Programs & Examples On #Most vexing parse

The term "most vexing parse" (coined by Scott Meyers in "Effective STL") refers to a particular syntactic ambiguity in C++ programs that leads to a counterintuitive interpretation of certain declarations. It is often accompanied by poor diagnostics, confusing many programmers who encounter it.

Cleanest way to write retry logic?

Building on the previous work, I thought about enhancing the retry logic in three ways:

  1. Specifying what exception type to catch/retry. This is the primary enhacement as retrying for any exception is just plain wrong.
  2. Not nesting the last try in a try/catch, achieving slightly better performance
  3. Making it an Action extension method

    static class ActionExtensions
    {
      public static void InvokeAndRetryOnException<T> (this Action action, int retries, TimeSpan retryDelay) where T : Exception
      {
        if (action == null)
          throw new ArgumentNullException("action");
    
        while( retries-- > 0 )
        {
          try
          {
            action( );
            return;
          }
          catch (T)
          {
            Thread.Sleep( retryDelay );
          }
        }
    
        action( );
      }
    }
    

The method can then be invoked like so (anonymous methods can be used as well, of course):

new Action( AMethodThatMightThrowIntermittentException )
  .InvokeAndRetryOnException<IntermittentException>( 2, TimeSpan.FromSeconds( 1 ) );

ReferenceError: variable is not defined

It's declared inside a closure, which means it can only be accessed there. If you want a variable accessible globally, you can remove the var:

$(function(){
    value = "10";
});
value; // "10"

This is equivalent to writing window.value = "10";.

Scroll RecyclerView to show selected item on top

what i did to restore the scroll position after refreshing the RecyclerView on button clicked:

if (linearLayoutManager != null) {

    index = linearLayoutManager.findFirstVisibleItemPosition();
    View v = linearLayoutManager.getChildAt(0);
    top = (v == null) ? 0 : (v.getTop() - linearLayoutManager.getPaddingTop());
    Log.d("TAG", "visible position " + " " + index);
}

else{
    index = 0;
}

linearLayoutManager = new LinearLayoutManager(getApplicationContext());
linearLayoutManager.scrollToPositionWithOffset(index, top);

getting the offset of the first visible item from the top before creating the linearLayoutManager object and after instantiating it the scrollToPositionWithOffset of the LinearLayoutManager object was called.

What is the best way to concatenate two vectors?

This is precisely what the member function std::vector::insert is for

std::vector<int> AB = A;
AB.insert(AB.end(), B.begin(), B.end());

fastest way to export blobs from table into individual files

For me what worked by combining all the posts I have read is:

1.Enable OLE automation - if not enabled

sp_configure 'show advanced options', 1;  
GO  
RECONFIGURE;  
GO  
sp_configure 'Ole Automation Procedures', 1;  
GO  
RECONFIGURE;  
GO

2.Create a folder where the generated files will be stored:

C:\GREGTESTING

3.Create DocTable that will be used for file generation and store there the blobs in Doc_Content
enter image description here

CREATE TABLE [dbo].[Document](
    [Doc_Num] [numeric](18, 0) IDENTITY(1,1) NOT NULL,
    [Extension] [varchar](50) NULL,
    [FileName] [varchar](200) NULL,
    [Doc_Content] [varbinary](max) NULL   
) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY] 

INSERT [dbo].[Document] ([Extension] ,[FileName] , [Doc_Content] )
    SELECT 'pdf', 'SHTP Notional hire - January 2019.pdf', 0x....(varbinary blob)

Important note!

Don't forget to add in Doc_Content column the varbinary of file you want to generate!

4.Run the below script

DECLARE @outPutPath varchar(50) = 'C:\GREGTESTING'
, @i bigint
, @init int
, @data varbinary(max) 
, @fPath varchar(max)  
, @folderPath  varchar(max)

--Get Data into temp Table variable so that we can iterate over it 
DECLARE @Doctable TABLE (id int identity(1,1), [Doc_Num]  varchar(100) , [FileName]  varchar(100), [Doc_Content] varBinary(max) )



INSERT INTO @Doctable([Doc_Num] , [FileName],[Doc_Content])
Select [Doc_Num] , [FileName],[Doc_Content] FROM  [dbo].[Document]



SELECT @i = COUNT(1) FROM @Doctable   

WHILE @i >= 1   

BEGIN    

SELECT 
    @data = [Doc_Content],
    @fPath = @outPutPath + '\' + [Doc_Num] +'_' +[FileName],
    @folderPath = @outPutPath + '\'+ [Doc_Num]
FROM @Doctable WHERE id = @i

EXEC sp_OACreate 'ADODB.Stream', @init OUTPUT; -- An instace created
EXEC sp_OASetProperty @init, 'Type', 1;  
EXEC sp_OAMethod @init, 'Open'; -- Calling a method
EXEC sp_OAMethod @init, 'Write', NULL, @data; -- Calling a method
EXEC sp_OAMethod @init, 'SaveToFile', NULL, @fPath, 2; -- Calling a method
EXEC sp_OAMethod @init, 'Close'; -- Calling a method
EXEC sp_OADestroy @init; -- Closed the resources
print 'Document Generated at - '+  @fPath   

--Reset the variables for next use
SELECT @data = NULL  
, @init = NULL
, @fPath = NULL  
, @folderPath = NULL
SET @i -= 1
END   

5.The results is shown below: enter image description here

Can a background image be larger than the div itself?

You mention already having a background image on body.

You could set that background image on html, and the new one on body. This will of course depend upon your layout, but you wouldn't need to use your footer for it.

How do I check in SQLite whether a table exists?

Table exists or not in database in swift

func tableExists(_ tableName:String) -> Bool {
        sqlStatement = "SELECT name FROM sqlite_master WHERE type='table' AND name='\(tableName)'"
        if sqlite3_prepare_v2(database, sqlStatement,-1, &compiledStatement, nil) == SQLITE_OK {
            if sqlite3_step(compiledStatement) == SQLITE_ROW {
                return true
            }
            else {
                return false
            }
        }
        else {
            return false
        }
            sqlite3_finalize(compiledStatement)
    }

How to get margin value of a div in plain JavaScript?

The properties on the style object are only the styles applied directly to the element (e.g., via a style attribute or in code). So .style.marginTop will only have something in it if you have something specifically assigned to that element (not assigned via a style sheet, etc.).

To get the current calculated style of the object, you use either the currentStyle property (Microsoft) or the getComputedStyle function (pretty much everyone else).

Example:

var p = document.getElementById("target");
var style = p.currentStyle || window.getComputedStyle(p);

display("Current marginTop: " + style.marginTop);

Fair warning: What you get back may not be in pixels. For instance, if I run the above on a p element in IE9, I get back "1em".

Live Copy | Source

Set background color in PHP?

CSS supports text input for colors (i.e. "black" = #000000 "white" = #ffffff) So I think the helpful solution we are looking for here is how can one have PHP take the output from an HTML form text input box and have it tell CSS to use this line of text for background color.

So that when a a user types "blue" into the text field titled "what is your favorite color", they are returned a page with a blue background, or whatever color they happen to type in so long as it is recognized by CSS.

I believe Dan is on the right track, but may need to elaborate for use PHP newbies, when I try this I am returned a green screen no matter what is typed in (I even set this up as an elseif to display a white background if no data is entered in the text field, still green?

jQuery: How can I create a simple overlay?

Here is a simple javascript only solution

function displayOverlay(text) {
    $("<table id='overlay'><tbody><tr><td>" + text + "</td></tr></tbody></table>").css({
        "position": "fixed",
        "top": 0,
        "left": 0,
        "width": "100%",
        "height": "100%",
        "background-color": "rgba(0,0,0,.5)",
        "z-index": 10000,
        "vertical-align": "middle",
        "text-align": "center",
        "color": "#fff",
        "font-size": "30px",
        "font-weight": "bold",
        "cursor": "wait"
    }).appendTo("body");
}

function removeOverlay() {
    $("#overlay").remove();
}

Demo:

http://jsfiddle.net/UziTech/9g0pko97/

Gist:

https://gist.github.com/UziTech/7edcaef02afa9734e8f2

$apply already in progress error

You can $apply your changes only if $apply is not already in progress. You can update your code as

if(!$scope.$$phase) $scope.$apply();

Inserting values into a SQL Server database using ado.net via C#

Remove the comma

... Gender,Contact, " + ") VALUES ...
                  ^-----------------here

How can I hide a TD tag using inline JavaScript or CSS?

.hide{

visibility: hidden

}

<td class="hide"/>

Edit- Just for you

The difference between display and visibility is this.

"display": has many properties or values, but the ones you're focused on are "none" and "block". "none" is like a hide value, and "block" is like show. If you use the "none" value you will totally hide what ever html tag you have applied this css style. If you use "block" you will see the html tag and it's content. very simple.

"visibility": has many values, but we want to know more about the "hidden" and "visible" values. "hidden" will work in the same way as the "block" value for display, but this will hide tag and it's content, but it will not hide the phisical space of that tag. For example, if you have a couple of text lines, then and image (picture) and then a table with three columns and two rows with icons and text. Now if you apply the visibility css with the hidden value to the image, the image will disappear but the space the image was using will remaing in it's place, in other words, you will end with a big space (hole) between the text and the table. Now if you use the "visible" value your target tag and it's elements will be visible again.

Python, compute list difference

most simple way,

use set().difference(set())

list_a = [1,2,3]
list_b = [2,3]
print set(list_a).difference(set(list_b))

answer is set([1])

Rethrowing exceptions in Java without losing the stack trace

Stack trace is prserved if you wrap the catched excetion into an other exception (to provide more info) or if you just rethrow the catched excetion.

try{ ... }catch (FooException e){ throw new BarException("Some usefull info", e); }

How to execute a query in ms-access in VBA code?

How about something like this...

Dim rs As RecordSet
Set rs = Currentdb.OpenRecordSet("SELECT PictureLocation, ID FROM MyAccessTable;")

Do While Not rs.EOF
   Debug.Print rs("PictureLocation") & " - " & rs("ID")
   rs.MoveNext
Loop

How to split a string with any whitespace chars as delimiters

String str = "Hello   World";
String res[] = str.split("\\s+");

Splitting words into letters in Java

You need to use split("");.

That will split it by every character.

However I think it would be better to iterate over a String's characters like so:

for (int i = 0;i < str.length(); i++){
    System.out.println(str.charAt(i));
}

It is unnecessary to create another copy of your String in a different form.

Byte and char conversion in Java

new String(byteArray, Charset.defaultCharset())

This will convert a byte array to the default charset in java. It may throw exceptions depending on what you supply with the byteArray.

How to change the color of a CheckBox?

You can change the color directly in XML. Use buttonTint for the box: (as of API level 23)

<CheckBox
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:buttonTint="@color/CHECK_COLOR" />

You can also do this using appCompatCheckbox v7 for older API levels:

<android.support.v7.widget.AppCompatCheckBox 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    app:buttonTint="@color/COLOR_HERE" /> 

Convert string to BigDecimal in java

May I add something. If you are using currency you should use Scale(2), and you should probably figure out a round method.

google chrome extension :: console.log() from background page?

Any extension page (except content scripts) has direct access to the background page via chrome.extension.getBackgroundPage().

That means, within the popup page, you can just do:

chrome.extension.getBackgroundPage().console.log('foo');

To make it easier to use:

var bkg = chrome.extension.getBackgroundPage();
bkg.console.log('foo');

Now if you want to do the same within content scripts you have to use Message Passing to achieve that. The reason, they both belong to different domains, which make sense. There are many examples in the Message Passing page for you to check out.

Hope that clears everything.

Value does not fall within the expected range

In case of WSS 3.0 recently I experienced same issue. It was because of column that was accessed from code was not present in the wss list.

call javascript function onchange event of dropdown list

You just try this, Its so easy

 <script>

  $("#YourDropDownId").change(function () {
            alert($("#YourDropDownId").val());
        });

</script>

Vertically center text in a 100% height div?

just wrap your content with a table like this:

  <table width="100%" height="100%">
         <tr align="center">
               <th align="center">
                 text
               </th>
          </tr>
  </table><

Excel Formula to SUMIF date falls in particular month

=Sumifs(B:B,A:A,">=1/1/2013",A:A,"<=1/31/2013")

The beauty of this formula is you can add more data to columns A and B and it will just recalculate.

Laravel PHP Command Not Found

Add the following to .bashrc file (not .bash_profile).

export PATH="~/.composer/vendor/bin:$PATH" 

at the end of the file and then in terminal run source ~/.bashrc

To verify that:

echo $PATH

(Restart the terminal, Check & Confirm the path is there)

Run the laravel command!

Note: For Ubuntu 16 and above use below:

export PATH="~/.config/composer/vendor/bin:$PATH" 

finding multiples of a number in Python

For the first ten multiples of 5, say

>>> [5*n for n in range(1,10+1)]
[5, 10, 15, 20, 25, 30, 35, 40, 45, 50]

What does this format means T00:00:00.000Z?

As one person may have already suggested,

I passed the ISO 8601 date string directly to moment like so...

`moment.utc('2019-11-03T05:00:00.000Z').format('MM/DD/YYYY')`

or

`moment('2019-11-03T05:00:00.000Z').utc().format('MM/DD/YYYY')`

either of these solutions will give you the same result.

`console.log(moment('2019-11-03T05:00:00.000Z').utc().format('MM/DD/YYYY')) // 11/3/2019`

java.security.cert.CertificateException: Certificates does not conform to algorithm constraints

I have this issue in SOAP-UI and no one solution above dont helped me.

Proper solution for me was to add

-Dsoapui.sslcontext.algorithm=TLSv1

in vmoptions file (in my case it was ...\SoapUI-5.4.0\bin\SoapUI-5.4.0.vmoptions)

Erase the current printed console line

there is a simple trick you can work here but it need preparation before you print, you have to put what ever you wants to print in a variable and then print so you will know the length to remove the string.here is an example.

#include <iostream>
#include <string> //actually this thing is not nessasory in tdm-gcc

using namespace  std;

int main(){

//create string variable

string str="Starting count";

//loop for printing numbers

    for(int i =0;i<=50000;i++){

        //get previous string length and clear it from screen with backspace charactor

        cout << string(str.length(),'\b');

        //create string line

        str="Starting count " +to_string(i);

        //print the new line in same spot

        cout <<str ;
    }

}

How to fit in an image inside span tag?

Try this.

<span style="padding-right:3px; padding-top: 3px; display:inline-block;">

<img class="manImg" src="images/ico_mandatory.gif"></img>

</span>

Pandas - How to flatten a hierarchical index in columns

df.columns = ['_'.join(tup).rstrip('_') for tup in df.columns.values]

How to check if a char is equal to an empty space?

My suggestion would be:

if (c == ' ')

Malformed String ValueError ast.literal_eval() with String representation of Tuple

I know this is an old question, but I think found a very simple answer, in case anybody needs it.

If you put string quotes inside your string ("'hello'"), ast_literaleval() will understand it perfectly.

You can use a simple function:

    def doubleStringify(a):
        b = "\'" + a + "\'"
        return b

Or probably more suitable for this example:

    def perfectEval(anonstring):
        try:
            ev = ast.literal_eval(anonstring)
            return ev
        except ValueError:
            corrected = "\'" + anonstring + "\'"
            ev = ast.literal_eval(corrected)
            return ev

Why doesn't catching Exception catch RuntimeException?

class Test extends Thread
{
    public void run(){  
        try{  
            Thread.sleep(10000);  
        }catch(InterruptedException e){  
            System.out.println("test1");
            throw new RuntimeException("Thread interrupted..."+e);  
        }  

    }  

    public static void main(String args[]){  
        Test t1=new Test1();  
        t1.start();  
        try{  
            t1.interrupt();  
        }catch(Exception e){
            System.out.println("test2");
            System.out.println("Exception handled "+e);
        }  

    }  
}

Its output doesn't contain test2 , so its not handling runtime exception. @jon skeet, @Jan Zyka

Remove Blank option from Select Option with AngularJS

Also check whether you have any falsy value or not. Angularjs will insert an empty option if you do have falsy value. I struggled for 2 days just due to falsy value. I hope it will be helpful for someone.

I had options as [0, 1] and initially I was set the model to 0 due to that it was inserted empty option. Workaround for this was ["0" , "1"].

How to rsync only a specific list of files?

For the record, none of the answers above helped except for one. To summarize, you can do the backup operation using --files-from= by using either:

 rsync -aSvuc `cat rsync-src-files` /mnt/d/rsync_test/

OR

 rsync -aSvuc --recursive --files-from=rsync-src-files . /mnt/d/rsync_test/

The former command is self explanatory, beside the content of the file rsync-src-files which I will elaborate down below. Now, if you want to use the latter version, you need to keep in mind the following four remarks:

  1. Notice one needs to specify both --files-from and the source directory
  2. One needs to explicitely specify --recursive.
  3. The file rsync-src-files is a user created file and it was placed within the src directory for this test
  4. The rsyn-src-files contain the files and folders to copy and they are taken relative to the source directory. IMPORTANT: Make sure there is not trailing spaces or blank lines in the file. In the example below, there are only two lines, not three (Figure it out by chance). Content of rsynch-src-files is:

folderName1
folderName2

Multi-character constant warnings

If you want to disable this warning it is important to know that there are two related warning parameters in GCC and Clang: GCC Compiler options -wno-four-char-constants and -wno-multichar

Execution failed for task ':app:processDebugResources' even with latest build tools

as a quick fix to this question, make sure your compile Sdk verion, your buildtoolsversion, your appcompat, and finally your support library are all running on the same sdk version, for further clarity take a look at the image i just uploaded. Cheers. Follow the red annotations and get rid of that trouble.

enter image description here

Normal arguments vs. keyword arguments

There are two ways to assign argument values to function parameters, both are used.

  1. By Position. Positional arguments do not have keywords and are assigned first.

  2. By Keyword. Keyword arguments have keywords and are assigned second, after positional arguments.

Note that you have the option to use positional arguments.

If you don't use positional arguments, then -- yes -- everything you wrote turns out to be a keyword argument.

When you call a function you make a decision to use position or keyword or a mixture. You can choose to do all keywords if you want. Some of us do not make this choice and use positional arguments.

Convert HashBytes to VarChar

Changing the datatype to varbinary seems to work the best for me.

How to convert an array to object in PHP?

Inspired by all these codes, i tried to create a enhanced version with support to: specific class name, avoid constructor method, 'beans' pattern and strict mode (set only existing properties):

    class Util {

static function arrayToObject($array, $class = 'stdClass', $strict = false) {
        if (!is_array($array)) {
            return $array;
        }

        //create an instance of an class without calling class's constructor
        $object = unserialize(
                sprintf(
                        'O:%d:"%s":0:{}', strlen($class), $class
                )
        );

        if (is_array($array) && count($array) > 0) {
            foreach ($array as $name => $value) {
                $name = strtolower(trim($name));
                if (!empty($name)) {

                    if(method_exists($object, 'set'.$name)){
                        $object->{'set'.$name}(Util::arrayToObject($value));
                    }else{
                        if(($strict)){

                            if(property_exists($class, $name)){

                                $object->$name = Util::arrayToObject($value); 

                            }

                        }else{
                            $object->$name = Util::arrayToObject($value); 
                        }

                    }

                }
            }
            return $object;
        } else {
            return FALSE;
        }
        }
}

Determine installed PowerShell version

The easiest way to forget this page and never return to it is to learn the Get-Variable:

Get-Variable | where {$_.Name -Like '*version*'} | %{$_[0].Value}

There is no need to remember every variable. Just Get-Variable is enough (and "There should be something about version").

Return index of highest value in an array

Other answers may have shorter code but this one should be the most efficient and is easy to understand.

/**
 * Get key of the max value
 *
 * @var array $array
 * @return mixed
*/
function array_key_max_value($array)
{
    $max = null;
    $result = null;
    foreach ($array as $key => $value) {
        if ($max === null || $value > $max) {
            $result = $key;
            $max = $value;
        }
    }

    return $result;
}

fatal error LNK1112: module machine type 'x64' conflicts with target machine type 'X86'

Many good suggestions above.

Also if you are trying to build in x86 Win32:

Make sure that any libraries you link to in Program Files(x86) are actually x86 libraries because they are not necessarily...

For example a lib file I linked to in C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\SDK threw that error, eventually I found an x86 version of it in C:\Program Files (x86)\Windows Kits\10\Lib\10.0.18362.0\um\x86 and everything worked fine.

How to format DateTime columns in DataGridView?

string stringtodate = ((DateTime)row.Cells[4].Value).ToString("MM-dd-yyyy");
textBox9.Text = stringtodate;

php Replacing multiple spaces with a single space

Use preg_replace() and instead of [ \t\n\r] use \s:

$output = preg_replace('!\s+!', ' ', $input);

From Regular Expression Basic Syntax Reference:

\d, \w and \s

Shorthand character classes matching digits, word characters (letters, digits, and underscores), and whitespace (spaces, tabs, and line breaks). Can be used inside and outside character classes.

How to install a specific JDK on Mac OS X?

Check this awesome tool sdkman to manage your jdk and other jdk related tools with great ease!

e.g.

$sdk list java
$sdk install java <VERSION>

Splitting templated C++ classes into .hpp/.cpp files--is it possible?

You can do it in this way

// xyz.h
#ifndef _XYZ_
#define _XYZ_

template <typename XYZTYPE>
class XYZ {
  //Class members declaration
};

#include "xyz.cpp"
#endif

//xyz.cpp
#ifdef _XYZ_
//Class definition goes here

#endif

This has been discussed in Daniweb

Also in FAQ but using C++ export keyword.

Delete all rows in a table based on another table

I think that you might get a little more performance if you tried this

DELETE FROM Table1
WHERE EXISTS (
  SELECT 1
  FROM Table2
  WHERE Table1.ID = Table2.ID
)

Replace invalid values with None in Pandas DataFrame

Before proceeding with this post, it is important to understand the difference between NaN and None. One is a float type, the other is an object type. Pandas is better suited to working with scalar types as many methods on these types can be vectorised. Pandas does try to handle None and NaN consistently, but NumPy cannot.

My suggestion (and Andy's) is to stick with NaN.

But to answer your question...

pandas >= 0.18: Use na_values=['-'] argument with read_csv

If you loaded this data from CSV/Excel, I have good news for you. You can quash this at the root during data loading instead of having to write a fix with code as a subsequent step.

Most of the pd.read_* functions (such as read_csv and read_excel) accept a na_values attribute.

file.csv

A,B
-,1
3,-
2,-
5,3
1,-2
-5,4
-1,-1
-,0
9,0

Now, to convert the - characters into NaNs, do,

import pandas as pd
df = pd.read_csv('file.csv', na_values=['-'])
df

     A    B
0  NaN  1.0
1  3.0  NaN
2  2.0  NaN
3  5.0  3.0
4  1.0 -2.0
5 -5.0  4.0
6 -1.0 -1.0
7  NaN  0.0
8  9.0  0.0

And similar for other functions/file formats.

P.S.: On v0.24+, you can preserve integer type even if your column has NaNs (yes, talk about having the cake and eating it too). You can specify dtype='Int32'

df = pd.read_csv('file.csv', na_values=['-'], dtype='Int32')
df

     A    B
0  NaN    1
1    3  NaN
2    2  NaN
3    5    3
4    1   -2
5   -5    4
6   -1   -1
7  NaN    0
8    9    0

df.dtypes

A    Int32
B    Int32
dtype: object

The dtype is not a conventional int type... but rather, a Nullable Integer Type. There are other options.


Handling Numeric Data: pd.to_numeric with errors='coerce

If you're dealing with numeric data, a faster solution is to use pd.to_numeric with the errors='coerce' argument, which coerces invalid values (values that cannot be cast to numeric) to NaN.

pd.to_numeric(df['A'], errors='coerce')

0    NaN
1    3.0
2    2.0
3    5.0
4    1.0
5   -5.0
6   -1.0
7    NaN
8    9.0
Name: A, dtype: float64

To retain (nullable) integer dtype, use

pd.to_numeric(df['A'], errors='coerce').astype('Int32')

0    NaN
1      3
2      2
3      5
4      1
5     -5
6     -1
7    NaN
8      9
Name: A, dtype: Int32 

To coerce multiple columns, use apply:

df[['A', 'B']].apply(pd.to_numeric, errors='coerce').astype('Int32')

     A    B
0  NaN    1
1    3  NaN
2    2  NaN
3    5    3
4    1   -2
5   -5    4
6   -1   -1
7  NaN    0
8    9    0

...and assign the result back after.

More information can be found in this answer.

Evenly distributing n points on a sphere

Healpix solves a closely related problem (pixelating the sphere with equal area pixels):

http://healpix.sourceforge.net/

It's probably overkill, but maybe after looking at it you'll realize some of it's other nice properties are interesting to you. It's way more than just a function that outputs a point cloud.

I landed here trying to find it again; the name "healpix" doesn't exactly evoke spheres...

How to add a custom right-click menu to a webpage?

<script>
function fun(){
document.getElementById('menu').style.display="block";
}

</script>
<div id="menu" style="display: none"> menu items</div>

<body oncontextmenu="fun();return false;">

What I'm doing up here

  1. Creat your own custom div menu and set the position: absolute and display:none in case.
  2. Add to the page or element to be clicked the oncontextmenu event.
  3. Cancel the default browser action with return false.
  4. User js to invoke your own actions.

How to save final model using keras?

Generally, we save the model and weights in the same file by calling the save() function.

For saving,

model.compile(optimizer='adam',
              loss = 'categorical_crossentropy',
              metrics = ["accuracy"])

model.fit(X_train, Y_train,
         batch_size = 32,
         epochs= 10,
         verbose = 2, 
         validation_data=(X_test, Y_test))

#here I have use filename as "my_model", you can choose whatever you want to.

model.save("my_model.h5") #using h5 extension
print("model saved!!!")

For Loading the model,

from keras.models import load_model

model = load_model('my_model.h5')
model.summary()

In this case, we can simply save and load the model without re-compiling our model again. Note - This is the preferred way for saving and loading your Keras model.

how to add css class to html generic control div?

To add a class to a div that is generated via the HtmlGenericControl way you can use:

div1.Attributes.Add("class", "classname"); 

If you are using the Panel option, it would be:

panel1.CssClass = "classname";

How do I check if file exists in Makefile so I can delete it?

The problem is when you split your command over multiple lines. So, you can either use the \ at the end of lines for continuation as above or you can get everything on one line with the && operator in bash.

Then you can use a test command to test if the file does exist, e.g.:

test -f myApp && echo File does exist

-f file True if file exists and is a regular file.

-s file True if file exists and has a size greater than zero.

or does not:

test -f myApp || echo File does not exist
test ! -f myApp && echo File does not exist

The test is equivalent to [ command.

[ -f myApp ] && rm myApp   # remove myApp if it exists

and it would work as in your original example.

See: help [ or help test for further syntax.

How to use querySelectorAll only for elements that have a specific attribute set?

Extra Tips:

Multiple "nots", input that is NOT hidden and NOT disabled:

:not([type="hidden"]):not([disabled])

Also did you know you can do this:

node.parentNode.querySelectorAll('div');

This is equivelent to jQuery's:

$(node).parent().find('div');

Which will effectively find all divs in "node" and below recursively, HOT DAMN!

Command to run a .bat file

Can refer to here: https://ss64.com/nt/start.html

start "" /D F:\- Big Packets -\kitterengine\Common\ /W Template.bat

How to read an external local JSON file in JavaScript?

I liked what Stano/Meetar commented above. I use it to read .json files. I have expanded their examples using Promise. Here is the plunker for the same. https://plnkr.co/edit/PaNhe1XizWZ7C0r3ZVQx?p=preview

function readTextFile(file, callback) {
    var rawFile = new XMLHttpRequest();
    rawFile.overrideMimeType("application/json");
    rawFile.open("GET", file, true);
    rawFile.onreadystatechange = function() {
        if (rawFile.readyState === 4 && rawFile.status == "200") {
            callback(rawFile.responseText);
        }
    }
    rawFile.send(null);
}

//usage:
// readTextFile("DATA.json", function(text){
//     var data = JSON.parse(text);
//     console.log(data); 
// });


var task1 = function (){
  return new Promise (function(resolve, reject){
    readTextFile("DATA.json", function(text){
    var data = JSON.parse(text);
    console.log('task1 called');
    console.log(data);
    resolve('task1 came back');
    }); 
  });
};

var task2 = function (){
  return new Promise (function(resolve, reject){
    readTextFile("DATA2.json", function(text){
    var data2 = JSON.parse(text);
    console.log('task2 called');
    console.log(data2);
    resolve('task2 came back');
    });
  });
}

Promise.race([task1(), task2()])
       .then(function(fromResolve){
          console.log(fromResolve); 
       });

The reading of JSON can be moved into another function, for DRY; but the example here is more of showcasing how to use promises.

DISABLE the Horizontal Scroll

Koala_dev's answer will work, but in case you are wondering this is the reason why it works:

.
q.html, body {              <--applying this css block to everything in the
                             html code.

q.max-width: 100%;          <--all items created must not exceed 100% of the 
                             users screen size. (no items can be off the page 
                             requiring scroll)

q.overflow-x: hidden;       <--anything that occurs off the X axis of the 
                             page is hidden, so that you wont see it going 
                             off the page.     

.

Convert NSNumber to int in Objective-C

A tested one-liner:

int number = ((NSNumber*)[dict objectForKey:@"integer"]).intValue;

make bootstrap twitter dialog modal draggable

Like others said, the simpliest solution is just call draggable() function from jQuery UI just after showing modal:

$('#my-modal').modal('show')
              .draggable({ handle: ".modal-header" });

But there is a several problems with compatibility between Bootstrap and jQuery UI so we need some addition fixes in css:

.modal
{
    overflow: hidden;
}
.modal-dialog{
    margin-right: 0;
    margin-left: 0;
}
.modal-header{      /* not necessary but imo important for user */
    cursor: move;
}

Doctrine and LIKE query

you can also do it like that :

$ver = $em->getRepository('GedDocumentBundle:version')->search($val);

$tail = sizeof($ver);

Add CSS to <head> with JavaScript?

As you are trying to add a string of CSS to <head> with JavaScript? injecting a string of CSS into a page it is easier to do this with the <link> element than the <style> element.

The following adds p { color: green; } rule to the page.

<link rel="stylesheet" type="text/css" href="data:text/css;charset=UTF-8,p%20%7B%20color%3A%20green%3B%20%7D" />

You can create this in JavaScript simply by URL encoding your string of CSS and adding it the HREF attribute. Much simpler than all the quirks of <style> elements or directly accessing stylesheets.

var linkElement = this.document.createElement('link');
linkElement.setAttribute('rel', 'stylesheet');
linkElement.setAttribute('type', 'text/css');
linkElement.setAttribute('href', 'data:text/css;charset=UTF-8,' + encodeURIComponent(myStringOfstyles));

This will work in IE 5.5 upwards

The solution you have marked will work but this solution requires fewer dom operations and only a single element.

Fit image into ImageView, keep aspect ratio and then resize ImageView to image dimensions?

Quick answer:

<ImageView
        android:id="@+id/imageView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:scaleType="center"
        android:src="@drawable/yourImage"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

Performance of FOR vs FOREACH in PHP

It's 2020 and stuffs had greatly evolved with php 7.4 and opcache.

Here is the OP^ benchmark, ran as unix CLI, without the echo and html parts.

Test ran locally on a regular computer.

php -v

PHP 7.4.6 (cli) (built: May 14 2020 10:02:44) ( NTS )

Modified benchmark script:

<?php 
 ## preperations; just a simple environment state

  $test_iterations = 100;
  $test_arr_size = 1000;

  // a shared function that makes use of the loop; this should
  // ensure no funny business is happening to fool the test
  function test($input)
  {
    //echo '<!-- '.trim($input).' -->';
  }

  // for each test we create a array this should avoid any of the
  // arrays internal representation or optimizations from getting
  // in the way.

  // normal array
  $test_arr1 = array();
  $test_arr2 = array();
  $test_arr3 = array();
  // hash tables
  $test_arr4 = array();
  $test_arr5 = array();

  for ($i = 0; $i < $test_arr_size; ++$i)
  {
    mt_srand();
    $hash = md5(mt_rand());
    $key = substr($hash, 0, 5).$i;

    $test_arr1[$i] = $test_arr2[$i] = $test_arr3[$i] = $test_arr4[$key] = $test_arr5[$key]
      = $hash;
  }

  ## foreach

  $start = microtime(true);
  for ($j = 0; $j < $test_iterations; ++$j)
  {
    foreach ($test_arr1 as $k => $v)
    {
      test($v);
    }
  }
  echo 'foreach '.(microtime(true) - $start)."\n";  

  ## foreach (using reference)

  $start = microtime(true);
  for ($j = 0; $j < $test_iterations; ++$j)
  {
    foreach ($test_arr2 as &$value)
    {
      test($value);
    }
  }
  echo 'foreach (using reference) '.(microtime(true) - $start)."\n";

  ## for

  $start = microtime(true);
  for ($j = 0; $j < $test_iterations; ++$j)
  {
    $size = count($test_arr3);
    for ($i = 0; $i < $size; ++$i)
    {
      test($test_arr3[$i]);
    }
  }
  echo 'for '.(microtime(true) - $start)."\n";  

  ## foreach (hash table)

  $start = microtime(true);
  for ($j = 0; $j < $test_iterations; ++$j)
  {
    foreach ($test_arr4 as $k => $v)
    {
      test($v);
    }
  }
  echo 'foreach (hash table) '.(microtime(true) - $start)."\n";

  ## for (hash table)

  $start = microtime(true);
  for ($j = 0; $j < $test_iterations; ++$j)
  {
    $keys = array_keys($test_arr5);
    $size = sizeOf($test_arr5);
    for ($i = 0; $i < $size; ++$i)
    {
      test($test_arr5[$keys[$i]]);
    }
  }
  echo 'for (hash table) '.(microtime(true) - $start)."\n";

Output:

foreach 0.0032877922058105
foreach (using reference) 0.0029420852661133
for 0.0025191307067871
foreach (hash table) 0.0035080909729004
for (hash table) 0.0061779022216797

As you can see the evolution is insane, about 560 time faster than reported in 2012.

On my machines and servers, following my numerous experiments, basics for loops are the fastest. This is even clearer using nested loops ($i $j $k..)

It is also the most flexible in usage, and has a better readability from my view.

Computing cross-correlation function?

To cross-correlate 1d arrays use numpy.correlate.

For 2d arrays, use scipy.signal.correlate2d.

There is also scipy.stsci.convolve.correlate2d.

There is also matplotlib.pyplot.xcorr which is based on numpy.correlate.

See this post on the SciPy mailing list for some links to different implementations.

Edit: @user333700 added a link to the SciPy ticket for this issue in a comment.

gitignore all files of extension in directory

I have tried opening the .gitignore file in my vscode, windows 10. There you can see, some previously added ignore files (if any).

To create a new rule to ignore a file with (.js) extension, append the extension of the file like this:

*.js

This will ignore all .js files in your git repository.

To exclude certain type of file from a particular directory, you can add this:

**/foo/*.js

This will ignore all .js files inside only /foo/ directory.

For a detailed learning you can visit: about git-ignore

Get a list of all threads currently running in Java

You can try something like this:

Thread.getAllStackTraces().keySet().forEach((t) -> System.out.println(t.getName() + "\nIs Daemon " + t.isDaemon() + "\nIs Alive " + t.isAlive()));

and you can obviously get more thread characteristic if you need.

Assert that a method was called in a Python unit test

Yes, I can give you the outline but my Python is a bit rusty and I'm too busy to explain in detail.

Basically, you need to put a proxy in the method that will call the original, eg:

 class fred(object):
   def blog(self):
     print "We Blog"


 class methCallLogger(object):
   def __init__(self, meth):
     self.meth = meth

   def __call__(self, code=None):
     self.meth()
     # would also log the fact that it invoked the method

 #example
 f = fred()
 f.blog = methCallLogger(f.blog)

This StackOverflow answer about callable may help you understand the above.

In more detail:

Although the answer was accepted, due to the interesting discussion with Glenn and having a few minutes free, I wanted to enlarge on my answer:

# helper class defined elsewhere
class methCallLogger(object):
   def __init__(self, meth):
     self.meth = meth
     self.was_called = False

   def __call__(self, code=None):
     self.meth()
     self.was_called = True

#example
class fred(object):
   def blog(self):
     print "We Blog"

f = fred()
g = fred()
f.blog = methCallLogger(f.blog)
g.blog = methCallLogger(g.blog)
f.blog()
assert(f.blog.was_called)
assert(not g.blog.was_called)

What does the Visual Studio "Any CPU" target mean?

I think most of the important stuff has been said, but I just thought I'd add one thing: If you compile as Any CPU and run on an x64 platform, then you won't be able to load 32-bit DLL files, because your application wasn't started in WoW64, but those DLL files need to run there.

If you compile as x86, then the x64 system will run your application in WoW64, and you'll be able to load 32-bit DLL files.

So I think you should choose "Any CPU" if your dependencies can run in either environment, but choose x86 if you have 32-bit dependencies. This article from Microsoft explains this a bit:

/CLRIMAGETYPE (Specify Type of CLR Image)

Incidentally, this other Microsoft documentation agrees that x86 is usually a more portable choice:

Choosing x86 is generally the safest configuration for an app package since it will run on nearly every device. On some devices, an app package with the x86 configuration won't run, such as the Xbox or some IoT Core devices. However, for a PC, an x86 package is the safest choice and has the largest reach for device deployment. A substantial portion of Windows 10 devices continue to run the x86 version of Windows.

How to know Hive and Hadoop versions from command prompt?

You can get Hive version

hive --version

if you want to know hive version and its related package versions.

rpm -qa|grep hive

Output will be like below.

libarchive2-2.5.5-5.19
hive-0.13.0.2.1.2.2-516
perl-Archive-Zip-1.24-2.7
hive-jdbc-0.13.0.2.1.2.2-516
webhcat-tar-hive-0.13.0.2.1.2.2_516-2
hive-webhcat-0.13.0.2.1.2.2-516
hive-hcatalog-0.13.0.2.1.2.2-516

Latter gives better understanding of hive and its dependents. Nevertheless rpm needs to be present.

C# how to convert File.ReadLines into string array?

File.ReadLines() returns an object of type System.Collections.Generic.IEnumerable<String>
File.ReadAllLines() returns an array of strings.

If you want to use an array of strings you need to call the correct function.

You could use Jim solution, just use ReadAllLines() or you could change your return type.

This would also work:

System.Collections.Generic.IEnumerable<String> lines = File.ReadLines("c:\\file.txt");

You can use any generic collection which implements IEnumerable. IList for an example.

Multiple left-hand assignment with JavaScript

Try this:

var var1=42;
var var2;

alert(var2 = var1); //show result of assignment expression is assigned value
alert(var2); // show assignment did occur.

Note the single '=' in the first alert. This will show that the result of an assignment expression is the assigned value, and the 2nd alert will show you that assignment did occur.

It follows logically that assignment must have chained from right to left. However, since this is all atomic to the javascript (there's no threading) a particular engine may choose to actually optimize it a little differently.

Nested routes with react router v4 / v5

React Router v6

allows to use both nested routes (like in v3) and separate, splitted routes (v4, v5).

Nested Routes

Keep all routes in one place for small/medium size apps:

<Routes>
  <Route path="/" element={<Home />} >
    <Route path="user" element={<User />} /> 
    <Route path="dash" element={<Dashboard />} /> 
  </Route>
</Routes>

_x000D_
_x000D_
const App = () => {
  return (
    <BrowserRouter>
      <Routes>
        // /js is start path of stack snippet
        <Route path="/js" element={<Home />} >
          <Route path="user" element={<User />} />
          <Route path="dash" element={<Dashboard />} />
        </Route>
      </Routes>
    </BrowserRouter>
  );
}

const Home = () => {
  const location = useLocation()
  return (
    <div>
      <p>URL path: {location.pathname}</p>
      <Outlet />
      <p>
        <Link to="user" style={{paddingRight: "10px"}}>user</Link>
        <Link to="dash">dashboard</Link>
      </p>
    </div>
  )
}

const User = () => <div>User profile</div>
const Dashboard = () => <div>Dashboard</div>

ReactDOM.render(<App />, document.getElementById("root"));
_x000D_
<div id="root"></div>
    <script src="https://unpkg.com/[email protected]/umd/react.production.min.js"></script>
    <script src="https://unpkg.com/[email protected]/umd/react-dom.production.min.js"></script>
    <script src="https://unpkg.com/[email protected]/umd/history.production.min.js"></script>
    <script src="https://unpkg.com/[email protected]/umd/react-router.production.min.js"></script>
    <script src="https://unpkg.com/[email protected]/umd/react-router-dom.production.min.js"></script>
    <script>var { BrowserRouter, Routes, Route, Link, Outlet, useNavigate, useLocation } = window.ReactRouterDOM;</script>
_x000D_
_x000D_
_x000D_

Alternative: Define your routes as plain JavaScript objects via useRoutes.

Separate Routes

You can use separates routes to meet requirements of larger apps like code splitting:

// inside App.jsx:
<Routes>
  <Route path="/*" element={<Home />} />
</Routes>

// inside Home.jsx:
<Routes>
  <Route path="user" element={<User />} />
  <Route path="dash" element={<Dashboard />} />
</Routes>

_x000D_
_x000D_
const App = () => {
  return (
    <BrowserRouter>
      <Routes>
        // /js is start path of stack snippet
        <Route path="/js/*" element={<Home />} />
      </Routes>
    </BrowserRouter>
  );
}

const Home = () => {
  const location = useLocation()
  return (
    <div>
      <p>URL path: {location.pathname}</p>
      <Routes>
        <Route path="user" element={<User />} />
        <Route path="dash" element={<Dashboard />} />
      </Routes>
      <p>
        <Link to="user" style={{paddingRight: "5px"}}>user</Link>
        <Link to="dash">dashboard</Link>
      </p>
    </div>
  )
}

const User = () => <div>User profile</div>
const Dashboard = () => <div>Dashboard</div>

ReactDOM.render(<App />, document.getElementById("root"));
_x000D_
<div id="root"></div>
    <script src="https://unpkg.com/[email protected]/umd/react.production.min.js"></script>
    <script src="https://unpkg.com/[email protected]/umd/react-dom.production.min.js"></script>
    <script src="https://unpkg.com/[email protected]/umd/history.production.min.js"></script>
    <script src="https://unpkg.com/[email protected]/umd/react-router.production.min.js"></script>
    <script src="https://unpkg.com/[email protected]/umd/react-router-dom.production.min.js"></script>
    <script>var { BrowserRouter, Routes, Route, Link, Outlet, useNavigate, useLocation } = window.ReactRouterDOM;</script>
_x000D_
_x000D_
_x000D_

How do I start Mongo DB from Windows?

For Windows users:

To add onto @CoderSpeed's answer above (CoderSpeed's answer). Create a batch file (.bat) with the commands you would usually enter on the CLI, e.g.:

cd "C:\Program Files\MongoDB\Server\4.0\bin" mongod.exe

Windows Script Host’s Run Method allows you run a program or script in invisible mode. Here is a sample Windows script code that launches a batch file named syncfiles.bat invisibly.

Let’s say we have a file named syncfiles.bat in C:\Batch Files directory. Let’s launch it in hidden mode using Windows Scripting.

Copy the following lines to Notepad.

Set WshShell = CreateObject("WScript.Shell") WshShell.Run chr(34) & "C:\Batch Files\syncfiles.bat" & Chr(34), 0 Set WshShell = Nothing

Note: Replace the batch file name/path accordingly in the script according to your requirement. Save the file with .VBS extension, say launch_bat.vbs Edit the .BAT file name and path accordingly, and save the file. Double-click to run the launch_bat.vbs file, which in-turn launches the batch file syncfiles.bat invisibly.

Sourced from: Run .BAT files invisibly

PowerShell: how to grep command output?

Your problem is that alias emits a stream of AliasInfo objects, rather than a stream of strings. This does what I think you want.

alias | out-string -stream | select-string Alias

or as a function

function grep {
  $input | out-string -stream | select-string $args
}

alias | grep Alias

When you don't handle things that are in the pipeline (like when you just ran 'alias'), the shell knows to use the ToString() method on each object (or use the output formats specified in the ETS info).

ggplot2 line chart gives "geom_path: Each group consist of only one observation. Do you need to adjust the group aesthetic?"

You get this error because one of your variables is actually a factor variable . Execute

str(df) 

to check this. Then do this double variable change to keep the year numbers instead of transforming into "1,2,3,4" level numbers:

df$year <- as.numeric(as.character(df$year))

EDIT: it appears that your data.frame has a variable of class "array" which might cause the pb. Try then:

df <- data.frame(apply(df, 2, unclass))

and plot again?

How to convert jsonString to JSONObject in Java

NOTE that GSON with deserializing an interface will result in exception like below.

"java.lang.RuntimeException: Unable to invoke no-args constructor for interface XXX. Register an InstanceCreator with Gson for this type may fix this problem."

While deserialize; GSON don't know which object has to be intantiated for that interface.

This is resolved somehow here.

However FlexJSON has this solution inherently. while serialize time it is adding class name as part of json like below.

{
    "HTTPStatus": "OK",
    "class": "com.XXX.YYY.HTTPViewResponse",
    "code": null,
    "outputContext": {
        "class": "com.XXX.YYY.ZZZ.OutputSuccessContext",
        "eligible": true
    }
}

So JSON will be cumber some; but you don't need write InstanceCreator which is required in GSON.

React JS get current date

OPTION 1: if you want to make a common utility function then you can use this

export function getCurrentDate(separator=''){

let newDate = new Date()
let date = newDate.getDate();
let month = newDate.getMonth() + 1;
let year = newDate.getFullYear();

return `${year}${separator}${month<10?`0${month}`:`${month}`}${separator}${date}`
}

and use it by just importing it as

import {getCurrentDate} from './utils'
console.log(getCurrentDate())

OPTION 2: or define and use in a class directly

getCurrentDate(separator=''){

let newDate = new Date()
let date = newDate.getDate();
let month = newDate.getMonth() + 1;
let year = newDate.getFullYear();

return `${year}${separator}${month<10?`0${month}`:`${month}`}${separator}${date}`
}

ERROR Source option 1.5 is no longer supported. Use 1.6 or later

This worked for me!!!!

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>academy.learnprogramming</groupId>
    <artifactId>hello-maven</artifactId>
    <version>1.0-SNAPSHOT</version>
<dependencies>
    <dependency>
        <groupId>ch.qos.logback</groupId>
        <artifactId>logback-classic</artifactId>
        <version>1.2.3</version>
    </dependency>

</dependencies>
<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.7.0</version>
            <configuration>
                <target>10</target>
                <source>10</source>
                <release>10</release>
            </configuration>

        </plugin>
    </plugins>
</build>
</project>

How to fluently build JSON in Java?

I got here looking for a nice way to write rest endpoint tests with a fluent json builder. In my case I used JSONObject to construct a specialized builder. It need a bit of instrumentation, but the usage is really nice:

import lombok.SneakyThrows;
import org.json.JSONObject;

public class MemberJson extends JSONObject {

    @SneakyThrows
    public static MemberJson builder() {
        return new MemberJson();
    }

    @SneakyThrows
    public MemberJson name(String name) {
        put("name", name);
        return this;
    }

}
MemberJson.builder().name("Member").toString();

Fragment onResume() & onPause() is not called on backstack

  • Since you have used ft2.replace(), FragmentTransaction.remove() method is called and the Loginfragment will be removed. Refer to this. So onStop() of LoginFragment will be called instead of onPause(). (As the new fragment completely replaces the old one).
  • But since you have also used ft2.addtobackstack(), the state of the Loginfragment will be saved as a bundle and when you click back button from HomeFragment, onViewStateRestored() will be called followed by onStart() of LoginFragment. So eventually onResume() won't be called.

How to append a newline to StringBuilder

It should be

r.append("\n");

But I recommend you to do as below,

r.append(System.getProperty("line.separator"));

System.getProperty("line.separator") gives you system-dependent newline in java. Also from Java 7 there's a method that returns the value directly: System.lineSeparator()

HTML - Alert Box when loading page

<script> 
    $(document).ready(function(){
        alert('Hi');
    });
</script>

Creating a UITableView Programmatically

#import "ViewController.h"

@interface ViewController ()

{

    NSMutableArray *name;

}

@end


- (void)viewDidLoad 

{

    [super viewDidLoad];
    name=[[NSMutableArray alloc]init];
    [name addObject:@"ronak"];
    [name addObject:@"vibha"];
    [name addObject:@"shivani"];
    [name addObject:@"nidhi"];
    [name addObject:@"firdosh"];
    [name addObject:@"himani"];

    _tableview_outlet.delegate = self;
    _tableview_outlet.dataSource = self;

}


- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section

{

return [name count];

}


- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath

{

    static NSString *simpleTableIdentifier = @"cell";

    UITableViewCell *cell = [tableView       dequeueReusableCellWithIdentifier:simpleTableIdentifier];

    if (cell == nil) {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:simpleTableIdentifier];
    }

    cell.textLabel.text = [name objectAtIndex:indexPath.row];
    return cell;
}

How to run Node.js as a background process and never die?

For Ubuntu i use this:

(exec PROG_SH &> /dev/null &)

regards

Any way to Invoke a private method?

Use getDeclaredMethod() to get a private Method object and then use method.setAccessible() to allow to actually call it.

Get the latest date from grouped MySQL data

Using max(date) didn't solve my problem as there is no assurance that other columns will be from the same row as the max(date) is. Instead of that this one solved my problem and sorted group by in a correct order and values of other columns are from the same row as the max date is:

SELECT model, date 
FROM (SELECT * FROM doc ORDER BY date DESC) as sortedTable
GROUP BY model

How to change the order of DataFrame columns?

Just flipping helps often.

df[df.columns[::-1]]

Or just shuffle for a look.

import random
cols = list(df.columns)
random.shuffle(cols)
df[cols]

"Logging out" of phpMyAdmin?

In one click

Logout from PhpMyAdmin with URL like /phpmyadmin/index.php?old_usr=xy

source : https://stackoverflow.com/a/23143634/4457531


EDIT: It works with PhpMyAdmin version 4.0.10.18?

SQL select * from column where year = 2010

NB: Should you want the year to be based on some reference date, the code below calculates the dates for the between statement:

declare @referenceTime datetime = getutcdate()
select *
from myTable
where SomeDate 
    between dateadd(year, year(@referenceTime) - 1900, '01-01-1900')                        --1st Jan this year (midnight)
    and dateadd(millisecond, -3, dateadd(year, year(@referenceTime) - 1900, '01-01-1901'))  --31st Dec end of this year (just before midnight of the new year)

Similarly, if you're using a year value, swapping year(@referenceDate) for your reference year's value will work

declare @referenceYear int = 2010
select *
from myTable
where SomeDate 
    between dateadd(year,@referenceYear - 1900, '01-01-1900')                       --1st Jan this year (midnight)
    and dateadd(millisecond, -3, dateadd(year,@referenceYear - 1900, '01-01-1901')) --31st Dec end of this year (just before midnight of the new year)

add id to dynamically created <div>

Here is an example of what I made to created ID's with my JavaScript.

function abs_demo_DemandeEnvoyee_absence(){

    var iDateInitiale = document.getElementById("abs_t_date_JourInitial_absence").value; /* On récupère la date initiale*/
    var iDateFinale = document.getElementById("abs_t_date_JourFinal_absence").value;     /*On récupère la date finale*/
    var sMotif = document.getElementById("abs_txt_motif_absence").value;                 /*On récupère le motif*/  
    var iCompteurDivNumero = 1;                                                         /*Le compteur est initialisé à 1 parce que la div 1 existe*/
    var TestDivVide = document.getElementById("abs_Autorisation_"+iCompteurDivNumero+"_absence") == undefined; //Boléenne, renvoie false si la div existe déjà
    var NewDivCreation = "";                                                            /*Initialisée en string vide pour concaténation*/
    var NewIdCreation;                                                                  /*Utilisée pour créer l'id d'une div dynamiquement*/
    var NewDivVersHTML;                                                                 /*Utilisée pour insérer la nouvelle div dans le html*/


    while(TestDivVide == false){                                                        /*Tant que la div pointée existe*/
        iCompteurDivNumero++;                                                           /*On incrémente le compteur de 1*/
        TestDivVide = document.getElementById("abs_Autorisation_"+iCompteurDivNumero+"_absence") == undefined; /*Abs_autorisation_1_ est écrite en dur.*/   
    }

    NewIdCreation = "abs_Autorisation_"+iCompteurDivNumero+"_absence"                   /*On crée donc la nouvelle ID de DIV*/

                                                                                        /*On crée la nouvelle DIV avec l'ID précédemment créée*/
    NewDivCreation += "<div class=\"abs_AutorisationsDynamiques_absence\" id=\""+NewIdCreation+"\">Votre demande d'autorisation d'absence du <b>"+iDateInitiale+"</b> au <b>"+iDateFinale+"</b>, pour le motif suivant : <i>\""+sMotif+"\"</i> a bien été <span class=\"abs_CouleurTexteEnvoye_absence\">envoyée</span>.</div>";

    document.getElementById("abs_AffichagePanneauDeControle_absence").innerHTML+=NewDivCreation; /*Et on concatenne la nouvelle div créée*/ 

    document.getElementById("abs_Autorisation_1_absence").style.display = 'none'; /*On cache la première div qui contient le message "vous n'avez pas de demande en attente" */

}

Will provide text translation if asked. :)

What does a just-in-time (JIT) compiler do?

A JIT compiler runs after the program has started and compiles the code (usually bytecode or some kind of VM instructions) on the fly (or just-in-time, as it's called) into a form that's usually faster, typically the host CPU's native instruction set. A JIT has access to dynamic runtime information whereas a standard compiler doesn't and can make better optimizations like inlining functions that are used frequently.

This is in contrast to a traditional compiler that compiles all the code to machine language before the program is first run.

To paraphrase, conventional compilers build the whole program as an EXE file BEFORE the first time you run it. For newer style programs, an assembly is generated with pseudocode (p-code). Only AFTER you execute the program on the OS (e.g., by double-clicking on its icon) will the (JIT) compiler kick in and generate machine code (m-code) that the Intel-based processor or whatever will understand.

VBA vlookup reference in different sheet

Your code work fine, provided the value in Sheet2!D2 exists in Sheet1!A:A. If it does not then error 1004 is raised.

To handle this case, try

Sub Demo()
    Dim MyStringVar1 As Variant
    On Error Resume Next
    MyStringVar1 = Application.WorksheetFunction.VLookup(Range("D2"), _
      Worksheets("Sheet1").Range("A:C"), 1, False)
    On Error GoTo 0
    If IsEmpty(MyStringVar1) Then
        MsgBox "Value not found!"
    End If

    Range("E2") = MyStringVar1

End Sub

select dept names who have more than 2 employees whose salary is greater than 1000

SELECT DEPTNAME
FROM(SELECT D.DEPTNAME,COUNT(EMPID) AS TOTEMP
     FROM DEPT AS D,EMPLOYEE AS E
     WHERE D.DEPTID=E.DEPTID AND SALARY>1000
     GROUP BY D.DEPTID
     )
WHERE TOTEMP>2;

Python JSON dump / append to .txt with each variable on new line

To avoid confusion, paraphrasing both question and answer. I am assuming that user who posted this question wanted to save dictionary type object in JSON file format but when the user used json.dump, this method dumped all its content in one line. Instead, he wanted to record each dictionary entry on a new line. To achieve this use:

with g as outfile:
  json.dump(hostDict, outfile,indent=2)

Using indent = 2 helped me to dump each dictionary entry on a new line. Thank you @agf. Rewriting this answer to avoid confusion.

How to convert array into comma separated string in javascript

Use the join method from the Array type.

a.value = [a, b, c, d, e, f];
var stringValueYouWant = a.join();

The join method will return a string that is the concatenation of all the array elements. It will use the first parameter you pass as a separator - if you don't use one, it will use the default separator, which is the comma.

Cannot run emulator in Android Studio

In my case (Windows 10) the reason was that I dared to unzip the android sdk into non default folder. When I moved it to the default one c:/Users/[username]/AppData/Local/Android/Sdk and changed the paths in Android Studio and System Variables, it started to work.

Why do I keep getting 'SVN: Working Copy XXXX locked; try performing 'cleanup'?

This type of problem can happen when you delete/move files around - in essence making changes to your directory structure. Subversion only checks for changes made in files already added to subversion, not changes made to the directory structure. Instead of using your OS's copy etc commands rather use svn copy etc. Please see http://svnbook.red-bean.com/en/1.7/svn.tour.cycle.html

Further, upon committing changes svn first stores a "summary" of changes in a todo list. Upon performing the svn operations in this todo list it locks the file to prevent other changes while these svn actions are performed. If the svn action is interrupted midway, say by a crash, the file will remain locked until svn could complete the actions in the todo list. This can be "reactivated" by using the svn cleanup command. Please see http://svnbook.red-bean.com/en/1.7/svn.tour.cleanup.html

Using Node.js require vs. ES6 import/export

Are there any performance benefits to using one over the other?

The current answer is no, because none of the current browser engines implements import/export from the ES6 standard.

Some comparison charts http://kangax.github.io/compat-table/es6/ don't take this into account, so when you see almost all greens for Chrome, just be careful. import keyword from ES6 hasn't been taken into account.

In other words, current browser engines including V8 cannot import new JavaScript file from the main JavaScript file via any JavaScript directive.

( We may be still just a few bugs away or years away until V8 implements that according to the ES6 specification. )

This document is what we need, and this document is what we must obey.

And the ES6 standard said that the module dependencies should be there before we read the module like in the programming language C, where we had (headers) .h files.

This is a good and well-tested structure, and I am sure the experts that created the ES6 standard had that in mind.

This is what enables Webpack or other package bundlers to optimize the bundle in some special cases, and reduce some dependencies from the bundle that are not needed. But in cases we have perfect dependencies this will never happen.

It will need some time until import/export native support goes live, and the require keyword will not go anywhere for a long time.

What is require?

This is node.js way to load modules. ( https://github.com/nodejs/node )

Node uses system-level methods to read files. You basically rely on that when using require. require will end in some system call like uv_fs_open (depends on the end system, Linux, Mac, Windows) to load JavaScript file/module.

To check that this is true, try to use Babel.js, and you will see that the import keyword will be converted into require.

enter image description here

How to iterate over a TreeMap?

Assuming type TreeMap<String,Integer> :

for(Map.Entry<String,Integer> entry : treeMap.entrySet()) {
  String key = entry.getKey();
  Integer value = entry.getValue();

  System.out.println(key + " => " + value);
}

(key and Value types can be any class of course)

remove item from stored array in angular 2

Use splice() to remove item from the array its refresh the array index to be consequence.

delete will remove the item from the array but its not refresh the array index which means if you want to remove third item from four array items the index of elements will be after delete the element 0,1,4

this.data.splice(this.data.indexOf(msg), 1)

Python, Matplotlib, subplot: How to set the axis range?

If you know the exact axis you want, then

pylab.ylim([0,1000])

works as answered previously. But if you want a more flexible axis to fit your exact data, as I did when I found this question, then set axis limit to be the length of your dataset. If your dataset is fft as in the question, then add this after your plot command:

length = (len(fft)) pylab.ylim([0,length])

syntaxerror: "unexpected character after line continuation character in python" math

You must press enter after continuation character

Note: Space after continuation character leads to error

cost = {"apples": [3.5, 2.4, 2.3], "bananas": [1.2, 1.8]}

0.9 * average(cost["apples"]) + \ """enter here"""
0.1 * average(cost["bananas"])

Can't connect to MySQL server on 'localhost' (10061) after Installation

this issue is very to solve by windows server users

  1. go to this path C:\Program Files\MySQL\MySQL Server 5.1\bin

  2. run this tool "MySQLInstanceConfig.exe"

and config the instatnce again and problem solved

How to turn off the Eclipse code formatter for certain sections of Java code?

Instead of turning the formatting off, you can configure it not to join already wrapped lines. Similar to Jitter's response, here's for Eclipse STS:

Properties ? Java Code Style ? Formatter ? Enable project specific settings OR Configure Workspace Settings ? Edit ? Line Wrapping (tab) ? check "Never join already wrapped lines"

Save, apply.

enter image description here

What is SYSNAME data type in SQL Server?

sysname is a built in datatype limited to 128 Unicode characters that, IIRC, is used primarily to store object names when creating scripts. Its value cannot be NULL

It is basically the same as using nvarchar(128) NOT NULL

EDIT

As mentioned by @Jim in the comments, I don't think there is really a business case where you would use sysname to be honest. It is mainly used by Microsoft when building the internal sys tables and stored procedures etc within SQL Server.

For example, by executing Exec sp_help 'sys.tables' you will see that the column name is defined as sysname this is because the value of this is actually an object in itself (a table)

I would worry too much about it.

It's also worth noting that for those people still using SQL Server 6.5 and lower (are there still people using it?) the built in type of sysname is the equivalent of varchar(30)

Documentation

sysname is defined with the documentation for nchar and nvarchar, in the remarks section:

sysname is a system-supplied user-defined data type that is functionally equivalent to nvarchar(128), except that it is not nullable. sysname is used to reference database object names.

To clarify the above remarks, by default sysname is defined as NOT NULL it is certainly possible to define it as nullable. It is also important to note that the exact definition can vary between instances of SQL Server.

Using Special Data Types

The sysname data type is used for table columns, variables, and stored procedure parameters that store object names. The exact definition of sysname is related to the rules for identifiers. Therefore, it can vary between instances of SQL Server. sysname is functionally the same as nvarchar(128) except that, by default, sysname is NOT NULL. In earlier versions of SQL Server, sysname is defined as varchar(30).

Some further information about sysname allowing or disallowing NULL values can be found here https://stackoverflow.com/a/52290792/300863

Just because it is the default (to be NOT NULL) does not guarantee that it will be!

Java Embedded Databases Comparison

HSQLDB is a good candidate (the fact that it is used in OpenOffice may convinced some of you), but for such a small personnal application, why not using an object database (instead of a classic relationnal database) ?

I used DB4O in one of my projects, and I'm very satisfied with it. Being object-oriented, you don't need the whole Hibernate layer, and can directly insert/update/delete/query objects ! Moreover, you don't need to worry about the schema, you directly work with the objects and DB4O does the rest !

I agree that it may take some time to get used to this new type of database, but check the DB40 tutorial to see how easy it makes working with the DB !

EDIT: As said in the comments, DB4O handles automatically the newer versions of the classes. Moreover, a tool for browsing and updating the database outside of the application is available here : http://code.google.com/p/db4o-om/

Reading a file character by character in C

I think the most significant problem is that you're incrementing code as you read stuff in, and then returning the final value of code, i.e. you'll be returning a pointer to the end of the string. You probably want to make a copy of code before the loop, and return that instead.

Also, C strings need to be null-terminated. You need to make sure that you place a '\0' directly after the final character that you read in.

Note: You could just use fgets() to get the entire line in one hit.

How to extract one column of a csv file

Landed here looking to extract from a tab separated file. Thought I would add.

cat textfile.tsv | cut -f2 -s

Where -f2 extracts the 2, non-zero indexed column, or the second column.

How do I convert a number to a numeric, comma-separated formatted string?

The reason you aren't finding easy examples for how to do this in T-SQL is that it is generally considered bad practice to implement formatting logic in SQL code. RDBMS's simply are not designed for presentation. While it is possible to do some limited formatting, it is almost always better to let the application or user interface handle formatting of this type.

But if you must (and sometimes we must!) use T-SQL, cast your int to money and convert it to varchar, like this:

select convert(varchar,cast(1234567 as money),1)

If you don't want the trailing decimals, do this:

select replace(convert(varchar,cast(1234567 as money),1), '.00','')

Good luck!

How to make a floated div 100% height of its parent?

I made an example resolving your problem.

You have to make a wrapper, float it, then position absolute your div and give to it 100% height.

HTML

<div class="container">
    <div class="left">"Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum." </div>
  <div class="right-wrapper">
    <div class="right">"Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua." </div>
  </div>
  <div class="clear">&nbsp;</div>
</div>

CSS:

.container {
    width: 100%;
    position:relative;
}
.left {
    width: 50%;
    background-color: rgba(0, 0, 255, 0.6);
    float: left;
}
.right-wrapper {
    width: 48%;
    float: left;
}
.right {
    height: 100%;
    position: absolute;
}

Explanation: The .right div is absolutely positioned. That means that its width and height, and top and left positiones will be calculed based on the first parent div absolutely or relative positioned ONLY if width or height properties are explicitly declared in CSS; if they aren't explicty declared, those properties will be calculed based on the parent container (.right-wrapper).

So, the 100% height of the DIV will be calculed based on .container final height, and the final position of .right position will be calculed based on the parent container.

When should use Readonly and Get only properties

Methods suggest something has to happen to return the value, properties suggest that the value is already there. This is a rule of thumb, sometimes you might want a property that does a little work (i.e. Count), but generally it's a useful way to decide.

How do I restart my C# WinForm Application?

I wanted the new application start up after the old one shuts down.

Using process.WaitForExit() to wait for your own process to shutdown makes no sense. It will always time out.

So, my approach is to use Application.Exit() then wait, but allow events to be processed, for a period of time. Then start a new application with the same arguments as the old.

static void restartApp() {
    string commandLineArgs = getCommandLineArgs();
    string exePath = Application.ExecutablePath;
    try {
        Application.Exit();
        wait_allowingEvents( 1000 );
    } catch( ArgumentException ex ) {
        throw;
    }
    Process.Start( exePath, commandLineArgs );
}

static string getCommandLineArgs() {
    Queue<string> args = new Queue<string>( Environment.GetCommandLineArgs() );
    args.Dequeue(); // args[0] is always exe path/filename
    return string.Join( " ", args.ToArray() );
}

static void wait_allowingEvents( int durationMS ) {
    DateTime start = DateTime.Now;
    do {
        Application.DoEvents();
    } while( start.Subtract( DateTime.Now ).TotalMilliseconds > durationMS );
}

How to change the date format from MM/DD/YYYY to YYYY-MM-DD in PL/SQL?

use

select to_char(date_column,'YYYY-MM-DD') from table;

Why and how to fix? IIS Express "The specified port is in use"

The error message should tell you which application is already using the port - in my case it was explorer.exe, so it was just a case of restarting explorer from task manager.

Has anyone gotten HTML emails working with Twitter Bootstrap?

What about Bootstrap Email? This seems to really nice and compatible with bootstrap 4.

how to bypass Access-Control-Allow-Origin?

It's a really bad idea to use *, which leaves you wide open to cross site scripting. You basically want your own domain all of the time, scoped to your current SSL settings, and optionally additional domains. You also want them all to be sent as one header. The following will always authorize your own domain in the same SSL scope as the current page, and can optionally also include any number of additional domains. It will send them all as one header, and overwrite the previous one(s) if something else already sent them to avoid any chance of the browser grumbling about multiple access control headers being sent.

class CorsAccessControl
{
    private $allowed = array();

    /**
     * Always adds your own domain with the current ssl settings.
     */
    public function __construct()
    {
        // Add your own domain, with respect to the current SSL settings.
        $this->allowed[] = 'http'
            . ( ( array_key_exists( 'HTTPS', $_SERVER )
                && $_SERVER['HTTPS'] 
                && strtolower( $_SERVER['HTTPS'] ) !== 'off' ) 
                    ? 's' 
                    : null )
            . '://' . $_SERVER['HTTP_HOST'];
    }

    /**
     * Optionally add additional domains. Each is only added one time.
     */
    public function add($domain)
    {
        if ( !in_array( $domain, $this->allowed )
        {
            $this->allowed[] = $domain;
        }
    /**
     * Send 'em all as one header so no browsers grumble about it.
     */
    public function send()
    {
        $domains = implode( ', ', $this->allowed );
        header( 'Access-Control-Allow-Origin: ' . $domains, true ); // We want to send them all as one shot, so replace should be true here.
    }
}

Usage:

$cors = new CorsAccessControl();

// If you are only authorizing your own domain:
$cors->send();

// If you are authorizing multiple domains:
foreach ($domains as $domain)
{
    $cors->add($domain);
}
$cors->send();

You get the idea.

How can I lock the first row and first column of a table when scrolling, possibly using JavaScript and CSS?

I ran across a site a few weeks back. This is a working example of the first column locked but it is not browser compatible with Firefox. I didn't do a lot of checking around but it seems it only works in IE. There are some notes the author provided along with it that you can read.

Lock the First column: http://home.tampabay.rr.com/bmerkey/examples/locked-column-csv.html

Let me know if you need the Javascript to lock the Table headers too.

Error: vector does not name a type

Also you can add #include<vector> in the header. When two of the above solutions don't work.

Why do I need to override the equals and hashCode methods in Java?

Adding to @Lombo 's answer

When will you need to override equals() ?

The default implementation of Object's equals() is

public boolean equals(Object obj) {
        return (this == obj);
}

which means two objects will be considered equal only if they have the same memory address which will be true only if you are comparing an object with itself.

But you might want to consider two objects the same if they have the same value for one or more of their properties (Refer the example given in @Lombo 's answer).

So you will override equals() in these situations and you would give your own conditions for equality.

I have successfully implemented equals() and it is working great.So why are they asking to override hashCode() as well?

Well.As long as you don't use "Hash" based Collections on your user-defined class,it is fine. But some time in the future you might want to use HashMap or HashSet and if you don't override and "correctly implement" hashCode(), these Hash based collection won't work as intended.

Override only equals (Addition to @Lombo 's answer)

myMap.put(first,someValue)
myMap.contains(second); --> But it should be the same since the key are the same.But returns false!!! How?

First of all,HashMap checks if the hashCode of second is the same as first. Only if the values are the same,it will proceed to check the equality in the same bucket.

But here the hashCode is different for these 2 objects (because they have different memory address-from default implementation). Hence it will not even care to check for equality.

If you have a breakpoint inside your overridden equals() method,it wouldn't step in if they have different hashCodes. contains() checks hashCode() and only if they are the same it would call your equals() method.

Why can't we make the HashMap check for equality in all the buckets? So there is no necessity for me to override hashCode() !!

Then you are missing the point of Hash based Collections. Consider the following :

Your hashCode() implementation : intObject%9.

The following are the keys stored in the form of buckets.

Bucket 1 : 1,10,19,... (in thousands)
Bucket 2 : 2,20,29...
Bucket 3 : 3,21,30,...
...

Say,you want to know if the map contains the key 10. Would you want to search all the buckets? or Would you want to search only one bucket?

Based on the hashCode,you would identify that if 10 is present,it must be present in Bucket 1. So only Bucket 1 will be searched !!

Cron and virtualenv

The best solution for me was to both

  • use the python binary in the venv bin/ directory
  • set the python path to include the venv modules directory.

man python mentions modifying the path in shell at $PYTHONPATH or in python with sys.path

Other answers mention ideas for doing this using the shell. From python, adding the following lines to my script allows me to successfully run it directly from cron.

import sys
sys.path.insert(0,'/path/to/venv/lib/python3.3/site-packages');

Here's how it looks in an interactive session --

Python 3.3.2+ (default, Feb 28 2014, 00:52:16) 
[GCC 4.8.1] on linux
Type "help", "copyright", "credits" or "license" for more information.

>>> import sys

>>> sys.path
['', '/usr/lib/python3.3', '/usr/lib/python3.3/plat-x86_64-linux-gnu', '/usr/lib/python3.3/lib-dynload']

>>> import requests
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: No module named 'requests'   

>>> sys.path.insert(0,'/path/to/venv/modules/');

>>> import requests
>>>

How do you update Xcode on OSX to the latest version?

You can try mas-cli (Mac Apple Store cli). Github project here

It would be

$ brew install mas
$ mas list
$ mas search Xcode
$ mas install <id> 

$ mas upgrade <id>

upd:

Had issues installing Xcode 12.2 in Big Sur. Solved them by entering into the App Store from the devs link.

https://developer.apple.com/download/release/

How to set default text for a Tkinter Entry widget

Use Entry.insert. For example:

try:
    from tkinter import *  # Python 3.x
except Import Error:
    from Tkinter import *  # Python 2.x

root = Tk()
e = Entry(root)
e.insert(END, 'default text')
e.pack()
root.mainloop()

Or use textvariable option:

try:
    from tkinter import *  # Python 3.x
except Import Error:
    from Tkinter import *  # Python 2.x

root = Tk()
v = StringVar(root, value='default text')
e = Entry(root, textvariable=v)
e.pack()
root.mainloop()

Load image from resources area of project in C#

Or you could use this line when dealing with WPF or Silverlight, especially where you have the source string already in the XAML markup:

(ImageSource)new ImageSourceConverter().ConvertFromString(ImagePath);

Where the ImagePath is something like:

string ImagePath  = "/ProjectName;component/Resource/ImageName.png";

How do I set ANDROID_SDK_HOME environment variable?

from command prompt:

set ANDROID_SDK_HOME=C:\[wherever your sdk folder is]

should do the trick.

Custom li list-style with font-awesome icon

Now that the ::marker element is available in evergreen browsers, this is how you could use it, including using :hover to change the marker. As you can see, now you can use any Unicode character you want as a list item marker and even use custom counters.

_x000D_
_x000D_
@charset "UTF-8";
@counter-style fancy {
  system: fixed;
  symbols:   ;
  suffix: " ";
}

p {
  margin-left: 8em;
}

p.note {
  display: list-item;
  counter-increment: note-counter;
}

p.note::marker {
  content: "Note " counter(note-counter) ":";
}

ol {
  margin-left: 8em;
  padding-left: 0;
}

ol li {
  list-style-type: lower-roman;
}

ol li::marker {
  color: blue;
  font-weight: bold;
}

ul {
  margin-left: 8em;
  padding-left: 0;
}

ul.happy li::marker {
  content: "";
}

ul.happy li:hover {
  color: blue;
}

ul.happy li:hover::marker {
  content: "";
}

ul.fancy {
  list-style: fancy;
}
_x000D_
<p>This is the first paragraph in this document.</p>
<p class="note">This is a very short document.</p>
<ol>
  <li>This is the first item.
    <li>This is the second item.
      <li>This is the third item.
</ol>
<p>This is the end.</p>

<ul class="happy">
  <li>Item 1</li>
  <li>Item 2</li>
  <li>Item 3</li>
</ul>

<ul class="fancy">
  <li>Item 1</li>
  <li>Item 2</li>
  <li>Item 3</li>
</ul>
_x000D_
_x000D_
_x000D_

Error: TypeError: $(...).dialog is not a function

Here are the complete list of scripts required to get rid of this problem. (Make sure the file exists at the given file path)

   <script src="@Url.Content("~/Scripts/jquery-1.8.2.js")" type="text/javascript">
    </script>
    <script src="@Url.Content("~/Scripts/jquery-ui-1.8.24.js")" type="text/javascript">
    </script>
    <script src="@Url.Content("~/Scripts/jquery.validate.js")" type="text/javascript">
    </script>
    <script src="@Url.Content("~/Scripts/jquery.validate.unobtrusive.js")" type="text/javascript">
    </script>
    <script src="@Url.Content("~/Scripts/jquery.unobtrusive-ajax.js")" type="text/javascript">
    </script>

and also include the below css link in _Layout.cshtml for a stylish popup.

<link rel="stylesheet" type="text/css" href="../../Content/themes/base/jquery-ui.css" />

What exactly does += do in python?

I'm seeing a lot of answers that don't bring up using += with multiple integers.

One example:

x -= 1 + 3

This would be similar to:

x = x - (1 + 3)

and not:

x = (x - 1) + 3

How to acces external json file objects in vue.js app

I have recently started working on a project using Vue JS, JSON Schema. I am trying to access nested JSON Objects from a JSON Schema file in the Vue app. I tried the below code and now I can load different JSON objects inside different Vue template tags. In the script tag add the below code

import  {JsonObject1name, JsonObject2name} from 'your Json file path';

Now you can access JsonObject1,2 names in data section of export default part as below:

data: () => ({ 
  
  schema: JsonObject1name,
  schema1: JsonObject2name,   
  
  model: {} 
}),

Now you can load the schema, schema1 data inside Vue template according to your requirement. See below code for example :

      <SchemaForm id="unique name representing your Json object1" class="form"  v-model="model" :schema="schema" :components="components">
      </SchemaForm>  

      <SchemaForm id="unique name representing your Json object2" class="form" v-model="model" :schema="schema1" :components="components">
      </SchemaForm>

SchemaForm is the local variable name for @formSchema/native library. I have implemented the data of different JSON objects through forms in different CSS tabs.

I hope this answer helps someone. I can help if there are any questions.

How do I use a file grep comparison inside a bash if/else statement?

Note that, for PIPE being any command or sequence of commands, then:

if PIPE ; then
  # do one thing if PIPE returned with zero status ($?=0)
else 
  # do another thing if PIPE returned with non-zero status ($?!=0), e.g. error
fi 

For the record, [ expr ] is a shell builtin† shorthand for test expr.

Since grep returns with status 0 in case of a match, and non-zero status in case of no matches, you can use:

if grep -lq '^MYSQL_ROLE=master' ; then 
  # do one thing 
else 
  # do another thing
fi 

Note the use of -l which only cares about the file having at least one match (so that grep returns as soon as it finds one match, without needlessly continuing to parse the input file.)

†on some platforms [ expr ] is not a builtin, but an actual executable /bin/[ (whose last argument will be ]), which is why [ expr ] should contain blanks around the square brackets, and why it must be followed by one of the command list separators (;, &&, ||, |, &, newline)

Android SDK is missing, out of date, or is missing templates. Please ensure you are using SDK version 22 or later

I had same issue in Android Studio 3. (the project was open) so I closed the current project and the IDE automatically prompted to download the latest components. once its done everything was working correctly.

Gradle to execute Java class (without modifying build.gradle)

There is no direct equivalent to mvn exec:java in gradle, you need to either apply the application plugin or have a JavaExec task.

application plugin

Activate the plugin:

plugins {
    id 'application'
    ...
}

Configure it as follows:

application {
    mainClassName = project.hasProperty("mainClass") ? getProperty("mainClass") : "NULL"
}

On the command line, write

$ gradle -PmainClass=Boo run

JavaExec task

Define a task, let's say execute:

task execute(type:JavaExec) {
   main = project.hasProperty("mainClass") ? getProperty("mainClass") : "NULL"
   classpath = sourceSets.main.runtimeClasspath
}

To run, write gradle -PmainClass=Boo execute. You get

$ gradle -PmainClass=Boo execute
:compileJava
:compileGroovy UP-TO-DATE
:processResources UP-TO-DATE
:classes
:execute
I am BOO!

mainClass is a property passed in dynamically at command line. classpath is set to pickup the latest classes.


If you do not pass in the mainClass property, both of the approaches fail as expected.

$ gradle execute

FAILURE: Build failed with an exception.

* Where:
Build file 'xxxx/build.gradle' line: 4

* What went wrong:
A problem occurred evaluating root project 'Foo'.
> Could not find property 'mainClass' on task ':execute'.

How to determine the version of the C++ standard used by the compiler?

By my knowledge there is no overall way to do this. If you look at the headers of cross platform/multiple compiler supporting libraries you'll always find a lot of defines that use compiler specific constructs to determine such things:

/*Define Microsoft Visual C++ .NET (32-bit) compiler */
#if (defined(_M_IX86) && defined(_MSC_VER) && (_MSC_VER >= 1300)
     ...
#endif

/*Define Borland 5.0 C++ (16-bit) compiler */
#if defined(__BORLANDC__) && !defined(__WIN32__)
     ...
#endif

You probably will have to do such defines yourself for all compilers you use.

Sieve of Eratosthenes - Finding Primes Python

You're not quite implementing the correct algorithm:

In your first example, primes_sieve doesn't maintain a list of primality flags to strike/unset (as in the algorithm), but instead resizes a list of integers continuously, which is very expensive: removing an item from a list requires shifting all subsequent items down by one.

In the second example, primes_sieve1 maintains a dictionary of primality flags, which is a step in the right direction, but it iterates over the dictionary in undefined order, and redundantly strikes out factors of factors (instead of only factors of primes, as in the algorithm). You could fix this by sorting the keys, and skipping non-primes (which already makes it an order of magnitude faster), but it's still much more efficient to just use a list directly.

The correct algorithm (with a list instead of a dictionary) looks something like:

def primes_sieve2(limit):
    a = [True] * limit                          # Initialize the primality list
    a[0] = a[1] = False

    for (i, isprime) in enumerate(a):
        if isprime:
            yield i
            for n in range(i*i, limit, i):     # Mark factors non-prime
                a[n] = False

(Note that this also includes the algorithmic optimization of starting the non-prime marking at the prime's square (i*i) instead of its double.)

Need to list all triggers in SQL Server database with table name and table's schema

SELECT tbl.name as Table_Name,trig.name as Trigger_Name,trig.is_disabled  
FROM [sys].[triggers] as trig inner join sys.tables as tbl on 
trig.parent_id = tbl.object_id 

Set up Python simpleHTTPserver on Windows

From Stack Overflow question What is the Python 3 equivalent of "python -m SimpleHTTPServer":

The following works for me:

python -m http.server [<portNo>]

Because I am using Python 3 the module SimpleHTTPServer has been replaced by http.server, at least in Windows.

Split page vertically using CSS

Just add overflow:auto; to parent div

<div style="width: 100%;overflow:auto;">
    <div style="float:left; width: 80%">
    </div>
    <div style="float:right;">
    </div>
</div>

Working Demo

Changing the CommandTimeout in SQL Management studio

Changing Command Execute Timeout in Management Studio:

Click on Tools -> Options

Select Query Execution from tree on left side and enter command timeout in "Execute Timeout" control.

Changing Command Timeout in Server:

In the object browser tree right click on the server which give you timeout and select "Properties" from context menu.

Now in "Server Properties -....." dialog click on "Connections" page in "Select a Page" list (on left side). On the right side you will get property

Remote query timeout (in seconds, 0 = no timeout):
[up/down control]

you can set the value in up/down control.

How to enable production mode?

ng build --prod replaces environment.ts with environment.prod.ts

ng build --prod

How can I add additional PHP versions to MAMP

The file /Applications/MAMP/bin/mamp/mamp.conf.json holds the MAMP configuration, look for the section:

{
  "name": "PHP",
  "version": "5.6.28, 7.0.20"
}

which lists the the php versions which will be displayed in the GUI, obviously you need to have downloaded the PHP version from the MAMP site first and placed it in /Applications/MAMP/bin/php for this to work.

Display QImage with QtGui

One common way is to add the image to a QLabel widget using QLabel::setPixmap(), and then display the QLabel as you would any other widget. Example:

#include <QtGui>

int main(int argc, char *argv[])
{
  QApplication app(argc, argv);
  QPixmap pm("your-image.jpg");
  QLabel lbl;
  lbl.setPixmap(pm);
  lbl.show();
  return app.exec();
}

Validate form field only on submit or user input

Use $dirty flag to show the error only after user interacted with the input:

<div>
  <input type="email" name="email" ng-model="user.email" required />
  <span ng-show="form.email.$dirty && form.email.$error.required">Email is required</span>
</div>

If you want to trigger the errors only after the user has submitted the form than you may use a separate flag variable as in:

<form ng-submit="submit()" name="form" ng-controller="MyCtrl">
  <div>
    <input type="email" name="email" ng-model="user.email" required />
    <span ng-show="(form.email.$dirty || submitted) && form.email.$error.required">
      Email is required
    </span>
  </div>

  <div>
    <button type="submit">Submit</button>
  </div>
</form>
function MyCtrl($scope){
  $scope.submit = function(){
    // Set the 'submitted' flag to true
    $scope.submitted = true;
    // Send the form to server
    // $http.post ...
  } 
};

Then, if all that JS inside ng-showexpression looks too much for you, you can abstract it into a separate method:

function MyCtrl($scope){
  $scope.submit = function(){
    // Set the 'submitted' flag to true
    $scope.submitted = true;
    // Send the form to server
    // $http.post ...
  }

  $scope.hasError = function(field, validation){
    if(validation){
      return ($scope.form[field].$dirty && $scope.form[field].$error[validation]) || ($scope.submitted && $scope.form[field].$error[validation]);
    }
    return ($scope.form[field].$dirty && $scope.form[field].$invalid) || ($scope.submitted && $scope.form[field].$invalid);
  };

};
<form ng-submit="submit()" name="form">
  <div>
    <input type="email" name="email" ng-model="user.email" required />
    <span ng-show="hasError('email', 'required')">required</span>
  </div>

  <div>
    <button type="submit">Submit</button>
  </div>
</form>

Disable cross domain web security in Firefox

While the question mentions Chrome and Firefox, there are other software without cross domain security. I mention it for people who ignore that such software exists.

For example, PhantomJS is an engine for browser automation, it supports cross domain security deactivation.

phantomjs.exe --web-security=no script.js

See this other comment of mine: Userscript to bypass same-origin policy for accessing nested iframes

When does Git refresh the list of remote branches?

Use git fetch to fetch all latest created branches.

How to get Maven project version to the bash command line

The Maven Help Plugin is somehow already proposing something for this:

  • help:evaluate evaluates Maven expressions given by the user in an interactive mode.

Here is how you would invoke it on the command line to get the ${project.version}:

mvn org.apache.maven.plugins:maven-help-plugin:2.1.1:evaluate \
    -Dexpression=project.version

How to stop C# console applications from closing automatically?

Console.ReadLine() to wait for the user to Enter or Console.ReadKey to wait for any key.

Android Material Design Button Styles

Beside android.support.design.button.MaterialButton (which mentioned by Gabriele Mariotti),

There is also another Button widget called com.google.android.material.button.MaterialButton which has different styles and extends from AppCompatButton:

style="@style/Widget.MaterialComponents.Button"
style="@style/Widget.MaterialComponents.Button.UnelevatedButton"
style="@style/Widget.MaterialComponents.Button.TextButton"
style="@style/Widget.MaterialComponents.Button.Icon"
style="@style/Widget.MaterialComponents.Button.TextButton.Icon"

Filled, elevated Button (default): enter image description here

style="@style/Widget.MaterialComponents.Button"

Filled, unelevated Button: enter image description here

style="@style/Widget.MaterialComponents.Button.UnelevatedButton"

Text Button: enter image description here

style="@style/Widget.MaterialComponents.Button.TextButton"

Icon Button: enter image description here

style="@style/Widget.MaterialComponents.Button.Icon"
app:icon="@drawable/icon_24px" // Icons can be added from this

A text Button with an icon:: enter image description here


Read: https://material.io/develop/android/components/material-button/

A convenience class for creating a new Material button.

This class supplies updated Material styles for the button in the constructor. The widget will display the correct default Material styles without the use of the style flag.

Font is not available to the JVM with Jasper Reports

There are three method to avoid such a problem.

Method 1 : by setting ignore missing font property.

JRProperties.setProperty("net.sf.jasperreports.awt.ignore.missing.font", "true");

or you can set this property by entering following line into .jrxml file.

<property name="net.sf.jasperreports.awt.ignore.missing.font" value="true"/>

Method 2 : by setting default font property.

JRProperties.setProperty("net.sf.jasperreports.default.font.name", "Sans Serif");

or you can set this property by entering following line into .jrxml file.

<property name="net.sf.jasperreports.default.font.name" value="Sans Serif"/>

Method 3 : by adding missing font property.

Firstly install missing fonts in IReport by selecting " Tools >> Options >> Fonts >> Install Font " then select the all font and Export this By clicking on "Export as Extension" with .jar Extension.

You can use this jar for Jasperreports-font.X.X.X.jar which will be present in your project library or classpath.

Get the cell value of a GridView row

Windows Form Iteration Technique

foreach (DataGridViewRow row in dataGridView1.Rows)
{
    if (row.Selected)
    {
        foreach (DataGridViewCell cell in row.Cells)
        {
            int index = cell.ColumnIndex;
            if (index == 0)
            {
                value = cell.Value.ToString();
                //do what you want with the value
            }
        }
    }
}

How to make an app's background image repeat

Expanding on plowman's answer, here is the non-deprecated version of changing the background image with java.

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    Bitmap bmp = BitmapFactory.decodeResource(getResources(),
            R.drawable.texture);
    BitmapDrawable bitmapDrawable = new BitmapDrawable(getResources(),bmp);
    bitmapDrawable.setTileModeXY(Shader.TileMode.REPEAT,
            Shader.TileMode.REPEAT);
    setBackground(bitmapDrawable);
}

Unable to set variables in bash script

here's your amended script

#!/bin/bash    
folder="ABC" #no spaces between assignment    
useracct='test'    
day=$(date "+%d") # use $() to assign return value of date command to variable    
month=$(date "+%B")     
year=$(date "+%Y")    
folderToBeMoved="/users/$useracct/Documents/Archive/Primetime.eyetv"    
newfoldername="/Volumes/Media/Network/$folder/$month$day$year"    
ECHO "Network is $network" $network    
ECHO "day is $day"    
ECHO "Month is $month"    
ECHO "YEAR is $year"    
ECHO "source is $folderToBeMoved"    
ECHO "dest is $newfoldername"    

mkdir "$newfoldername"    
cp -R "$folderToBeMoved" "$newfoldername"
if [ -f "$newfoldername/Primetime.eyetv" ]; then # <-- put a space at square brackets and quote your variables.
 rm "$folderToBeMoved";
fi

How does internationalization work in JavaScript?

Mozilla recently released the awesome L20n or localization 2.0. In their own words L20n is

an open source, localization-specific scripting language used to process gender, plurals, conjugations, and most of the other quirky elements of natural language.

Their js implementation is on the github L20n repository.

Open directory dialog

For those who don't want to create a custom dialog but still prefer a 100% WPF way and don't want to use separate DDLs, additional dependencies or outdated APIs, I came up with a very simple hack using the Save As dialog.

No using directive needed, you may simply copy-paste the code below !

It should still be very user-friendly and most people will never notice.

The idea comes from the fact that we can change the title of that dialog, hide files, and work around the resulting filename quite easily.

It is a big hack for sure, but maybe it will do the job just fine for your usage...

In this example I have a textbox object to contain the resulting path, but you may remove the related lines and use a return value if you wish...

// Create a "Save As" dialog for selecting a directory (HACK)
var dialog = new Microsoft.Win32.SaveFileDialog();
dialog.InitialDirectory = textbox.Text; // Use current value for initial dir
dialog.Title = "Select a Directory"; // instead of default "Save As"
dialog.Filter = "Directory|*.this.directory"; // Prevents displaying files
dialog.FileName = "select"; // Filename will then be "select.this.directory"
if (dialog.ShowDialog() == true) {
    string path = dialog.FileName;
    // Remove fake filename from resulting path
    path = path.Replace("\\select.this.directory", "");
    path = path.Replace(".this.directory", "");
    // If user has changed the filename, create the new directory
    if (!System.IO.Directory.Exists(path)) {
        System.IO.Directory.CreateDirectory(path);
    }
    // Our final value is in path
    textbox.Text = path;
}

The only issues with this hack are :

  • Acknowledge button still says "Save" instead of something like "Select directory", but in a case like mines I "Save" the directory selection so it still works...
  • Input field still says "File name" instead of "Directory name", but we can say that a directory is a type of file...
  • There is still a "Save as type" dropdown, but its value says "Directory (*.this.directory)", and the user cannot change it for something else, works for me...

Most people won't notice these, although I would definitely prefer using an official WPF way if microsoft would get their heads out of their asses, but until they do, that's my temporary fix.

Best implementation for Key Value Pair Data Structure?

There is an actual Data Type called KeyValuePair, use like this

KeyValuePair<string, string> myKeyValuePair = new KeyValuePair<string,string>("defaultkey", "defaultvalue");

Replacing .NET WebBrowser control with a better browser, like Chrome?

You can use registry to set IE version for webbrowser control. Go to: HKLM\SOFTWARE\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_BROWSER_EMULATION and add "yourApplicationName.exe" with value of browser_emulation To see value of browser_emulation, refer link: http://msdn.microsoft.com/en-us/library/ee330730%28VS.85%29.aspx#browser_emulation

Setting environment variable in react-native?

If you are using Expo there are 2 ways to do this according to the docs https://docs.expo.io/guides/environment-variables/

Method #1 - Using the .extra prop in the app manifest (app.json):

In your app.json file

{
  expo: {
    "slug": "my-app",
    "name": "My App",
    "version": "0.10.0",
    "extra": {
      "myVariable": "foo"
    }
  }
}

Then to access the data on your code (i.e. App.js) simply import expo-constants:

import Constants from 'expo-constants';

export const Sample = (props) => (
  <View>
    <Text>{Constants.manifest.extra.myVariable}</Text>
  </View>
);

This option is a good built-in option that doesn't require any other package to be installed.

Method #2 - Using Babel to "replace" variables. This is the method you would likely need especially if you are using a bare workflow. The other answers already mentioned how to implement this using babel-plugin-transform-inline-environment-variables, but I will leave a link here to the official docs to how to implement it: https://docs.expo.io/guides/environment-variables/#using-babel-to-replace-variables

Display last git commit comment

git show

is the fastest to type, but shows you the diff as well.

git log -1

is fast and simple.

git log -1 --pretty=%B

if you need just the commit message and nothing else.

How to set a text box for inputing password in winforms?

Just set the property of textbox that is PasswordChar and set the * as a property of textbox. That will work for password.

  passwordtextbox.PasswordChar = '*';

where passwordtextbox is the text box name.

How to list all properties of a PowerShell object

I like

 Get-WmiObject Win32_computersystem | format-custom *

That seems to expand everything.

There's also a show-object command in the PowerShellCookbook module that does it in a GUI. Jeffrey Snover, the PowerShell creator, uses it in his unplugged videos (recommended).

Although most often I use

Get-WmiObject Win32_computersystem | fl *

It avoids the .format.ps1xml file that defines a table or list view for the object type, if there are any. The format file may even define column headers that don't match any property names.

Can dplyr package be used for conditional mutating?

Since you ask for other better ways to handle the problem, here's another way using data.table:

require(data.table) ## 1.9.2+
setDT(df)
df[a %in% c(0,1,3,4) | c == 4, g := 3L]
df[a %in% c(2,5,7) | (a==1 & b==4), g := 2L]

Note the order of conditional statements is reversed to get g correctly. There's no copy of g made, even during the second assignment - it's replaced in-place.

On larger data this would have better performance than using nested if-else, as it can evaluate both 'yes' and 'no' cases, and nesting can get harder to read/maintain IMHO.


Here's a benchmark on relatively bigger data:

# R version 3.1.0
require(data.table) ## 1.9.2
require(dplyr)
DT <- setDT(lapply(1:6, function(x) sample(7, 1e7, TRUE)))
setnames(DT, letters[1:6])
# > dim(DT) 
# [1] 10000000        6
DF <- as.data.frame(DT)

DT_fun <- function(DT) {
    DT[(a %in% c(0,1,3,4) | c == 4), g := 3L]
    DT[a %in% c(2,5,7) | (a==1 & b==4), g := 2L]
}

DPLYR_fun <- function(DF) {
    mutate(DF, g = ifelse(a %in% c(2,5,7) | (a==1 & b==4), 2L, 
            ifelse(a %in% c(0,1,3,4) | c==4, 3L, NA_integer_)))
}

BASE_fun <- function(DF) { # R v3.1.0
    transform(DF, g = ifelse(a %in% c(2,5,7) | (a==1 & b==4), 2L, 
            ifelse(a %in% c(0,1,3,4) | c==4, 3L, NA_integer_)))
}

system.time(ans1 <- DT_fun(DT))
#   user  system elapsed 
#  2.659   0.420   3.107 

system.time(ans2 <- DPLYR_fun(DF))
#   user  system elapsed 
# 11.822   1.075  12.976 

system.time(ans3 <- BASE_fun(DF))
#   user  system elapsed 
# 11.676   1.530  13.319 

identical(as.data.frame(ans1), as.data.frame(ans2))
# [1] TRUE

identical(as.data.frame(ans1), as.data.frame(ans3))
# [1] TRUE

Not sure if this is an alternative you'd asked for, but I hope it helps.

What's the algorithm to calculate aspect ratio?

Here is a version of James Farey's best rational approximation algorithm with adjustable level of fuzziness ported to javascript from the aspect ratio calculation code originally written in python.

The method takes a float (width/height) and an upper limit for the fraction numerator/denominator.

In the example below I am setting an upper limit of 50 because I need 1035x582 (1.77835051546) to be treated as 16:9 (1.77777777778) rather than 345:194 which you get with the plain gcd algorithm listed in other answers.

<html>
<body>
<script type="text/javascript">
function aspect_ratio(val, lim) {

    var lower = [0, 1];
    var upper = [1, 0];

    while (true) {
        var mediant = [lower[0] + upper[0], lower[1] + upper[1]];

        if (val * mediant[1] > mediant[0]) {
            if (lim < mediant[1]) {
                return upper;
            }
            lower = mediant;
        } else if (val * mediant[1] == mediant[0]) {
            if (lim >= mediant[1]) {
                return mediant;
            }
            if (lower[1] < upper[1]) {
                return lower;
            }
            return upper;
        } else {
            if (lim < mediant[1]) {
                return lower;
            }
            upper = mediant;
        }
    }
}

document.write (aspect_ratio(800 / 600, 50) +"<br/>");
document.write (aspect_ratio(1035 / 582, 50) + "<br/>");
document.write (aspect_ratio(2560 / 1440, 50) + "<br/>");

    </script>
</body></html>

The result:

 4,3  // (1.33333333333) (800 x 600)
 16,9 // (1.77777777778) (2560.0 x 1440)
 16,9 // (1.77835051546) (1035.0 x 582)

"Too many characters in character literal error"

This is because, in C#, single quotes ('') denote (or encapsulate) a single character, whereas double quotes ("") are used for a string of characters. For example:

var myChar = '=';

var myString = "==";

Python match a string with regex

The r makes the string a raw string, which doesn't process escape characters (however, since there are none in the string, it is actually not needed here).

Also, re.match matches from the beginning of the string. In other words, it looks for an exact match between the string and the pattern. To match stuff that could be anywhere in the string, use re.search. See a demonstration below:

>>> import re
>>> line = 'This,is,a,sample,string'
>>> re.match("sample", line)
>>> re.search("sample", line)
<_sre.SRE_Match object at 0x021D32C0>
>>>

How to get the current plugin directory in WordPress?

When I need to get the directory, not only for the plugins (plugin_dir_path), but a more generic one, you can use __DIR__, it will give you the path of the directory of the file where is called. Now you can used from functions.php or another file!

Description:

The directory of the file. If used inside an include, the directory of the included file is returned. This is equivalent to dirname(__FILE__). This directory name does not have a trailing slash unless it is the root directory. 1

Compile a DLL in C/C++, then call it from another program

There is but one difference. You have to take care or name mangling win C++. But on windows you have to take care about 1) decrating the functions to be exported from the DLL 2) write a so called .def file which lists all the exported symbols.

In Windows while compiling a DLL have have to use

__declspec(dllexport)

but while using it you have to write __declspec(dllimport)

So the usual way of doing that is something like

#ifdef BUILD_DLL
#define EXPORT __declspec(dllexport)
#else
#define EXPORT __declspec(dllimport)
#endif

The naming is a bit confusing, because it is often named EXPORT.. But that's what you'll find in most of the headers somwhere. So in your case you'd write (with the above #define)

int DLL_EXPORT add.... int DLL_EXPORT mult...

Remember that you have to add the Preprocessor directive BUILD_DLL during building the shared library.

Regards Friedrich

Transparent scrollbar with css

To control the background-color of the scrollbar, you need to target the primary element, instead of -track.

::-webkit-scrollbar {
    background-color: blue;
}

::-webkit-scrollbar-track {
    -webkit-box-shadow: inset 0 0 6px rgba(0, 0, 0, 0.3);
}

I haven't succeeded in rendering it transparent, but I did manage to set its color.

Since this is limited to webkit, it is still preferable to use JS with a polyfill: CSS customized scroll bar in div

SQL Error: ORA-01861: literal does not match format string 01861

ORA-01861: literal does not match format string

This happens because you have tried to enter a literal with a format string, but the length of the format string was not the same length as the literal.

You can overcome this issue by carrying out following alteration.

TO_DATE('1989-12-09','YYYY-MM-DD')

As a general rule, if you are using the TO_DATE function, TO_TIMESTAMP function, TO_CHAR function, and similar functions, make sure that the literal that you provide matches the format string that you've specified

Read a file line by line assigning the value to a variable

Using the following Bash template should allow you to read one value at a time from a file and process it.

while read name; do
    # Do what you want to $name
done < filename

ASP.net Repeater get current index, pointer, or counter

To display the item number on the repeater you can use the Container.ItemIndex property.

<asp:repeater id="rptRepeater" runat="server">
    <itemtemplate>
        Item <%# Container.ItemIndex + 1 %>| <%# Eval("Column1") %>
    </itemtemplate>
    <separatortemplate>
        <br />
    </separatortemplate>
</asp:repeater>

Cannot Resolve Collation Conflict

The thing about collations is that although the database has its own collation, every table, and every column can have its own collation. If not specified it takes the default of its parent object, but can be different.

When you change collation of the database, it will be the new default for all new tables and columns, but it doesn't change the collation of existing objects inside the database. You have to go and change manually the collation of every table and column.

Luckily there are scripts available on the internet that can do the job. I am not going to recommend any as I haven't tried them but here are few links:

http://www.codeproject.com/Articles/302405/The-Easy-way-of-changing-Collation-of-all-Database

Update Collation of all fields in database on the fly

http://www.sqlservercentral.com/Forums/Topic820675-146-1.aspx

If you need to have different collation on two objects or can't change collations - you can still JOIN between them using COLLATE command, and choosing the collation you want for join.

SELECT * FROM A JOIN B ON A.Text = B.Text COLLATE Latin1_General_CI_AS 

or using default database collation:

SELECT * FROM A JOIN B ON A.Text = B.Text COLLATE DATABASE_DEFAULT

How to make python Requests work via socks proxy

# SOCKS5 proxy for HTTP/HTTPS
proxiesDict = {
    'http' : "socks5://1.2.3.4:1080",
    'https' : "socks5://1.2.3.4:1080"
}

# SOCKS4 proxy for HTTP/HTTPS
proxiesDict = {
    'http' : "socks4://1.2.3.4:1080",
    'https' : "socks4://1.2.3.4:1080"
}

# HTTP proxy for HTTP/HTTPS
proxiesDict = {
    'http' : "1.2.3.4:1080",
    'https' : "1.2.3.4:1080"
}

What are the differences between a multidimensional array and an array of arrays in C#?

I would like to update on this, because in .NET Core multi-dimensional arrays are faster than jagged arrays. I ran the tests from John Leidegren and these are the results on .NET Core 2.0 preview 2. I increased the dimension value to make any possible influences from background apps less visible.

Debug (code optimalization disabled)
Running jagged 
187.232 200.585 219.927 227.765 225.334 222.745 224.036 222.396 219.912 222.737 

Running multi-dimensional  
130.732 151.398 131.763 129.740 129.572 159.948 145.464 131.930 133.117 129.342 

Running single-dimensional  
 91.153 145.657 111.974  96.436 100.015  97.640  94.581 139.658 108.326  92.931 


Release (code optimalization enabled)
Running jagged 
108.503 95.409 128.187 121.877 119.295 118.201 102.321 116.393 125.499 116.459 

Running multi-dimensional 
 62.292  60.627  60.611  60.883  61.167  60.923  62.083  60.932  61.444  62.974 

Running single-dimensional 
 34.974  33.901  34.088  34.659  34.064  34.735  34.919  34.694  35.006  34.796 

I looked into disassemblies and this is what I found

jagged[i][j][k] = i * j * k; needed 34 instructions to execute

multi[i, j, k] = i * j * k; needed 11 instructions to execute

single[i * dim * dim + j * dim + k] = i * j * k; needed 23 instructions to execute

I wasn't able to identify why single-dimensional arrays were still faster than multi-dimensional but my guess is that it has to do with some optimalization made on the CPU

How to run .sql file in Oracle SQL developer tool to import database?

You can use Load function

Load TableName fullfilepath; 

Decoding and verifying JWT token using System.IdentityModel.Tokens.Jwt

I am just wondering why to use some libraries for JWT token decoding and verification at all.

Encoded JWT token can be created using following pseudocode

var headers = base64URLencode(myHeaders);
var claims = base64URLencode(myClaims);
var payload = header + "." + claims;

var signature = base64URLencode(HMACSHA256(payload, secret));

var encodedJWT = payload + "." + signature;

It is very easy to do without any specific library. Using following code:

using System;
using System.Text;
using System.Security.Cryptography;

public class Program
{   
    // More info: https://stormpath.com/blog/jwt-the-right-way/
    public static void Main()
    {           
        var header = "{\"typ\":\"JWT\",\"alg\":\"HS256\"}";
        var claims = "{\"sub\":\"1047986\",\"email\":\"[email protected]\",\"given_name\":\"John\",\"family_name\":\"Doe\",\"primarysid\":\"b521a2af99bfdc65e04010ac1d046ff5\",\"iss\":\"http://example.com\",\"aud\":\"myapp\",\"exp\":1460555281,\"nbf\":1457963281}";

        var b64header = Convert.ToBase64String(Encoding.UTF8.GetBytes(header))
            .Replace('+', '-')
            .Replace('/', '_')
            .Replace("=", "");
        var b64claims = Convert.ToBase64String(Encoding.UTF8.GetBytes(claims))
            .Replace('+', '-')
            .Replace('/', '_')
            .Replace("=", "");

        var payload = b64header + "." + b64claims;
        Console.WriteLine("JWT without sig:    " + payload);

        byte[] key = Convert.FromBase64String("mPorwQB8kMDNQeeYO35KOrMMFn6rFVmbIohBphJPnp4=");
        byte[] message = Encoding.UTF8.GetBytes(payload);

        string sig = Convert.ToBase64String(HashHMAC(key, message))
            .Replace('+', '-')
            .Replace('/', '_')
            .Replace("=", "");

        Console.WriteLine("JWT with signature: " + payload + "." + sig);        
    }

    private static byte[] HashHMAC(byte[] key, byte[] message)
    {
        var hash = new HMACSHA256(key);
        return hash.ComputeHash(message);
    }
}

The token decoding is reversed version of the code above.To verify the signature you will need to the same and compare signature part with calculated signature.

UPDATE: For those how are struggling how to do base64 urlsafe encoding/decoding please see another SO question, and also wiki and RFCs

Excel VBA Copy a Range into a New Workbook

Modify to suit your specifics, or make more generic as needed:

Private Sub CopyItOver()
  Set NewBook = Workbooks.Add
  Workbooks("Whatever.xlsx").Worksheets("output").Range("A1:K10").Copy
  NewBook.Worksheets("Sheet1").Range("A1").PasteSpecial (xlPasteValues)
  NewBook.SaveAs FileName:=NewBook.Worksheets("Sheet1").Range("E3").Value
End Sub

How to test the type of a thrown exception in Jest

It is a little bit weird, but it works and IMHO is good readable:

it('should throw Error with message \'UNKNOWN ERROR\' when no parameters were passed', () => {
  try {
      throwError();
      // Fail test if above expression doesn't throw anything.
      expect(true).toBe(false);
  } catch (e) {
      expect(e.message).toBe("UNKNOWN ERROR");
  }
});

The Catch block catches your exception, and then you can test on your raised Error. Strange expect(true).toBe(false); is needed to fail your test if the expected Error will be not thrown. Otherwise, this line is never reachable (Error should be raised before them).

@Kenny Body suggested a better solution which improve a code quality if you use expect.assertions():

it('should throw Error with message \'UNKNOWN ERROR\' when no parameters were passed', () => {
  expect.assertions(1);
  try {
      throwError();
  } catch (e) {
      expect(e.message).toBe("UNKNOWN ERROR");
  }
});

See the original answer with more explanations: How to test the type of a thrown exception in Jest

NameError: name 'reduce' is not defined in Python

you need to install and import reduce from functools python package

How do I access my webcam in Python?

OpenCV has support for getting data from a webcam, and it comes with Python wrappers by default, you also need to install numpy for the OpenCV Python extension (called cv2) to work. As of 2019, you can install both of these libraries with pip: pip install numpy pip install opencv-python

More information on using OpenCV with Python.

An example copied from Displaying webcam feed using opencv and python:

import cv2

cv2.namedWindow("preview")
vc = cv2.VideoCapture(0)

if vc.isOpened(): # try to get the first frame
    rval, frame = vc.read()
else:
    rval = False

while rval:
    cv2.imshow("preview", frame)
    rval, frame = vc.read()
    key = cv2.waitKey(20)
    if key == 27: # exit on ESC
        break
cv2.destroyWindow("preview")

Overloading and overriding

Another point to add.

Overloading More than one method with Same name. Same or different return type. Different no of parameters or Different type of parameters. In Same Class or Derived class.

int Add(int num1, int num2) int Add(int num1, int num2, int num3) double Add(int num1, int num2) double Add(double num1, double num2)

Can be possible in same class or derived class. Generally prefers in same class. E.g. Console.WriteLine() has 19 overloaded methods.

Can overload class constructors, methods.

Can consider as Compile Time (static / Early Binding) polymorphism.

=====================================================================================================

Overriding cannot be possible in same class. Can Override class methods, properties, indexers, events.

Has some limitations like The overridden base method must be virtual, abstract, or override. You cannot use the new, static, or virtual modifiers to modify an override method.

Can Consider as Run Time (Dynamic / Late Binding) polymorphism.

Helps in versioning http://msdn.microsoft.com/en-us/library/6fawty39.aspx

=====================================================================================================

Helpful Links

http://msdn.microsoft.com/en-us/library/ms173152.aspx Compile time polymorphism vs. run time polymorphism

How to restart tomcat 6 in ubuntu

if you are using extracted tomcat then,

startup.sh and shutdown.sh are two script located in TOMCAT/bin/ to start and shutdown tomcat, You could use that

if tomcat is installed then

/etc/init.d/tomcat5.5 start
/etc/init.d/tomcat5.5 stop
/etc/init.d/tomcat5.5 restart

How can I escape double quotes in XML attributes values?

From the XML specification:

To allow attribute values to contain both single and double quotes, the apostrophe or single-quote character (') may be represented as "&apos;", and the double-quote character (") as "&quot;".

How to use XPath in Python?

PyXML works well.

You didn't say what platform you're using, however if you're on Ubuntu you can get it with sudo apt-get install python-xml. I'm sure other Linux distros have it as well.

If you're on a Mac, xpath is already installed but not immediately accessible. You can set PY_USE_XMLPLUS in your environment or do it the Python way before you import xml.xpath:

if sys.platform.startswith('darwin'):
    os.environ['PY_USE_XMLPLUS'] = '1'

In the worst case you may have to build it yourself. This package is no longer maintained but still builds fine and works with modern 2.x Pythons. Basic docs are here.

How to remove unused C/C++ symbols with GCC and ld?

While not strictly about symbols, if going for size - always compile with -Os and -s flags. -Os optimizes the resulting code for minimum executable size and -s removes the symbol table and relocation information from the executable.

Sometimes - if small size is desired - playing around with different optimization flags may - or may not - have significance. For example toggling -ffast-math and/or -fomit-frame-pointer may at times save you even dozens of bytes.

How to find char in string and get all the indexes?

def find_idx(str, ch):
    yield [i for i, c in enumerate(str) if c == ch]

for idx in find_idx('babak karchini is a beginner in python ', 'i'):
    print(idx)

output:

[11, 13, 15, 23, 29]

How to print a string at a fixed width?

I find using str.format much more elegant:

>>> '{0: <5}'.format('s')
's    '
>>> '{0: <5}'.format('ss')
'ss   '
>>> '{0: <5}'.format('sss')
'sss  '
>>> '{0: <5}'.format('ssss')
'ssss '
>>> '{0: <5}'.format('sssss')
'sssss'

If you want to align the string to the right use > instead of <:

>>> '{0: >5}'.format('ss')
'   ss'

Edit 1: As mentioned in the comments: the 0 in '{0: <5}' indicates the argument’s index passed to str.format().


Edit 2: In python3 one could use also f-strings:

sub_str='s'
for i in range(1,6):
    s = sub_str*i
    print(f'{s:>5}')
    
'    s'
'   ss'
'  sss'
' ssss'
'sssss'

or:

for i in range(1,5):
    s = sub_str*i
    print(f'{s:<5}')
's    '
'ss   '
'sss  '
'ssss '
'sssss'

of note, in some places above, ' ' (single quotation marks) were added to emphasize the width of the printed strings.

How to convert a NumPy array to PIL image applying matplotlib colormap

  • input = numpy_image
  • np.unit8 -> converts to integers
  • convert('RGB') -> converts to RGB
  • Image.fromarray -> returns an image object

    from PIL import Image
    import numpy as np
    
    PIL_image = Image.fromarray(np.uint8(numpy_image)).convert('RGB')
    
    PIL_image = Image.fromarray(numpy_image.astype('uint8'), 'RGB')
    

Using ConfigurationManager to load config from an arbitrary location

Another solution is to override the default environment configuration file path.

I find it the best solution for the of non-trivial-path configuration file load, specifically the best way to attach configuration file to dll.

AppDomain.CurrentDomain.SetData("APP_CONFIG_FILE", <Full_Path_To_The_Configuration_File>);

Example:

AppDomain.CurrentDomain.SetData("APP_CONFIG_FILE", @"C:\Shared\app.config");

More details may be found at this blog.

Additionally, this other answer has an excellent solution, complete with code to refresh the app config and an IDisposable object to reset it back to it's original state. With this solution, you can keep the temporary app config scoped:

using(AppConfig.Change(tempFileName))
{
    // tempFileName is used for the app config during this context
}

How to configure nginx to enable kinda 'file browser' mode?

All answers contain part of the answer. Let me try to combine all in one.

Quick setup "file browser" mode on freshly installed nginx server:

  1. Edit default config for nginx:

    sudo vim /etc/nginx/sites-available/default
    
  2. Add following to config section:

    location /myfolder {  # new url path
       alias /home/username/myfolder/; # directory to list
       autoindex on;
    }
    
  3. Create folder and sample file there:

    mkdir -p /home/username/myfolder/
    ls -la >/home/username/myfolder/mytestfile.txt
    
  4. Restart nginx

    sudo systemctl restart nginx
    
  5. Check result: http://<your-server-ip>/myfolder for example http://192.168.0.10/myfolder/

enter image description here

Catching KeyboardInterrupt in Python during program shutdown

Checkout this thread, it has some useful information about exiting and tracebacks.

If you are more interested in just killing the program, try something like this (this will take the legs out from under the cleanup code as well):

if __name__ == '__main__':
    try:
        main()
    except KeyboardInterrupt:
        print('Interrupted')
        try:
            sys.exit(0)
        except SystemExit:
            os._exit(0)

PostgreSQL error 'Could not connect to server: No such file or directory'

One of the reason could be that

unix_socket_directories in postgresql.conf file is not listed with the directory it is looking for.

In the question example it is looking for directory /tmp this has to be provided in the postgresql.conf file

something like this:

unix_socket_directories = '/var/run/postgresql,/tmp'    # comma-separated list of directories

This solution worked for me.

how to use JSON.stringify and json_decode() properly

When you save some data using JSON.stringify() and then need to read that in php. The following code worked for me.

json_decode( html_entity_decode( stripslashes ($jsonString ) ) );

Thanks to @Thisguyhastwothumbs