JsonProperty("team")]
public string Team { get; set; } //Todo.
/// <summary>
/// A collection of the User's linked accounts.
/// </summary>
[JsonProperty("accounts")]
public Account Accounts { get; set; }
/// <summary>
/// A collection of the User's awarded badges.
/// </summary>
[JsonProperty("badges")]
public List<Badge> Badges { get; set; }
}
public class Account
{
public string github;
}
public class Badge
{
[JsonProperty("name")]
public string Name;
[JsonProperty("description")]
public string Description;
[JsonProperty("created")]
public string Created;
[JsonProperty("badge")]
public string BadgeUrl;
}
A select query selecting a select statement
I was over-complicating myself. After taking a long break and coming back, the desired output could be accomplished by this simple query:
SELECT Sandwiches.[Sandwich Type], Sandwich.Bread, Count(Sandwiches.[SandwichID]) AS [Total Sandwiches]
FROM Sandwiches
GROUP BY Sandwiches.[Sandwiches Type], Sandwiches.Bread;
Thanks for answering, it helped my train of thought.