How to check if a table contains an element in Lua?
I can't think of another way to compare values, but if you use the element of the set as the key, you can set the value to anything other than nil. Then you get fast lookups without having to search the entire table.
Select unique or distinct values from a list in UNIX shell script
For larger data sets where sorting may not be desirable, you can also use the following perl script:
./yourscript.ksh | perl -ne 'if (!defined $x{$_}) { print $_; $x{$_} = 1; }'
This basically just remembers every line output so that it doesn't output it again.
It has the advantage over the "sort | uniq
" solution in that there's no sorting required up front.
How to create a unique index on a NULL column?
The calculated column trick is widely known as a "nullbuster"; my notes credit Steve Kass:
CREATE TABLE dupNulls (
pk int identity(1,1) primary key,
X int NULL,
nullbuster as (case when X is null then pk else 0 end),
CONSTRAINT dupNulls_uqX UNIQUE (X,nullbuster)
)
Python: How to create a unique file name?
You can use the datetime module
import datetime
uniq_filename = str(datetime.datetime.now().date()) + '_' + str(datetime.datetime.now().time()).replace(':', '.')
Note that:
I am using replace
since the colons are not allowed in filenames in many operating systems.
That's it, this will give you a unique filename every single time.
How can I do SELECT UNIQUE with LINQ?
Using query comprehension syntax you could achieve the orderby as follows:
var uniqueColors = (from dbo in database.MainTable
where dbo.Property
orderby dbo.Color.Name ascending
select dbo.Color.Name).Distinct();
How can I check if the array of objects have duplicate property values?
ECMA Script 6 Version
If you are in an environment which supports ECMA Script 6's Set
, then you can use Array.prototype.some
and a Set
object, like this
let seen = new Set();
var hasDuplicates = values.some(function(currentObject) {
return seen.size === seen.add(currentObject.name).size;
});
Here, we insert each and every object's name
into the Set
and we check if the size
before and after adding are the same. This works because Set.size
returns a number based on unique data (set only adds entries if the data is unique). If/when you have duplicate names, the size won't increase (because the data won't be unique) which means that we would have already seen the current name and it will return true.
ECMA Script 5 Version
If you don't have Set
support, then you can use a normal JavaScript object itself, like this
var seen = {};
var hasDuplicates = values.some(function(currentObject) {
if (seen.hasOwnProperty(currentObject.name)) {
// Current name is already seen
return true;
}
// Current name is being seen for the first time
return (seen[currentObject.name] = false);
});
The same can be written succinctly, like this
var seen = {};
var hasDuplicates = values.some(function (currentObject) {
return seen.hasOwnProperty(currentObject.name)
|| (seen[currentObject.name] = false);
});
Note: In both the cases, we use Array.prototype.some
because it will short-circuit. The moment it gets a truthy value from the function, it will return true
immediately, it will not process rest of the elements.
Combine two arrays
Just use:
$output = array_merge($array1, $array2);
That should solve it. Because you use string keys if one key occurs more than one time (like '44'
in your example) one key will overwrite proceding ones with the same name. Because in your case they both have the same value anyway it doesn't matter and it will also remove duplicates.
Update: I just realised, that PHP treats the numeric string-keys as numbers (integers) and so will behave like this, what means, that it renumbers the keys too...
A workaround is to recreate the keys.
$output = array_combine($output, $output);
Update 2: I always forget, that there is also an operator (in bold, because this is really what you are looking for! :D)
$output = $array1 + $array2;
All of this can be seen in:
http://php.net/manual/en/function.array-merge.php
How do you remove duplicates from a list whilst preserving order?
this will preserve order and run in O(n) time. basically the idea is to create a hole wherever there is a duplicate found and sink it down to the bottom. makes use of a read and write pointer. whenever a duplicate is found only the read pointer advances and write pointer stays on the duplicate entry to overwrite it.
def deduplicate(l):
count = {}
(read,write) = (0,0)
while read < len(l):
if l[read] in count:
read += 1
continue
count[l[read]] = True
l[write] = l[read]
read += 1
write += 1
return l[0:write]
Unique on a dataframe with only selected columns
Here are a couple dplyr
options that keep non-duplicate rows based on columns id and id2:
library(dplyr)
df %>% distinct(id, id2, .keep_all = TRUE)
df %>% group_by(id, id2) %>% filter(row_number() == 1)
df %>% group_by(id, id2) %>% slice(1)
Firebase: how to generate a unique numeric ID for key?
I'd suggest reading through the Firebase documentation. Specifically, see the Saving Data portion of the Firebase JavaScript Web Guide.
From the guide:
Getting the Unique ID Generated by push()
Calling push()
will return a reference to the new data path, which you can use to get the value of its ID or set data to it. The following code will result in the same data as the above example, but now we'll have access to the unique push ID that was generated
// Generate a reference to a new location and add some data using push()
var newPostRef = postsRef.push({
author: "gracehop",
title: "Announcing COBOL, a New Programming Language"
});
// Get the unique ID generated by push() by accessing its key
var postID = newPostRef.key;
Source: https://firebase.google.com/docs/database/admin/save-data#section-ways-to-save
- A push generates a new data path, with a server timestamp as its
key
. These keys look like -JiGh_31GA20JabpZBfa
, so not numeric.
- If you wanted to make a numeric only ID, you would make that a parameter of the object to avoid overwriting the generated key.
- The keys (the paths of the new data) are guaranteed to be unique, so there's no point in overwriting them with a numeric key.
- You can instead set the numeric ID as a child of the object.
- You can then query objects by that ID child using Firebase Queries.
From the guide:
In JavaScript, the pattern of calling push()
and then immediately calling set()
is so common that we let you combine them by just passing the data to be set directly to push()
as follows. Both of the following write operations will result in the same data being saved to Firebase:
// These two methods are equivalent:
postsRef.push().set({
author: "gracehop",
title: "Announcing COBOL, a New Programming Language"
});
postsRef.push({
author: "gracehop",
title: "Announcing COBOL, a New Programming Language"
});
Source: https://firebase.google.com/docs/database/admin/save-data#getting-the-unique-key-generated-by-push
Generate 'n' unique random numbers within a range
Generate the range of data first and then shuffle it like this
import random
data = range(numLow, numHigh)
random.shuffle(data)
print data
By doing this way, you will get all the numbers in the particular range but in a random order.
But you can use random.sample
to get the number of elements you need, from a range of numbers like this
print random.sample(range(numLow, numHigh), 3)
In Postgresql, force unique on combination of two columns
If, like me, you landed here with:
- a pre-existing table,
- to which you need to add a new column, and
- also need to add a new unique constraint on the new column as well as an old one, AND
- be able to undo it all (i.e. write a down migration)
Here is what worked for me, utilizing one of the above answers and expanding it:
-- up
ALTER TABLE myoldtable ADD COLUMN newcolumn TEXT;
ALTER TABLE myoldtable ADD CONSTRAINT myoldtable_oldcolumn_newcolumn_key UNIQUE (oldcolumn, newcolumn);
---
ALTER TABLE myoldtable DROP CONSTRAINT myoldtable_oldcolumn_newcolumn_key;
ALTER TABLE myoldtable DROP COLUMN newcolumn;
-- down
Create a unique number with javascript time
function UniqueValue(d){
var dat_e = new Date();
var uniqu_e = ((Math.random() *1000) +"").slice(-4)
dat_e = dat_e.toISOString().replace(/[^0-9]/g, "").replace(dat_e.getFullYear(),uniqu_e);
if(d==dat_e)
dat_e = UniqueValue(dat_e);
return dat_e;
}
Call 1: UniqueValue('0')
Call 2: UniqueValue(UniqueValue('0')) // will be complex
Sample Output:
for(var i =0;i<10;i++){ console.log(UniqueValue(UniqueValue('0')));}
60950116113248802
26780116113248803
53920116113248803
35840116113248803
47430116113248803
41680116113248803
42980116113248804
34750116113248804
20950116113248804
03730116113248804
Plot multiple lines (data series) each with unique color in R
You have the right general strategy for doing this using base graphics, but as was pointed out you're essentially telling R to pick a random color from a set of 10 for each line. Given that, it's not surprising that you will occasionally get two lines with the same color. Here's an example using base graphics:
plot(0,0,xlim = c(-10,10),ylim = c(-10,10),type = "n")
cl <- rainbow(5)
for (i in 1:5){
lines(-10:10,runif(21,-10,10),col = cl[i],type = 'b')
}
Note the use of type = "n"
to suppress all plotting in the original call to set up the window, and the indexing of cl
inside the for loop.
Count unique values with pandas per groups
Generally to count distinct values in single column, you can use Series.value_counts
:
df.domain.value_counts()
#'vk.com' 5
#'twitter.com' 2
#'facebook.com' 1
#'google.com' 1
#Name: domain, dtype: int64
To see how many unique values in a column, use Series.nunique
:
df.domain.nunique()
# 4
To get all these distinct values, you can use unique
or drop_duplicates
, the slight difference between the two functions is that unique
return a numpy.array
while drop_duplicates
returns a pandas.Series
:
df.domain.unique()
# array(["'vk.com'", "'twitter.com'", "'facebook.com'", "'google.com'"], dtype=object)
df.domain.drop_duplicates()
#0 'vk.com'
#2 'twitter.com'
#4 'facebook.com'
#6 'google.com'
#Name: domain, dtype: object
As for this specific problem, since you'd like to count distinct value with respect to another variable, besides groupby
method provided by other answers here, you can also simply drop duplicates firstly and then do value_counts()
:
import pandas as pd
df.drop_duplicates().domain.value_counts()
# 'vk.com' 3
# 'twitter.com' 2
# 'facebook.com' 1
# 'google.com' 1
# Name: domain, dtype: int64
Find unique lines
While sort
takes O(n log(n)) time, I prefer using
awk '!seen[$0]++'
awk '!seen[$0]++'
is an abbreviation for awk '!seen[$0]++ {print}'
, print line(=$0) if seen[$0]
is not zero.
It take more space but only O(n) time.
unique() for more than one variable
How about using unique()
itself?
df <- data.frame(yad = c("BARBIE", "BARBIE", "BAKUGAN", "BAKUGAN"),
per = c("AYLIK", "AYLIK", "2 AYLIK", "2 AYLIK"),
hmm = 1:4)
df
# yad per hmm
# 1 BARBIE AYLIK 1
# 2 BARBIE AYLIK 2
# 3 BAKUGAN 2 AYLIK 3
# 4 BAKUGAN 2 AYLIK 4
unique(df[c("yad", "per")])
# yad per
# 1 BARBIE AYLIK
# 3 BAKUGAN 2 AYLIK
vba: get unique values from array
If the order of the deduplicated array does not matter to you, you can use my pragmatic function:
Function DeDupArray(ia() As String)
Dim newa() As String
ReDim newa(999)
ni = -1
For n = LBound(ia) To UBound(ia)
dup = False
If n <= UBound(ia) Then
For k = n + 1 To UBound(ia)
If ia(k) = ia(n) Then dup = True
Next k
If dup = False And Trim(ia(n)) <> "" Then
ni = ni + 1
newa(ni) = ia(n)
End If
End If
Next n
If ni > -1 Then
ReDim Preserve newa(ni)
Else
ReDim Preserve newa(1)
End If
DeDupArray = newa
End Function
Sub testdedup()
Dim m(5) As String
Dim m2() As String
m(0) = "Horse"
m(1) = "Cow"
m(2) = "Dear"
m(3) = "Horse"
m(4) = "Joke"
m(5) = "Cow"
m2 = DeDupArray(m)
t = ""
For n = LBound(m2) To UBound(m2)
t = t & n & "=" & m2(n) & " "
Next n
MsgBox t
End Sub
From the test function, it will result in the following deduplicated array:
"0=Dear 1=Horse 2=Joke 3=Cow "
How do I remove duplicate items from an array in Perl?
Previous answers pretty much summarize the possible ways of accomplishing this task.
However, I suggest a modification for those who don't care about counting the duplicates, but do care about order.
my @record = qw( yeah I mean uh right right uh yeah so well right I maybe );
my %record;
print grep !$record{$_} && ++$record{$_}, @record;
Note that the previously suggested grep !$seen{$_}++ ...
increments $seen{$_}
before negating, so the increment occurs regardless of whether it has already been %seen
or not. The above, however, short-circuits when $record{$_}
is true, leaving what's been heard once 'off the %record
'.
You could also go for this ridiculousness, which takes advantage of autovivification and existence of hash keys:
...
grep !(exists $record{$_} || undef $record{$_}), @record;
That, however, might lead to some confusion.
And if you care about neither order or duplicate count, you could for another hack using hash slices and the trick I just mentioned:
...
undef @record{@record};
keys %record; # your record, now probably scrambled but at least deduped
How to select only the first rows for each unique value of a column?
You can use row_number()
to get the row number of the row. It uses the over
command - the partition by
clause specifies when to restart the numbering and the order by
selects what to order the row number on. Even if you added an order by
to the end of your query, it would preserve the ordering in the over
command when numbering.
select *
from mytable
where row_number() over(partition by Name order by AddressLine) = 1
Javascript array sort and unique
A way to use a custom sort function
//func has to return 0 in the case in which they are equal
sort_unique = function(arr,func) {
func = func || function (a, b) {
return a*1 - b*1;
};
arr = arr.sort(func);
var ret = [arr[0]];
for (var i = 1; i < arr.length; i++) {
if (func(arr[i-1],arr[i]) != 0)
ret.push(arr[i]);
}
}
return ret;
}
Example: desc order for an array of objects
MyArray = sort_unique(MyArray , function(a,b){
return b.iterator_internal*1 - a.iterator_internal*1;
});
.NET unique object identifier
How about this method:
Set a field in the first object to a new value. If the same field in the second object has the same value, it's probably the same instance. Otherwise, exit as different.
Now set the field in the first object to a different new value. If the same field in the second object has changed to the different value, it's definitely the same instance.
Don't forget to set field in the first object back to it's original value on exit.
Problems?
Can I use VARCHAR as the PRIMARY KEY?
Of course you can, in the sense that your RDBMS will let you do it. The answer to a question of whether or not you should do it is different, though: in most situations, values that have a meaning outside your database system should not be chosen to be a primary key.
If you know that the value is unique in the system that you are modeling, it is appropriate to add a unique index or a unique constraint to your table. However, your primary key should generally be some "meaningless" value, such as an auto-incremented number or a GUID.
The rationale for this is simple: data entry errors and infrequent changes to things that appear non-changeable do happen. They become much harder to fix on values which are used as primary keys.
SQL - select distinct only on one column
You will use the following query:
SELECT * FROM [table] GROUP BY NUMBER;
Where [table]
is the name of the table.
This provides a unique listing for the NUMBER
column however the other columns may be meaningless depending on the vendor implementation; which is to say they may not together correspond to a specific row or rows.
pandas unique values multiple columns
Non-pandas
solution: using set().
import pandas as pd
import numpy as np
df = pd.DataFrame({'Col1' : ['Bob', 'Joe', 'Bill', 'Mary', 'Joe'],
'Col2' : ['Joe', 'Steve', 'Bob', 'Bob', 'Steve'],
'Col3' : np.random.random(5)})
print df
print set(df.Col1.append(df.Col2).values)
Output:
Col1 Col2 Col3
0 Bob Joe 0.201079
1 Joe Steve 0.703279
2 Bill Bob 0.722724
3 Mary Bob 0.093912
4 Joe Steve 0.766027
set(['Steve', 'Bob', 'Bill', 'Joe', 'Mary'])
Count number of occurences for each unique value
If you need to have the number of unique values as an additional column in the data frame containing your values (a column which may represent sample size for example), plyr provides a neat way:
data_frame <- data.frame(v = rep(c(1,2, 2, 2), 25))
library("plyr")
data_frame <- ddply(data_frame, .(v), transform, n = length(v))
Get all unique values in a JavaScript array (remove duplicates)
This one is not pure, it will modify the array, but this is the fastest one. If yours is faster, then please write in the comments ;)
http://jsperf.com/unique-array-webdeb
Array.prototype.uniq = function(){
for(var i = 0, l = this.length; i < l; ++i){
var item = this[i];
var duplicateIdx = this.indexOf(item, i + 1);
while(duplicateIdx != -1) {
this.splice(duplicateIdx, 1);
duplicateIdx = this.indexOf(item, duplicateIdx);
l--;
}
}
return this;
}
[
"",2,4,"A","abc",
"",2,4,"A","abc",
"",2,4,"A","abc",
"",2,4,"A","abc",
"",2,4,"A","abc",
"",2,4,"A","abc",
"",2,4,"A","abc",
"",2,4,"A","abc"
].uniq() // ["",2,4,"A","abc"]
How do I count unique values inside a list
For ndarray there is a numpy method called unique:
np.unique(array_name)
Examples:
>>> np.unique([1, 1, 2, 2, 3, 3])
array([1, 2, 3])
>>> a = np.array([[1, 1], [2, 3]])
>>> np.unique(a)
array([1, 2, 3])
For a Series there is a function call value_counts():
Series_name.value_counts()
Count number of times a date occurs and make a graph out of it
The simplest is to do a PivotChart.
Select your array of dates (with a header) and create a new Pivot Chart (Insert / PivotChart / Ok)
Then on the field list window, drag and drop the date column in the Axis list first and then in the value list first.
Step 1:
Step 2:
Getting unique items from a list
Use a HashSet<T>
. For example:
var items = "A B A D A C".Split(' ');
var unique_items = new HashSet<string>(items);
foreach (string s in unique_items)
Console.WriteLine(s);
prints
A
B
D
C
Find unique rows in numpy.array
Beyond @Jaime excellent answer, another way to collapse a row is to uses a.strides[0]
(assuming a
is C-contiguous) which is equal to a.dtype.itemsize*a.shape[0]
. Furthermore void(n)
is a shortcut for dtype((void,n))
. we arrive finally to this shortest version :
a[unique(a.view(void(a.strides[0])),1)[1]]
For
[[0 1 1 1 0 0]
[1 1 1 0 0 0]
[1 1 1 1 1 0]]
Remove duplicate values from JS array
In ECMAScript 6 (aka ECMAScript 2015), Set
can be used to filter out duplicates. Then it can be converted back to an array using the spread operator.
var names = ["Mike","Matt","Nancy","Adam","Jenny","Nancy","Carl"],
unique = [...new Set(names)];
Select unique values with 'select' function in 'dplyr' library
Just to add to the other answers, if you would prefer to return a vector rather than a dataframe, you have the following options:
dplyr < 0.7.0
Enclose the dplyr functions in a parentheses and combine it with $
syntax:
(mtcars %>% distinct(cyl))$cyl
dplyr >= 0.7.0
Use the pull
verb:
mtcars %>% distinct(cyl) %>% pull()
Find the unique values in a column and then sort them
sorted
return a new sorted list from the items in iterable.
CODE
import pandas as pd
df = pd.DataFrame({'A':[1,1,3,2,6,2,8]})
a = df['A'].unique()
print sorted(a)
OUTPUT
[1, 2, 3, 6, 8]
Using .Select and .Where in a single LINQ statement
Did you add the Select()
after the Where()
or before?
You should add it after, because of the concurrency logic:
1 Take the entire table
2 Filter it accordingly
3 Select only the ID's
4 Make them distinct.
If you do a Select first, the Where clause can only contain the ID attribute because all other attributes have already been edited out.
Update: For clarity, this order of operators should work:
db.Items.Where(x=> x.userid == user_ID).Select(x=>x.Id).Distinct();
Probably want to add a .toList()
at the end but that's optional :)
How to get distinct values from an array of objects in JavaScript?
Here's a versatile solution that uses reduce, allows for mapping, and maintains insertion order.
items: An array
mapper: A unary function that maps the item to the criteria, or empty to map the item itself.
function distinct(items, mapper) {
if (!mapper) mapper = (item)=>item;
return items.map(mapper).reduce((acc, item) => {
if (acc.indexOf(item) === -1) acc.push(item);
return acc;
}, []);
}
Usage
const distinctLastNames = distinct(items, (item)=>item.lastName);
const distinctItems = distinct(items);
You can add this to your Array prototype and leave out the items parameter if that's your style...
const distinctLastNames = items.distinct( (item)=>item.lastName) ) ;
const distinctItems = items.distinct() ;
You can also use a Set instead of an Array to speed up the matching.
function distinct(items, mapper) {
if (!mapper) mapper = (item)=>item;
return items.map(mapper).reduce((acc, item) => {
acc.add(item);
return acc;
}, new Set());
}
Regular cast vs. static_cast vs. dynamic_cast
C-style casts conflate const_cast, static_cast, and reinterpret_cast.
I wish C++ didn't have C-style casts. C++ casts stand out properly (as they should; casts are normally indicative of doing something bad) and properly distinguish between the different kinds of conversion that casts perform. They also permit similar-looking functions to be written, e.g. boost::lexical_cast, which is quite nice from a consistency perspective.
Could not load file or assembly ... An attempt was made to load a program with an incorrect format (System.BadImageFormatException)
The Chilkat .NET 4.5 assembly requires the VC++ 2012 or 2013 runtime to be installed on any computer where your application runs. Most computers will already have it installed. Your development computer will have it because Visual Studio has been installed. However, if deploying to a computer where the required VC++ runtime is not available, the above error will occur:
Install all of the bellow packages
Visual C++ Redistributable Packages for Visual Studio 2013 - vcredist_x64
Visual C++ Redistributable Packages for Visual Studio 2013 - vcredist_x86
Visual C++ Redistributable Packages for Visual Studio 2012 - vcredist_x64
Visual C++ Redistributable Packages for Visual Studio 2012 - vcredist_x86
How to import a CSS file in a React Component
I would suggest using CSS Modules:
React
import React from 'react';
import styles from './table.css';
export default class Table extends React.Component {
render () {
return <div className={styles.table}>
<div className={styles.row}>
<div className={styles.cell}>A0</div>
<div className={styles.cell}>B0</div>
</div>
</div>;
}
}
Rendering the Component:
<div class="table__table___32osj">
<div class="table__row___2w27N">
<div class="table__cell___2w27N">A0</div>
<div class="table__cell___1oVw5">B0</div>
</div>
</div>
How to use forEach in vueJs?
You can also use .map() as:
var list=[];
response.data.message.map(function(value, key) {
list.push(value);
});
How to export data to an excel file using PHPExcel
I currently use this function in my project after a series of googling to download excel file from sql statement
// $sql = sql query e.g "select * from mytablename"
// $filename = name of the file to download
function queryToExcel($sql, $fileName = 'name.xlsx') {
// initialise excel column name
// currently limited to queries with less than 27 columns
$columnArray = array("A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z");
// Execute the database query
$result = mysql_query($sql) or die(mysql_error());
// Instantiate a new PHPExcel object
$objPHPExcel = new PHPExcel();
// Set the active Excel worksheet to sheet 0
$objPHPExcel->setActiveSheetIndex(0);
// Initialise the Excel row number
$rowCount = 1;
// fetch result set column information
$finfo = mysqli_fetch_fields($result);
// initialise columnlenght counter
$columnlenght = 0;
foreach ($finfo as $val) {
// set column header values
$objPHPExcel->getActiveSheet()->SetCellValue($columnArray[$columnlenght++] . $rowCount, $val->name);
}
// make the column headers bold
$objPHPExcel->getActiveSheet()->getStyle($columnArray[0]."1:".$columnArray[$columnlenght]."1")->getFont()->setBold(true);
$rowCount++;
// Iterate through each result from the SQL query in turn
// We fetch each database result row into $row in turn
while ($row = mysqli_fetch_array($result, MYSQL_NUM)) {
for ($i = 0; $i < $columnLenght; $i++) {
$objPHPExcel->getActiveSheet()->SetCellValue($columnArray[$i] . $rowCount, $row[$i]);
}
$rowCount++;
}
// set header information to force download
header('Content-type: application/vnd.ms-excel');
header('Content-Disposition: attachment; filename="' . $fileName . '"');
// Instantiate a Writer to create an OfficeOpenXML Excel .xlsx file
// Write the Excel file to filename some_excel_file.xlsx in the current directory
$objWriter = new PHPExcel_Writer_Excel2007($objPHPExcel);
// Write the Excel file to filename some_excel_file.xlsx in the current directory
$objWriter->save('php://output');
}
What is difference between cacerts and keystore?
Cacerts are details of trusted signing authorities who can issue certs. This what most of the browsers have due to which certs determined to be authentic.
Keystone has your service related certs to authenticate clients.
Convert UNIX epoch to Date object
With library(lubridate)
, numeric representations of date and time saved as the number of seconds since
1970-01-01 00:00:00 UTC, can be coerced into dates with as_datetime()
:
lubridate::as_datetime(1352068320)
[1] "2012-11-04 22:32:00 UTC"
Importing CSV with line breaks in Excel 2007
Excel is incredibly broken when dealing with CSVs. LibreOffice does a much better job. So, I found out that:
- The file must be encoded in UTF-8 with BOM, so consider this for all the points below
- The best result, by far, is achieved by opening it from File Explorer
- If you open it from within Excel there are two possible outcomes:
- If it has only ASCII characters, it will most likely work
- If it has non-ASCII characters, it will mess your line breaks
- It seems to be heavily dependent on the decimal separator configured in the
OS's regional settings, so you have to select the right one
- I would bet that it may also behave differently depending on OS and
Office version
Finding the average of an array using JS
For the second part of your question you can use reduce
to good effect here:
_x000D_
_x000D_
const grades = [80, 77, 88, 95, 68];_x000D_
_x000D_
function getAvg(grades) {_x000D_
const total = grades.reduce((acc, c) => acc + c, 0);_x000D_
return total / grades.length;_x000D_
}_x000D_
_x000D_
const average = getAvg(grades);_x000D_
console.log(average);
_x000D_
_x000D_
_x000D_
The other answers have given good insight into why you got 68, so I won't repeat it here.
How to check whether input value is integer or float?
You can use Scanner Class to find whether a given number could be read as Int or Float type.
import java.util.Scanner;
public class Test {
public static void main(String args[] ) throws Exception {
Scanner sc=new Scanner(System.in);
if(sc.hasNextInt())
System.out.println("This input is of type Integer");
else if(sc.hasNextFloat())
System.out.println("This input is of type Float");
else
System.out.println("This is something else");
}
}
Rename column SQL Server 2008
Alternatively to SQL
, you can do this in Microsoft SQL Server Management Studio. Here are a few quick ways using the GUI:
First Way
Slow double-click on the column. The column name will become an editable text box.
Second Way
Right click on column and choose Rename from the context menu.
For example:
Third Way
This way is preferable for when you need to rename multiple columns in one go.
- Right-click on the table that contains the column that needs renaming.
- Click Design.
- In the table design panel, click and edit the textbox of the column name you want to alter.
For example:
NOTE: I know OP specifically asked for SQL solution, thought this might help others :)
How to add "active" class to wp_nav_menu() current menu item (simple way)
In addition to previous answers, if your menu items are Categories and you want to highlight them when navigating through posts, check also for current-post-ancestor
:
add_filter('nav_menu_css_class' , 'special_nav_class' , 10 , 2);
function special_nav_class ($classes, $item) {
if (in_array('current-post-ancestor', $classes) || in_array('current-page-ancestor', $classes) || in_array('current-menu-item', $classes) ){
$classes[] = 'active ';
}
return $classes;
}
Empty ArrayList equals null
If you want to check whether the array contains items with null values, use this:
private boolean isListOfNulls(ArrayList<String> stringList){
for (String s: stringList)
if( s != null) return false;
return true;
}
You could replace <String>
with the corresponding type for your ArrayList
How to do a redirect to another route with react-router?
With react-router v2.8.1 (probably other 2.x.x versions as well, but I haven't tested it) you can use this implementation to do a Router redirect.
import { Router } from 'react-router';
export default class Foo extends Component {
static get contextTypes() {
return {
router: React.PropTypes.object.isRequired,
};
}
handleClick() {
this.context.router.push('/some-path');
}
}
python save image from url
For linux in case; you can use wget command
import os
url1 = 'YOUR_URL_WHATEVER'
os.system('wget {}'.format(url1))
How to create a Custom Dialog box in android?
Simple first create a class
public class ViewDialog {
public void showDialog(Activity activity, String msg){
final Dialog dialog = new Dialog(activity);
dialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
dialog.setCancelable(false);
dialog.setContentView(R.layout.custom_dialogbox_otp);
dialog.getWindow().setBackgroundDrawable(new ColorDrawable(android.graphics.Color.TRANSPARENT));
TextView text = (TextView) dialog.findViewById(R.id.txt_file_path);
text.setText(msg);
Button dialogBtn_cancel = (Button) dialog.findViewById(R.id.btn_cancel);
dialogBtn_cancel.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// Toast.makeText(getApplicationContext(),"Cancel" ,Toast.LENGTH_SHORT).show();
dialog.dismiss();
}
});
Button dialogBtn_okay = (Button) dialog.findViewById(R.id.btn_okay);
dialogBtn_okay.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// Toast.makeText(getApplicationContext(),"Okay" ,Toast.LENGTH_SHORT).show();
dialog.cancel();
}
});
dialog.show();
}
}
then create a custom_dialogbox_otp
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="330dp"
android:layout_height="160dp"
android:background="#00555555"
android:orientation="vertical"
android:padding="5dp"
android:weightSum="100">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@drawable/round_layout_otp"
android:orientation="vertical"
android:padding="7dp"
android:weightSum="100">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="60"
android:orientation="horizontal"
android:weightSum="100">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="80"
android:gravity="center">
<ImageView
android:id="@+id/a"
android:layout_width="50dp"
android:layout_height="50dp"
android:background="#DA5F6A"
android:gravity="center"
android:scaleType="fitCenter"
android:src="@mipmap/infoonetwo" />
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="20">
<TextView
android:id="@+id/txt_file_path"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:singleLine="true"
android:text="TEXTO"
android:textColor="#FFFFFF"
android:textSize="17sp"
android:textStyle="bold" />
</LinearLayout>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="40"
android:background="@drawable/round_layout_white_otp"
android:orientation="vertical"
android:weightSum="100">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity="center"
android:layout_weight="60">
<TextView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center"
android:text="Do you wanna Exit..?"
android:textColor="#ff000000"
android:textSize="15dp"
android:textStyle="bold" />
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="40"
android:orientation="horizontal"
android:weightSum="100">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginRight="30dp"
android:layout_weight="50"
android:gravity="center|right">
<Button
android:id="@+id/btn_cancel"
android:layout_width="80dp"
android:layout_height="25dp"
android:background="@drawable/round_button"
android:gravity="center"
android:text="CANCEL"
android:textSize="13dp"
android:textStyle="bold"
android:textColor="#ffffffff" />
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginLeft="30dp"
android:layout_weight="50"
android:gravity="center|left">
<Button
android:id="@+id/btn_okay"
android:layout_width="80dp"
android:layout_height="25dp"
android:background="@drawable/round_button"
android:text="OKAY"
android:textSize="13dp"
android:textStyle="bold"
android:textColor="#ffffffff" />
</LinearLayout>
</LinearLayout>
</LinearLayout>
</LinearLayout>
</LinearLayout>
then in your drawable create beneath xml files.
for round_layout_white_otp.xml
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle" >
<!-- <corners android:radius="10dp" /> -->
<corners
android:bottomLeftRadius="18dp"
android:bottomRightRadius="16dp"
android:topLeftRadius="38dp"
android:topRightRadius="36dp" />
<solid android:color="#C0C0C0" />
</shape>
for round_layout_otp.xml
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle" >
<!-- <corners android:radius="10dp" /> -->
<corners
android:bottomLeftRadius="18dp"
android:bottomRightRadius="16dp"
android:topLeftRadius="38dp"
android:topRightRadius="38dp" />
<solid android:color="#DA5F6A" />
</shape>
round_button
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle" >
<!-- <corners android:radius="10dp" /> -->
<corners
android:bottomLeftRadius="7dp"
android:bottomRightRadius="7dp"
android:topLeftRadius="7dp"
android:topRightRadius="7dp" />
<solid android:color="#06A19E" />
</shape>
Then finally use the underneath code to visual ur dialog :)
ViewDialog alert = new ViewDialog();
alert.showDialog(ReceivingOTPRegActivity.this, "OTP has been sent to your Mail ");
your output :)
Removing multiple keys from a dictionary safely
Another map() way to remove list of keys from dictionary
and avoid raising KeyError exception
dic = {
'key1': 1,
'key2': 2,
'key3': 3,
'key4': 4,
'key5': 5,
}
keys_to_remove = ['key_not_exist', 'key1', 'key2', 'key3']
k = list(map(dic.pop, keys_to_remove, keys_to_remove))
print('k=', k)
print('dic after = \n', dic)
**this will produce output**
k= ['key_not_exist', 1, 2, 3]
dic after = {'key4': 4, 'key5': 5}
Duplicate keys_to_remove
is artificial, it needs to supply defaults values for dict.pop() function.
You can add here any array with len_ = len(key_to_remove)
For example
dic = {
'key1': 1,
'key2': 2,
'key3': 3,
'key4': 4,
'key5': 5,
}
keys_to_remove = ['key_not_exist', 'key1', 'key2', 'key3']
k = list(map(dic.pop, keys_to_remove, np.zeros(len(keys_to_remove))))
print('k=', k)
print('dic after = ', dic)
** will produce output **
k= [0.0, 1, 2, 3]
dic after = {'key4': 4, 'key5': 5}
How to get current route in Symfony 2?
With Symfony 4.2.7, I'm able to implement the following in my twig template, which displays the custom route name I defined in my controller(s).
In index.html.twig
<div class="col">
{% set current_path = app.request.get('_route') %}
{{ current_path }}
</div>
In my controller
...
class ArticleController extends AbstractController {
/**
* @Route("/", name="article_list")
* @Method({"GET"})
*/
public function index() {
...
}
...
}
The result prints out "article_list" to the desired page in my browser.
CSS two divs next to each other
Unfortunately, this is not a trivial thing to solve for the general case. The easiest thing would be to add a css-style property "float: right;" to your 200px div, however, this would also cause your "main"-div to actually be full width and any text in there would float around the edge of the 200px-div, which often looks weird, depending on the content (pretty much in all cases except if it's a floating image).
EDIT:
As suggested by Dom, the wrapping problem could of course be solved with a margin. Silly me.
What is tail recursion?
Here is a Common Lisp example that does factorials using tail-recursion. Due to the stack-less nature, one could perform insanely large factorial computations ...
(defun ! (n &optional (product 1))
(if (zerop n) product
(! (1- n) (* product n))))
And then for fun you could try (format nil "~R" (! 25))
Generate random integers between 0 and 9
>>> import random
>>> random.randrange(10)
3
>>> random.randrange(10)
1
To get a list of ten samples:
>>> [random.randrange(10) for x in range(10)]
[9, 0, 4, 0, 5, 7, 4, 3, 6, 8]
How to overcome "datetime.datetime not JSON serializable"?
Here is a simple solution to over come "datetime not JSON serializable"
problem.
enco = lambda obj: (
obj.isoformat()
if isinstance(obj, datetime.datetime)
or isinstance(obj, datetime.date)
else None
)
json.dumps({'date': datetime.datetime.now()}, default=enco)
Output:-> {"date": "2015-12-16T04:48:20.024609"}
How to get the total number of rows of a GROUP BY query?
What about putting the query results in an array, where you can do a count($array) and use the query resulting rows after? Example:
$sc='SELECT * FROM comments';
$res=array();
foreach($db->query($sc) as $row){
$res[]=$row;
}
echo "num rows: ".count($res);
echo "Select output:";
foreach($res as $row){ echo $row['comment'];}
How to pass extra variables in URL with WordPress
add following code in function.php
add_filter( 'query_vars', 'addnew_query_vars', 10, 1 );
function addnew_query_vars($vars)
{
$vars[] = 'var1'; // var1 is the name of variable you want to add
return $vars;
}
then you will b able to use $_GET['var1']
Saving plots (AxesSubPlot) generated from python pandas with matplotlib's savefig
You can use ax.figure.savefig()
, as suggested in a comment on the question:
import pandas as pd
df = pd.DataFrame([0, 1])
ax = df.plot.line()
ax.figure.savefig('demo-file.pdf')
This has no practical benefit over ax.get_figure().savefig()
as suggested in other answers, so you can pick the option you find the most aesthetically pleasing. In fact, get_figure()
simply returns self.figure
:
# Source from snippet linked above
def get_figure(self):
"""Return the `.Figure` instance the artist belongs to."""
return self.figure
Best data type to store money values in MySQL
Storing money as BIGINT
multiplied by 100 or more with the reason to use less storage space makes no sense in all "normal" situations.
- To stay aligned with GAAP it is sufficient to store currencies in
DECIMAL(13,4)
- MySQL manual reads that it needs 4 bytes per 9 digits to store
DECIMAL
.
DECIMAL(13,4)
represents 9 digits + 4 fraction digits (decimal places) => 4 + 2 bytes = 6 bytes
- compare to 8 bytes required to store
BIGINT
.
Difference between add(), replace(), and addToBackStack()
The FragmentManger's function add and replace can be described as these
1. add means it will add the fragment in the fragment back stack and it will show at given frame you are providing
like
getFragmentManager.beginTransaction.add(R.id.contentframe,Fragment1.newInstance(),null)
2.replace means that you are replacing the fragment with another fragment at the given frame
getFragmentManager.beginTransaction.replace(R.id.contentframe,Fragment1.newInstance(),null)
The Main utility between the two is that when you are back stacking the replace will refresh the fragment but add will not refresh previous fragment.
Django TemplateDoesNotExist?
I'm embarrassed to admit this, but the problem for me was that a template had been specified as ….hml
instead of ….html
. Watch out!
To the power of in C?
Actually in C, you don't have an power operator. You will need to manually run a loop to get the result. Even the exp function just operates in that way only. But if you need to use that function, include the following header
#include <math.h>
then you can use pow().
onSaveInstanceState () and onRestoreInstanceState ()
Usually you restore your state in onCreate()
. It is possible to restore it in onRestoreInstanceState()
as well, but not very common. (onRestoreInstanceState()
is called after onStart()
, whereas onCreate()
is called before onStart()
.
Use the put methods to store values in onSaveInstanceState()
:
protected void onSaveInstanceState(Bundle icicle) {
super.onSaveInstanceState(icicle);
icicle.putLong("param", value);
}
And restore the values in onCreate()
:
public void onCreate(Bundle icicle) {
if (icicle != null){
value = icicle.getLong("param");
}
}
jQuery: Get selected element tag name
nodeName will give you the tag name in uppercase, while localName will give you the lower case.
$("yourelement")[0].localName
will give you : yourelement instead of YOURELEMENT
jQuery How do you get an image to fade in on load?
Like Sohne mentions, but I would add this:
$("img").hide();
$("img").bind("load", function () { $(this).fadeIn(); });
or:
$("img").bind("load", function () {
$(this).css({opacity: 0, visibility: "visible"}).animate({opacity: 1}, "slow");
});
How to install Python package from GitHub?
To install Python package from github, you need to clone that repository.
git clone https://github.com/jkbr/httpie.git
Then just run the setup.py file from that directory,
sudo python setup.py install
Batch file include external file for variables
While trying to use the method with excutable configuration
I noticed that it may work or may NOT work
depending on where in the script is located the call:
call config.cmd
I know it doesn't make any sens, but for me it's a fact.
When "call config.cmd" is located at the top of the
script, it works, but if further in the script it doesn't.
By doesn't work, I mean the variable are not set un the calling script.
Very very strange !!!!
Checking session if empty or not
If It is simple Session you can apply NULL
Check directly Session["emp_num"] != null
But if it's a session of a list Item then You need to apply any one of the following option
Option 1:
if (((List<int>)(Session["emp_num"])) != null && (List<int>)Session["emp_num"])).Count > 0)
{
//Your Logic here
}
Option 2:
List<int> val= Session["emp_num"] as List<int>; //Get the value from Session.
if (val.FirstOrDefault() != null)
{
//Your Logic here
}
Simple (non-secure) hash function for JavaScript?
I didn't verify this myself, but you can look at this JavaScript implementation of Java's String.hashCode() method. Seems reasonably short.
With this prototype you can simply call .hashCode()
on any string, e.g. "some string".hashCode()
, and receive a numerical hash code (more specifically, a Java equivalent) such as 1395333309.
String.prototype.hashCode = function() {
var hash = 0;
if (this.length == 0) {
return hash;
}
for (var i = 0; i < this.length; i++) {
var char = this.charCodeAt(i);
hash = ((hash<<5)-hash)+char;
hash = hash & hash; // Convert to 32bit integer
}
return hash;
}
How to change the blue highlight color of a UITableViewCell?
Based on @user's answer, you can just add this extension anywhere in your app code and have your selection color directly in storyboard editor for every cells of your app :
@IBDesignable extension UITableViewCell {
@IBInspectable var selectedColor: UIColor? {
set {
if let color = newValue {
selectedBackgroundView = UIView()
selectedBackgroundView!.backgroundColor = color
} else {
selectedBackgroundView = nil
}
}
get {
return selectedBackgroundView?.backgroundColor
}
}
}
Angular2: How to load data before rendering the component?
You can pre-fetch your data by using Resolvers in Angular2+, Resolvers process your data before your Component fully be loaded.
There are many cases that you want to load your component only if there is certain thing happening, for example navigate to Dashboard only if the person already logged in, in this case Resolvers are so handy.
Look at the simple diagram I created for you for one of the way you can use the resolver to send the data to your component.
Applying Resolver to your code is pretty simple, I created the snippets for you to see how the Resolver can be created:
import { Injectable } from '@angular/core';
import { Router, Resolve, RouterStateSnapshot, ActivatedRouteSnapshot } from '@angular/router';
import { MyData, MyService } from './my.service';
@Injectable()
export class MyResolver implements Resolve<MyData> {
constructor(private ms: MyService, private router: Router) {}
resolve(route: ActivatedRouteSnapshot, state: RouterStateSnapshot): Promise<MyData> {
let id = route.params['id'];
return this.ms.getId(id).then(data => {
if (data) {
return data;
} else {
this.router.navigate(['/login']);
return;
}
});
}
}
and in the module:
import { MyResolver } from './my-resolver.service';
@NgModule({
imports: [
RouterModule.forChild(myRoutes)
],
exports: [
RouterModule
],
providers: [
MyResolver
]
})
export class MyModule { }
and you can access it in your Component like this:
/////
ngOnInit() {
this.route.data
.subscribe((data: { mydata: myData }) => {
this.id = data.mydata.id;
});
}
/////
And in the Route something like this (usually in the app.routing.ts file):
////
{path: 'yourpath/:id', component: YourComponent, resolve: { myData: MyResolver}}
////
How to auto-scroll to end of div when data is added?
If you don't know when data will be added to #data
, you could set an interval to update the element's scrollTop to its scrollHeight every couple of seconds. If you are controlling when data is added, just call the internal of the following function after the data has been added.
window.setInterval(function() {
var elem = document.getElementById('data');
elem.scrollTop = elem.scrollHeight;
}, 5000);
Read lines from a file into a Bash array
Your first attempt was close. Here is the simplistic approach using your idea.
file="somefileondisk"
lines=`cat $file`
for line in $lines; do
echo "$line"
done
Dynamically creating keys in a JavaScript associative array
JavaScript does not have associative arrays. It has objects.
The following lines of code all do exactly the same thing - set the 'name' field on an object to 'orion'.
var f = new Object(); f.name = 'orion';
var f = new Object(); f['name'] = 'orion';
var f = new Array(); f.name = 'orion';
var f = new Array(); f['name'] = 'orion';
var f = new XMLHttpRequest(); f['name'] = 'orion';
It looks like you have an associative array because an Array
is also an Object
- however you're not actually adding things into the array at all; you're setting fields on the object.
Now that that is cleared up, here is a working solution to your example:
var text = '{ name = oscar }'
var dict = new Object();
// Remove {} and spaces
var cleaned = text.replace(/[{} ]/g, '');
// Split into key and value
var kvp = cleaned.split('=');
// Put in the object
dict[ kvp[0] ] = kvp[1];
alert( dict.name ); // Prints oscar.
What exactly does += do in python?
Remember when you used to sum, for example 2 & 3, in your old calculator and every time you hit the =
you see 3 added to the total, the +=
does similar job. Example:
>>> orange = 2
>>> orange += 3
>>> print(orange)
5
>>> orange +=3
>>> print(orange)
8
Inserting image into IPython notebook markdown
Most of the answers given so far go in the wrong direction, suggesting to load additional libraries and use the code instead of markup. In Ipython/Jupyter Notebooks it is very simple. Make sure the cell is indeed in markup and to display a image use:
![alt text](imagename.png "Title")
Further advantage compared to the other methods proposed is that you can display all common file formats including jpg, png, and gif (animations).
How to change the floating label color of TextInputLayout
Can use app:hintTextColor
if you use com.google.android.material.textfield.TextInputLayout
, try this
<com.google.android.material.textfield.TextInputLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="@string/app_name"
app:hintTextColor="@android:color/white">
<com.google.android.material.textfield.TextInputEditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
/>
</com.google.android.material.textfield.TextInputLayout>
What is the difference between a definition and a declaration?
The concept of Declaration and Definition will form a pitfall when you are using the extern storage class because your definition will be in some other location and you are declaring the variable in your local code file (page). One difference between C and C++ is that in C you the declarations are done normally at the beginning of a function or code page. In C++ it's not like that. You can declare at a place of your choice.
JavaScript associative array to JSON
There are no associative arrays in JavaScript. However, there are objects with named properties, so just don't initialise your "array" with new Array
, then it becomes a generic object.
How to set minDate to current date in jQuery UI Datepicker?
You can use the minDate
property, like this:
$("input.DateFrom").datepicker({
changeMonth: true,
changeYear: true,
dateFormat: 'yy-mm-dd',
minDate: 0, // 0 days offset = today
maxDate: 'today',
onSelect: function(dateText) {
$sD = new Date(dateText);
$("input#DateTo").datepicker('option', 'minDate', min);
}
});
You can also specify a date, like this:
minDate: new Date(), // = today
afxwin.h file is missing in VC++ Express Edition
Including the header afxwin.h
signalizes use of MFC. The following instructions (based on those on CodeProject.com) could help to get MFC code compiling:
Download and install the Windows Driver Kit.
Select menu Tools > Options… > Projects and Solutions > VC++ Directories.
In the drop-down menu Show directories for select Include files.
Add the following paths (replace $(WDK_directory)
with the directory where you installed Windows Driver Kit in the first step):
$(WDK_directory)\inc\mfc42
$(WDK_directory)\inc\atl30
In the drop-down menu Show directories for select Library files and add (replace $(WDK_directory)
like before):
$(WDK_directory)\lib\mfc\i386
$(WDK_directory)\lib\atl\i386
In the $(WDK_directory)\inc\mfc42\afxwin.inl
file, edit the following lines (starting from 1033):
_AFXWIN_INLINE CMenu::operator==(const CMenu& menu) const
{ return ((HMENU) menu) == m_hMenu; }
_AFXWIN_INLINE CMenu::operator!=(const CMenu& menu) const
{ return ((HMENU) menu) != m_hMenu; }
to
_AFXWIN_INLINE BOOL CMenu::operator==(const CMenu& menu) const
{ return ((HMENU) menu) == m_hMenu; }
_AFXWIN_INLINE BOOL CMenu::operator!=(const CMenu& menu) const
{ return ((HMENU) menu) != m_hMenu; }
In other words, add BOOL
after _AFXWIN_INLINE
.
How is a JavaScript hash map implemented?
While plain old JavaScript objects can be used as maps, they are usually implemented in a way to preserve insertion-order for compatibility with most browsers (see Craig Barnes's answer) and are thus not simple hash maps.
ES6 introduces proper Maps (see MDN JavaScript Map) of which the standard says:
Map object must be implemented using either hash tables or other mechanisms that, on average, provide access times that are sublinear on the number of elements in the collection.
HTML table with horizontal scrolling (first column fixed)
I have a similar table styled like so:
<table style="width:100%; table-layout:fixed">
<tr>
<td style="width: 150px">Hello, World!</td>
<td>
<div>
<pre style="margin:0; overflow:scroll">My preformatted content</pre>
</div>
</td>
</tr>
</table>
WordPress path url in js script file
wp_register_script('custom-js',WP_PLUGIN_URL.'/PLUGIN_NAME/js/custom.js',array(),NULL,true);
wp_enqueue_script('custom-js');
$wnm_custom = array( 'template_url' => get_bloginfo('template_url') );
wp_localize_script( 'custom-js', 'wnm_custom', $wnm_custom );
and in custom.js
alert(wnm_custom.template_url);
How to disable the ability to select in a DataGridView?
I liked user4101525's answer best in theory but it doesn't actually work.
Selection is not an overlay so you see whatever is under the control
Ramgy Borja's answer doesn't deal with the fact that default style is not actually a color at all so applying it doesn't help.
This handles the default style and works if applying your own colors (which may be what edhubbell refers to as nasty results)
dgv.RowsDefaultCellStyle.SelectionBackColor = dgv.RowsDefaultCellStyle.BackColor.IsEmpty ? System.Drawing.Color.White : dgv.RowsDefaultCellStyle.BackColor;
dgv.RowsDefaultCellStyle.SelectionForeColor = dgv.RowsDefaultCellStyle.ForeColor.IsEmpty ? System.Drawing.Color.Black : dgv.RowsDefaultCellStyle.ForeColor;
Left padding a String with Zeros
This will pad left any string to a total width of 10 without worrying about parse errors:
String unpadded = "12345";
String padded = "##########".substring(unpadded.length()) + unpadded;
//unpadded is "12345"
//padded is "#####12345"
If you want to pad right:
String unpadded = "12345";
String padded = unpadded + "##########".substring(unpadded.length());
//unpadded is "12345"
//padded is "12345#####"
You can replace the "#" characters with whatever character you would like to pad with, repeated the amount of times that you want the total width of the string to be. E.g. if you want to add zeros to the left so that the whole string is 15 characters long:
String unpadded = "12345";
String padded = "000000000000000".substring(unpadded.length()) + unpadded;
//unpadded is "12345"
//padded is "000000000012345"
The benefit of this over khachik's answer is that this does not use Integer.parseInt, which can throw an Exception (for example, if the number you want to pad is too large like 12147483647). The disadvantage is that if what you're padding is already an int, then you'll have to convert it to a String and back, which is undesirable.
So, if you know for sure that it's an int, khachik's answer works great. If not, then this is a possible strategy.
How to play .mp4 video in videoview in android?
Finally it works for me.
private VideoView videoView;
videoView = (VideoView) findViewById(R.id.videoView);
Uri video = Uri.parse("http://www.servername.com/projects/projectname/videos/1361439400.mp4");
videoView.setVideoURI(video);
videoView.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {
@Override
public void onPrepared(MediaPlayer mp) {
mp.setLooping(true);
videoView.start();
}
});
Hope this would help others.
What's the difference between git clone --mirror and git clone --bare
$ git clone --bare https://github.com/example
This command will make the new "example
" directory itself the $GIT_DIR (instead of example/.git
). Also the branch heads at the remote are copied directly to corresponding local branch heads, without mapping. When this option is used, neither remote-tracking branches nor the related configuration variables are created.
$ git clone --mirror https://github.com/example
As with a bare clone, a mirrored clone includes all remote branches and tags, but all local references (including remote-tracking branches, notes etc.) will be overwritten each time you fetch, so it will always be the same as the original repository.
How to disable Paste (Ctrl+V) with jQuery?
You can catch key event :
function checkEventObj ( _event_ ){
// --- IE explorer
if ( window.event )
return window.event;
// --- Netscape and other explorers
else
return _event_;
}
document.keydown = function(_event) {
var e = checkEventObject(_event);
if( e.ctrlKey && (e.keyCode == 86) )
window.clipboardData.clearData();
}
Not tested but, could help.
Source from comentcamarche and Zakaria
Ignore self-signed ssl cert using Jersey Client
Just adding the same code with the imports. Also contains the unimplemented code that is needed for compilation. I initially had trouble finding out what was imported for this code. Also adding the right package for the X509Certificate. Got this working with trial and error:
import javax.net.ssl.HttpsURLConnection;
import javax.net.ssl.SSLContext;
import javax.net.ssl.TrustManager;
import javax.net.ssl.X509TrustManager;
import javax.security.cert.CertificateException;
import javax.security.cert.X509Certificate;
import javax.ws.rs.core.MultivaluedMap;
TrustManager[] trustAllCerts = new TrustManager[] { new X509TrustManager() {
public java.security.cert.X509Certificate[] getAcceptedIssuers() {
java.security.cert.X509Certificate[] chck = null;
;
return chck;
}
public void checkServerTrusted(X509Certificate[] arg0, String arg1)
throws CertificateException {
// TODO Auto-generated method stub
}
public void checkClientTrusted(X509Certificate[] arg0, String arg1)
throws CertificateException {
}
public void checkClientTrusted(
java.security.cert.X509Certificate[] arg0, String arg1)
throws java.security.cert.CertificateException {
// TODO Auto-generated method stub
}
public void checkServerTrusted(
java.security.cert.X509Certificate[] arg0, String arg1)
throws java.security.cert.CertificateException {
// TODO Auto-generated method stub
}
} };
// Install the all-trusting trust manager
try {
SSLContext sc = SSLContext.getInstance("TLS");
sc.init(null, trustAllCerts, new SecureRandom());
HttpsURLConnection
.setDefaultSSLSocketFactory(sc.getSocketFactory());
} catch (Exception e) {
;
}
How to deselect a selected UITableView cell?
If you want to select any table cell with the first click and deselect with the second, you should use this code:
- (void)tableView:(UITableView *)tableView
didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
if (self.selectedIndexPath &&
[indexPath compare:self.selectedIndexPath] == NSOrderedSame) {
[tableView deselectRowAtIndexPath:indexPath animated:YES];
self.selectedIndexPath = nil;
}
else {
self.selectedIndexPath = indexPath;
}
}
Convert .pfx to .cer
If you're working in PowerShell you can use something like the following, given a pfx file InputBundle.pfx, to produce a DER encoded (binary) certificate file OutputCert.der:
Get-PfxCertificate -FilePath InputBundle.pfx |
Export-Certificate -FilePath OutputCert.der -Type CERT
Newline added for clarity, but you can of course have this all on a single line.
If you need the certificate in ASCII/Base64 encoded PEM format, you can take extra steps to do so as documented elsewhere, such as here: https://superuser.com/questions/351548/windows-integrated-utility-to-convert-der-to-pem
If you need to export to a different format than DER encoded, you can change the -Type
parameter for Export-Certificate to use the types supported by .NET, as seen in help Export-Certificate -Detailed
:
-Type <CertType>
Specifies the type of output file for the certificate export as follows.
-- SST: A Microsoft serialized certificate store (.sst) file format which can contain one or more certificates. This is the default value for multiple certificates.
-- CERT: A .cer file format which contains a single DER-encoded certificate. This is the default value for one certificate.
-- P7B: A PKCS#7 file format which can contain one or more certificates.
Is Python faster and lighter than C++?
It's the same problem with managed and easy to use programming language as always - they are slow (and sometimes memory-eating).
These are languages to do control rather than processing. If I would have to write application to transform images and had to use Python too all the processing could be written in C++ and connected to Python via bindings while interface and process control would be definetely Python.
How to set HTTP header to UTF-8 using PHP which is valid in W3C validator?
For a correct implementation, you need to change a series of things.
Database (immediately after the connection):
mysql_query("SET NAMES utf8");
// Meta tag HTML (probably it's already set):
meta charset="utf-8"
header php (before any output of the HTML):
header('Content-Type: text/html; charset=utf-8')
table-rows-charset (for each row):
utf8_unicode_ci
Remove duplicates from a list of objects based on property in Java 8
You can get a stream from the List
and put in in the TreeSet
from which you provide a custom comparator that compares id uniquely.
Then if you really need a list you can put then back this collection into an ArrayList.
import static java.util.Comparator.comparingInt;
import static java.util.stream.Collectors.collectingAndThen;
import static java.util.stream.Collectors.toCollection;
...
List<Employee> unique = employee.stream()
.collect(collectingAndThen(toCollection(() -> new TreeSet<>(comparingInt(Employee::getId))),
ArrayList::new));
Given the example:
List<Employee> employee = Arrays.asList(new Employee(1, "John"), new Employee(1, "Bob"), new Employee(2, "Alice"));
It will output:
[Employee{id=1, name='John'}, Employee{id=2, name='Alice'}]
Another idea could be to use a wrapper that wraps an employee and have the equals and hashcode method based with its id:
class WrapperEmployee {
private Employee e;
public WrapperEmployee(Employee e) {
this.e = e;
}
public Employee unwrap() {
return this.e;
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
WrapperEmployee that = (WrapperEmployee) o;
return Objects.equals(e.getId(), that.e.getId());
}
@Override
public int hashCode() {
return Objects.hash(e.getId());
}
}
Then you wrap each instance, call distinct()
, unwrap them and collect the result in a list.
List<Employee> unique = employee.stream()
.map(WrapperEmployee::new)
.distinct()
.map(WrapperEmployee::unwrap)
.collect(Collectors.toList());
In fact, I think you can make this wrapper generic by providing a function that will do the comparison:
public class Wrapper<T, U> {
private T t;
private Function<T, U> equalityFunction;
public Wrapper(T t, Function<T, U> equalityFunction) {
this.t = t;
this.equalityFunction = equalityFunction;
}
public T unwrap() {
return this.t;
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
@SuppressWarnings("unchecked")
Wrapper<T, U> that = (Wrapper<T, U>) o;
return Objects.equals(equalityFunction.apply(this.t), that.equalityFunction.apply(that.t));
}
@Override
public int hashCode() {
return Objects.hash(equalityFunction.apply(this.t));
}
}
and the mapping will be:
.map(e -> new Wrapper<>(e, Employee::getId))
React.js create loop through Array
As @Alexander solves, the issue is one of async data load - you're rendering immediately and you will not have participants loaded until the async ajax call resolves and populates data
with participants
.
The alternative to the solution they provided would be to prevent render until participants exist, something like this:
render: function() {
if (!this.props.data.participants) {
return null;
}
return (
<ul className="PlayerList">
// I'm the Player List {this.props.data}
// <Player author="The Mini John" />
{
this.props.data.participants.map(function(player) {
return <li key={player}>{player}</li>
})
}
</ul>
);
}
Better way to generate array of all letters in the alphabet
Define any languages an enum, and call getAlphabet();
char[] armenianAlphabet = getAlphabet(LocaleLanguage.ARMENIAN);
char[] russianAlphabet = getAlphabet(LocaleLanguage.RUSSIAN);
// get uppercase alphabet
char[] currentAlphabet = getAlphabet(true);
System.out.println(armenianAlphabet);
System.out.println(russianAlphabet);
System.out.println(currentAlphabet);
result
I/System.out: ??????????????????????????????????????
I/System.out: ????????????????????????????????
I/System.out: ABCDEFGHIJKLMNOPQRSTUVWXYZ
private char[] getAlphabet(){
return getAlphabet(false);
}
private char[] getAlphabet(boolean flagToUpperCase){
Locale locale = getResources().getConfiguration().locale;
LocaleLanguage language = LocaleLanguage.getLocalLanguage(locale);
return getAlphabet(language, flagToUpperCase);
}
private char[] getAlphabet(LocaleLanguage localeLanguage, boolean flagToUpperCase){
if (localeLanguage == null)
localeLanguage = LocaleLanguage.ENGLISH;
char firstLetter = localeLanguage.getFirstLetter();
char lastLetter = localeLanguage.getLastLetter();
int alphabetSize = lastLetter - firstLetter + 1;
char[] alphabet = new char[alphabetSize];
for (int index = 0; index < alphabetSize; index++ ){
alphabet[index] = (char) (index + firstLetter);
}
if (flagToUpperCase){
alphabet = new String(alphabet).toUpperCase().toCharArray();
}
return alphabet;
}
private enum LocaleLanguage{
ARMENIAN(new Locale("hy"), '?', '?'),
RUSSIAN(new Locale("ru"), '?','?'),
ENGLISH(new Locale("en"), 'a','z');
private final Locale mLocale;
private final char mFirstLetter;
private final char mLastLetter;
LocaleLanguage(Locale locale, char firstLetter, char lastLetter) {
this.mLocale = locale;
this.mFirstLetter = firstLetter;
this.mLastLetter = lastLetter;
}
public Locale getLocale() {
return mLocale;
}
public char getFirstLetter() {
return mFirstLetter;
}
public char getLastLetter() {
return mLastLetter;
}
public String getDisplayLanguage(){
return getLocale().getDisplayLanguage();
}
public String getDisplayLanguage(LocaleLanguage locale){
return getLocale().getDisplayLanguage(locale.getLocale());
}
@Nullable
public static LocaleLanguage getLocalLanguage(Locale locale){
if (locale == null)
return LocaleLanguage.ENGLISH;
for (LocaleLanguage localeLanguage : LocaleLanguage.values()){
if (localeLanguage.getLocale().getLanguage().equals(locale.getLanguage()))
return localeLanguage;
}
return null;
}
}
PHP Excel Header
The problem is you typed the wrong file extension for excel file. you used .xsl instead of xls.
I know i came in late but it can help future readers of this post.
Send JavaScript variable to PHP variable
PHP runs on the server and Javascript runs on the client, so you can't set a PHP variable to equal a Javascript variable without sending the value to the server. You can, however, set a Javascript variable to equal a PHP variable:
<script type="text/javascript">
var foo = '<?php echo $foo ?>';
</script>
To send a Javascript value to PHP you'd need to use AJAX. With jQuery, it would look something like this (most basic example possible):
var variableToSend = 'foo';
$.post('file.php', {variable: variableToSend});
On your server, you would need to receive the variable sent in the post:
$variable = $_POST['variable'];
How to set proxy for wget?
start wget through socks5 proxy using tsocks:
- install tsocks:
sudo apt install tsocks
config tsocks
# vi /etc/tsocks.conf
server = 127.0.0.1
server_type = 5
server_port = 1080
- start:
tsocks wget http://url_to_get
AttributeError: can't set attribute in python
items[node.ind] = items[node.ind]._replace(v=node.v)
(Note: Don't be discouraged to use this solution because of the leading underscore in the function _replace. Specifically for namedtuple some functions have leading underscore which is not for indicating they are meant to be "private")
Using NSLog for debugging
Why do you have the brackets around digit
?
It should be
NSLog("%@", digit);
You're also missing an =
in the first line...
NSString *digit = [[sender titlelabel] text];
Python reshape list to ndim array
You can think of reshaping that the new shape is filled row by row (last dimension varies fastest) from the flattened original list/array.
An easy solution is to shape the list into a (100, 28) array and then transpose it:
x = np.reshape(list_data, (100, 28)).T
Update regarding the updated example:
np.reshape([0, 0, 1, 1, 2, 2, 3, 3], (4, 2)).T
# array([[0, 1, 2, 3],
# [0, 1, 2, 3]])
np.reshape([0, 0, 1, 1, 2, 2, 3, 3], (2, 4))
# array([[0, 0, 1, 1],
# [2, 2, 3, 3]])
Does the target directory for a git clone have to match the repo name?
Yes, it is possible:
git clone https://github.com/pitosalas/st3_packages Packages
You can specify the local root directory when using git clone.
<directory>
The name of a new directory to clone into.
The "humanish" part of the source repository is used if no directory is explicitly given (repo
for /path/to/repo.git
and foo
for host.xz:foo/.git
).
Cloning into an existing directory is only allowed if the directory is empty.
As Chris comments, you can then rename that top directory.
Git only cares about the .git
within said top folder, which you can get with various commands:
git rev-parse --show-toplevel git rev-parse --git-dir
How to save a base64 image to user's disk using JavaScript?
This Works
function saveBase64AsFile(base64, fileName) {
var link = document.createElement("a");
document.body.appendChild(link);
link.setAttribute("type", "hidden");
link.href = "data:text/plain;base64," + base64;
link.download = fileName;
link.click();
document.body.removeChild(link);
}
Based on the answer above but with some changes
What is the maximum recursion depth in Python, and how to increase it?
resource.setrlimit
must also be used to increase the stack size and prevent segfault
The Linux kernel limits the stack of processes.
Python stores local variables on the stack of the interpreter, and so recursion takes up stack space of the interpreter.
If the Python interpreter tries to go over the stack limit, the Linux kernel makes it segmentation fault.
The stack limit size is controlled with the getrlimit
and setrlimit
system calls.
Python offers access to those system calls through the resource
module.
sys.setrecursionlimit
mentioned e.g. at https://stackoverflow.com/a/3323013/895245 only increases the limit that the Python interpreter self imposes on its own stack size, but it does not touch the limit imposed by the Linux kernel on the Python process.
Example program:
main.py
import resource
import sys
print resource.getrlimit(resource.RLIMIT_STACK)
print sys.getrecursionlimit()
print
# Will segfault without this line.
resource.setrlimit(resource.RLIMIT_STACK, [0x10000000, resource.RLIM_INFINITY])
sys.setrecursionlimit(0x100000)
def f(i):
print i
sys.stdout.flush()
f(i + 1)
f(0)
Of course, if you keep increasing setrlimit
, your RAM will eventually run out, which will either slow your computer to a halt due to swap madness, or kill Python via the OOM Killer.
From bash, you can see and set the stack limit (in kb) with:
ulimit -s
ulimit -s 10000
The default value for me is 8Mb.
See also:
Tested on Ubuntu 16.10, Python 2.7.12.
Where does Java's String constant pool live, the heap or the stack?
String pooling
String pooling (sometimes also called as string canonicalisation) is a
process of replacing several String objects with equal value but
different identity with a single shared String object. You can achieve
this goal by keeping your own Map (with possibly soft
or weak references depending on your requirements) and using map
values as canonicalised values. Or you can use String.intern() method
which is provided to you by JDK.
At times of Java 6 using String.intern() was forbidden by many
standards due to a high possibility to get an OutOfMemoryException if
pooling went out of control. Oracle Java 7 implementation of string
pooling was changed considerably. You can look for details in
http://bugs.sun.com/view_bug.do?bug_id=6962931 and
http://bugs.sun.com/view_bug.do?bug_id=6962930.
String.intern() in Java 6
In those good old days all interned strings were stored in the PermGen
– the fixed size part of heap mainly used for storing loaded classes
and string pool. Besides explicitly interned strings, PermGen string
pool also contained all literal strings earlier used in your program
(the important word here is used – if a class or method was never
loaded/called, any constants defined in it will not be loaded).
The biggest issue with such string pool in Java 6 was its location –
the PermGen. PermGen has a fixed size and can not be expanded at
runtime. You can set it using -XX:MaxPermSize=96m option. As far as I
know, the default PermGen size varies between 32M and 96M depending on
the platform. You can increase its size, but its size will still be
fixed. Such limitation required very careful usage of String.intern –
you’d better not intern any uncontrolled user input using this method.
That’s why string pooling at times of Java 6 was mostly implemented in
the manually managed maps.
String.intern() in Java 7
Oracle engineers made an extremely important change to the string
pooling logic in Java 7 – the string pool was relocated to the heap.
It means that you are no longer limited by a separate fixed size
memory area. All strings are now located in the heap, as most of other
ordinary objects, which allows you to manage only the heap size while
tuning your application. Technically, this alone could be a sufficient
reason to reconsider using String.intern() in your Java 7 programs.
But there are other reasons.
String pool values are garbage collected
Yes, all strings in the JVM string pool are eligible for garbage
collection if there are no references to them from your program roots.
It applies to all discussed versions of Java. It means that if your
interned string went out of scope and there are no other references to
it – it will be garbage collected from the JVM string pool.
Being eligible for garbage collection and residing in the heap, a JVM
string pool seems to be a right place for all your strings, isn’t it?
In theory it is true – non-used strings will be garbage collected from
the pool, used strings will allow you to save memory in case then you
get an equal string from the input. Seems to be a perfect memory
saving strategy? Nearly so. You must know how the string pool is
implemented before making any decisions.
source.
PYTHONPATH vs. sys.path
I think, that in this case using PYTHONPATH is a better thing, mostly because it doesn't introduce (questionable) unneccessary code.
After all, if you think of it, your user doesn't need that sys.path
thing, because your package will get installed into site-packages, because you will be using a packaging system.
If the user chooses to run from a "local copy", as you call it, then I've observed, that the usual practice is to state, that the package needs to be added to PYTHONPATH manually, if used outside the site-packages.
Parse JSON String to JSON Object in C#.NET
Another choice besides JObject is System.Json.JsonValue for Weak-Typed JSON object.
It also has a JsonValue blob = JsonValue.Parse(json);
you can use. The blob will most likely be of type JsonObject
which is derived from JsonValue
, but could be JsonArray
. Check the blob.JsonType
if you need to know.
And to answer you question, YES, you may replace json
with the name of your actual variable that holds the JSON string. ;-D
There is a System.Json.dll you should add to your project References.
-Jesse
Do on-demand Mac OS X cloud services exist, comparable to Amazon's EC2 on-demand instances?
Here are some methods that may help others, though they aren't really services as much as they may be described as "methods that may, after some torture of effort or logic, lead to a claim of on-demand access to Mac OS X" (no doubt I should patent that phrase).
Fundamentally, I am inclined to believe that on-demand (per-hour) hosting does not exist, and @Erik has given information for the shortest feasible services, i.e. monthly hosting.
It seems that one may use EC2 itself, but install OS X on the instance through a lot of elbow grease.
- This article on Lifehacker.com gives instructions for setting up OSX under Virtual Box and depends on hardware virtualization. It seems that the Cluster Compute instances (and Cluster GPU, but ignore these) are the only ones supporting hardware virtualization.
- This article gives instructions for transferring a VirtualBox image to EC2.
Where this gets tricky is I'm not sure if this will work for a cluster compute instance. In fact, I think this is likely to be a royal pain. A similar approach may work for Rackspace or other cloud services.
I found only this site claiming on-demand Mac hosting, with a Mac Mini. It doesn't look particularly accurate: it offers free on-demand access to a Mini if one pays for a month of bandwidth. That's like free bandwidth if one rents a Mini for a month. That's not really how "on-demand" works.
Update 1: In the end, it seems that nobody offers a comparable service. An outfit called Media Temple claims they will offer the first virtual servers using Parallels, OS X Leopard, and some other stuff (in other words, I wonder if there is some caveat that makes them unique, but, without that caveat, someone else may have a usable offering).
After this search, I think that a counterpart to EC2 does not exist for the OS X operating system. It is extraordinarily unlikely that one would exist, offer a scalable solution, and yet be very difficult to find. One could set it up internally, but there's no reseller/vendor offering on-demand, hourly virtual servers. This may be disappointing, but not surprising - apparently iCloud is running on Amazon and Microsoft systems.
I can pass a variable from a JSP scriptlet to JSTL but not from JSTL to a JSP scriptlet without an error
Scripts are raw java embedded in the page code, and if you declare variables in your scripts, then they become local variables embedded in the page.
In contrast, JSTL works entirely with scoped attributes, either at page
, request
or session
scope. You need to rework your scriptlet to fish test
out as an attribute:
<c:set var="test" value="test1"/>
<%
String resp = "abc";
String test = pageContext.getAttribute("test");
resp = resp + test;
pageContext.setAttribute("resp", resp);
%>
<c:out value="${resp}"/>
If you look at the docs for <c:set>
, you'll see you can specify scope
as page
, request
or session
, and it defaults to page
.
Better yet, don't use scriptlets at all: they make the baby jesus cry.
Difference between string and char[] types in C++
Think of (char *) as string.begin(). The essential difference is that (char *) is an iterator and std::string is a container. If you stick to basic strings a (char *) will give you what std::string::iterator does. You could use (char *) when you want the benefit of an iterator and also compatibility with C, but that's the exception and not the rule. As always, be careful of iterator invalidation. When people say (char *) isn't safe this is what they mean. It's as safe as any other C++ iterator.
Postgresql query between date ranges
With dates (and times) many things become simpler if you use >= start AND < end
.
For example:
SELECT
user_id
FROM
user_logs
WHERE
login_date >= '2014-02-01'
AND login_date < '2014-03-01'
In this case you still need to calculate the start date of the month you need, but that should be straight forward in any number of ways.
The end date is also simplified; just add exactly one month. No messing about with 28th, 30th, 31st, etc.
This structure also has the advantage of being able to maintain use of indexes.
Many people may suggest a form such as the following, but they do not use indexes:
WHERE
DATEPART('year', login_date) = 2014
AND DATEPART('month', login_date) = 2
This involves calculating the conditions for every single row in the table (a scan) and not using index to find the range of rows that will match (a range-seek).
How do I reverse an int array in Java?
Try this program in JAVA :-
import java.util.Scanner;
public class Rev_one_D {
static int row;
static int[] trans_arr = new int[row];
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
int n = sc.nextInt();
row = n;
int[] arr = new int[row];
for (int i = 0; i < row; i++) {
arr[i] = sc.nextInt();
System.out.print(arr[i] + " ");
System.out.println();
}
for (int i = 0; i < arr.length / 2; i++) {
int temp = arr[i];
arr[i] = arr[arr.length - i - 1];
arr[arr.length - i - 1] = temp;
}
for (int i = 0; i < row; i++) {
System.out.print(arr[i] + " ");
System.out.println();
}
}
}
Java logical operator short-circuiting
The &&
and ||
operators "short-circuit", meaning they don't evaluate the right-hand side if it isn't necessary.
The &
and |
operators, when used as logical operators, always evaluate both sides.
There is only one case of short-circuiting for each operator, and they are:
false && ...
- it is not necessary to know what the right-hand side is because the result can only be false
regardless of the value there
true || ...
- it is not necessary to know what the right-hand side is because the result can only be true
regardless of the value there
Let's compare the behaviour in a simple example:
public boolean longerThan(String input, int length) {
return input != null && input.length() > length;
}
public boolean longerThan(String input, int length) {
return input != null & input.length() > length;
}
The 2nd version uses the non-short-circuiting operator &
and will throw a NullPointerException
if input
is null
, but the 1st version will return false
without an exception.
Adding a column after another column within SQL
It depends on what database you are using. In MySQL, you would use the "ALTER TABLE" syntax. I don't remember exactly how, but it would go something like this if you wanted to add a column called 'newcol' that was a 200 character varchar:
ALTER TABLE example ADD newCol VARCHAR(200) AFTER otherCol;
Using Excel VBA to run SQL query
Below is code that I currently use to pull data from a MS SQL Server 2008 into VBA. You need to make sure you have the proper ADODB reference [VBA Editor->Tools->References] and make sure you have Microsoft ActiveX Data Objects 2.8 Library checked, which is the second from the bottom row that is checked (I'm using Excel 2010 on Windows 7; you might have a slightly different ActiveX version, but it will still begin with Microsoft ActiveX):
Sub Module for Connecting to MS SQL with Remote Host & Username/Password
Sub Download_Standard_BOM()
'Initializes variables
Dim cnn As New ADODB.Connection
Dim rst As New ADODB.Recordset
Dim ConnectionString As String
Dim StrQuery As String
'Setup the connection string for accessing MS SQL database
'Make sure to change:
'1: PASSWORD
'2: USERNAME
'3: REMOTE_IP_ADDRESS
'4: DATABASE
ConnectionString = "Provider=SQLOLEDB.1;Password=PASSWORD;Persist Security Info=True;User ID=USERNAME;Data Source=REMOTE_IP_ADDRESS;Use Procedure for Prepare=1;Auto Translate=True;Packet Size=4096;Use Encryption for Data=False;Tag with column collation when possible=False;Initial Catalog=DATABASE"
'Opens connection to the database
cnn.Open ConnectionString
'Timeout error in seconds for executing the entire query; this will run for 15 minutes before VBA timesout, but your database might timeout before this value
cnn.CommandTimeout = 900
'This is your actual MS SQL query that you need to run; you should check this query first using a more robust SQL editor (such as HeidiSQL) to ensure your query is valid
StrQuery = "SELECT TOP 10 * FROM tbl_table"
'Performs the actual query
rst.Open StrQuery, cnn
'Dumps all the results from the StrQuery into cell A2 of the first sheet in the active workbook
Sheets(1).Range("A2").CopyFromRecordset rst
End Sub
How to close a JavaFX application on window close?
For reference, here is a minimal implementation using Java 8 :
@Override
public void start(Stage mainStage) throws Exception {
Scene scene = new Scene(new Region());
mainStage.setWidth(640);
mainStage.setHeight(480);
mainStage.setScene(scene);
//this makes all stages close and the app exit when the main stage is closed
mainStage.setOnCloseRequest(e -> Platform.exit());
//add real stuff to the scene...
//open secondary stages... etc...
}
Asp.Net WebApi2 Enable CORS not working with AspNet.WebApi.Cors 5.2.3
I found this question because I was having issues with the OPTIONS request most browsers send. My app was routing the OPTIONS requests and using my IoC to construct lots of objects and some were throwing exceptions on this odd request type for various reasons.
Basically put in an ignore route for all OPTIONS requests if they are causing you problems:
var constraints = new { httpMethod = new HttpMethodConstraint(HttpMethod.Options) };
config.Routes.IgnoreRoute("OPTIONS", "{*pathInfo}", constraints);
More info: Stop Web API processing OPTIONS requests
PreparedStatement IN clause alternatives?
No simple way AFAIK.
If the target is to keep statement cache ratio high (i.e to not create a statement per every parameter count), you may do the following:
create a statement with a few (e.g. 10) parameters:
... WHERE A IN (?,?,?,?,?,?,?,?,?,?) ...
Bind all actuall parameters
setString(1,"foo");
setString(2,"bar");
Bind the rest as NULL
setNull(3,Types.VARCHAR)
...
setNull(10,Types.VARCHAR)
NULL never matches anything, so it gets optimized out by the SQL plan builder.
The logic is easy to automate when you pass a List into a DAO function:
while( i < param.size() ) {
ps.setString(i+1,param.get(i));
i++;
}
while( i < MAX_PARAMS ) {
ps.setNull(i+1,Types.VARCHAR);
i++;
}
How can I build a recursive function in python?
Recursion in Python works just as recursion in an other language, with the recursive construct defined in terms of itself:
For example a recursive class could be a binary tree (or any tree):
class tree():
def __init__(self):
'''Initialise the tree'''
self.Data = None
self.Count = 0
self.LeftSubtree = None
self.RightSubtree = None
def Insert(self, data):
'''Add an item of data to the tree'''
if self.Data == None:
self.Data = data
self.Count += 1
elif data < self.Data:
if self.LeftSubtree == None:
# tree is a recurive class definition
self.LeftSubtree = tree()
# Insert is a recursive function
self.LeftSubtree.Insert(data)
elif data == self.Data:
self.Count += 1
elif data > self.Data:
if self.RightSubtree == None:
self.RightSubtree = tree()
self.RightSubtree.Insert(data)
if __name__ == '__main__':
T = tree()
# The root node
T.Insert('b')
# Will be put into the left subtree
T.Insert('a')
# Will be put into the right subtree
T.Insert('c')
As already mentioned a recursive structure must have a termination condition. In this class, it is not so obvious because it only recurses if new elements are added, and only does it a single time extra.
Also worth noting, python by default has a limit to the depth of recursion available, to avoid absorbing all of the computer's memory. On my computer this is 1000. I don't know if this changes depending on hardware, etc. To see yours :
import sys
sys.getrecursionlimit()
and to set it :
import sys #(if you haven't already)
sys.setrecursionlimit()
edit: I can't guarentee that my binary tree is the most efficient design ever. If anyone can improve it, I'd be happy to hear how
Component is not part of any NgModule or the module has not been imported into your module
I ran into the same issue.
I had created another component with the same name under a different folder.
so in my app module I had to import both components but with a trick
import {DuplicateComponent as AdminDuplicateComponent} from '/the/path/to/the/component';
Then in declarations I could add AdminDuplicateComponent instead.
Just thought that I would leave that there for future reference.
IIS_IUSRS and IUSR permissions in IIS8
@EvilDr
You can create an IUSR_[identifier] account within your AD environment and let the particular application pool run under that IUSR_[identifier] account:
"Application pool" > "Advanced Settings" > "Identity" > "Custom account"
Set your website to "Applicaton user (pass-through authentication)" and not "Specific user", in the Advanced Settings.
Now give that IUSR_[identifier] the appropriate NTFS permissions on files and folders, for example: modify on companydata.
Automatically accept all SDK licences
Here is my Docker setup.
You can follow from a plain Linux environment.
Note that yes |
and --licenses --sdk_root=${ANDROID_HOME}
clauses.
It seems sdkmanager --update
reverts agreements, so yes |
is appeared twice.
FROM openjdk:8
# Install dev-essential(gnumake)
RUN apt update
RUN apt install -y build-essential
# Set ENV
ENV SDK_URL="https://dl.google.com/android/repository/sdk-tools-linux-4333796.zip" \
ANDROID_HOME="/usr/local/android-sdk" \
ANDROID_VERSION=28 \
ANDROID_BUILD_TOOLS_VERSION=28.0.3 \
GRADLE_VERSION=4.10.3 \
NDK_VERSION=r16b
# Download Android SDK
RUN mkdir "$ANDROID_HOME" .android \
&& cd "$ANDROID_HOME" \
&& curl -o sdk.zip $SDK_URL \
&& unzip sdk.zip \
&& rm sdk.zip \
&& yes | $ANDROID_HOME/tools/bin/sdkmanager --licenses --sdk_root=${ANDROID_HOME}
# Install Android Build Tool and Libraries
RUN $ANDROID_HOME/tools/bin/sdkmanager --update
RUN yes | $ANDROID_HOME/tools/bin/sdkmanager "build-tools;${ANDROID_BUILD_TOOLS_VERSION}" \
"platforms;android-${ANDROID_VERSION}" \
"platform-tools" --sdk_root=${ANDROID_HOME}
# Install Gradle
RUN wget https://services.gradle.org/distributions/gradle-${GRADLE_VERSION}-all.zip
RUN mkdir /opt/gradle
RUN unzip gradle-${GRADLE_VERSION}-all.zip -d /opt/gradle
ENV PATH=${PATH}:/opt/gradle/gradle-${GRADLE_VERSION}/bin
# Install NDK
RUN wget https://dl.google.com/android/repository/android-ndk-${NDK_VERSION}-linux-x86_64.zip
RUN mkdir /opt/ndk-bundle
RUN unzip android-ndk-${NDK_VERSION}-linux-x86_64.zip -d /opt/ndk-bundle
ENV PATH=${PATH}:/opt/ndk-bundle
RUN mkdir /application
WORKDIR /application
Replace non-ASCII characters with a single space
When we use the ascii()
it escapes the non-ascii characters and it doesn't change ascii characters correctly. So my main thought is, it doesn't change the ASCII characters, so I am iterating through the string and checking if the character is changed. If it changed then replacing it with the replacer, what you give.
For example: ' '(a single space) or '?' (with a question mark).
def remove(x, replacer):
for i in x:
if f"'{i}'" == ascii(i):
pass
else:
x=x.replace(i,replacer)
return x
remove('hái',' ')
Result: "h i" (with single space between).
Syntax : remove(str,non_ascii_replacer)
str = Here you will give the string you want to work with.
non_ascii_replacer = Here you will give the replacer which you want to replace all the non ASCII characters with.
How to parse a JSON and turn its values into an Array?
for your example:
{'profiles': [{'name':'john', 'age': 44}, {'name':'Alex','age':11}]}
you will have to do something of this effect:
JSONObject myjson = new JSONObject(the_json);
JSONArray the_json_array = myjson.getJSONArray("profiles");
this returns the array object.
Then iterating will be as follows:
int size = the_json_array.length();
ArrayList<JSONObject> arrays = new ArrayList<JSONObject>();
for (int i = 0; i < size; i++) {
JSONObject another_json_object = the_json_array.getJSONObject(i);
//Blah blah blah...
arrays.add(another_json_object);
}
//Finally
JSONObject[] jsons = new JSONObject[arrays.size()];
arrays.toArray(jsons);
//The end...
You will have to determine if the data is an array (simply checking that charAt(0)
starts with [
character).
Hope this helps.
How do you push a tag to a remote repository using Git?
git push --follow-tags
This is a sane option introduced in Git 1.8.3:
git push --follow-tags
It pushes both commits and only tags that are both:
- annotated
- reachable (an ancestor) from the pushed commits
This is sane because:
It is for those reasons that --tags
should be avoided.
Git 2.4 has added the push.followTags
option to turn that flag on by default which you can set with:
git config --global push.followTags true
or by adding followTags = true
to the [push]
section of your ~/.gitconfig
file.
How to get config parameters in Symfony2 Twig Templates
You can use parameter substitution in the twig globals section of the config:
Parameter config:
parameters:
app.version: 0.1.0
Twig config:
twig:
globals:
version: '%app.version%'
Twig template:
{{ version }}
This method provides the benefit of allowing you to use the parameter in ContainerAware
classes as well, using:
$container->getParameter('app.version');
Push JSON Objects to array in localStorage
One thing I can suggest you is to extend the storage object to handle objects and arrays.
LocalStorage can handle only strings so you can achieve that using these methods
Storage.prototype.setObj = function(key, obj) {
return this.setItem(key, JSON.stringify(obj))
}
Storage.prototype.getObj = function(key) {
return JSON.parse(this.getItem(key))
}
Using it every values will be converted to json string on set and parsed on get
Rolling back bad changes with svn in Eclipse
In Eclipse Ganymede (Subclipse)
Select project/file that contains bad change, and from pop-up menu choose:
Team -> Show History
Revisions related to that project/file will be shown in History tab.
Find revision where "bad changes" were committed and from pop-up menu choose:
Revert Changes from Revision X
This will merge changes in file(s) modified within bad revision, with revision prior to bad revision.
There are two scenarios from here:
If you committed no changes for that file (bad revision is last revision for that file), it will simply remove changes made in bad revision. Those changes are merged to your working copy so you have to commit them.
If you committed some changes for that file (bad revision is not last revision for that file), you will have to manually resolve conflict. Let say that you have file readme.txt with, and bad revision number is 33. Also, you've made another commit for that file in revision 34. After you choose Revert Changes from Revision 33 you will have following in your working copy:
readme.txt.merge-left.r33 - bad revision
readme.txt.merge-right.r32 - before bad revision
readme.txt.working - working copy version (same as in r34 if you don't have any uncommitted changes)
Original readme.txt will be marked conflicted, and will contain merged version (where changes from bad revision are removed) with some markers (<<<<<<< .working etc). If you just want to remove changes from bad revision and keep changes made after that, then all you have to do is remove markers. Otherwise, you can copy contents from one of 3 files mentioned above to original file. Whatever you choose, when you are done, mark conflict resolved by
Team - Mark Resolved
Temporary files will be removed and your file will be marked changed. As in 1, you have to commit changes.
Note that this does not remove revision from revision history in svn repository. You simply made new revision where changes from bad revision are removed.
How do I sort a list of datetime or date objects?
You're getting None
because list.sort()
it operates in-place, meaning that it doesn't return anything, but modifies the list itself. You only need to call a.sort()
without assigning it to a
again.
There is a built in function sorted()
, which returns a sorted version of the list - a = sorted(a)
will do what you want as well.
Run a PostgreSQL .sql file using command line arguments
you could even do it in this way:
sudo -u postgres psql -d myDataBase -a -f myInsertFile
If you have sudo
access on machine and it's not recommended for production scripts just for test on your own machine it's the easiest way.
Error message "Unable to install or run the application. The application requires stdole Version 7.0.3300.0 in the GAC"
We had the same issue with our ClickOnce application that uses Interop with Microsoft Office. It happened only on a few computers in the company.
The best fix we found out was to modify MS Office installation on problematic computers (through the Programs and Features panel) and ensure that ".NET programmability feature" (not sure of the name of the component - our Microsoft_Office versions are not English) was installed for each of the MS Office applications (Excel, Word, Outlook, etc.). This seems to not be included in a default install.
Then the problem with stdole.dll was fixed.
I hope this might help.
How do I convert a column of text URLs into active hyperlinks in Excel?
For me I just copied the entire column which has the URLs in text format into another application (say Evernote), and when they were pasted there they became links, and then I just copied them back into Excel.
The only thing here is you need to make sure the data you copy back lines up with the rest of the columns.
Clear dropdownlist with JQuery
Just use .empty()
:
// snip...
}).done(function (data) {
// Clear drop down list
$(dropdown).empty(); // <<<<<< No more issue here
// Fill drop down list with new data
$(data).each(function () {
// snip...
There's also a more concise way to build up the options:
// snip...
$(data).each(function () {
$("<option />", {
val: this.value,
text: this.text
}).appendTo(dropdown);
});
How can I set an SQL Server connection string?
You can use the connection string as follows and you only need to add your database name.
string connetionString = "Data Source=.;Initial Catalog=DB name;Integrated Security=True;MultipleActiveResultSets=True";
Check time difference in Javascript
grab the input values after form submission in php
$start_time = $_POST('start_time');
$end_time =$_POST('end_time');
$start = $start_time;
$end = $end_time;
$datetime1 = new DateTime($end);
$datetime2 = new DateTime($start);
//echo $datetime1->format('H:i:s');
$interval = $datetime1->diff($datetime2);
$elapsed = $interval->format('%h:%i');
$time = explode(":",$elapsed);
$hours = $time[0];
$minutes = $time[1];
$tminutes = $minutes + ($hours*60);
the variable $tminutes is total diff in minutes , working hour is $hour
.
this code is for php use this logic and convert this code to js
summing two columns in a pandas dataframe
I think you've misunderstood some python syntax, the following does two assignments:
In [11]: a = b = 1
In [12]: a
Out[12]: 1
In [13]: b
Out[13]: 1
So in your code it was as if you were doing:
sum = df['budget'] + df['actual'] # a Series
# and
df['variance'] = df['budget'] + df['actual'] # assigned to a column
The latter creates a new column for df:
In [21]: df
Out[21]:
cluster date budget actual
0 a 2014-01-01 00:00:00 11000 10000
1 a 2014-02-01 00:00:00 1200 1000
2 a 2014-03-01 00:00:00 200 100
3 b 2014-04-01 00:00:00 200 300
4 b 2014-05-01 00:00:00 400 450
5 c 2014-06-01 00:00:00 700 1000
6 c 2014-07-01 00:00:00 1200 1000
7 c 2014-08-01 00:00:00 200 100
8 c 2014-09-01 00:00:00 200 300
In [22]: df['variance'] = df['budget'] + df['actual']
In [23]: df
Out[23]:
cluster date budget actual variance
0 a 2014-01-01 00:00:00 11000 10000 21000
1 a 2014-02-01 00:00:00 1200 1000 2200
2 a 2014-03-01 00:00:00 200 100 300
3 b 2014-04-01 00:00:00 200 300 500
4 b 2014-05-01 00:00:00 400 450 850
5 c 2014-06-01 00:00:00 700 1000 1700
6 c 2014-07-01 00:00:00 1200 1000 2200
7 c 2014-08-01 00:00:00 200 100 300
8 c 2014-09-01 00:00:00 200 300 500
As an aside, you shouldn't use sum
as a variable name as the overrides the built-in sum function.
How to set initial size of std::vector?
std::vector<CustomClass *> whatever(20000);
or:
std::vector<CustomClass *> whatever;
whatever.reserve(20000);
The former sets the actual size of the array -- i.e., makes it a vector of 20000 pointers. The latter leaves the vector empty, but reserves space for 20000 pointers, so you can insert (up to) that many without it having to reallocate.
At least in my experience, it's fairly unusual for either of these to make a huge difference in performance--but either can affect correctness under some circumstances. In particular, as long as no reallocation takes place, iterators into the vector are guaranteed to remain valid, and once you've set the size/reserved space, you're guaranteed there won't be any reallocations as long as you don't increase the size beyond that.
How to find out the MySQL root password
Follow these steps to reset password in Windows system
Stop Mysql service from task manager
Create a text file and paste the below statement
MySQL 5.7.5 and earlier:
SET PASSWORD FOR 'root'@'localhost' = PASSWORD('yournewpassword');
MySQL 5.7.6 and later:
ALTER USER 'root'@'localhost' IDENTIFIED BY 'yournewpassword';
Save as mysql-init.txt
and place it in 'C' drive
.
Open command prompt and paste the following
C:\> mysqld --init-file=C:\\mysql-init.txt
Check if a number is int or float
I like @ninjagecko's answer the most.
This would also work:
for Python 2.x
isinstance(n, (int, long, float))
Python 3.x doesn't have long
isinstance(n, (int, float))
there is also type complex for complex numbers
Django Admin - change header 'Django administration' text
For Django 2.1.1 add following lines to urls.py
from django.contrib import admin
# Admin Site Config
admin.sites.AdminSite.site_header = 'My site admin header'
admin.sites.AdminSite.site_title = 'My site admin title'
admin.sites.AdminSite.index_title = 'My site admin index'
java.lang.NullPointerException: Attempt to invoke virtual method 'int android.view.View.getImportantForAccessibility()' on a null object reference
My silly mistake was this:
change != to ==
if(convertView != null) { // <---- HERE
LayoutInflater layoutInflater = LayoutInflater.from(z_selBoardElectricity.this);
convertView = layoutInflater.inflate(R.layout.listview_board_alert, null);
TextView textView = convertView.findViewById(R.id.board_name_tv);
ImageView imageView = convertView.findViewById(R.id.board_imageview);
textView.setText(text_list.get(position));
imageView.setImageDrawable(imageAddressList.get(position));
convertView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent();
intent.putExtra("MESSAGE", text_list.get(pos));
setResult(98, intent);
finish();
}
});
}
return convertView;
Combine Date and Time columns using python pandas
My dataset had 1second resolution data for a few days and parsing by the suggested methods here was very slow. Instead I used:
dates = pandas.to_datetime(df.Date, cache=True)
times = pandas.to_timedelta(df.Time)
datetimes = dates + times
Note the use of cache=True
makes parsing the dates very efficient since there are only a couple unique dates in my files, which is not true for a combined date and time column.
Calculate rolling / moving average in C++
One way can be to circularly store the values in the buffer array. and calculate average this way.
int j = (int) (counter % size);
buffer[j] = mostrecentvalue;
avg = (avg * size - buffer[j - 1 == -1 ? size - 1 : j - 1] + buffer[j]) / size;
counter++;
// buffer[j - 1 == -1 ? size - 1 : j - 1] is the oldest value stored
The whole thing runs in a loop where most recent value is dynamic.
How to unmount a busy device
Another alternative when anything works is editing /etc/fstab
, adding noauto
flag and rebooting the machine. The device won't be mounted, and when you're finished doing whatever, remove flag and reboot again.
What is Func, how and when is it used
Func<T1, T2, ..., Tn, Tr>
represents a function, that takes (T1, T2, ..., Tn) arguments and returns Tr.
For example, if you have a function:
double sqr(double x) { return x * x; }
You could save it as some kind of a function-variable:
Func<double, double> f1 = sqr;
Func<double, double> f2 = x => x * x;
And then use exactly as you would use sqr:
f1(2);
Console.WriteLine(f2(f1(4)));
etc.
Remember though, that it's a delegate, for more advanced info refer to documentation.
Getting JavaScript object key list
If you only want the keys which are specific to that particular object and not any derived prototype
properties:
function getKeys(obj) {
var r = []
for (var k in obj) {
if (!obj.hasOwnProperty(k))
continue
r.push(k)
}
return r
}
e.g:
var keys = getKeys({'eggs': null, 'spam': true})
var length = keys.length // access the `length` property as usual for arrays
Android: combining text & image on a Button or ImageButton
<Button
android:layout_width="0dp"
android:layout_weight="1"
android:background="@drawable/home_button"
android:drawableLeft="@android:drawable/ic_menu_edit"
android:drawablePadding="6dp"
android:gravity="left|center"
android:height="60dp"
android:padding="6dp"
android:text="AndroidDhina"
android:textColor="#000"
android:textStyle="bold" />
Failed to load JavaHL Library
Check out this blog. It has a ton of information.
Also if installing through brew don´t miss this note:
You may need to link the Java bindings into the Java Extensions folder:
$ sudo mkdir -p /Library/Java/Extensions
$ sudo ln -s /usr/local/lib/libsvnjavahl-1.dylib /Library/Java/Extensions/libsvnjavahl-1.dylib
jQuery Scroll to bottom of page/iframe
After this thread didn't work out for me for my specific need (scrolling inside a particular element, in my case a textarea) I found this out in the great beyond, which could prove helpful to someone else reading this discussion:
Alternative on planetcloud
Since I already had a cached version of my jQuery object (the myPanel
in the code below is the jQuery object), the code I added to my event handler was simply this:
myPanel.scrollTop(myPanel[0].scrollHeight - myPanel.height());
(thanks Ben)
How to set the title text color of UIButton?
This is swift 5 compatible answer. If you want to use one of the built-in colours then you can simply use
button.setTitleColor(.red, for: .normal)
If you want some custom colours, then create an extension for a UIColor as below first.
import UIKit
extension UIColor {
static var themeMoreButton = UIColor.init(red: 53/255, green: 150/255, blue: 36/255, alpha: 1)
}
Then use it for your button as below.
button.setTitleColor(UIColor.themeMoreButton, for: .normal)
Tip: You can use this method to store custom colours from rgba colour code and reuse it throughout your application.
Regular expression to find two strings anywhere in input
/^.*?\bcat\b.*?\bmat\b.*?$/m
Using the m
modifier (which ensures the beginning/end metacharacters match on line breaks rather than at the very beginning and end of the string):
^
matches the line beginning
.*?
matches anything on the line before...
\b
matches a word boundary the first occurrence of a word boundary (as @codaddict discussed)
- then the string
cat
and another word boundary; note that underscores are treated as "word" characters, so _cat_
would not match*;
.*?
: any characters before...
- boundary,
mat
, boundary
.*?
: any remaining characters before...
$
: the end of the line.
It's important to use \b
to ensure the specified words aren't part of longer words, and it's important to use non-greedy wildcards (.*?
) versus greedy (.*
) because the latter would fail on strings like "There is a cat on top of the mat which is under the cat." (It would match the last occurrence of "cat" rather than the first.)
* If you want to be able to match _cat_
, you can use:
/^.*?(?:\b|_)cat(?:\b|_).*?(?:\b|_)mat(?:\b|_).*?$/m
which matches either underscores or word boundaries around the specified words. (?:)
indicates a non-capturing group, which can help with performance or avoid conflicted captures.
Edit: A question was raised in the comments about whether the solution would work for phrases rather than just words. The answer is, absolutely yes. The following would match "A line which includes both the first phrase and the second phrase":
/^.*?(?:\b|_)first phrase here(?:\b|_).*?(?:\b|_)second phrase here(?:\b|_).*?$/m
Edit 2: If order doesn't matter you can use:
/^.*?(?:\b|_)(first(?:\b|_).*?(?:\b|_)second|second(?:\b|_).*?(?:\b|_)first)(?:\b|_).*?$/m
And if performance is really an issue here, it's possible lookaround (if your regex engine supports it) might (but probably won't) perform better than the above, but I'll leave both the arguably more complex lookaround version and performance testing as an exercise to the questioner/reader.
Edited per @Alan Moore's comment. I didn't have a chance to test it, but I'll take your word for it.
eclipse stuck when building workspace
I was able to fix this with the following:
First, exit Eclipse. Then temporarily move the following .projects
folder to a safe location:
mv .metadata\.plugins\org.eclipse.core.resources\.projects projects
Start and exit Eclipse, then move the .projects
folder back to where it was originally:
mv projects .metadata\.plugins\org.eclipse.core.resources\.projects
Use at your own risk, of course.
Generate a range of dates using SQL
This query generates a list of dates 4000 days in the future and 5000 in the past as of today (inspired on http://blogs.x2line.com/al/articles/207.aspx):
SELECT * FROM (SELECT
(CONVERT(SMALLDATETIME, CONVERT(CHAR,GETDATE() ,103)) + 4000 -
n4.num * 1000 -
n3.num * 100 -
n2.num * 10 -
n1.num) AS Date,
year(CONVERT(SMALLDATETIME, CONVERT(CHAR,GETDATE() ,103)) + 4000 -
n4.num * 1000 -
n3.num * 100 -
n2.num * 10 -
n1.num) as Year,
month(CONVERT(SMALLDATETIME, CONVERT(CHAR,GETDATE() ,103)) + 4000 -
n4.num * 1000 -
n3.num * 100 -
n2.num * 10 -
n1.num) as Month,
day(CONVERT(SMALLDATETIME, CONVERT(CHAR,GETDATE() ,103)) + 4000 -
n4.num * 1000 -
n3.num * 100 -
n2.num * 10 -
n1.num) as Day
FROM (SELECT 0 AS num union ALL
SELECT 1 UNION ALL
SELECT 2 UNION ALL
SELECT 3 UNION ALL
SELECT 4 UNION ALL
SELECT 5 UNION ALL
SELECT 6 UNION ALL
SELECT 7 UNION ALL
SELECT 8 UNION ALL
SELECT 9) n1
,(SELECT 0 AS num UNION ALL
SELECT 1 UNION ALL
SELECT 2 UNION ALL
SELECT 3 UNION ALL
SELECT 4 UNION ALL
SELECT 5 UNION ALL
SELECT 6 UNION ALL
SELECT 7 UNION ALL
SELECT 8 UNION ALL
SELECT 9) n2
,(SELECT 0 AS num union ALL
SELECT 1 UNION ALL
SELECT 2 UNION ALL
SELECT 3 UNION ALL
SELECT 4 UNION ALL
SELECT 5 UNION ALL
SELECT 6 UNION ALL
SELECT 7 UNION ALL
SELECT 8 UNION ALL
SELECT 9) n3
,(SELECT 0 AS num UNION ALL
SELECT 1 UNION ALL
SELECT 2 UNION ALL
SELECT 3 UNION ALL
SELECT 4 UNION ALL
SELECT 5 UNION ALL
SELECT 6 UNION ALL
SELECT 7 UNION ALL
SELECT 8) n4
) GenCalendar ORDER BY 1
decompiling DEX into Java sourcecode
A more complete version of fred's answer:
Manual way
First you need a tool to extract all the (compiled) classes on the DEX to a JAR.
There's one called dex2jar, which is made by a chinese student.
Then, you can use jd-gui to decompile the classes on the JAR to source code.
The resulting source should be quite readable, as dex2jar applies some optimizations.
Automatic way
You can use APKTool. It will automatically extract all the classes (.dex
), resources (.asrc
), then it will convert binary XML to human-readable XML, and it will also dissassemble the classes for you.
Disassembly will always be more robust than decompiling, especially with
JARs obfuscated with Pro Guard!
Just tell APKTool to decode the APK into a directory, then modify what you want,
and finally encode it back to an APK. That's all.
Important: APKTool dissassembles. It doesn't decompile.
The generated code won't be Java source.
But you should be able to read it, and even edit it if you're familiar with jasmin.
If you want Java source, please go over the Manual way.
Error "The goal you specified requires a project to execute but there is no POM in this directory" after executing maven command
1.create a lib folder in your project file,
2.copy your jarFiles to the lib folder
3.right click on to your jarFile go to build path>Add to build path (now your jar file is part of your refrerenced libraries )
4.open command prompt and navigate to your project directory and write
mvn install: install-file "-Dfile=<yourJarFileName>.jar" "-DgroupId=<yourGroupID>" "-DartifactId=<yourArtifactId>" "-Dversion=<yourVersion>" "-Dpackaging=jar"
6.Rebuild your local repository index by opening in eclipse-
go to window>show view>other>maven>maven Repositories.
Right click on local Repositores and hit "RebuildIndex"
5.open your pom.xml file and add your dependency
<dependency>
<groupId><yourGroupID></groupId>
<artifactId><yourArtifactId></artifactId>
<version><yourVersion></version>
</dependency>
and run
mvn clean
mvn compile
mvn test
How to check that an element is in a std::set?
I use
if(!my_set.count(that_element)) //Element is present...
;
But it is not as efficient as
if(my_set.find(that_element)!=my_set.end()) ....;
My version only saves my time in writing the code. I prefer it this way for competitive coding.
HTML5 tag for horizontal line break
You can make a div that has the same attributes as the <hr>
tag. This way it is fully able to be customized. Here is some sample code:
The HTML:
<h3>This is a header.</h3>
<div class="customHr">.</div>
<p>Here is some sample paragraph text.<br>
This demonstrates what could go below a custom hr.</p>
The CSS:
.customHr {
width: 95%
font-size: 1px;
color: rgba(0, 0, 0, 0);
line-height: 1px;
background-color: grey;
margin-top: -6px;
margin-bottom: 10px;
}
To see how the project turns out, here is a JSFiddle for the above code: http://jsfiddle.net/SplashHero/qmccsc06/1/
Does file_get_contents() have a timeout setting?
As @diyism mentioned, "default_socket_timeout, stream_set_timeout, and stream_context_create timeout are all the timeout of every line read/write, not the whole connection timeout." And the top answer by @stewe has failed me.
As an alternative to using file_get_contents
, you can always use curl
with a timeout.
So here's a working code that works for calling links.
$url='http://example.com/';
$ch=curl_init();
$timeout=5;
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_TIMEOUT, $timeout);
curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, $timeout);
$result=curl_exec($ch);
curl_close($ch);
echo $result;
python dataframe pandas drop column using int
Drop multiple columns like this:
cols = [1,2,4,5,12]
df.drop(df.columns[cols],axis=1,inplace=True)
inplace=True
is used to make the changes in the dataframe itself without doing the column dropping on a copy of the data frame. If you need to keep your original intact, use:
df_after_dropping = df.drop(df.columns[cols],axis=1)
Getting a union of two arrays in JavaScript
_x000D_
_x000D_
function unionArrays() {_x000D_
var args = arguments,_x000D_
l = args.length,_x000D_
obj = {},_x000D_
res = [],_x000D_
i, j, k;_x000D_
_x000D_
while (l--) {_x000D_
k = args[l];_x000D_
i = k.length;_x000D_
_x000D_
while (i--) {_x000D_
j = k[i];_x000D_
if (!obj[j]) {_x000D_
obj[j] = 1;_x000D_
res.push(j);_x000D_
}_x000D_
} _x000D_
}_x000D_
_x000D_
return res;_x000D_
}_x000D_
var unionArr = unionArrays([34, 35, 45, 48, 49], [44, 55]);_x000D_
console.log(unionArr);
_x000D_
_x000D_
_x000D_
Somewhat similar in approach to alejandro's method, but a little shorter and should work with any number of arrays.
Selecting only numeric columns from a data frame
iris %>% dplyr::select(where(is.numeric)) #as per most recent updates
Another option with purrr
would be to negate discard
function:
iris %>% purrr::discard(~!is.numeric(.))
If you want the names of the numeric columns, you can add names
or colnames
:
iris %>% purrr::discard(~!is.numeric(.)) %>% names
jquery beforeunload when closing (not leaving) the page?
Try javascript into your Ajax
window.onbeforeunload = function(){
return 'Are you sure you want to leave?';
};
Reference link
Example 2:
document.getElementsByClassName('eStore_buy_now_button')[0].onclick = function(){
window.btn_clicked = true;
};
window.onbeforeunload = function(){
if(!window.btn_clicked){
return 'You must click "Buy Now" to make payment and finish your order. If you leave now your order will be canceled.';
}
};
Here it will alert the user every time he leaves the page, until he clicks on the button.
DEMO: http://jsfiddle.net/DerekL/GSWbB/show/
What is Dependency Injection?
It means that objects should only have as many dependencies as is needed to do their job and the dependencies should be few. Furthermore, an object’s dependencies should be on interfaces and not on “concrete” objects, when possible. (A concrete object is any object created with the keyword new.) Loose coupling promotes greater reusability, easier maintainability, and allows you to easily provide “mock” objects in place of expensive services.
The “Dependency Injection” (DI) is also known as “Inversion of Control” (IoC), can be used as a technique for encouraging this loose coupling.
There are two primary approaches to implementing DI:
- Constructor injection
- Setter injection
Constructor injection
It’s the technique of passing objects dependencies to its constructor.
Note that the constructor accepts an interface and not concrete object. Also, note that an exception is thrown if the orderDao parameter is null. This emphasizes the importance of receiving a valid dependency. Constructor Injection is, in my opinion, the preferred mechanism for giving an object its dependencies. It is clear to the developer while invoking the object which dependencies need to be given to the “Person” object for proper execution.
Setter Injection
But consider the following example… Suppose you have a class with ten methods that have no dependencies, but you’re adding a new method that does have a dependency on IDAO. You could change the constructor to use Constructor Injection, but this may force you to changes to all constructor calls all over the place. Alternatively, you could just add a new constructor that takes the dependency, but then how does a developer easily know when to use one constructor over the other. Finally, if the dependency is very expensive to create, why should it be created and passed to the constructor when it may only be used rarely? “Setter Injection” is another DI technique that can be used in situations such as this.
Setter Injection does not force dependencies to be passed to the constructor. Instead, the dependencies are set onto public properties exposed by the object in need. As implied previously, the primary motivators for doing this include:
- Supporting dependency injection without having to modify the constructor of a legacy class.
- Allowing expensive resources or services to be created as late as possible and only when needed.
Here is the example of how the above code would look like:
public class Person {
public Person() {}
public IDAO Address {
set { addressdao = value; }
get {
if (addressdao == null)
throw new MemberAccessException("addressdao" +
" has not been initialized");
return addressdao;
}
}
public Address GetAddress() {
// ... code that uses the addressdao object
// to fetch address details from the datasource ...
}
// Should not be called directly;
// use the public property instead
private IDAO addressdao;
What are XAND and XOR
Have a look
x y A B C D E F G H I J K L M N
· · T · T · T · T · T · T · T ·
· T · T T · · T T · · T T · · T
T · · · · T T T T · · · · T T T
T T · · · · · · · T T T T T T T
A) !(x OR y)
B) !(x) AND y
C) !(x)
D) x AND !(y)
E) !(y)
F) x XOR y
G) !(x AND y)
H) x AND y
I) !(x XOR y)
J) y
K) !(x) OR y
L) x
M) x OR !(y)
N) x OR y
jQuery prevent change for select
This worked for me, no need to keep a lastSelected
if you know the optionIndex
to select.
var optionIndex = ...
$(this)[0].options[optionIndex].selected = true;
event Action<> vs event EventHandler<>
Looking at Standard .NET event patterns we find
The standard signature for a .NET event delegate is:
void OnEventRaised(object sender, EventArgs args);
[...]
The argument list contains two arguments: the sender, and the event arguments. The compile time type of sender is System.Object, even though you likely know a more derived type that would always be correct. By convention, use object.
Below on same page we find an example of the typical event definition which is something like
public event EventHandler<EventArgs> EventName;
Had we defined
class MyClass
{
public event Action<MyClass, EventArgs> EventName;
}
the handler could have been
void OnEventRaised(MyClass sender, EventArgs args);
where sender
has the correct (more derived) type.
Export table to file with column headers (column names) using the bcp utility and SQL Server 2008
From all I know, BCP only exports the data - I don't think there's any way to make it export the header row with column names, too.
One common technique seen to solve this is to use a view over your actual data for export, which basically does a UNION ALL over two statements:
- the first statement to give back one row with the column headers
- the actual data to be export
and then use bcp on that view, instead of your underlying data table directly.
Marc
How do you find the current user in a Windows environment?
As far as find BlueBearr response the best (while I,m running my batch script with eg. SYSTEM rights) I have to add something to it.
Because in my Windows language version (Polish) line that is to be catched by "%%a %%b"=="User Name:" gets REALLY COMPLICATED (it contains some diacritic characters in my language) I skip first 7 lines and operate on the 8th.
@for /f "SKIP= 7 TOKENS=3,4 DELIMS=\ " %%G in ('tasklist /FI "IMAGENAME eq explorer.exe" /FO LIST /V') do @IF %%G==%COMPUTERNAME% set _currdomain_user=%%H
HTML <input type='file'> File Selection Event
When you have to reload the file, you can erase the value of input. Next time you add a file, 'on change' event will trigger.
document.getElementById('my_input').value = null;
// ^ that just erase the file path but do the trick
Case vs If Else If: Which is more efficient?
Many programming language optimize the switch statement so that it is much faster than a standard if-else if structure provided the cases are compiler constants. Many languages use a jump table or indexed branch table to optimize switch statements. Wikipedia has a good discussion of the switch statement. Also, here is a discussion of switch optimization in C.
One thing to note is that switch statements can be abused and, depending on the case, it may be preferable to use polymorphism instead of switch statements. See here for an example.
Why use double indirection? or Why use pointers to pointers?
Compare modifying value of variable versus modifying value of pointer:
#include <stdio.h>
#include <stdlib.h>
void changeA(int (*a))
{
(*a) = 10;
}
void changeP(int *(*P))
{
(*P) = malloc(sizeof((*P)));
}
int main(void)
{
int A = 0;
printf("orig. A = %d\n", A);
changeA(&A);
printf("modi. A = %d\n", A);
/*************************/
int *P = NULL;
printf("orig. P = %p\n", P);
changeP(&P);
printf("modi. P = %p\n", P);
free(P);
return EXIT_SUCCESS;
}
This helped me to avoid returning value of pointer when the pointer was modified by the called function (used in singly linked list).
OLD (bad):
int *func(int *P)
{
...
return P;
}
int main(void)
{
int *pointer;
pointer = func(pointer);
...
}
NEW (better):
void func(int **pointer)
{
...
}
int main(void)
{
int *pointer;
func(&pointer);
...
}
Why is the <center> tag deprecated in HTML?
I still use the <center> tag sometimes because nothing in CSS works as well. Examples of trying to use a <div> trick and failing:
_x000D_
_x000D_
<div style="text-align: center;">This div is centered, but it's a simple example.</div>_x000D_
<br />_x000D_
<div style="text-align: center;"><table border="1"><tr><td><div style="text-align: center;"> didn't center correctly.</td></tr></table></div>_x000D_
<br />_x000D_
<div style="text-align: center;margin-left:auto;margin-right:auto"><table border="1"><tr><td><div style="text-align: center;margin-left:auto;margin-right:auto"> still didn't center either</td></tr></table></div>_x000D_
<br />_x000D_
<center><table border="1"><tr><td>Actually Centered with <center> tag</td></tr></table></center>
_x000D_
_x000D_
_x000D_
<center> gets results. To use CSS instead, you sometimes have to put CSS in several places and mess with it to get it to center right. To answer your question, CSS has become a religion with believers and followers who shunned <center> <b> <i> <u> as blasphemy, unholy, and much too simple for the sake of their own job security. And if they try to take your <table> away from you, ask them what the CSS equivalent of the colspan or rowspan attribute is.
It is not the abstract or bookish truth, but the lived truth that counts.
-- Zen
Use Robocopy to copy only changed files?
Looks like /e
option is what you need, it'll skip same files/directories.
robocopy c:\data c:\backup /e
If you run the command twice, you'll see the second round is much faster since it skips a lot of things.
OCI runtime exec failed: exec failed: (...) executable file not found in $PATH": unknown
This happened to me on windows.
Any of these commands will work
On Windows CMD (not switching to bash)
docker exec -it <container-id> /bin/sh
On Windows CMD (after switching to bash)
docker exec -it <container-id> //bin//sh
or
winpty docker exec -it <container-id> //bin//sh
On Git Bash
winpty docker exec -it <container-id> //bin//sh
NB: You might need to run use /bin/bash
or /bin/sh
, depending on the shell in your container.
The reason is documented in the ReleaseNotes file of Git and it is well explained here - Bash in Git for Windows: Weirdness...
"The cause has to do with trying to ensure that posix paths end up being passed to the git utilities properly. For this reason, Git for Windows includes a modified MSYS layer that affects command arguments."
How do I rotate a picture in WinForms
This will work as long as the image you want to rotate is already in your Properties resources folder.
In Partial Class:
Bitmap bmp2;
OnLoad:
bmp2 = new Bitmap(Tycoon.Properties.Resources.save2);
pictureBox6.SizeMode = PictureBoxSizeMode.StretchImage;
pictureBox6.Image = bmp2;
Button or Onclick
private void pictureBox6_Click(object sender, EventArgs e)
{
if (bmp2 != null)
{
bmp2.RotateFlip(RotateFlipType.Rotate90FlipNone);
pictureBox6.Image = bmp2;
}
}
"unmappable character for encoding" warning in Java
If you're using Maven, set the <encoding>
explicitly in the compiler plugin's configuration, e.g.
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>2.3.2</version>
<configuration>
<encoding>UTF-8</encoding>
</configuration>
</plugin>
Best way to clear a PHP array's values
I see this questions is realla old, but for that problem I wrote a recursive function to unset all values in an array. Recursive because its possible that values from the given array are also an array. So that works for me:
function empty_array(& $complete_array) {
foreach($complete_array as $ckey => $cvalue)
{
if (!is_array($cvalue)) {
$complete_array[$ckey] = "";
} else {
empty_array( $complete_array[$ckey]);
}
}
return $complete_array;
}
So with that i get the array with all keys and sub-arrays, but empty values.