How do the post increment (i++) and pre increment (++i) operators work in Java?

++a increments a before it is evaluated. a++ evaluates a and then increments it.

Related to your expression given:

i = ((++a) + (++a) + (a++)) == ((6) + (7) + (7)); // a is 8 at the end
i = ((a++) + (++a) + (++a)) == ((5) + (7) + (8)); // a is 8 at the end

The parenteses I used above are implicitly used by Java. If you look at the terms this way you can easily see, that they are both the same as they are commutative.

TCP vs UDP on video stream

For video streaming bandwidth is likely the constraint on the system. Using multicast you can greatly reduce the amount of upstream bandwidth used. With UDP you can easily multicast your packets to all connected terminals. You could also use a reliable multicast protocol, one is called Pragmatic General Multicast (PGM), I don't know anything about it and I guess it isn't widespread in its use.

How to check View Source in Mobile Browsers (Both Android && Feature Phone)

The view-source url prefix trick didn't work for me using chrome on an iphone. There are apps I could have installed to do this I guess but for whatever reason I just preferred to do it myself rather than install 'yet another app'.

I found this nice quick tutorial for how to setup a bookmark on mobile safari that will automatically open the view source of a page: https://appletoolbox.com/2014/03/how-to-view-webpage-html-source-codes-on-ipad-iphone-no-app-required/

It worked flawlessly for me and now I have it set as a permanent bookmark any time I want, with no app installed.

Edit: There are basically 6 steps which should work for either Chrome or Safari. Instructions for Safari are:

Open Safari and browse to an arbitrary page.
Select the "Share" (or action") button in Safari (looks like a square with an arrow coming out of the top).
Select "Add Bookmark"
Delete the page title and replace it with something useful like "Show Page Source". Click Save.
Next browse to this exact Stack Overflow answer on your phone and copy the javascript code below to your phone clipboard (code credit: Rob Flaherty):

javascript:(function(){var a=window.open('about:blank').document;a.write('<!DOCTYPE html><html><head><title>Source of '+location.href+'</title><meta name="viewport" content="width=device-width" /></head><body></body></html>');a.close();var b=a.body.appendChild(a.createElement('pre'));b.style.overflow='auto';b.style.whiteSpace='pre-wrap';b.appendChild(a.createTextNode(document.documentElement.innerHTML))})();

Open the "Bookmarks" in Safari and opt to Edit the newly created Show Page Source bookmark. Delete whatever was previously saved in the Address field and instead paste in the Javascript code. Save it.
(Optional) Profit!

How to roundup a number to the closest ten?

Use ROUND but with num_digits = -1

=ROUND(A1,-1)

Also applies to ROUNDUP and ROUNDDOWN

From Excel help:

If num_digits is greater than 0 (zero), then number is rounded to the specified number of decimal places.
If num_digits is 0, then number is rounded to the nearest integer.
If num_digits is less than 0, then number is rounded to the left of the decimal point.

EDIT: To get the numbers to always round up use =ROUNDUP(A1,-1)

Laravel - Session store not set on request

Do you can use ->stateless() before the ->redirect(). Then you dont need the session anymore.

How do I iterate through table rows and cells in JavaScript?

If you want one with a functional style, like this:

    const table = document.getElementById("mytab1");
    const cells = table.rows.toArray()
                  .flatMap(row => row.cells.toArray())
                  .map(cell => cell.innerHTML); //["col1 Val1", "col2 Val2", "col1 Val3", "col2 Val4"]

You may modify the prototype object of HTMLCollection (allowing to use in a way that resembles extension methods in C#) and embed into it a function that converts collection into array, allowing to use higher order funcions with the above style (kind of linq style in C#):

    Object.defineProperty(HTMLCollection.prototype, "toArray", {
        value: function toArray() {
            return Array.prototype.slice.call(this, 0);
        },
        writable: true,
        configurable: true
    });

Remove header and footer from window.print()

Today my colleague stumbled upon the same issue.

As the "margin:0" solution works for chromium based browsers, however, Internet Explorer continue to print footer even if @page margins are set to zero.

The solution (more of a hack) was to put negative margin on the @page.

@page {margin:0 -6cm}
html {margin:0 6cm}

Please note that negative margin won't work for Y axis, only for X

Hope it helps.

Installing SciPy with pip

Addon for Ubuntu (Ubuntu 10.04 LTS (Lucid Lynx)):

The repository moved, but a

pip install -e git+http://github.com/scipy/scipy/#egg=scipy

failed for me... With the following steps, it finally worked out (as root in a virtual environment, where python3 is a link to Python 3.2.2): install the Ubuntu dependencies (see elaichi), clone NumPy and SciPy:

git clone git://github.com/scipy/scipy.git scipy

git clone git://github.com/numpy/numpy.git numpy

Build NumPy (within the numpy folder):

python3 setup.py build --fcompiler=gnu95

Install SciPy (within the scipy folder):

python3 setup.py install

Batch Files - Error Handling

I generally find the conditional command concatenation operators much more convenient than ERRORLEVEL.

yourCommand && (
  echo yourCommand was successful
) || (
  echo yourCommand failed
)

There is one complication you should be aware of. The error branch will fire if the last command in the success branch raises an error.

yourCommand && (
  someCommandThatMayFail
) || (
  echo This will fire if yourCommand or someCommandThatMayFail raises an error
)

The fix is to insert a harmless command that is guaranteed to succeed at the end of the success branch. I like to use (call ), which does nothing except set the ERRORLEVEL to 0. There is a corollary (call) that does nothing except set the ERRORLEVEL to 1.

yourCommand && (
  someCommandThatMayFail
  (call )
) || (
  echo This can only fire if yourCommand raises an error
)

See Foolproof way to check for nonzero (error) return code in windows batch file for examples of the intricacies needed when using ERRORLEVEL to detect errors.

What function is to replace a substring from a string in C?

You can use this function (the comments explain how it works):

void strreplace(char *string, const char *find, const char *replaceWith){
    if(strstr(string, replaceWith) != NULL){
        char *temporaryString = malloc(strlen(strstr(string, find) + strlen(find)) + 1);
        strcpy(temporaryString, strstr(string, find) + strlen(find));    //Create a string with what's after the replaced part
        *strstr(string, find) = '\0';    //Take away the part to replace and the part after it in the initial string
        strcat(string, replaceWith);    //Concat the first part of the string with the part to replace with
        strcat(string, temporaryString);    //Concat the first part of the string with the part after the replaced part
        free(temporaryString);    //Free the memory to avoid memory leaks
    }
}

Cannot find java. Please use the --jdkhome switch

Try Java SE Runtime Environment 8. It fixed it for me.

How do I set browser width and height in Selenium WebDriver?

Try something like this:

IWebDriver _driver = new FirefoxDriver();
_driver.Manage().Window.Position = new Point(0, 0);
_driver.Manage().Window.Size = new Size(1024, 768);

Not sure if it'll resize after being launched though, so maybe it's not what you want

How to shrink/purge ibdata1 file in MySQL

If you use the InnoDB storage engine for (some of) your MySQL tables, you’ve probably already came across a problem with its default configuration. As you may have noticed in your MySQL’s data directory (in Debian/Ubuntu – /var/lib/mysql) lies a file called ‘ibdata1'. It holds almost all the InnoDB data (it’s not a transaction log) of the MySQL instance and could get quite big. By default this file has a initial size of 10Mb and it automatically extends. Unfortunately, by design InnoDB data files cannot be shrinked. That’s why DELETEs, TRUNCATEs, DROPs, etc. will not reclaim the space used by the file.

I think you can find good explanation and solution there :

http://vdachev.net/2007/02/22/mysql-reducing-ibdata1/

endforeach in loops?

How about that?

<?php
    while($items = array_pop($lists)){
        echo "<ul>";
        foreach($items as $item){
            echo "<li>$item</li>";
        }
        echo "</ul>";
    }
?>

Failed to instantiate module error in Angular js

I got this error due to not pointing the script to the correct path. So make absolutely sure that you are pointing to the correct path in you html file.

select unique rows based on single distinct column

Quick one in TSQL

SELECT a.*
FROM emails a
INNER JOIN 
  (SELECT email,
    MIN(id) as id
  FROM emails 
  GROUP BY email 
) AS b
  ON a.email = b.email 
  AND a.id = b.id;

Rename multiple files in a folder, add a prefix (Windows)

The problem with the two Powershell answers here is that the prefix can end up being duplicated since the script will potentially run over the file both before and after it has been renamed, depending on the directory being resorted as the renaming process runs. To get around this, simply use the -Exclude option:

Get-ChildItem -Exclude "house chores-*" | rename-item -NewName { "house chores-" + $_.Name }

This will prevent the process from renaming any one file more than once.

Why should you use strncpy instead of strcpy?

strncpy fills the destination up with '\0' for the size of source, eventhough the size of the destination is smaller....

manpage:

If the length of src is less than n, strncpy() pads the remainder of dest with null bytes.

and not only the remainder...also after this until n characters is reached. And thus you get an overflow... (see the man page implementation)

Read input numbers separated by spaces

int main() {
int sum = 0;
cout << "enter number" << endl;
int i = 0;
while (true) {
    cin >> i;
    sum += i;
    //cout << i << endl;
    if (cin.peek() == '\n') {
        break;
    }
    
}

cout << "result: " << sum << endl;
return 0;
}

I think this code works, you may enter any int numbers and spaces, it will calculate the sum of input ints

How do I completely remove root password

Did you try passwd -d root? Most likely, this will do what you want.

You can also manually edit /etc/shadow: (Create a backup copy. Be sure that you can log even if you mess up, for example from a rescue system.) Search for "root". Typically, the root entry looks similar to

root:$X$SK5xfLB1ZW:0:0...

There, delete the second field (everything between the first and second colon):

root::0:0...

Some systems will make you put an asterisk (*) in the password field instead of blank, where a blank field would allow no password (CentOS 8 for example)

root:*:0:0...

Save the file, and try logging in as root. It should skip the password prompt. (Like passwd -d, this is a "no password" solution. If you are really looking for a "blank password", that is "ask for a password, but accept if the user just presses Enter", look at the manpage of mkpasswd, and use mkpasswd to create the second field for the /etc/shadow.)

.datepicker('setdate') issues, in jQuery

When you trying to call setDate you must provide valid javascript Date object.

queryDate = '2009-11-01';

var parsedDate = $.datepicker.parseDate('yy-mm-dd', queryDate);

$('#datePicker').datepicker('setDate', parsedDate);

This will allow you to use different formats for query date and string date representation in datepicker. This approach is very helpful when you create multilingual site. Another helpful function is formatDate, which formats javascript date object to string.

$.datepicker.formatDate( format, date, settings );

How to add text at the end of each line in Vim?

Another solution, using another great feature:

:'<,'>norm A,

See :help :normal.

How to use curl in a shell script?

url=”http://shahkrunalm.wordpress.com“
content=”$(curl -sLI “$url” | grep HTTP/1.1 | tail -1 | awk {‘print $2'})”
if [ ! -z $content ] && [ $content -eq 200 ]
then
echo “valid url”
else
echo “invalid url”
fi

Break out of a While...Wend loop

A While/Wend loop can only be exited prematurely with a GOTO or by exiting from an outer block (Exit sub/function or another exitable loop)

Change to a Do loop instead:

Do While True
    count = count + 1

    If count = 10 Then
        Exit Do
    End If
Loop

Or for looping a set number of times:

for count = 1 to 10
   msgbox count
next

(Exit For can be used above to exit prematurely)

@Html.DropDownListFor how to set default value

SelectListItem has a Selected property. If you are creating the SelectListItems dynamically, you can just set the one you want as Selected = true and it will then be the default.

SelectListItem defaultItem = new SelectListItem()
{
   Value = 1,
   Text = "Default Item",
   Selected = true
};

I just assigned a variable, but echo $variable shows something else

In all of the cases above, the variable is correctly set, but not correctly read! The right way is to use double quotes when referencing:

echo "$var"

This gives the expected value in all the examples given. Always quote variable references!

Why?

When a variable is unquoted, it will:

Undergo field splitting where the value is split into multiple words on whitespace (by default):

Before: /* Foobar is free software */

After: /*, Foobar, is, free, software, */
Each of these words will undergo pathname expansion, where patterns are expanded into matching files:

Before: /*

After: /bin, /boot, /dev, /etc, /home, ...
Finally, all the arguments are passed to echo, which writes them out separated by single spaces, giving
```
/bin /boot /dev /etc /home Foobar is free software Desktop/ Downloads/
```
instead of the variable's value.

When the variable is quoted it will:

Be substituted for its value.
There is no step 2.

This is why you should always quote all variable references, unless you specifically require word splitting and pathname expansion. Tools like shellcheck are there to help, and will warn about missing quotes in all the cases above.

Docker: Container keeps on restarting again on again

try running

docker stop CONTAINER_ID & docker rm -v CONTAINER_ID

Thanks

Detect network connection type on Android

You can make custom Method to accomplish this task.

  public String getNetworkClass(Context context) {
        TelephonyManager mTelephonyManager = (TelephonyManager)
                context.getSystemService(Context.TELEPHONY_SERVICE);
        int networkType = mTelephonyManager.getNetworkType();
        switch (networkType) {
            case TelephonyManager.NETWORK_TYPE_GPRS:
            case TelephonyManager.NETWORK_TYPE_EDGE:
            case TelephonyManager.NETWORK_TYPE_CDMA:
            case TelephonyManager.NETWORK_TYPE_1xRTT:
            case TelephonyManager.NETWORK_TYPE_IDEN:
                return "2G";
            case TelephonyManager.NETWORK_TYPE_UMTS:
            case TelephonyManager.NETWORK_TYPE_EVDO_0:
            case TelephonyManager.NETWORK_TYPE_EVDO_A:
            case TelephonyManager.NETWORK_TYPE_HSDPA:
            case TelephonyManager.NETWORK_TYPE_HSUPA:
            case TelephonyManager.NETWORK_TYPE_HSPA:
            case TelephonyManager.NETWORK_TYPE_EVDO_B:
            case TelephonyManager.NETWORK_TYPE_EHRPD:
            case TelephonyManager.NETWORK_TYPE_HSPAP:
                return "3G";
            case TelephonyManager.NETWORK_TYPE_LTE:
                return "4G";
            default:
                return "Unknown";
        }
    }

Where does Visual Studio look for C++ header files?

If the project came with a Visual Studio project file, then that should already be configured to find the headers for you. If not, you'll have to add the include file directory to the project settings by right-clicking the project and selecting Properties, clicking on "C/C++", and adding the directory containing the include files to the "Additional Include Directories" edit box.

nodejs - How to read and output jpg image?

Here is how you can read the entire file contents, and if done successfully, start a webserver which displays the JPG image in response to every request:

var http = require('http')
var fs = require('fs')

fs.readFile('image.jpg', function(err, data) {
  if (err) throw err // Fail if the file can't be read.
  http.createServer(function(req, res) {
    res.writeHead(200, {'Content-Type': 'image/jpeg'})
    res.end(data) // Send the file data to the browser.
  }).listen(8124)
  console.log('Server running at http://localhost:8124/')
})

Note that the server is launched by the "readFile" callback function and the response header has Content-Type: image/jpeg.

[Edit] You could even embed the image in an HTML page directly by using an <img> with a data URI source. For example:

  res.writeHead(200, {'Content-Type': 'text/html'});
  res.write('<html><body><img src="data:image/jpeg;base64,')
  res.write(Buffer.from(data).toString('base64'));
  res.end('"/></body></html>');

Read a plain text file with php

$your_variable = file_get_contents("file_to_read.txt");

Attaching a Sass/SCSS to HTML docs

You can not "attach" a SASS/SCSS file to an HTML document.

SASS/SCSS is a CSS preprocessor that runs on the server and compiles to CSS code that your browser understands.

There are client-side alternatives to SASS that can be compiled in the browser using javascript such as LESS CSS, though I advise you compile to CSS for production use.

It's as simple as adding 2 lines of code to your HTML file.

<link rel="stylesheet/less" type="text/css" href="styles.less" />
<script src="less.js" type="text/javascript"></script>

Git Diff with Beyond Compare

http://rubenlaguna.com/wp/2010/08/05/visual-difftool-cygwin-git/ has a solution that I adopted to work for BeyondCompare: http://gist.github.com/564573

How to set image to fit width of the page using jsPDF?

My answer deals with a more specific case of what you are asking but I think one could draw some ideas from this to apply more generally. Also, I would post this as a comment to Purushoth's answer (on which mine is based), if only I could.

Ok, so my problem was how to fit a web page into the pdf document, without losing the aspect ratio. I used jsPDF in conjuction with html2canvas and I calculated the ratio from my div's width and height. I applied that same ratio to the pdf document and the page fit perfectly onto the page without any distortion.

var divHeight = $('#div_id').height();
var divWidth = $('#div_id').width();
var ratio = divHeight / divWidth;
html2canvas(document.getElementById("div_id"), {
     height: divHeight,
     width: divWidth,
     onrendered: function(canvas) {
          var image = canvas.toDataURL("image/jpeg");
          var doc = new jsPDF(); // using defaults: orientation=portrait, unit=mm, size=A4
          var width = doc.internal.pageSize.getWidth();    
          var height = doc.internal.pageSize.getHeight();
          height = ratio * width;
          doc.addImage(image, 'JPEG', 0, 0, width-20, height-10);
          doc.save('myPage.pdf'); //Download the rendered PDF.
     }
});

Using command line arguments in VBscript

Set args = Wscript.Arguments

For Each arg In args
  Wscript.Echo arg
Next

From a command prompt, run the script like this:

CSCRIPT MyScript.vbs 1 2 A B "Arg with spaces"

Will give results like this:

1
2
A
B
Arg with spaces

The first day of the current month in php using date_modify as DateTime object

Currently I'm using this solution:

$firstDay = new \DateTime('first day of this month');
$lastDay = new \DateTime('last day of this month');

The only issue I came upon is that strange time is being set. I needed correct range for our search interface and I ended up with this:

$firstDay = new \DateTime('first day of this month 00:00:00');
$lastDay = new \DateTime('first day of next month 00:00:00');

Laravel: Validation unique on update

For unique rule in the controller - which obviously will be different for the store method and the update method, I usually make a function within the controller for rules which will return an array of rules.

protected function rules($request)
{
    $commonRules = [
        'first_name' => "required",
        'last_name' => "required",
        'password' => "required|min:6|same:password_confirm",
        'password_confirm' => "required:min:6|same:password",
        'password_current' => "required:min:6"
    ];

    $uniqueRules = $request->id

          //update
        ? ['email_address' => ['required', 'email', 'unique:users,email' . $request->get('id')]]

          //store
        : ['email_address' => ['required', 'email', 'unique:users,email']];


    return array_merge($commonRules, $uinqueRules);
}

Then in the respective store and update methods

$validatedData = $request->validate($this->rules($request));

This saves from defining two different rule sets for store and update methods.

If you can afford to compromise a bit on readability, it can also be

protected function rules($request)
{
    return [
        'first_name' => "required",
        'last_name' => "required",
        'password' => "required|min:6|same:password_confirm",
        'password_confirm' => "required:min:6|same:password",
        'password_current' => "required:min:6",
        'email_address' => ['required', 'email', 'unique:users,email' . $request->id ?: null]
    ];
}

Increase max_execution_time in PHP?

For increasing execution time and file size, you need to mention below values in your .htaccess file. It will work.

php_value upload_max_filesize 80M
php_value post_max_size 80M
php_value max_input_time 18000
php_value max_execution_time 18000

How to set min-height for bootstrap container

Usually, if you are using bootstrap you can do this to set a min-height of 100%.

 <div class="container-fluid min-vh-100"></div>

this will also solve the footer not sticking at the bottom.

you can also do this from CSS with the following class

.stickDamnFooter{min-height: 100vh;}

if this class does not stick your footer just add position: fixed; to that same css class and you will not have this issue in a lifetime. Cheers.

Display number always with 2 decimal places in <input>

Another shorthand to (@maudulus's answer) to remove {maxFractionDigits} since it's optional.

You can use {{numberExample | number : '1.2'}}

nginx: [emerg] "server" directive is not allowed here

That is not an nginx configuration file. It is part of an nginx configuration file.

The nginx configuration file (usually called nginx.conf) will look like:

events {
    ...
}
http {
    ...
    server {
        ...
    }
}

The server block is enclosed within an http block.

Often the configuration is distributed across multiple files, by using the include directives to pull in additional fragments (for example from the sites-enabled directory).

Use sudo nginx -t to test the complete configuration file, which starts at nginx.conf and pulls in additional fragments using the include directive. See this document for more.

How do I encode URI parameter values?

Mmhh I know you've already discarded URLEncoder, but despite of what the docs say, I decided to give it a try.

You said:

For example, given an input:

http://google.com/resource?key=value

I expect the output:

http%3a%2f%2fgoogle.com%2fresource%3fkey%3dvalue

So:

C:\oreyes\samples\java\URL>type URLEncodeSample.java
import java.net.*;

public class URLEncodeSample {
    public static void main( String [] args ) throws Throwable {
        System.out.println( URLEncoder.encode( args[0], "UTF-8" ));
    }
}

C:\oreyes\samples\java\URL>javac URLEncodeSample.java

C:\oreyes\samples\java\URL>java URLEncodeSample "http://google.com/resource?key=value"
http%3A%2F%2Fgoogle.com%2Fresource%3Fkey%3Dvalue

As expected.

What would be the problem with this?

jquery data selector

At the moment I'm selecting like this:

$('a[data-attribute=true]')

Which seems to work just fine, but it would be nice if jQuery was able to select by that attribute without the 'data-' prefix.

I haven't tested this with data added to elements via jQuery dynamically, so that could be the downfall of this method.

Creating an array of objects in Java

This is correct. You can also do :

A[] a = new A[] { new A("args"), new A("other args"), .. };

This syntax can also be used to create and initialize an array anywhere, such as in a method argument:

someMethod( new A[] { new A("args"), new A("other args"), . . } )

Android studio 3.0: Unable to resolve dependency for :app@dexOptions/compileClasspath': Could not resolve project :animators

I had the same issue, and solved it by adding 'mavenCentral()' to build.gradle(Project)

allprojects {
    repositories {
        ...
        mavenCentral()
    }
}

copy from one database to another using oracle sql developer - connection failed

The copy command is a SQL*Plus command (not a SQL Developer command). If you have your tnsname entries setup for SID1 and SID2 (e.g. try a tnsping), you should be able to execute your command.

Another assumption is that table1 has the same columns as the message_table (and the columns have only the following data types: CHAR, DATE, LONG, NUMBER or VARCHAR2). Also, with an insert command, you would need to be concerned about primary keys (e.g. that you are not inserting duplicate records).

I tried a variation of your command as follows in SQL*Plus (with no errors):

copy from scott/tiger@db1 to scott/tiger@db2 create new_emp using select * from emp;

After I executed the above statement, I also truncate the new_emp table and executed this command:

copy from scott/tiger@db1 to scott/tiger@db2 insert new_emp using select * from emp;

With SQL Developer, you could do the following to perform a similar approach to copying objects:

On the tool bar, select Tools>Database copy.
Identify source and destination connections with the copy options you would like.
For object type, select table(s).
Specify the specific table(s) (e.g. table1).

The copy command approach is old and its features are not being updated with the release of new data types. There are a number of more current approaches to this like Oracle's data pump (even for tables).

SQL Stored Procedure set variables using SELECT

One advantage your current approach does have is that it will raise an error if multiple rows are returned by the predicate. To reproduce that you can use.

SELECT @currentTerm = currentterm,
       @termID = termid,
       @endDate = enddate
FROM   table1
WHERE  iscurrent = 1

IF( @@ROWCOUNT <> 1 )
  BEGIN
      RAISERROR ('Unexpected number of matching rows',
                 16,
                 1)

      RETURN
  END

How to update npm

In case you want to update npm to a specific version, you can use this :

npm install npm@version-number

Python in Xcode 4+?

Another way, which I've been using for awhile in XCode3:

See steps 1-15 above.

Choose /bin/bash as your executable
For the "Debugger" field, select "None".
In the "Arguments" tab, click the "Base Expansions On" field and select the target you created earlier.
Click the "+" icon under "Arguments Passed On Launch". You may have to expand that section by clicking on the triangle pointing to the right.
Type in "-l". This will tell bash to use your login environment (PYTHONPATH, etc..)
Do step #19 again.
Type in "-c '$(SOURCE_ROOT)/.py'"
Click "OK".
Start coding.

The nice thing about this way is it will use the same environment to develop in that you would use to run in outside of XCode (as setup from your bash .profile).

It's also generic enough to let you develop/run any type of file, not just python.

What is the easiest way to parse an INI file in Java?

Here's a simple, yet powerful example, using the apache class HierarchicalINIConfiguration:

HierarchicalINIConfiguration iniConfObj = new HierarchicalINIConfiguration(iniFile); 

// Get Section names in ini file     
Set setOfSections = iniConfObj.getSections();
Iterator sectionNames = setOfSections.iterator();

while(sectionNames.hasNext()){

 String sectionName = sectionNames.next().toString();

 SubnodeConfiguration sObj = iniObj.getSection(sectionName);
 Iterator it1 =   sObj.getKeys();

    while (it1.hasNext()) {
    // Get element
    Object key = it1.next();
    System.out.print("Key " + key.toString() +  " Value " +  
                     sObj.getString(key.toString()) + "\n");
}

Commons Configuration has a number of runtime dependencies. At a minimum, commons-lang and commons-logging are required. Depending on what you're doing with it, you may require additional libraries (see previous link for details).

Git Stash vs Shelve in IntelliJ IDEA

When using JetBrains IDE's with Git, "stashing and unstashing actions are supported in addition to shelving and unshelving. These features have much in common; the major difference is in the way patches are generated and applied. Shelve can operate with either individual files or bunch of files, while Stash can only operate with a whole bunch of changed files at once. Here are some more details on the differences between them."

How to clear/delete the contents of a Tkinter Text widget?

I checked on my side by just adding '1.0' and it start working

tex.delete('1.0', END)

you can also try this

Getting TypeError: init() missing 1 required positional argument: 'on_delete' when trying to add parent table after child table with entries

Since Django 2.x, on_delete is required.

Django Documentation

Deprecated since version 1.9: on_delete will become a required argument in Django 2.0. In older versions it defaults to CASCADE.

Archive the artifacts in Jenkins

In Jenkins 2.60.3 there is a way to delete build artifacts (not the archived artifacts) in order to save hard drive space on the build machine. In the General section, check "Discard old builds" with strategy "Log Rotation" and then go into its Advanced options. Two more options will appear related to keeping build artifacts for the job based on number of days or builds.

The settings that work for me are to enter 1 for "Max # of builds to keep with artifacts" and then to have a post-build action to archive the artifacts. This way, all artifacts from all builds will be archived, all information from builds will be saved, but only the last build will keep its own artifacts.

Discard old builds options

Reading and writing to serial port in C on Linux

I've solved my problems, so I post here the correct code in case someone needs similar stuff.

Open Port

int USB = open( "/dev/ttyUSB0", O_RDWR| O_NOCTTY );

Set parameters

struct termios tty;
struct termios tty_old;
memset (&tty, 0, sizeof tty);

/* Error Handling */
if ( tcgetattr ( USB, &tty ) != 0 ) {
   std::cout << "Error " << errno << " from tcgetattr: " << strerror(errno) << std::endl;
}

/* Save old tty parameters */
tty_old = tty;

/* Set Baud Rate */
cfsetospeed (&tty, (speed_t)B9600);
cfsetispeed (&tty, (speed_t)B9600);

/* Setting other Port Stuff */
tty.c_cflag     &=  ~PARENB;            // Make 8n1
tty.c_cflag     &=  ~CSTOPB;
tty.c_cflag     &=  ~CSIZE;
tty.c_cflag     |=  CS8;

tty.c_cflag     &=  ~CRTSCTS;           // no flow control
tty.c_cc[VMIN]   =  1;                  // read doesn't block
tty.c_cc[VTIME]  =  5;                  // 0.5 seconds read timeout
tty.c_cflag     |=  CREAD | CLOCAL;     // turn on READ & ignore ctrl lines

/* Make raw */
cfmakeraw(&tty);

/* Flush Port, then applies attributes */
tcflush( USB, TCIFLUSH );
if ( tcsetattr ( USB, TCSANOW, &tty ) != 0) {
   std::cout << "Error " << errno << " from tcsetattr" << std::endl;
}

Write

unsigned char cmd[] = "INIT \r";
int n_written = 0,
    spot = 0;

do {
    n_written = write( USB, &cmd[spot], 1 );
    spot += n_written;
} while (cmd[spot-1] != '\r' && n_written > 0);

It was definitely not necessary to write byte per byte, also int n_written = write( USB, cmd, sizeof(cmd) -1) worked fine.

At last, read:

int n = 0,
    spot = 0;
char buf = '\0';

/* Whole response*/
char response[1024];
memset(response, '\0', sizeof response);

do {
    n = read( USB, &buf, 1 );
    sprintf( &response[spot], "%c", buf );
    spot += n;
} while( buf != '\r' && n > 0);

if (n < 0) {
    std::cout << "Error reading: " << strerror(errno) << std::endl;
}
else if (n == 0) {
    std::cout << "Read nothing!" << std::endl;
}
else {
    std::cout << "Response: " << response << std::endl;
}

This one worked for me. Thank you all!

How to insert multiple rows from a single query using eloquent/fluent

It is really easy to do a bulk insert in Laravel with or without the query builder. You can use the following official approach.

Entity::upsert([
    ['name' => 'Pierre Yem Mback', 'city' => 'Eseka', 'salary' => 10000000],
    ['name' => 'Dial rock 360', 'city' => 'Yaounde', 'salary' => 20000000],
    ['name' => 'Ndibou La Menace', 'city' => 'Dakar', 'salary' => 40000000]
], ['name', 'city'], ['salary']);

How to get First and Last record from a sql query?

Why not use order by asc limit 1 and the reverse, order by desc limit 1?

Do on-demand Mac OS X cloud services exist, comparable to Amazon's EC2 on-demand instances?

Amazon EC2 cannot offer Mac OS X EC2 instances due to Apple's tight licensing to only allow it to legally run on Apple hardware and the current EC2 infrastructure relies upon virtualized hardware.

Apple Mac image on Amazon EC2?

Can you run OS X on an Amazon EC2 instance?

There are other companies that do provide Mac OS X hosting, presumably on Apple hardware. One example is Go Daddy:

Go Daddy Product Catalog (see Mac® Powered Cloud Servers under Web Hosting)

To find more, search for "Mac OS X hosting" and you'll find more options.

Windows service on Local Computer started and then stopped error

You may want to unit test the initialization - but because it's in the OnStart method this is near to impossible. I would suggest moving the initialization code out into a separate class so that it can be tested or at least re-used in a form tester.

Secondly to add some logging (using Log4Net or similar) and add some verbose logging so that you can see details about runtime errors. Examples of runtime errors would be AccessViolation etc. especially if your service is running without enough privileges to access the config files.

Convert SVG to PNG in Python

Actually, I did not want to be dependent of anything else but Python (Cairo, Ink.., etc.) My requirements were to be as simple as possible, at most, a simple pip install "savior" would suffice, that's why any of those above didn't suit for me.

I came through this (going further than Stackoverflow on the research). https://www.tutorialexample.com/best-practice-to-python-convert-svg-to-png-with-svglib-python-tutorial/

Looks good, so far. So I share it in case anyone in the same situation.

jQuery: get parent, parent id?

 $(this).closest('ul').attr('id');

What does the [Flags] Enum Attribute mean in C#?

@Nidonocu

To add another flag to an existing set of values, use the OR assignment operator.

Mode = Mode.Read;
//Add Mode.Write
Mode |= Mode.Write;
Assert.True(((Mode & Mode.Write) == Mode.Write)
  && ((Mode & Mode.Read) == Mode.Read)));

Why do you have to link the math library in C?

If I put stdlib.h or stdio.h, I don't have to link those but I have to link when I compile:

stdlib.h, stdio.h are the header files. You include them for your convenience. They only forecast what symbols will become available if you link in the proper library. The implementations are in the library files, that's where the functions really live.

Including math.h is only the first step to gaining access to all the math functions.

Also, you don't have to link against libm if you don't use it's functions, even if you do a #include <math.h> which is only an informational step for you, for the compiler about the symbols.

stdlib.h, stdio.h refer to functions available in libc, which happens to be always linked in so that the user doesn't have to do it himself.

How to encode text to base64 in python

To compatibility with both py2 and py3

import six
import base64

def b64encode(source):
    if six.PY3:
        source = source.encode('utf-8')
    content = base64.b64encode(source).decode('utf-8')

How to increase the max connections in postgres?

Just increasing max_connections is bad idea. You need to increase shared_buffers and kernel.shmmax as well.

Considerations

max_connections determines the maximum number of concurrent connections to the database server. The default is typically 100 connections.

Before increasing your connection count you might need to scale up your deployment. But before that, you should consider whether you really need an increased connection limit.

Each PostgreSQL connection consumes RAM for managing the connection or the client using it. The more connections you have, the more RAM you will be using that could instead be used to run the database.

A well-written app typically doesn't need a large number of connections. If you have an app that does need a large number of connections then consider using a tool such as pg_bouncer which can pool connections for you. As each connection consumes RAM, you should be looking to minimize their use.

How to increase max connections

1. Increase max_connection and shared_buffers

in /var/lib/pgsql/{version_number}/data/postgresql.conf

change

max_connections = 100
shared_buffers = 24MB

max_connections = 300
shared_buffers = 80MB

The shared_buffers configuration parameter determines how much memory is dedicated to PostgreSQL to use for caching data.

If you have a system with 1GB or more of RAM, a reasonable starting value for shared_buffers is 1/4 of the memory in your system.
it's unlikely you'll find using more than 40% of RAM to work better than a smaller amount (like 25%)
Be aware that if your system or PostgreSQL build is 32-bit, it might not be practical to set shared_buffers above 2 ~ 2.5GB.
Note that on Windows, large values for shared_buffers aren't as effective, and you may find better results keeping it relatively low and using the OS cache more instead. On Windows the useful range is 64MB to 512MB.

2. Change kernel.shmmax

You would need to increase kernel max segment size to be slightly larger than the shared_buffers.

In file /etc/sysctl.conf set the parameter as shown below. It will take effect when postgresql reboots (The following line makes the kernel max to 96Mb)

kernel.shmmax=100663296

References

Postgres Max Connections And Shared Buffers

Tuning Your PostgreSQL Server

R solve:system is exactly singular

Lapack is a Linear Algebra package which is used by R (actually it's used everywhere) underneath solve(), dgesv spits this kind of error when the matrix you passed as a parameter is singular.

As an addendum: dgesv performs LU decomposition, which, when using your matrix, forces a division by 0, since this is ill-defined, it throws this error. This only happens when matrix is singular or when it's singular on your machine (due to approximation you can have a really small number be considered 0)

I'd suggest you check its determinant if the matrix you're using contains mostly integers and is not big. If it's big, then take a look at this link.

day of the week to day number (Monday = 1, Tuesday = 2)

The date function can return this if you specify the format correctly:

$daynum = date("w", strtotime("wednesday"));

will return 0 for Sunday through to 6 for Saturday.

An alternative format is:

$daynum = date("N", strtotime("wednesday"));

which will return 1 for Monday through to 7 for Sunday (this is the ISO-8601 represensation).

Python object.repr(self) should be an expression?

>>> from datetime import date
>>>
>>> repr(date.today())        # calls date.today().__repr__()
'datetime.date(2009, 1, 16)'
>>> eval(_)                   # _ is the output of the last command
datetime.date(2009, 1, 16)

The output is a string that can be parsed by the python interpreter and results in an equal object.

If that's not possible, it should return a string in the form of <...some useful description...>.

WPF Datagrid Get Selected Cell Value

Worked For me

object item = dgwLoadItems.SelectedItem;
string ID = (dgwLoadItems.SelectedCells[0].Column.GetCellContent(item) as TextBlock).Text;
MessageBox.Show(ID);

java.lang.UnsupportedClassVersionError

This was a fresh linux Mint xfce machine

I have been battling this for a about a week. I'm trying to learn Java on Netbeans IDE and so naturally I get the combo file straight from Oracle. Which is a package of the JDK and the Netbeans IDE together in a tar file located here.

located http://www.oracle.com/technetwork/java/javase/downloads/index.html file name JDK 8u25 with NetBeans 8.0.1

after installing them (or so I thought) I would make/compile a simple program like "hello world" and that would spit out a jar file that you would be able to run in a terminal. Keep in mind that the program ran in the Netbeans IDE.

I would end up with this error: java.lang.UnsupportedClassVersionError:

Even though I ran the file from oracle website I still had the old version of the Java runtime which was not compatible to run my jar file which was compiled with the new java runtime.

After messing with stuff that was mostly over my head from setting Paths to editing .bashrc with no remedy.

I came across a solution that was easy enough for even me. I have come across something that auto installs java and configures it on your system and it works with the latest 1.8.*

One of the steps is adding a PPA wasn't sure about this at first but seems ok as it has worked for me

sudo add-apt-repository ppa:webupd8team/java

sudo apt-get update

sudo apt-get install oracle-java8-installer

domenic@domenic-AO532h ~ $ java -version java version "1.8.0_25" Java(TM) SE Runtime Environment (build 1.8.0_25-b17) Java HotSpot(TM) Server VM (build 25.25-b02, mixed mode)

I think it also configures the browser java as well.

I hope this helps others.

Javascript: Setting location.href versus location

You might set location directly because it's slightly shorter. If you're trying to be terse, you can usually omit the window. too.

URL assignments to both location.href and location are defined to work in JavaScript 1.0, back in Netscape 2, and have been implemented in every browser since. So take your pick and use whichever you find clearest.

How to write a Unit Test?

Like @CoolBeans mentioned, take a look at jUnit. Here is a short tutorial to get you started as well with jUnit 4.x

Finally, if you really want to learn more about testing and test-driven development (TDD) I recommend you take a look at the following book by Kent Beck: Test-Driven Development By Example.

How do you update a DateTime field in T-SQL?

That should work, I'd put brackets around [Date] as it's a reserved keyword.

How to convert UTF-8 byte[] to string?

Converting a byte[] to a string seems simple but any kind of encoding is likely to mess up the output string. This little function just works without any unexpected results:

private string ToString(byte[] bytes)
{
    string response = string.Empty;

    foreach (byte b in bytes)
        response += (Char)b;

    return response;
}

What is the difference between Task.Run() and Task.Factory.StartNew()

See this blog article that describes the difference. Basically doing:

Task.Run(A)

Is the same as doing:

Task.Factory.StartNew(A, CancellationToken.None, TaskCreationOptions.DenyChildAttach, TaskScheduler.Default);

Mysql password expired. Can't connect

The password expiration is a new feature in MySQL 5.6 or 5.7.

The answer is clear: Use a client which is capable of expired password changing (I think Sequel Pro can do it).

MySQLi library obviously isnt able to change the expired password.

If you have limited access to localhost and you only have a console client, the standard mysql client can do it.

React-Router: No Not Found Route?

According to the documentation, the route was found, even though the resource wasn't.

Note: This is not intended to be used for when a resource is not found. There is a difference between the router not finding a matched path and a valid URL that results in a resource not being found. The url courses/123 is a valid url and results in a matched route, therefore it was "found" as far as routing is concerned. Then, if we fetch some data and discover that the course 123 does not exist, we do not want to transition to a new route. Just like on the server, you go ahead and serve the url but render different UI (and use a different status code). You shouldn't ever try to transition to a NotFoundRoute.

So, you could always add a line in the Router.run() before React.render() to check if the resource is valid. Just pass a prop down to the component or override the Handler component with a custom one to display the NotFound view.

Why isn't Python very good for functional programming?

In addition to other answers, one reason Python and most other multi-paradigm languages are not well suited for true functional programming is because their compilers / virtual machines / run-times do not support functional optimization. This sort of optimization is achieved by the compiler understanding mathematical rules. For example, many programming languages support a map function or method. This is a fairly standard function that takes a function as one argument and a iterable as the second argument then applies that function to each element in the iterable.

Anyways it turns out that map( foo() , x ) * map( foo(), y ) is the same as map( foo(), x * y ). The latter case is actually faster than the former because the former performs two copies where the latter performs one.

Better functional languages recognize these mathematically based relationships and automatically perform the optimization. Languages that aren't dedicated to the functional paradigm will likely not optimize.

Visual Studio Code - Convert spaces to tabs

Ctrl+Shift+P, then "Convert Indentation to Tabs"

Compute row average in pandas

If you are looking to average column wise. Try this,

df.drop('Region', axis=1).apply(lambda x: x.mean())

# it drops the Region column
df.drop('Region', axis=1,inplace=True)

Delete/Reset all entries in Core Data?

iOS 10 and Swift 3

Assuming that your entity name is "Photo", and that you create a CoreDataStack class...

 func clearData() {
        do {            
            let context = CoreDataStack.sharedInstance.persistentContainer.viewContext
            let fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName: "Photo")
            do {
                let objects  = try context.fetch(fetchRequest) as? [NSManagedObject]
                _ = objects.map{$0.map{context.delete($0)}}
                CoreDataStack.sharedInstance.saveContext()
            } catch let error {
                print("ERROR DELETING : \(error)")
            }
        }
    }

Here is a good tutorial of how to use CoreData and how to use this method. https://medium.com/compileswift/parsing-json-response-and-save-it-in-coredata-step-by-step-fb58fc6ce16f#.1tu6kt8qb

Getting DOM elements by classname

There is also another approach without the use of DomXPath or Zend_Dom_Query.

Based on dav's original function, I wrote the following function that returns all the children of the parent node whose tag and class match the parameters.

function getElementsByClass(&$parentNode, $tagName, $className) {
    $nodes=array();

    $childNodeList = $parentNode->getElementsByTagName($tagName);
    for ($i = 0; $i < $childNodeList->length; $i++) {
        $temp = $childNodeList->item($i);
        if (stripos($temp->getAttribute('class'), $className) !== false) {
            $nodes[]=$temp;
        }
    }

    return $nodes;
}

suppose you have a variable $html the following HTML:

<html>
 <body>
  <div id="content_node">
    <p class="a">I am in the content node.</p>
    <p class="a">I am in the content node.</p>
    <p class="a">I am in the content node.</p>    
  </div>
  <div id="footer_node">
    <p class="a">I am in the footer node.</p>
  </div>
 </body>
</html>

use of getElementsByClass is as simple as:

$dom = new DOMDocument('1.0', 'utf-8');
$dom->loadHTML($html);
$content_node=$dom->getElementById("content_node");

$div_a_class_nodes=getElementsByClass($content_node, 'div', 'a');//will contain the three nodes under "content_node".

:after and :before pseudo-element selectors in Sass

Use ampersand to specify the parent selector.

SCSS syntax:

p {
    margin: 2em auto;

    > a {
        color: red;
    }

    &:before {
        content: "";
    }

    &:after {
        content: "* * *";
    }
}

Component is part of the declaration of 2 modules

IN Angular 4. This error is considered as ng serve run time cache issue.

case:1 this error will occur, once you import the component in one module and again import in sub modules will occur.

case:2 Import one Component in wrong place and removed and replaced in Correct module, That time it consider as ng serve cache issue. Need to Stop the project and start -do again ng serve, It will work as expected.

jQuery Ajax error handling, show custom exception messages

I believe the Ajax response handler uses the HTTP status code to check if there was an error.

So if you just throw a Java exception on your server side code but then the HTTP response doesn't have a 500 status code jQuery (or in this case probably the XMLHttpRequest object) will just assume that everything was fine.

I'm saying this because I had a similar problem in ASP.NET where I was throwing something like a ArgumentException("Don't know what to do...") but the error handler wasn't firing.

I then set the Response.StatusCode to either 500 or 200 whether I had an error or not.

Unsigned values in C

In the hexadecimal it can't get a negative value. So it shows it like ffffffff.

The advantage to using the unsigned version (when you know the values contained will be non-negative) is that sometimes the computer will spot errors for you (the program will "crash" when a negative value is assigned to the variable).

Updating MySQL primary key

Next time, use a single "alter table" statement to update the primary key.

alter table xx drop primary key, add primary key(k1, k2, k3);

To fix things:

create table fixit (user_2, user_1, type, timestamp, n, primary key( user_2, user_1, type) );
lock table fixit write, user_interactions u write, user_interactions write;

insert into fixit 
select user_2, user_1, type, max(timestamp), count(*) n from user_interactions u 
group by user_2, user_1, type
having n > 1;

delete u from user_interactions u, fixit 
where fixit.user_2 = u.user_2 
  and fixit.user_1 = u.user_1 
  and fixit.type = u.type 
  and fixit.timestamp != u.timestamp;

alter table user_interactions add primary key (user_2, user_1, type );

unlock tables;

The lock should stop further updates coming in while your are doing this. How long this takes obviously depends on the size of your table.

The main problem is if you have some duplicates with the same timestamp.

PivotTable's Report Filter using "greater than"

One way to do this is to pull your field into the rows section of the pivot table from the Filter section. Then group the values that you want to keep into a group, using the group option on the menu. After that is completed, drag your field back into the Filters section. The grouping will remain and you can check or uncheck one box to remove lots of values.

Java equivalent to #region in C#

vscode

I use vscode for java and it works pretty much the same as visual studio except you use comments:

//#region name

//code

//#endregion

XSLT getting last element

You need to put the last() indexing on the nodelist result, rather than as part of the selection criteria. Try:

(//element[@name='D'])[last()]

ToString() function in Go

Another example with a struct :

package types

import "fmt"

type MyType struct {
    Id   int    
    Name string
}

func (t MyType) String() string {
    return fmt.Sprintf(
    "[%d : %s]",
    t.Id, 
    t.Name)
}

Be careful when using it,
concatenation with '+' doesn't compile :

t := types.MyType{ 12, "Blabla" }

fmt.Println(t) // OK
fmt.Printf("t : %s \n", t) // OK
//fmt.Println("t : " + t) // Compiler error !!!
fmt.Println("t : " + t.String()) // OK if calling the function explicitly

ReadFile in Base64 Nodejs

var fs = require('fs');

function base64Encode(file) {
    var body = fs.readFileSync(file);
    return body.toString('base64');
}


var base64String = base64Encode('test.jpg');
console.log(base64String);

Java: parse int value from a char

Using binary AND with 0b1111:

String element = "el5";

char c = element.charAt(2);

System.out.println(c & 0b1111); // => '5' & 0b1111 => 0b0011_0101 & 0b0000_1111 => 5

// '0' & 0b1111 => 0b0011_0000 & 0b0000_1111 => 0
// '1' & 0b1111 => 0b0011_0001 & 0b0000_1111 => 1
// '2' & 0b1111 => 0b0011_0010 & 0b0000_1111 => 2
// '3' & 0b1111 => 0b0011_0011 & 0b0000_1111 => 3
// '4' & 0b1111 => 0b0011_0100 & 0b0000_1111 => 4
// '5' & 0b1111 => 0b0011_0101 & 0b0000_1111 => 5
// '6' & 0b1111 => 0b0011_0110 & 0b0000_1111 => 6
// '7' & 0b1111 => 0b0011_0111 & 0b0000_1111 => 7
// '8' & 0b1111 => 0b0011_1000 & 0b0000_1111 => 8
// '9' & 0b1111 => 0b0011_1001 & 0b0000_1111 => 9

How to know if .keyup() is a character key (jQuery)

Note: In hindsight this was a quick and dirty answer, and may not work in all situations. To have a reliable solution, see Tim Down's answer (copy pasting that here as this answer is still getting views and upvotes):

You can't do this reliably with the keyup event. If you want to know something about the character that was typed, you have to use the keypress event instead.

The following example will work all the time in most browsers but there are some edge cases that you should be aware of. For what is in my view the definitive guide on this, see http://unixpapa.com/js/key.html.
$("input").keypress(function(e) {
    if (e.which !== 0) {
        alert("Character was typed. It was: " + String.fromCharCode(e.which));
    }
});
keyup and keydown give you information about the physical key that was pressed. On standard US/UK keyboards in their standard layouts, it looks like there is a correlation between the keyCode property of these events and the character they represent. However, this is not reliable: different keyboard layouts will have different mappings.

The following was the original answer, but is not correct and may not work reliably in all situations.

~~To match the keycode with a word character (eg., a would match. space would not)~~

~~$("input").keyup(function(event) { var c= String.fromCharCode(event.keyCode); var isWordcharacter = c.match(/\w/); });~~

~~Ok, that was a quick answer. The approach is the same, but beware of keycode issues, see this article in quirksmode.~~

python NameError: name 'file' is not defined

To solve this error, it is enough to add from google.colab import files in your code!

Decode JSON with unknown structure

You really just need a single struct, and as mentioned in the comments the correct annotations on the field will yield the desired results. JSON is not some extremely variant data format, it is well defined and any piece of json, no matter how complicated and confusing it might be to you can be represented fairly easily and with 100% accuracy both by a schema and in objects in Go and most other OO programming languages. Here's an example;

package main

import (
    "fmt"
    "encoding/json"
)

type Data struct {
    Votes *Votes `json:"votes"`
    Count string `json:"count,omitempty"`
}

type Votes struct {
    OptionA string `json:"option_A"`
}

func main() {
    s := `{ "votes": { "option_A": "3" } }`
    data := &Data{
        Votes: &Votes{},
    }
    err := json.Unmarshal([]byte(s), data)
    fmt.Println(err)
    fmt.Println(data.Votes)
    s2, _ := json.Marshal(data)
    fmt.Println(string(s2))
    data.Count = "2"
    s3, _ := json.Marshal(data)
    fmt.Println(string(s3))
}

https://play.golang.org/p/ScuxESTW5i

Based on your most recent comment you could address that by using an interface{} to represent data besides the count, making the count a string and having the rest of the blob shoved into the interface{} which will accept essentially anything. That being said, Go is a statically typed language with a fairly strict type system and to reiterate, your comments stating 'it can be anything' are not true. JSON cannot be anything. For any piece of JSON there is schema and a single schema can define many many variations of JSON. I advise you take the time to understand the structure of your data rather than hacking something together under the notion that it cannot be defined when it absolutely can and is probably quite easy for someone who knows what they're doing.

Windows Forms - Enter keypress activates submit button?

As previously stated, set your form's AcceptButton property to one of its buttons AND set the DialogResult property for that button to DialogResult.OK, in order for the caller to know if the dialog was accepted or dismissed.

Passing an array as a function parameter in JavaScript

Why don't you pass the entire array and process it as needed inside the function?

var x = [ 'p0', 'p1', 'p2' ]; 
call_me(x);

function call_me(params) {
  for (i=0; i<params.length; i++) {
    alert(params[i])
  }
}

Get program execution time in the shell

You can use time and subshell ():

time (
  for (( i=1; i<10000; i++ )); do
    echo 1 >/dev/null
  done
)

Or in same shell {}:

time {
  for (( i=1; i<10000; i++ )); do
    echo 1 >/dev/null
  done
}

TextView bold via xml file?

Just you need to use 

//for bold
android:textStyle="bold"

//for italic
android:textStyle="italic"

//for normal
android:textStyle="normal"

<TextView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:textStyle="bold"
    android:text="@string/userName"
    android:layout_gravity="left"
    android:textSize="16sp"
/>

How to undo local changes to a specific file

You don't want git revert. That undoes a previous commit. You want git checkout to get git's version of the file from master.

git checkout -- filename.txt

In general, when you want to perform a git operation on a single file, use -- filename.

2020 Update

Git introduced a new command git restore in version 2.23.0. Therefore, if you have git version 2.23.0+, you can simply git restore filename.txt - which does the same thing as git checkout -- filename.txt. The docs for this command do note that it is currently experimental.

git-restore Documentation

Can a shell script set environment variables of the calling shell?

This works — it isn't what I'd use, but it 'works'. Let's create a script teredo to set the environment variable TEREDO_WORMS:

#!/bin/ksh
export TEREDO_WORMS=ukelele
exec $SHELL -i

It will be interpreted by the Korn shell, exports the environment variable, and then replaces itself with a new interactive shell.

Before running this script, we have SHELL set in the environment to the C shell, and the environment variable TEREDO_WORMS is not set:

% env | grep SHELL
SHELL=/bin/csh
% env | grep TEREDO
%

When the script is run, you are in a new shell, another interactive C shell, but the environment variable is set:

% teredo
% env | grep TEREDO
TEREDO_WORMS=ukelele
%

When you exit from this shell, the original shell takes over:

% exit
% env | grep TEREDO
%

The environment variable is not set in the original shell's environment. If you use exec teredo to run the command, then the original interactive shell is replaced by the Korn shell that sets the environment, and then that in turn is replaced by a new interactive C shell:

% exec teredo
% env | grep TEREDO
TEREDO_WORMS=ukelele
%

If you type exit (or Control-D), then your shell exits, probably logging you out of that window, or taking you back to the previous level of shell from where the experiments started.

The same mechanism works for Bash or Korn shell. You may find that the prompt after the exit commands appears in funny places.

Note the discussion in the comments. This is not a solution I would recommend, but it does achieve the stated purpose of a single script to set the environment that works with all shells (that accept the -i option to make an interactive shell). You could also add "$@" after the option to relay any other arguments, which might then make the shell usable as a general 'set environment and execute command' tool. You might want to omit the -i if there are other arguments, leading to:

#!/bin/ksh
export TEREDO_WORMS=ukelele
exec $SHELL "${@-'-i'}"

The "${@-'-i'}" bit means 'if the argument list contains at least one argument, use the original argument list; otherwise, substitute -i for the non-existent arguments'.

Get string after character

echo "GenFiltEff=7.092200e-01" | cut -d "=" -f2

C read file line by line

Provide a portable and generic getdelim function, test passed via msvc, clang, gcc.

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

ssize_t
portabl_getdelim(char ** restrict linep,
                 size_t * restrict linecapp,
                 int delimiter,
                 FILE * restrict stream) {
    if (0 == *linep) {
        *linecapp = 8;
        *linep = malloc(*linecapp);
        if (0 == *linep) {
            return EOF;
        }
    }

    ssize_t linelen = 0;
    int c = 0;
    char *p = *linep;

    while (EOF != (c = fgetc(stream))) {
        if (linelen == (ssize_t) *linecapp - 1) {
            *linecapp <<= 1;
            char *p1 = realloc(*linep, *linecapp);
            if (0 == *p1) {
                return EOF;
            }
            p = p1 + linelen;
        }
        *p++ = c;
        linelen++;

        if (delimiter == c) {
            *p = 0;
            return linelen;
        }
    }
    return EOF == c ? EOF : linelen;
}


int
main(int argc, char **argv) {
    const char *filename = "/a/b/c.c";
    FILE *file = fopen(filename, "r");
    if (!file) {
        perror(filename);
        return 1;
    }

    char *line = 0;
    size_t linecap = 0;
    ssize_t linelen;

    while (0 < (linelen = portabl_getdelim(&line, &linecap, '\n', file))) {
        fwrite(line, linelen, 1, stdout);
    }
    if (line) {
        free(line);
    }
    fclose(file);   

    return 0;
}

ps command doesn't work in docker container

ps is not installed in the base wheezy image. Try this from within the container:

RUN apt-get update && apt-get install -y procps

Adding a directory to the PATH environment variable in Windows

As trivial as it may be, I had to restart Windows when faced with this problem.

I am running Windows 7 x64. I did a manual update to the system PATH variable. This worked okay if I ran cmd.exe from the stat menu. But if I type "cmd" in the Windows Explorer address bar, it seems to load the PATH from elsewhere, which doesn't have my manual changes.

(To avoid doubt - yes, I did close and rerun cmd a couple of times before I restarted and it didn't help.)

ngFor with index as value in attribute

In Angular 5/6/7/8:

<ul>
  <li *ngFor="let item of items; index as i">
    {{i+1}} {{item}}
  </li>
</ul>

In older versions

<ul *ngFor="let item of items; index as i">
  <li>{{i+1}} {{item}}</li>
</ul>

Angular.io ? API ? NgForOf

Unit test examples

ng_for_spec.ts

Another interesting example

Grouping

How many socket connections can a web server handle?

I think that the number of concurrent socket connections one web server can handle largely depends on the amount of resources each connection consumes and the amount of total resource available on the server barring any other web server resource limiting configuration.

To illustrate, if every socket connection consumed 1MB of server resource and the server has 16GB of RAM available (theoretically) this would mean it would only be able to handle (16GB / 1MB) concurrent connections. I think it's as simple as that... REALLY!

So regardless of how the web server handles connections, every connection will ultimately consume some resource.

Could not find tools.jar. Please check that C:\Program Files\Java\jre1.8.0_151 contains a valid JDK installation

Solution 1:

Go to your android folder > Gradle.properties > add your jdk path.
Clean and rebuild then it is done. // For Example Purpose Only

org.gradle.java.home=/Library/Java/JavaVirtualMachines/jdk1.8.0_251.jdk/Contents/Home

Solution 2 At last, here I found the solution.

Add jdk path

to gradle.properties file and did a rebuild.

This will also solve your error.

Here is all Solution could not find tools.jar

CSS '>' selector; what is it?

`>` selects all direct descendants/children

A space selector will select all deep descendants whereas a greater than > selector will only select all immediate descendants. See fiddle for example.

_x000D_

div { border: 1px solid black; margin-bottom: 10px; }_x000D_
.a b { color: red; } /* every John is red */_x000D_
.b > b { color: blue; } /* Only John 3 and John 4 are blue */

_x000D_

<div class="a">_x000D_
  <p><b>John 1</b></p>_x000D_
  <p><b>John 2</b></p>_x000D_
  <b>John 3</b>_x000D_
  <b>John 4</b>_x000D_
</div>_x000D_
_x000D_
<div class="b">_x000D_
  <p><b>John 1</b></p>_x000D_
  <p><b>John 2</b></p>_x000D_
  <b>John 3</b>_x000D_
  <b>John 4</b>_x000D_
</div>

_x000D_

How do I create a folder in VB if it doesn't exist?

Try the System.IO.DirectoryInfo class.

The sample from MSDN:

Imports System
Imports System.IO

Public Class Test
    Public Shared Sub Main()
        ' Specify the directories you want to manipulate.
        Dim di As DirectoryInfo = New DirectoryInfo("c:\MyDir")
        Try
            ' Determine whether the directory exists.
            If di.Exists Then
                ' Indicate that it already exists.
                Console.WriteLine("That path exists already.")
                Return
            End If

            ' Try to create the directory.
            di.Create()
            Console.WriteLine("The directory was created successfully.")

            ' Delete the directory.
            di.Delete()
            Console.WriteLine("The directory was deleted successfully.")

        Catch e As Exception
            Console.WriteLine("The process failed: {0}", e.ToString())
        End Try
    End Sub
End Class

Date format Mapping to JSON Jackson

What is the formatting I need to use to carry out conversion with Jackson? Is Date a good field type for this?

Date is a fine field type for this. You can make the JSON parse-able pretty easily by using ObjectMapper.setDateFormat:

DateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm a z");
myObjectMapper.setDateFormat(df);

In general, is there a way to process the variables before they get mapped to Object members by Jackson? Something like, changing the format, calculations, etc.

Yes. You have a few options, including implementing a custom JsonDeserializer, e.g. extending JsonDeserializer<Date>. This is a good start.

What is the difference between loose coupling and tight coupling in the object oriented paradigm?

The way I understand it is, that tightly coupled architecture does not provide a lot of flexibility for change when compared to loosely coupled architecture.

But in case of loosely coupled architectures, message formats or operating platforms or revamping the business logic does not impact the other end. If the system is taken down for a revamp, of course the other end will not be able to access the service for a while but other than that, the unchanged end can resume message exchange as it was before the revamp.

How to display images from a folder using php - PHP

You had a mistake on the statement below. Use . not ,

echo '<img src="', $dir, '/', $file, '" alt="', $file, $

echo '<img src="'. $dir. '/'. $file. '" alt="'. $file. $

and

echo 'Directory \'', $dir, '\' not found!';

echo 'Directory \''. $dir. '\' not found!';

Python: How exactly can you take a string, split it, reverse it and join it back together again?

Do you mean like this?

import string
astr='a(b[c])d'

deleter=string.maketrans('()[]','    ')
print(astr.translate(deleter))
# a b c  d
print(astr.translate(deleter).split())
# ['a', 'b', 'c', 'd']
print(list(reversed(astr.translate(deleter).split())))
# ['d', 'c', 'b', 'a']
print(' '.join(reversed(astr.translate(deleter).split())))
# d c b a

Invoking a static method using reflection

// String.class here is the parameter type, that might not be the case with you
Method method = clazz.getMethod("methodName", String.class);
Object o = method.invoke(null, "whatever");

In case the method is private use getDeclaredMethod() instead of getMethod(). And call setAccessible(true) on the method object.

Is there a better way to compare dictionary values

Uhm, you are describing dict1 == dict2 ( check if boths dicts are equal )

But what your code does is all( dict1[k]==dict2[k] for k in dict1 ) ( check if all entries in dict1 are equal to those in dict2 )

How to do an Integer.parseInt() for a decimal number?

0.01 is not an integer (whole number), so you of course can't parse it as one. Use Double.parseDouble or Float.parseFloat instead.

Get the list of stored procedures created and / or modified on a particular date?

For SQL Server 2012:

SELECT name, modify_date, create_date, type
FROM sys.procedures
WHERE name like '%XXX%' 
ORDER BY modify_date desc

Save Dataframe to csv directly to s3 Python

You can directly use the S3 path. I am using Pandas 0.24.1

In [1]: import pandas as pd

In [2]: df = pd.DataFrame( [ [1, 1, 1], [2, 2, 2] ], columns=['a', 'b', 'c'])

In [3]: df
Out[3]:
   a  b  c
0  1  1  1
1  2  2  2

In [4]: df.to_csv('s3://experimental/playground/temp_csv/dummy.csv', index=False)

In [5]: pd.__version__
Out[5]: '0.24.1'

In [6]: new_df = pd.read_csv('s3://experimental/playground/temp_csv/dummy.csv')

In [7]: new_df
Out[7]:
   a  b  c
0  1  1  1
1  2  2  2

Release Note:

S3 File Handling

pandas now uses s3fs for handling S3 connections. This shouldn’t break any code. However, since s3fs is not a required dependency, you will need to install it separately, like boto in prior versions of pandas. GH11915.

Array functions in jQuery

You can use Underscore.js. It really makes things simple.

For example, removing elements from an array, you need to do:

_.without([1, 2, 3], 2);

And the result will be [1, 3].

It reduces the code that you write using jQuery.grep, etc. in jQuery.

EOL conversion in notepad ++

I open files "directly" from WinSCP which opens the files in Notepad++ I had a php files on my linux server which always opened in Mac format no matter what I did :-(

If I downloaded the file and then opened it from local (windows) it was open as Dos/Windows....hmmm

The solution was to EOL-convert the local file to "UNIX/OSX Format", save it and then upload it.

Now when I open the file directly from the server it's open as "Dos/Windows" :-)

How to add List<> to a List<> in asp.net

Use .AddRange to append any Enumrable collection to the list.

text flowing out of div

You should use overflow:hidden; or scroll

http://jsfiddle.net/UJ6zG/1/

or with php you could short the long words...

how to inherit Constructor from super class to sub class

You inherit class attributes, not class constructors .This is how it goes :

If no constructor is added in the super class, if no then the compiler adds a no argument contructor. This default constructor is invoked implicitly whenever a new instance of the sub class is created . Here the sub class may or may not have constructor, all is ok .

if a constructor is provided in the super class, the compiler will see if it is a no arg constructor or a constructor with parameters.

if no args, then the compiler will invoke it for any sub class instanciation . Here also the sub class may or may not have constructor, all is ok .

if 1 or more contructors in the parent class have parameters and no args constructor is absent, then the subclass has to have at least 1 constructor where an implicit call for the parent class construct is made via super (parent_contractor params) .

this way you are sure that the inherited class attributes are always instanciated .

sqlalchemy filter multiple columns

There are number of ways to do it:

Using filter() (and operator)

query = meta.Session.query(User).filter(
    User.firstname.like(search_var1),
    User.lastname.like(search_var2)
    )

Using filter_by() (and operator)

query = meta.Session.query(User).filter_by(
    firstname.like(search_var1),
    lastname.like(search_var2)
    )

Chaining filter() or filter_by() (and operator)

query = meta.Session.query(User).\
    filter_by(firstname.like(search_var1)).\
    filter_by(lastname.like(search_var2))

Using or_(), and_(), and not()

from sqlalchemy import and_, or_, not_

query = meta.Session.query(User).filter(
    and_(
        User.firstname.like(search_var1),
        User.lastname.like(search_var2)
    )
)

How can I find the version of php that is running on a distinct domain name?

There is a surprisingly effective way that consists of using the easter eggs.

They differ from version to version.

How can I display a list view in an Android Alert Dialog?

In Kotlin:

fun showListDialog(context: Context){
    // setup alert builder
    val builder = AlertDialog.Builder(context)
    builder.setTitle("Choose an Item")

    // add list items
    val listItems = arrayOf("Item 0","Item 1","Item 2")
    builder.setItems(listItems) { dialog, which ->
        when (which) {
            0 ->{
                Toast.makeText(context,"You Clicked Item 0",Toast.LENGTH_LONG).show()
                dialog.dismiss()
            }
            1->{
                Toast.makeText(context,"You Clicked Item 1",Toast.LENGTH_LONG).show()
                dialog.dismiss()
            }
            2->{
                Toast.makeText(context,"You Clicked Item 2",Toast.LENGTH_LONG).show()
                dialog.dismiss()
            }
        }
    }

    // create & show alert dialog
    val dialog = builder.create()
    dialog.show()
}

Cannot resolve method 'getSupportFragmentManager ( )' inside Fragment

Replace getSupportFragmentManager() with getFragmentManager() if you are working in api 21. OR If your app supports versions of Android older than 3.0, be sure you've set up your Android project with the support library as described in Setting Up a Project to Use a Library and use getSupportFragmentManager() this time.

push object into array

You have to create an object. Assign the values to the object. Then push it into the array:

var nietos = [];
var obj = {};
obj["01"] = nieto.label;
obj["02"] = nieto.value;
nietos.push(obj);

Switch to another Git tag

Clone the repository as normal:

git clone git://github.com/rspec/rspec-tmbundle.git RSpec.tmbundle

Then checkout the tag you want like so:

git checkout tags/1.1.4

This will checkout out the tag in a 'detached HEAD' state. In this state, "you can look around, make experimental changes and commit them, and [discard those commits] without impacting any branches by performing another checkout".

To retain any changes made, move them to a new branch:

git checkout -b 1.1.4-jspooner

You can get back to the master branch by using:

git checkout master

Note, as was mentioned in the first revision of this answer, there is another way to checkout a tag:

git checkout 1.1.4

But as was mentioned in a comment, if you have a branch by that same name, this will result in git warning you that the refname is ambiguous and checking out the branch by default:

warning: refname 'test' is ambiguous.
Switched to branch '1.1.4'

The shorthand can be safely used if the repository does not share names between branches and tags.

How to use ArgumentCaptor for stubbing?

The line

when(someObject.doSomething(argumentCaptor.capture())).thenReturn(true);

would do the same as

when(someObject.doSomething(Matchers.any())).thenReturn(true);

So, using argumentCaptor.capture() when stubbing has no added value. Using Matchers.any() shows better what really happens and therefor is better for readability. With argumentCaptor.capture(), you can't read what arguments are really matched. And instead of using any(), you can use more specific matchers when you have more information (class of the expected argument), to improve your test.

And another problem: If using argumentCaptor.capture() when stubbing it becomes unclear how many values you should expect to be captured after verification. We want to capture a value during verification, not during stubbing because at that point there is no value to capture yet. So what does the argument captors capture method capture during stubbing? It capture anything because there is nothing to be captured yet. I consider it to be undefined behavior and I don't want to use undefined behavior.

How can I fix MySQL error #1064?

For my case, I was trying to execute procedure code in MySQL, and due to some issue with server in which Server can't figure out where to end the statement I was getting Error Code 1064. So I wrapped the procedure with custom DELIMITER and it worked fine.

For example, Before it was:

DROP PROCEDURE IF EXISTS getStats;
CREATE PROCEDURE `getStats` (param_id INT, param_offset INT, param_startDate datetime, param_endDate datetime)
BEGIN
    /*Procedure Code Here*/
END;

After putting DELIMITER it was like this:

DROP PROCEDURE IF EXISTS getStats;
DELIMITER $$
CREATE PROCEDURE `getStats` (param_id INT, param_offset INT, param_startDate datetime, param_endDate datetime)
BEGIN
    /*Procedure Code Here*/
END;
$$
DELIMITER ;

What is the reason for java.lang.IllegalArgumentException: No enum const class even though iterating through values() works just fine?

Enum.valueOf() only checks the constant name, so you need to pass it "COLUMN_HEADINGS" instead of "columnHeadings". Your name property has nothing to do with Enum internals.

To address the questions/concerns in the comments:

The enum's "builtin" (implicitly declared) valueOf(String name) method will look up an enum constant with that exact name. If your input is "columnHeadings", you have (at least) three choices:

Forget about the naming conventions for a bit and just name your constants as it makes most sense: enum PropName { contents, columnHeadings, ...}. This is obviously the most convenient.
Convert your camelCase input into UPPER_SNAKE_CASE before calling valueOf, if you're really fond of naming conventions.
Implement your own lookup method instead of the builtin valueOf to find the corresponding constant for an input. This makes most sense if there are multiple possible mappings for the same set of constants.

Hide text within HTML?

you can use css property to hide style="display:none;"

<div style="display:none;">CREDITS_HERE</div>

Where are the recorded macros stored in Notepad++?

If you install Notepad++ on Linux system by wine (In my case desktop Ubuntu 14.04-LTS_X64) the file "shortcuts.xml" is under :

$/home/[USER-NAME]/.wine/drive_c/users/[USER-NAME]/My Documents/.wine/drive_c/Program Files (x86)/Notepad++/shortcuts.xml

Thanks to Harrison and all that have suggestions for that isssue.

Passing parameters on button action:@selector

Add the hidden titleLabel to the parameter is the best solution.

I generated a array arrUrl which store the NSURL of the mov files in my phone album by enumerate assets block.

After that, I grab on Frame, lets say, get the frame at 3:00 second in the movie file, and generated the image file from the frame.

Next, loop over the arrUrl, and use program generate the button with image in the button, append the button to subview of the self.view.

Because I have to pass the movie Url to playMovie function, I have to assign the button.titleLabel.text with one movie url. and the the button events function, retrieve the url from the buttontitleLable.txt.

-(void)listVideos

{
   for(index=0;index<[self.arrUrl count];index++{
      UIButton *imageButton = [UIButton buttonWithType:UIButtonTypeCustom];
      imageButton.frame = CGRectMake(20,50+60*index,50,50);

      NSURL *dUrl = [self.arrUrl objectAtIndex:index];

      [imageButton setImage:[[UIImage allow] initWithCGImage:*[self getFrameFromeVideo:dUrl]] forState:UIControlStateNormal];
      [imageButton addTarget:self action:@selector(playMovie:) forControlEvents:UIControlEventTouchUpInside];
      imageButton.titleLabel.text = [NSString strinfWithFormat:@"%@",dUrl];
      imageButton.titleLabel.hidden = YES;

      [self.view addSubView:imageButton];
   }
}

-(void)playMovie:(id) sender{
   UIButton *btn = (UIButton *)sender;
   NSURL *movUrl = [NSURL URLWithString:btn.titleLabel.text];
   moviePlayer = [[MPMoviePlayerViewController alloc] initWithContentURL:movUrl];
   [self presentMoviePlayerViewControllerAnimated:moviePlayer];
}

-(CGIImageRef *)getFrameFromVideo:(NSURL *)mUrl{
   AVURLAsset *asset = [[AVURLAsset alloc] initWithURL:mUrl option:nil];
   AVAssetImageGenerator *generator = [[AVAssetImageGenerator alloc] initWithAsset:asset];
   generator.appliesPreferredTrackTransform = YES;
   NSError *error =nil;
   CMTime = CMTimeMake(3,1);
   CGImageRef imageRef = [generator copyCGImageAtTime:time actualTime:nil error:&error];
   if(error !=nil) {
      NSLog(@"%@",sekf,error);
   }

   return @imageRef;
}

What do I use for a max-heap implementation in Python?

You can use

import heapq
listForTree = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15]    
heapq.heapify(listForTree)             # for a min heap
heapq._heapify_max(listForTree)        # for a maxheap!!

If you then want to pop elements, use:

heapq.heappop(minheap)      # pop from minheap
heapq._heappop_max(maxheap) # pop from maxheap

Get last 3 characters of string

The easiest way would be using Substring

string str = "AM0122200204";
string substr = str.Substring(str.Length - 3);

Using the overload with one int as I put would get the substring of a string, starting from the index int. In your case being str.Length - 3, since you want to get the last three chars.

Passing multiple values for a single parameter in Reporting Services

Just a comment - I ran into a world of hurt trying to get an IN clause to work in a connection to Oracle 10g. I don't think the rewritten query can be correctly passed to a 10g db. I had to drop the multi-value completely. The query would return data only when a single value (from the multi-value parameter selector) was chosen. I tried the MS and Oracle drivers with the same results. I'd love to hear if anyone has had success with this.

Best way to include CSS? Why use @import?

This might help a PHP developer out. The below functions will strip white space, remove comments, and concatenate of all your CSS files. Then insert it into a <style> tag in the head before page load.

The function below will strip comments and minify the passed in css. It is paired in conjunction with the next function.

<?php
function minifyCSS($string)
{
    // Minify CSS and strip comments

    # Strips Comments
    $string = preg_replace('!/\*.*?\*/!s','', $string);
    $string = preg_replace('/\n\s*\n/',"\n", $string);

    # Minifies
    $string = preg_replace('/[\n\r \t]/',' ', $string);
    $string = preg_replace('/ +/',' ', $string);
    $string = preg_replace('/ ?([,:;{}]) ?/','$1',$string);

    # Remove semicolon
    $string = preg_replace('/;}/','}',$string);

    # Return Minified CSS
    return $string;
}
?>

You will call this function in the head of your document.

<?php
function concatenateCSS($cssFiles)
{
    // Load all relevant css files

    # concatenate all relevant css files
    $css = '';
    foreach ($cssFiles as $cssFile)
    {
        $css = $css . file_get_contents("$cssFile.css");
    }

    # minify all css
    $css = minifyCSS($css);
    echo "<style>$css</style>";
}
?>

Include the function concatenateCSS() in your document head. Pass in an array with the names of your stylesheets with its path IE: css/styles.css. You are not required to add the extension .css as it is added automatically in the function above.

<head>
    <title></title>
    <?php
    $stylesheets = array(
        "bootstrap/css/bootstrap.min", 
        "css/owl-carousel.min", 
        "css/style"
        );
    concatenateCSS( $stylesheets );
    ?>
</head>

sql query distinct with Row_Number

Question is too old and my answer might not add much but here are my two cents for making query a little useful:

;WITH DistinctRecords AS (
    SELECT  DISTINCT [col1,col2,col3,..] 
    FROM    tableName 
    where   [my condition]
), 
serialize AS (
   SELECT
    ROW_NUMBER() OVER (PARTITION BY [colNameAsNeeded] ORDER BY  [colNameNeeded]) AS Sr,*
    FROM    DistinctRecords 
)
SELECT * FROM serialize

Usefulness of using two cte's lies in the fact that now you can use serialized record much easily in your query and do count(*) etc very easily.

DistinctRecords will select all distinct records and serialize apply serial numbers to distinct records. after wards you can use final serialized result for your purposes without clutter.

Partition By might not be needed in most cases

Most recent previous business day in Python

Why don't you try something like:

lastBusDay = datetime.datetime.today()
if datetime.date.weekday(lastBusDay) not in range(0,5):
    lastBusDay = 5

link with target="_blank" does not open in new tab in Chrome

Because JavaScript is handling the click event. When you click, the following code is called:

el.addEvent('click', function(e){
    if(obj.options.onOpen){
        new Event(e).stop();
        if(obj.options.open == i){
            obj.options.open = null;
            obj.options.onClose(this.href, i);
        }else{
            obj.options.open = i;
            obj.options.onOpen(this.href, i);
        }   
    }       
})

The onOpen manually changes the location.

Edit: Regarding your comment... If you can modify ImageMenu.js, you could update the script which calls onClose to pass the a element object (this, rather than this.href)

obj.options.onClose(this, i);

Then update your ImageMenu instance, with the following onOpen change:

window.addEvent('domready', function(){
    var myMenu = new ImageMenu($$('#imageMenu a'), {
        openWidth: 310,
        border: 2,
        onOpen: function(e, i) {
            if (e.target === '_blank') {
                window.open(e.href);    
            } else {
                location = e.href;
            }
        }
    });
});

This would check for the target property of the element to see if it's _blank, and then call window.open, if found.

If you'd prefer not to modify ImageMenu.js, another option would be to modify your links to identify them in your onOpen handler. Say something like:

<a href="http://www.foracure.org.au/#_b=1" target="_blank" style="width: 105px;"></a>

Then, update your onOpen call to:

onOpen: function(e, i) {
    if (e.indexOf('_b=1') > -1) {
        window.open(e);   
    } else {
        location = e;
    }
}

The only downside to this is the user sees the hash on hover.

Finally, if the number of links that you plan to open in a new window are low, you could create a map and check against that. Something like:

var linksThatOpenInANewWindow = {
    'http://www.foracure.org.au': 1
};

onOpen: function(e, i) {
    if (linksThatOpenInANewWindow[e] === 1) {
        window.open(e);   
    } else {
        location = e
    }
}

The only downside is maintenance, depending on the number of links.

Others have suggested modifying the link (using # or javascript:) and adding an inline event handler (onclick) - I don't recommend that at all as it breaks links when JS is disabled/not supported.

How to install PostgreSQL's pg gem on Ubuntu?

Installing libpq-dev did not work for me. I also needed to install build-essential

sudo apt-get install libpq-dev build-essential

Calculating how many minutes there are between two times

You just need to query the TotalMinutes property like this varTime.TotalMinutes

How to serve static files in Flask

By default, flask use a "templates" folder to contain all your template files(any plain-text file, but usually .html or some kind of template language such as jinja2 ) & a "static" folder to contain all your static files(i.e. .js .css and your images).
In your routes, u can use render_template() to render a template file (as I say above, by default it is placed in the templates folder) as the response for your request. And in the template file (it's usually a .html-like file), u may use some .js and/or `.css' files, so I guess your question is how u link these static files to the current template file.

Python Script execute commands in Terminal

I prefer usage of subprocess module:

from subprocess import call
call(["ls", "-l"])

Reason is that if you want to pass some variable in the script this gives very easy way for example take the following part of the code

abc = a.c
call(["vim", abc])

How can I bind a background color in WPF/XAML?

The xaml code:

<Grid x:Name="Message2">
   <TextBlock Text="This one is manually orange."/>
</Grid>

The c# code:

protected override void OnNavigatedTo(NavigationEventArgs e)
    {
        CreateNewColorBrush();
    }

    private void CreateNewColorBrush()
    {

        SolidColorBrush my_brush = new SolidColorBrush(Color.FromArgb(255, 255, 215, 0));
        Message2.Background = my_brush;

    }

This one works in windows 8 store app. Try and see. Good luck !

How to create JSON object using jQuery

var model = {"Id": "xx", "Name":"Ravi"};
$.ajax({    url: 'test/set',
                        type: "POST",
                        data: model,
                        success: function (res) {
                            if (res != null) {
                                alert("done.");
                            }
                        },
                        error: function (res) {

                        }
                    });

How can you represent inheritance in a database?

Check out the answer I gave here

Fluent NHibernate one-to-one mapping with synthetic keys

How to parse XML using shellscript?

Do you have xml_grep installed? It's a perl based utility standard on some distributions (it came pre-installed on my CentOS system). Rather than giving it a regular expression, you give it an xpath expression.

Message 'src refspec master does not match any' when pushing commits in Git

git push -u origin master

error: src refspec master does not match any.
error: failed to push some refs to 'http://REPO.git'

This is caused by the repository still being empty. There are no commits in the repository and thus no master branch to push to the server.

It worked for me

Resolution

1) git init
2)git commit -m "first commit"
3)git add app
4)git commit -m "first commit"
5)git push -u origin master

matplotlib has no attribute 'pyplot'

Did you import it? Importing matplotlib is not enough.

>>> import matplotlib
>>> matplotlib.pyplot
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'module' object has no attribute 'pyplot'

but

>>> import matplotlib.pyplot
>>> matplotlib.pyplot

works.

pyplot is a submodule of matplotlib and not immediately imported when you import matplotlib.

The most common form of importing pyplot is

import matplotlib.pyplot as plt

Thus, your statements won't be too long, e.g.

plt.plot([1,2,3,4,5])

instead of

matplotlib.pyplot.plot([1,2,3,4,5])

And: pyplot is not a function, it's a module! So don't call it, use the functions defined inside this module instead. See my example above

Twitter Bootstrap - add top space between rows

Bootstrap 3

If you need to separate rows in bootstrap, you can simply use .form-group. This adds 15px margin to the bottom of row.

In your case, to get margin top, you can add this class to previous .row element

<div class="row form-group">

/* From bootstrap.css */
.form-group {
        margin-bottom: 15px;
}

Bootstrap 4

You can use built-in spacing classes

<div class="row mt-3"></div>

The "t" in class name makes it apply only to "top" side, there are similar classes for bottom, left, right. The number defines space size.

Android Facebook style slide

Here is the design and development guide found in official android documentation no need to add unofficial external library. Only android support library will do. Find the links here.

design and develop.

How to prevent a background process from being stopped after closing SSH client in Linux

Nohup allows a client process to not be killed if a the parent process is killed, for argument when you logout. Even better still use:

nohup /bin/sh -c "echo \$\$ > $pidfile; exec $FOO_BIN $FOO_CONFIG  " > /dev/null

Nohup makes the process you start immune to termination which your SSH session and its child processes are kill upon you logging out. The command i gave provides you with a way you can store the pid of the application in a pid file so that you can correcly kill it later and allows the process to run after you have logged out.

Not Equal to This OR That in Lua

Your problem stems from a misunderstanding of the or operator that is common to people learning programming languages like this. Yes, your immediate problem can be solved by writing x ~= 0 and x ~= 1, but I'll go into a little more detail about why your attempted solution doesn't work.

When you read x ~=(0 or 1) or x ~= 0 or 1 it's natural to parse this as you would the sentence "x is not equal to zero or one". In the ordinary understanding of that statement, "x" is the subject, "is not equal to" is the predicate or verb phrase, and "zero or one" is the object, a set of possibilities joined by a conjunction. You apply the subject with the verb to each item in the set.

However, Lua does not parse this based on the rules of English grammar, it parses it in binary comparisons of two elements based on its order of operations. Each operator has a precedence which determines the order in which it will be evaluated. or has a lower precedence than ~=, just as addition in mathematics has a lower precedence than multiplication. Everything has a lower precedence than parentheses.

As a result, when evaluating x ~=(0 or 1), the interpreter will first compute 0 or 1 (because of the parentheses) and then x ~= the result of the first computation, and in the second example, it will compute x ~= 0 and then apply the result of that computation to or 1.

The logical operator or "returns its first argument if this value is different from nil and false; otherwise, or returns its second argument". The relational operator ~= is the inverse of the equality operator ==; it returns true if its arguments are different types (x is a number, right?), and otherwise compares its arguments normally.

Using these rules, x ~=(0 or 1) will decompose to x ~= 0 (after applying the or operator) and this will return 'true' if x is anything other than 0, including 1, which is undesirable. The other form, x ~= 0 or 1 will first evaluate x ~= 0 (which may return true or false, depending on the value of x). Then, it will decompose to one of false or 1 or true or 1. In the first case, the statement will return 1, and in the second case, the statement will return true. Because control structures in Lua only consider nil and false to be false, and anything else to be true, this will always enter the if statement, which is not what you want either.

There is no way that you can use binary operators like those provided in programming languages to compare a single variable to a list of values. Instead, you need to compare the variable to each value one by one. There are a few ways to do this. The simplest way is to use De Morgan's laws to express the statement 'not one or zero' (which can't be evaluated with binary operators) as 'not one and not zero', which can trivially be written with binary operators:

if x ~= 1 and x ~= 0 then
    print( "X must be equal to 1 or 0" )
    return
end

Alternatively, you can use a loop to check these values:

local x_is_ok = false
for i = 0,1 do 
    if x == i then
        x_is_ok = true
    end
end
if not x_is_ok then
    print( "X must be equal to 1 or 0" )
    return
end

Finally, you could use relational operators to check a range and then test that x was an integer in the range (you don't want 0.5, right?)

if not (x >= 0 and x <= 1 and math.floor(x) == x) then
    print( "X must be equal to 1 or 0" )
    return
end

Note that I wrote x >= 0 and x <= 1. If you understood the above explanation, you should now be able to explain why I didn't write 0 <= x <= 1, and what this erroneous expression would return!

How to make a circle around content using CSS?

Matplotlib different size subplots

You can use gridspec and figure:

import numpy as np
import matplotlib.pyplot as plt 
from matplotlib import gridspec

# generate some data
x = np.arange(0, 10, 0.2)
y = np.sin(x)

# plot it
fig = plt.figure(figsize=(8, 6)) 
gs = gridspec.GridSpec(1, 2, width_ratios=[3, 1]) 
ax0 = plt.subplot(gs[0])
ax0.plot(x, y)
ax1 = plt.subplot(gs[1])
ax1.plot(y, x)

plt.tight_layout()
plt.savefig('grid_figure.pdf')

resulting plot

How can I get the status code from an http error in Axios?

Axios. get('foo.com')
.then((response) => {})
.catch((error) => {
    if(error. response){
       console.log(error. response. data)
       console.log(error. response. status);

      }
})

How to make a deep copy of Java ArrayList

Cloning the objects before adding them. For example, instead of newList.addAll(oldList);

for(Person p : oldList) {
    newList.add(p.clone());
}

Assuming clone is correctly overriden inPerson.

SignalR - Sending a message to a specific user using (IUserIdProvider) NEW 2.0.0

Old thread, but just came across this in a sample:

services.AddSignalR()
            .AddAzureSignalR(options =>
        {
            options.ClaimsProvider = context => new[]
            {
                new Claim(ClaimTypes.NameIdentifier, context.Request.Query["username"])
            };
        });

AttributeError: 'module' object has no attribute 'model'

As the error message says in the last line: the module models in the file c:\projects\mysite..\mysite\polls\models.py contains no class model. This error occurs in the definition of the Poll class:

class Poll(models.model):

Either the class model is misspelled in the definition of the class Poll or it is misspelled in the module models. Another possibility is that it is completely missing from the module models. Maybe it is in another module or it is not yet implemented in models.

Using MySQL with Entity Framework

Check out my post on this subject.

http://pattersonc.com/blog/index.php/2009/04/01/using-mysql-with-entity-framework-and-aspnet-mvc-–-part-i/

Set UITableView content inset permanently

After one hour of tests the only way that works 100% is this one:

-(void)hideSearchBar
{
    if([self.tableSearchBar.text length]<=0 && !self.tableSearchBar.isFirstResponder)
    {
        self.tableView.contentOffset = CGPointMake(0, self.tableSearchBar.bounds.size.height);
        self.edgesForExtendedLayout = UIRectEdgeBottom;
    }
}

-(void)viewDidLayoutSubviews
{
    [self hideSearchBar];
}

with this approach you can always hide the search bar if is empty

Override hosts variable of Ansible playbook from the command line

Here's a cool solution I came up to safely specify hosts via the --limit option. In this example, the play will end if the playbook was executed without any hosts specified via the --limit option.

This was tested on Ansible version 2.7.10

---
- name: Playbook will fail if hosts not specified via --limit option.
  # Hosts must be set via limit. 
  hosts: "{{ play_hosts }}"
  connection: local
  gather_facts: false
  tasks:
  - set_fact:
      inventory_hosts: []
  - set_fact:
      inventory_hosts: "{{inventory_hosts + [item]}}"
    with_items: "{{hostvars.keys()|list}}"

  - meta: end_play
    when: "(play_hosts|length) == (inventory_hosts|length)"

  - debug:
      msg: "About to execute tasks/roles for {{inventory_hostname}}"

insert datetime value in sql database with c#

This is an older question with a proper answer (please use parameterized queries) which I'd like to extend with some timezone discussion. For my current project I was interested in how do the datetime columns handle timezones and this question is the one I found.

Turns out, they do not, at all.

datetime column stores the given DateTime as is, without any conversion. It does not matter if the given datetime is UTC or local.

You can see for yourself:

using (var connection = new SqlConnection(connectionString))
{
    connection.Open();
    using (var command = connection.CreateCommand())
    {
        command.CommandText = "SELECT * FROM (VALUES (@a, @b, @c)) example(a, b, c);";

        var local = DateTime.Now;
        var utc = local.ToUniversalTime();

        command.Parameters.AddWithValue("@a", utc);
        command.Parameters.AddWithValue("@b", local);
        command.Parameters.AddWithValue("@c", utc.ToLocalTime());

        using (var reader = command.ExecuteReader())
        {
            reader.Read();

            var localRendered = local.ToString("o");

            Console.WriteLine($"a = {utc.ToString("o").PadRight(localRendered.Length, ' ')} read = {reader.GetDateTime(0):o}, {reader.GetDateTime(0).Kind}");
            Console.WriteLine($"b = {local:o} read = {reader.GetDateTime(1):o}, {reader.GetDateTime(1).Kind}");
            Console.WriteLine($"{"".PadRight(localRendered.Length + 4, ' ')} read = {reader.GetDateTime(2):o}, {reader.GetDateTime(2).Kind}");
        }
    }
}

What this will print will of course depend on your time zone but most importantly the read values will all have Kind = Unspecified. The first and second output line will be different by your timezone offset. Second and third will be the same. Using the "o" format string (roundtrip) will not show any timezone specifiers for the read values.

Example output from GMT+02:00:

a = 2018-11-20T10:17:56.8710881Z      read = 2018-11-20T10:17:56.8700000, Unspecified
b = 2018-11-20T12:17:56.8710881+02:00 read = 2018-11-20T12:17:56.8700000, Unspecified
                                      read = 2018-11-20T12:17:56.8700000, Unspecified

Also note of how the data gets truncated (or rounded) to what seems like 10ms.

How to set full calendar to a specific start date when it's initialized for the 1st time?

I've had better luck with calling the gotoDate in the viewRender callback:

$('#calendar').fullCalendar({
  firstDay: 0,
  defaultView: 'basicWeek',
  header: {
    left: '',
    center: 'basicDay,basicWeek,month',
    right:  'today prev,next'
  },
  viewRender: function(view, element) {
    $('#calendar').fullCalendar( 'gotoDate', 2014, 4, 24 );
  }
});

Calling gotoDate outside of the callback didn't have the expected results due to a race condition.

Inline <style> tags vs. inline css properties

To answer your direct question: neither of these is the preferred method. Use a separate file.

Inline styles should only be used as a last resort, or set by Javascript code. Inline styles have the highest level of specificity, so override your actual stylesheets. This can make them hard to control (you should avoid !important as well for the same reason).

An embedded <style> block is not recommended, because you lose the browser's ability to cache the stylesheet across multiple pages on your site.

So in short, wherever possible, you should put your styles into a separate CSS file.

Show tables, describe tables equivalent in redshift

In the following post, I documented queries to retrieve TABLE and COLUMN comments from Redshift. https://sqlsylvia.wordpress.com/2017/04/29/redshift-comment-views-documenting-data/

Enjoy!

Table Comments

    SELECT n.nspname AS schema_name
     , pg_get_userbyid(c.relowner) AS table_owner
     , c.relname AS table_name
     , CASE WHEN c.relkind = 'v' THEN 'view' ELSE 'table' END 
       AS table_type
     , d.description AS table_description
     FROM pg_class As c
     LEFT JOIN pg_namespace n ON n.oid = c.relnamespace
     LEFT JOIN pg_tablespace t ON t.oid = c.reltablespace
     LEFT JOIN pg_description As d 
          ON (d.objoid = c.oid AND d.objsubid = 0)
     WHERE c.relkind IN('r', 'v') AND d.description > ''
     ORDER BY n.nspname, c.relname ;

Column Comments

    SELECT n.nspname AS schema_name
     , pg_get_userbyid(c.relowner) AS table_owner
     , c.relname AS table_name
     , a.attname AS column_name
     , d.description AS column_description
    FROM pg_class AS c
    INNER JOIN pg_attribute As a ON c.oid = a.attrelid
    INNER JOIN pg_namespace n ON n.oid = c.relnamespace
    LEFT JOIN pg_tablespace t ON t.oid = c.reltablespace
    LEFT JOIN pg_description As d 
     ON (d.objoid = c.oid AND d.objsubid = a.attnum)
    WHERE c.relkind IN('r', 'v')
     AND a.attname NOT         
     IN ('cmax', 'oid', 'cmin', 'deletexid', 'ctid', 'tableoid','xmax', 'xmin', 'insertxid')
    ORDER BY n.nspname, c.relname, a.attname;

Class Not Found: Empty Test Suite in IntelliJ

Was getting same error. My device was not connected to android studio. When I connected to studio. It works. This solves my problem.

What is the difference between docker-compose ports vs expose

Ports This section is used to define the mapping between the host server and Docker container.

ports:
   - 10005:80

It means the application running inside the container is exposed at port 80. But external system/entity cannot access it, so it need to be mapped to host server port.

Note: you have to open the host port 10005 and modify firewall rules to allow external entities to access the application.

They can use

http://{host IP}:10005

something like this

EXPOSE This is exclusively used to define the port on which application is running inside the docker container.

You can define it in dockerfile as well. Generally, it is good and widely used practice to define EXPOSE inside dockerfile because very rarely anyone run them on other port than default 80 port

How to emulate GPS location in the Android Emulator?

If the above solutions don't work. Try this:

Inside your android Manifest.xml, add the following two links OUTSIDE of the application tag, but inside your manifest tag of course

<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" ></uses-permission>
<uses-permission android:name="android.permission.INTERNET" ></uses-permission>

How to delete a record by id in Flask-SQLAlchemy

Another possible solution specially if you want batch delete

deleted_objects = User.__table__.delete().where(User.id.in_([1, 2, 3]))
session.execute(deleted_objects)
session.commit()

How can I rename column in laravel using migration?

I know this is an old question, but I faced the same problem recently in Laravel 7 application. To make renaming columns work I used a tip from this answer where instead of composer require doctrine/dbal I have issued composer require doctrine/dbal:^2.12.1 because the latest version of doctrine/dbal still throws an error.

Just keep in mind that if you already use a higher version, this answer might not be appropriate for you.

Using wget to recursively fetch a directory with arbitrary files in it

Wget 1.18 may work better, e.g., I got bitten by a version 1.12 bug where...

wget --recursive (...)

...only retrieves index.html instead of all files.

Workaround was to notice some 301 redirects and try the new location — given the new URL, wget got all the files in the directory.

Java int to String - Integer.toString(i) vs new Integer(i).toString()

new Integer(i).toString() first creates a (redundant) wrapper object around i (which itself may be a wrapper object Integer).

Integer.toString(i) is preferred because it doesn't create any unnecessary objects.

How to check if a string is a valid JSON string in JavaScript without using Try/Catch

function get_json(txt)
{  var data

   try     {  data = eval('('+txt+')'); }
   catch(e){  data = false;             }

   return data;
}

If there are errors, return false.

If there are no errors, return json data

MySQL update CASE WHEN/THEN/ELSE

That's because you missed ELSE.

"Returns the result for the first condition that is true. If there was no matching result value, the result after ELSE is returned, or NULL if there is no ELSE part." (http://dev.mysql.com/doc/refman/5.0/en/control-flow-functions.html#operator_case)

Convert double/float to string

sprintf can do this:

#include <stdio.h>
int main() {
  float w = 234.567;
  char x[__SIZEOF_FLOAT__];
  sprintf(x, "%g", w);
  puts(x);
}

How do I filter ForeignKey choices in a Django ModelForm?

To do this with a generic view, like CreateView...

class AddPhotoToProject(CreateView):
    """
    a view where a user can associate a photo with a project
    """
    model = Connection
    form_class = CreateConnectionForm


    def get_context_data(self, **kwargs):
        context = super(AddPhotoToProject, self).get_context_data(**kwargs)
        context['photo'] = self.kwargs['pk']
        context['form'].fields['project'].queryset = Project.objects.for_user(self.request.user)
        return context
    def form_valid(self, form):
        pobj = Photo.objects.get(pk=self.kwargs['pk'])
        obj = form.save(commit=False)
        obj.photo = pobj
        obj.save()

        return_json = {'success': True}

        if self.request.is_ajax():

            final_response = json.dumps(return_json)
            return HttpResponse(final_response)

        else:

            messages.success(self.request, 'photo was added to project!')
            return HttpResponseRedirect(reverse('MyPhotos'))

the most important part of that...

    context['form'].fields['project'].queryset = Project.objects.for_user(self.request.user)

, read my post here

How can I parse a time string containing milliseconds in it with python?

My first thought was to try passing it '30/03/09 16:31:32.123' (with a period instead of a colon between the seconds and the milliseconds.) But that didn't work. A quick glance at the docs indicates that fractional seconds are ignored in any case...

Ah, version differences. This was reported as a bug and now in 2.6+ you can use "%S.%f" to parse it.

How to add 30 minutes to a JavaScript Date object?

For the lazy like myself:

Kip's answer (from above) in coffeescript, using an "enum", and operating on the same object:

Date.UNIT =
  YEAR: 0
  QUARTER: 1
  MONTH: 2
  WEEK: 3
  DAY: 4
  HOUR: 5
  MINUTE: 6
  SECOND: 7
Date::add = (unit, quantity) ->
  switch unit
    when Date.UNIT.YEAR then @setFullYear(@getFullYear() + quantity)
    when Date.UNIT.QUARTER then @setMonth(@getMonth() + (3 * quantity))
    when Date.UNIT.MONTH then @setMonth(@getMonth() + quantity)
    when Date.UNIT.WEEK then @setDate(@getDate() + (7 * quantity))
    when Date.UNIT.DAY then @setDate(@getDate() + quantity)
    when Date.UNIT.HOUR then @setTime(@getTime() + (3600000 * quantity))
    when Date.UNIT.MINUTE then @setTime(@getTime() + (60000 * quantity))
    when Date.UNIT.SECOND then @setTime(@getTime() + (1000 * quantity))
    else throw new Error "Unrecognized unit provided"
  @ # for chaining

Ubuntu apt-get unable to fetch packages

I have been fighting the same thing for a while.

after all the research, this is the best solution.....

add the following to your resolve.conf file /etc/resolv.conf
nameserver 8.8.8.8
nameserver 8.8.4.4

https://serverfault.com/questions/717226/ubuntu14-04-unable-to-apt-get-update/771826#771826

How to check if JSON return is empty with jquery

You can use $.isEmptyObject(json)

https://api.jquery.com/jQuery.isEmptyObject

Connect to network drive with user name and password

I really don't know the hidden process, but I use a webrequest, this way I'm able to pass the credentials, and it worked perfectly for me.

var ftpDownloadFile = WebRequest.Create("filePath");
ftpDownloadFile.Method = WebRequestMethods.Ftp.DownloadFile;
ftpDownloadFile.Credentials = new NetworkCredential("user", "pass");
using (var reader = (FtpWebResponse)ftpDownloadFile.GetResponse())
using (var responseStream = reader.GetResponseStream())
{
    var writeStream = new FileStream(Path.Combine(LocalStorage), FileMode.Create);
    const int length = 2048;
    var buffer = new Byte[length];
    if (responseStream != null)
    {
        var bytesRead = responseStream.Read(buffer, 0, length);
        while (bytesRead > 0)
        {
            writeStream.Write(buffer, 0, bytesRead);
            bytesRead = responseStream.Read(buffer, 0, length);
        }
    }
    reader.Close();
    writeStream.Close();
}

upstream sent too big header while reading response header from upstream

This is still the highest SO-question on Google when searching for this error, so let's bump it.

When getting this error and not wanting to deep-dive into the NGINX settings immediately, you might want to check your outputs to the debug console. In my case I was outputting loads of text to the FirePHP / Chromelogger console, and since this is all sent as a header, it was causing the overflow.

It might not be needed to change the webserver settings if this error is caused by just sending insane amounts of log messages.

Code snippet or shortcut to create a constructor in Visual Studio

If you use ReSharper, you can quickly generate constructors by typing:

'ctor' + Tab + Tab (without parameters),
'ctorf' + Tab + Tab (with parameters that initialize all fields) or
'ctorp' + Tab + Tab (with parameters that initialize all properties).

Resolve absolute path from relative path and/or file name

Most of these answers seem crazy over complicated and super buggy, here's mine -- it works on any environment variable, no %CD% or PUSHD/POPD, or for /f nonsense -- just plain old batch functions. -- The directory & file don't even have to exist.

CALL :NORMALIZEPATH "..\..\..\foo\bar.txt"
SET BLAH=%RETVAL%

ECHO "%BLAH%"

:: ========== FUNCTIONS ==========
EXIT /B

:NORMALIZEPATH
  SET RETVAL=%~f1
  EXIT /B

Failed to auto-configure a DataSource: 'spring.datasource.url' is not specified

Add the line below in application.properties file under resource folder and restart your application.

spring.autoconfigure.exclude=org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration

Angular CLI SASS options

For Angular 9.0 and above, update the "schematics":{} object in angular.json file like this:

"schematics": {
  "@schematics/angular:component": {
    "style": "scss"
  }
}

Declare a const array

I believe you can only make it readonly.

Arithmetic operation resulted in an overflow. (Adding integers)

Maximum value fo int is 2147483647, so 2055786000+93552000 > 2147483647 and it caused overflow

How can I detect Internet Explorer (IE) and Microsoft Edge using JavaScript?

This function worked perfectly for me. It detects Edge as well.

Originally from this Codepen:

https://codepen.io/gapcode/pen/vEJNZN

/**
 * detect IE
 * returns version of IE or false, if browser is not Internet Explorer
 */
function detectIE() {
  var ua = window.navigator.userAgent;

  // Test values; Uncomment to check result …

  // IE 10
  // ua = 'Mozilla/5.0 (compatible; MSIE 10.0; Windows NT 6.2; Trident/6.0)';

  // IE 11
  // ua = 'Mozilla/5.0 (Windows NT 6.3; Trident/7.0; rv:11.0) like Gecko';

  // Edge 12 (Spartan)
  // ua = 'Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/39.0.2171.71 Safari/537.36 Edge/12.0';

  // Edge 13
  // ua = 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/46.0.2486.0 Safari/537.36 Edge/13.10586';

  var msie = ua.indexOf('MSIE ');
  if (msie > 0) {
    // IE 10 or older => return version number
    return parseInt(ua.substring(msie + 5, ua.indexOf('.', msie)), 10);
  }

  var trident = ua.indexOf('Trident/');
  if (trident > 0) {
    // IE 11 => return version number
    var rv = ua.indexOf('rv:');
    return parseInt(ua.substring(rv + 3, ua.indexOf('.', rv)), 10);
  }

  var edge = ua.indexOf('Edge/');
  if (edge > 0) {
    // Edge (IE 12+) => return version number
    return parseInt(ua.substring(edge + 5, ua.indexOf('.', edge)), 10);
  }

  // other browser
  return false;
}

Then you can use if (detectIE()) { /* do IE stuff */ } in your code.

How do I implement getattribute without an infinite recursion error?

You get a recursion error because your attempt to access the self.__dict__ attribute inside __getattribute__ invokes your __getattribute__ again. If you use object's __getattribute__ instead, it works:

class D(object):
    def __init__(self):
        self.test=20
        self.test2=21
    def __getattribute__(self,name):
        if name=='test':
            return 0.
        else:
            return object.__getattribute__(self, name)

This works because object (in this example) is the base class. By calling the base version of __getattribute__ you avoid the recursive hell you were in before.

Ipython output with code in foo.py:

In [1]: from foo import *

In [2]: d = D()

In [3]: d.test
Out[3]: 0.0

In [4]: d.test2
Out[4]: 21

Update:

There's something in the section titled More attribute access for new-style classes in the current documentation, where they recommend doing exactly this to avoid the infinite recursion.

What is the right way to debug in iPython notebook?

A native debugger is being made available as an extension to JupyterLab. Released a few weeks ago, this can be installed by getting the relevant extension, as well as xeus-python kernel (which notably comes without the magics well-known to ipykernel users):

jupyter labextension install @jupyterlab/debugger
conda install xeus-python -c conda-forge

This enables a visual debugging experience well-known from other IDEs.

Source: A visual debugger for Jupyter

MVC 4 - Return error message from Controller - Show in View

Thanks for all the replies.

I was able to solve this by doing the following:

CONTROLLER:

[HttpPost]       
public ActionResult form_edit(FormModels model)
{
  model.error_msg = model.update_content(model);
  return RedirectToAction("Form_edit", "Form", model);
}

public ActionResult form_edit(FormModels model, string searchString,string id)
{
  string test = model.selectedvalue;
  var bal = new FormModels();
  bal.Countries = bal.get_contentdetails(searchString);
  bal.selectedvalue = id;
  bal.dd_text = "content_name";
  bal.dd_value = "content_id";

  test = model.error_msg;
  ViewBag.head = "Heading";

  if (model.error_msg != null)
  {
    ModelState.AddModelError("error_msg", test);
  }

  model.error_msg = "";
  return View(bal);
}

VIEW:

@using (Html.BeginForm("form_edit", "Form", FormMethod.Post))
{
  <table>
    <tr>
      <td>
        @ViewBag.error
        @Html.ValidationMessage("error_msg")
      </td>
    </tr>
    <tr>
      <th>
        @Html.DisplayNameFor(model => model.content_name)
        @Html.DropDownListFor(x => x.selectedvalue, new SelectList(Model.Countries, Model.dd_value, Model.dd_text), "-- Select Product--")
      </th>
    </tr>
  </table>
}

Cropping an UIImage

Here's an updated Swift 3 version based on Noodles answer

func cropping(to rect: CGRect) -> UIImage? {

    if let cgCrop = cgImage?.cropping(to: rect) {
        return UIImage(cgImage: cgCrop)
    }
    else if let ciCrop = ciImage?.cropping(to: rect) {
        return UIImage(ciImage: ciCrop)
    }

    return nil
}

In PHP, how do you change the key of an array element?

You can write simple function that applies the callback to the keys of the given array. Similar to array_map

<?php
function array_map_keys(callable $callback, array $array) {
    return array_merge([], ...array_map(
        function ($key, $value) use ($callback) { return [$callback($key) => $value]; },
        array_keys($array),
        $array
    ));
}

$array = ['a' => 1, 'b' => 'test', 'c' => ['x' => 1, 'y' => 2]];
$newArray = array_map_keys(function($key) { return 'new' . ucfirst($key); }, $array);

echo json_encode($array); // {"a":1,"b":"test","c":{"x":1,"y":2}}
echo json_encode($newArray); // {"newA":1,"newB":"test","newC":{"x":1,"y":2}}

Here is a gist https://gist.github.com/vardius/650367e15abfb58bcd72ca47eff096ca#file-array_map_keys-php.

Programs & Examples On #Mapserver

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TCP vs UDP on video stream

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Batch Files - Error Handling

What function is to replace a substring from a string in C?

Cannot find java. Please use the --jdkhome switch

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endforeach in loops?

Failed to instantiate module error in Angular js

select unique rows based on single distinct column

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Read input numbers separated by spaces

How do I completely remove root password

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How to add text at the end of each line in Vim?

How to use curl in a shell script?

Break out of a While...Wend loop

@Html.DropDownListFor how to set default value

I just assigned a variable, but echo $variable shows something else

Docker: Container keeps on restarting again on again

Detect network connection type on Android

Where does Visual Studio look for C++ header files?

nodejs - How to read and output jpg image?

Read a plain text file with php

Attaching a Sass/SCSS to HTML docs

Git Diff with Beyond Compare

How to set image to fit width of the page using jsPDF?

Using command line arguments in VBscript

The first day of the current month in php using date_modify as DateTime object

Laravel: Validation unique on update

Increase max_execution_time in PHP?

How to set min-height for bootstrap container

Display number always with 2 decimal places in <input>

nginx: [emerg] "server" directive is not allowed here

How do I encode URI parameter values?

jquery data selector

Creating an array of objects in Java

Android studio 3.0: Unable to resolve dependency for :app@dexOptions/compileClasspath': Could not resolve project :animators

copy from one database to another using oracle sql developer - connection failed

SQL Stored Procedure set variables using SELECT

How to update npm

Python in Xcode 4+?

What is the easiest way to parse an INI file in Java?

Git Stash vs Shelve in IntelliJ IDEA

How to clear/delete the contents of a Tkinter Text widget?

Getting TypeError: __init__() missing 1 required positional argument: 'on_delete' when trying to add parent table after child table with entries

Archive the artifacts in Jenkins

Reading and writing to serial port in C on Linux

How to insert multiple rows from a single query using eloquent/fluent

How to get First and Last record from a sql query?

Do on-demand Mac OS X cloud services exist, comparable to Amazon's EC2 on-demand instances?

Windows service on Local Computer started and then stopped error

Convert SVG to PNG in Python

jQuery: get parent, parent id?

What does the [Flags] Enum Attribute mean in C#?

Why do you have to link the math library in C?

How to encode text to base64 in python

How to increase the max connections in postgres?

R solve:system is exactly singular

day of the week to day number (Monday = 1, Tuesday = 2)

Python object.__repr__(self) should be an expression?

WPF Datagrid Get Selected Cell Value

java.lang.UnsupportedClassVersionError

Javascript: Setting location.href versus location

How to write a Unit Test?

How do you update a DateTime field in T-SQL?

How to convert UTF-8 byte[] to string?

What is the difference between Task.Run() and Task.Factory.StartNew()

Mysql password expired. Can't connect

React-Router: No Not Found Route?

Why isn't Python very good for functional programming?

Visual Studio Code - Convert spaces to tabs

Getting TypeError: init() missing 1 required positional argument: 'on_delete' when trying to add parent table after child table with entries

Python object.repr(self) should be an expression?

`>` selects all direct descendants/children