Programs & Examples On #Lambdaj

LambdaJ is a library to manipulate a collections without any iterations.

DTO pattern: Best way to copy properties between two objects

You can use Apache Commmons Beanutils. The API is

org.apache.commons.beanutils.PropertyUtilsBean.copyProperties(Object dest, Object orig).

It copies property values from the "origin" bean to the "destination" bean for all cases where the property names are the same.

Now I am going to off topic. Using DTO is mostly considered an anti-pattern in EJB3. If your DTO and your domain objects are very alike, there is really no need to duplicate codes. DTO still has merits, especially for saving network bandwidth when remote access is involved. I do not have details about your application architecture, but if the layers you talked about are logical layers and does not cross network, I do not see the need for DTO.

Generic type conversion FROM string

For many types (integer, double, DateTime etc), there is a static Parse method. You can invoke it using reflection:

MethodInfo m = typeof(T).GetMethod("Parse", new Type[] { typeof(string) } );

if (m != null)
    return m.Invoke(null, new object[] { base.Value });

How to completely remove node.js from Windows

I came here because the Remove button was not available from Add/Remove programs. It was saying "Node.js cannot be removed".

This worked:

  1. Got the .msi of my installed Node version. Ran it to repair the installation just in case.
  2. Opened the Administrator command prompt and ran msiexec /uninstall <node.msi>.

Change the default editor for files opened in the terminal? (e.g. set it to TextEdit/Coda/Textmate)

For anyone coming here in 2018:

  • go to iTerm -> Preferences -> Profiles -> Advanced -> Semantic History
  • from the dropdown, choose Open with Editor and from the right dropdown choose your editor of choice

How to get relative path from absolute path

If you have a readonly text box, could you not not make it a label and set AutoEllipsis=true?

alternatively there are posts with code for generating the autoellipsis yourself: (this does it for a grid, you would need to pass i the width for the text box instead. It isn't quite right as it hacks off a bit more than is necessary, and I haven;t got around to finding where the calculation is incorrect. it would be easy enough to modify to remove the first part of the directory rather than the last if you desire.

Private Function AddEllipsisPath(ByVal text As String, ByVal colIndex As Integer, ByVal grid As DataGridView) As String
    'Get the size with the column's width 
    Dim colWidth As Integer = grid.Columns(colIndex).Width

    'Calculate the dimensions of the text with the current font
    Dim textSize As SizeF = MeasureString(text, grid.Font)

    Dim rawText As String = text
    Dim FileNameLen As Integer = text.Length - text.LastIndexOf("\")
    Dim ReplaceWith As String = "\..."

    Do While textSize.Width > colWidth
        ' Trim to make room for the ellipsis
        Dim LastFolder As Integer = rawText.LastIndexOf("\", rawText.Length - FileNameLen - 1)

        If LastFolder < 0 Then
            Exit Do
        End If

        rawText = rawText.Substring(0, LastFolder) + ReplaceWith + rawText.Substring(rawText.Length - FileNameLen)

        If ReplaceWith.Length > 0 Then
            FileNameLen += 4
            ReplaceWith = ""
        End If
        textSize = MeasureString(rawText, grid.Font)

    Return rawText
End Function

Private Function MeasureString(ByVal text As String, ByVal fontInfo As Font) As SizeF
    Dim size As SizeF
    Dim emSize As Single = fontInfo.Size
    If emSize = 0 Then emSize = 12

    Dim stringFont As New Font(fontInfo.Name, emSize)

    Dim bmp As New Bitmap(1000, 100)
    Dim g As Graphics = Graphics.FromImage(bmp)

    size = g.MeasureString(text, stringFont)
    Return size
End Function

How to hide form code from view code/inspect element browser?

There is a smart way to disable inspect element in your website. Just add the following snippet inside script tag :

$(document).bind("contextmenu",function(e) {

Please check out this blog

The function key F12 which directly take inspect element from browser, we can also disable it, by using the following code:

    if(e.which === 123){
       return false;

Skip download if files exist in wget?

The -nc, --no-clobber option isn't the best solution as newer files will not be downloaded. One should use -N instead which will download and overwrite the file only if the server has a newer version, so the correct answer is:

wget -N

Then running Wget with -N, with or without -r or -p, the decision as to whether or not to download a newer copy of a file depends on the local and remote timestamp and size of the file. -nc may not be specified at the same time as -N.

-N, --timestamping: Turn on time-stamping.

What is the difference between a database and a data warehouse?

DataBase :- OLTP(online transaction process)

  • It is current data, up-to-date detailed data, flat relational isolated data.
  • Entity relationship is used to design the database
  • DB size 100MB-GB simple transaction or quires


  • OLAP(Online Analytical process)
  • It is about Historical data Star schema,snow flexed schema and galaxy
  • schema is used to design the data warehouse
  • DB size 100GB-TB Improved query performance foundation for DATA MINING DATA VISUALIZATION
  • Enables users to gain a deeper understanding and knowledge about various aspects of their corporate data through fast, consistent, interactive access to a wide variety of possible views of the data

Using ng-if as a switch inside ng-repeat?

Try to surround strings (hoot, story, article) with quotes ':

<div ng-repeat = "data in comments">
    <div ng-if="data.type == 'hoot' ">
        //different template with hoot data
    <div ng-if="data.type == 'story' ">
        //different template with story data
    <div ng-if="data.type == 'article' ">
        //different template with article data

How to push to History in React Router v4?

Be careful that don't use [email protected] or [email protected] with [email protected]. URL will update after history.push or any other push to history instructions but navigation is not working with react-router. use npm install [email protected] to change the history version. see React router not working after upgrading to v 5.

I think this problem is happening when push to history happened. for example using <NavLink to="/apps"> facing a problem in NavLink.js that consume <RouterContext.Consumer>. context.location is changing to an object with action and location properties when the push to history occurs. So currentLocation.pathname is null to match the path.

VB.Net: Dynamically Select Image from My.Resources

Dim resources As Object = My.Resources.ResourceManager
PictureBoxName.Image = resources.GetObject("Company_Logo")

MongoDB "root" user

Mongodb user management:

roles list:


create user:

db.createUser(user, writeConcern)

db.createUser({ user: "user",
  pwd: "pass",
  roles: [
    { role: "read", db: "database" } 

update user:

  roles: [
    { role: "readWrite", db: "database" } 

drop user:




view users:


more information:

How to set up Android emulator proxy settings

In case if you are under proxy environment and internet is not running in your emulator, then please don't change any setting in emulator. Go to your eclipse project, right click , click on "Run as" then click on "Run Configuration". In pop up window choose "Target" and scroll down a little, you will find "Additional Emulator Command Line Options" Enter your proxy setting here in "Additional Emulator Command Line Options" as i entered

-http-proxy http://ee11s040:[email protected]:3128

enter image description here

Then start a new Emulator.

How to retrieve the hash for the current commit in Git?

Commit hash

git show -s --format=%H

Abbreviated commit hash

git show -s --format=%h

Click here for more git show examples.

Is optimisation level -O3 dangerous in g++?

In the early days of gcc (2.8 etc.) and in the times of egcs, and redhat 2.96 -O3 was quite buggy sometimes. But this is over a decade ago, and -O3 is not much different than other levels of optimizations (in buggyness).

It does however tend to reveal cases where people rely on undefined behavior, due to relying more strictly on the rules, and especially corner cases, of the language(s).

As a personal note, I am running production software in the financial sector for many years now with -O3 and have not yet encountered a bug that would not have been there if I would have used -O2.

By popular demand, here an addition:

-O3 and especially additional flags like -funroll-loops (not enabled by -O3) can sometimes lead to more machine code being generated. Under certain circumstances (e.g. on a cpu with exceptionally small L1 instruction cache) this can cause a slowdown due to all the code of e.g. some inner loop now not fitting anymore into L1I. Generally gcc tries quite hard to not to generate so much code, but since it usually optimizes the generic case, this can happen. Options especially prone to this (like loop unrolling) are normally not included in -O3 and are marked accordingly in the manpage. As such it is generally a good idea to use -O3 for generating fast code, and only fall back to -O2 or -Os (which tries to optimize for code size) when appropriate (e.g. when a profiler indicates L1I misses).

If you want to take optimization into the extreme, you can tweak in gcc via --param the costs associated with certain optimizations. Additionally note that gcc now has the ability to put attributes at functions that control optimization settings just for these functions, so when you find you have a problem with -O3 in one function (or want to try out special flags for just that function), you don't need to compile the whole file or even whole project with O2.

otoh it seems that care must be taken when using -Ofast, which states:

-Ofast enables all -O3 optimizations. It also enables optimizations that are not valid for all standard compliant programs.

which makes me conclude that -O3 is intended to be fully standards compliant.

How do you fix a MySQL "Incorrect key file" error when you can't repair the table?

You'll need to run this command from the MySQL prompt:


From MySQL's documentation on the Repair command:

The USE_FRM option is available for use if the .MYI index file is missing or if its header is corrupted. This option tells MySQL not to trust the information in the .MYI file header and to re-create it using information from the .frm file. This kind of repair cannot be done with myisamchk.

Folder is locked and I can't unlock it

I had this problem where I couldn't unlock a file from the client side. I decided to go to the sever side which was much simpler.

On SVN Server:

Locate locks

 svnadmin lslocks /root/of/repo
 (in my case it was var/www/svn/[name of Company])

 You can add a specific path to this by svnadmin lslocks /root/of/repo "path/to/file"

Remove lock

 svnadmin rmlocks /root/of/repo “path/to/file” 

That's it!

Undefined reference to vtable

I think it's also worth mentioning that you will also get the message when you try to link to object of any class that has at least one virtual method and linker cannot find the file. For example:


class Foo
    virtual void StartFooing();


#include "Foo.hpp"

void Foo::StartFooing(){ //fooing }

Compiled with:

g++ Foo.cpp -c

And main.cpp:

#include "Foo.hpp"

int main()
    Foo foo;

Compiled and linked with:

g++ main.cpp -o main

Gives our favourite error:

/tmp/cclKnW0g.o: In function main': main.cpp:(.text+0x1a): undefined reference tovtable for Foo' collect2: error: ld returned 1 exit status

This occure from my undestanding becasue:

  1. Vtable is created per class at compile time

  2. Linker does not have access to vtable that is in Foo.o

How do I automatically resize an image for a mobile site?

You can use the following css to resize the image for mobile view

object-fit: scale-down; max-width: 100%

PHP get dropdown value and text

$animals = array('--Select Animal--', 'Cat', 'Dog', 'Cow');
$selected_key = $_POST['animal'];
$selected_val = $animals[$_POST['animal']];

Use your $animals list to generate your dropdown list; you now can get the key & the value of that key.

Create XML file using java

You can use Xembly, a small open source library that makes this XML creating process much more intuitive:

String xml = new Xembler(
  new Directives()
    .attr("id", "553")

Xembly is a wrapper around native Java DOM, and is a very lightweight library.

What is the simplest way to convert array to vector?

One simple way can be the use of assign() function that is pre-defined in vector class.



vector<int> v;
v.assign(array, array+5); // 5 is size of array.

Python Git Module experiences?

The git interaction library part of StGit is actually pretty good. However, it isn't broken out as a separate package but if there is sufficient interest, I'm sure that can be fixed.

It has very nice abstractions for representing commits, trees etc, and for creating new commits and trees.

How to play only the audio of a Youtube video using HTML 5?

The answer is simple: Use a 3rd party product like jwplayer or similar, then set it to the minimal player size which is the audio player size (only shows player controls).


Been using this for over 8 years.

Where can I get Google developer key

"Public API access" the key generated there is the key you got to paste into your public static final String DEVELOPER_KEY as part of this writing 26.12.2013 It is not the clientID but you got take the steps mentioned above to obtain one and generate the public api access key.

How to add border around linear layout except at the bottom?

Save this xml and add as a background for the linear layout....

<shape xmlns:android=""> 
    <stroke android:width="4dp" android:color="#FF00FF00" /> 
    <solid android:color="#ffffff" /> 
    <padding android:left="7dp" android:top="7dp" 
            android:right="7dp" android:bottom="0dp" /> 
    <corners android:radius="4dp" /> 

Hope this helps! :)

What is the garbage collector in Java?

Many people think garbage collection collects and discards dead objects.
In reality, Java garbage collection is doing the opposite! Live objects are tracked and everything else designated garbage.

When an object is no longer used, the garbage collector reclaims the underlying memory and reuses it for future object allocation. This means there is no explicit deletion and no memory is given back to the operating system. To determine which objects are no longer in use, the JVM intermittently runs what is very aptly called a mark-and-sweep algorithm.

Check this for more detail information:

Redraw datatables after using ajax to refresh the table content?

It looks as if you could use the API functions to

  • clear the table ( fnClearTable )
  • add new data to the table ( fnAddData)
  • redraw the table ( fnDraw )


I guess you're using the DOM Data Source (for server-side processing) to generate your table. I didn't really get that at first, so my previous answer won't work for that.

To get it to work without rewriting your server side code:

What you'll need to do is totally remove the old table (in the dom) and replace it with the ajax result content, then reinitialize the datatable:

// in your $.post callback:

function (data) {

    // remove the old table

    // replace with the new table

    // reinitialize the datatable
    $('#rankings').dataTable( {
    "bAutoWidth": false,
    "sPaginationType": "full_numbers",
        "aoColumns": [ 
        { "bSortable": false, "sWidth": "10px" },


Tomcat: java.lang.IllegalArgumentException: Invalid character found in method name. HTTP method names must be tokens

Answering this old question (for others which may help)

Configuring your httpd conf correctly will make the problem solved. Install any httpd server, if you don't have one.

Listing my config here.

[smilyface@box002 ~]$ cat /etc/httpd/conf/httpd.conf | grep shirts | grep -v "#"

        ProxyPass /shirts-service
        ProxyPassReverse /shirts-service
        ProxyPass /shirts
        ProxyPassReverse /shirts

edit the file as above and then restart httpd as below

[smilyface@box002 ~]$ sudo service httpd restart

And then request with with https will work without exception.
Also request with http will forward to https ! No worries.

How to get input textfield values when enter key is pressed in react js?

Use onKeyDown event, and inside that check the key code of the key pressed by user. Key code of Enter key is 13, check the code and put the logic there.

Check this example:

class CartridgeShell extends React.Component {_x000D_
   constructor(props) {_x000D_
      this.state = {value:''}_x000D_
      this.handleChange = this.handleChange.bind(this);_x000D_
      this.keyPress = this.keyPress.bind(this);_x000D_
   } _x000D_
   handleChange(e) {_x000D_
      this.setState({ value: });_x000D_
      if(e.keyCode == 13){_x000D_
         // put the login here_x000D_
         <input value={this.state.value} onKeyDown={this.keyPress} onChange={this.handleChange} fullWidth={true} />_x000D_
ReactDOM.render(<CartridgeShell/>, document.getElementById('app'))
<script src=""></script>_x000D_
<script src=""></script>_x000D_
<div id = 'app' />

Note: Replace the input element by Material-Ui TextField and define the other properties also.

How to fix HTTP 404 on Github Pages?

Also, GitHub pages doesn't currently support Git LFS. As such, if you have images (or other binary assets) in GitHub pages committed with Git LFS, you'll get 404 not found for those files.

This will be quite common for documentation generated with Doxygen or similar tool.

The solution in this case is to simply not commit those files with Git LFS.

Ansible: get current target host's IP address

so in template, for e. g.:

{{ lookup('dig', ansible_host) }}


  • Since not only DNS name could be used in inventory a check if it's not IP already better be added
  • Obviously enough this receipt wouldn't work as intended for indirect host specifications (like using jump hosts, for e. g.)

But still it serves 99 % (figuratively speaking) of use cases.

Select rows from a data frame based on values in a vector

Have a look at ?"%in%".

dt[dt$fct %in% vc,]
   fct X
1    a 2
3    c 3
5    c 5
7    a 7
9    c 9
10   a 1
12   c 2
14   c 4

You could also use ?is.element:

dt[is.element(dt$fct, vc),]

Node.js: Python not found exception due to node-sass and node-gyp

The error message means that it cannot locate your python executable or binary.

In many cases, it's installed at c:\python27. if it's not installed yet, you can install it with npm install --global windows-build-tools, which will only work if it hasn't been installed yet.

Adding it to the environment variables does not always work. A better alternative, is to just set it in the npm config.

npm config set python c:\python27\python.exe

Making text bold using attributed string in swift

Swift 4 and higher

For Swift 4 and higher that is a good way:

    let attributsBold = [NSAttributedString.Key.font : UIFont.systemFont(ofSize: 16, weight: .bold)]
    let attributsNormal = [NSAttributedString.Key.font : UIFont.systemFont(ofSize: 16, weight: .regular)]
    var attributedString = NSMutableAttributedString(string: "Hi ", attributes:attributsNormal)
    let boldStringPart = NSMutableAttributedString(string: "John", attributes:attributsBold)
    yourLabel.attributedText = attributedString

In the Label the Text looks like: "Hi John"

Compare dates in MySQL

You can try below query,

select * from players
    us_reg_date between '2000-07-05'
    DATE_ADD('2011-11-10',INTERVAL 1 DAY)

When should null values of Boolean be used?

Main purpose for Boolean is null value. Null value says, that property is undefined, for example take database nullable column.

If you really need to convert everyting from primitive boolean to wrapper Boolean, then you could use following to support old code:

Boolean set = Boolean.FALSE; //set to default value primitive value (false)
if (set) ...

Could not find server 'server name' in sys.servers. SQL Server 2014

I figured out the issue. The linked server was created correctly. However, after the server was upgraded and switched the server name in sys.servers still had the old server name.

I had to drop the old server name and add the new server name to sys.servers on the new server

sp_dropserver 'Server_A'
sp_addserver  'Server',local

How to get the date from the DatePicker widget in Android?

The DatePicker class has methods for getting the month, year, day of month. Or you can use an OnDateChangedListener.

Get file content from URL?

Depending on your PHP configuration, this may be a easy as using:

$jsonData = json_decode(file_get_contents(',40&chl=Hello|World&chof=json'));

However, if allow_url_fopen isn't enabled on your system, you could read the data via CURL as follows:

    $curlSession = curl_init();
    curl_setopt($curlSession, CURLOPT_URL, ',40&chl=Hello|World&chof=json');
    curl_setopt($curlSession, CURLOPT_BINARYTRANSFER, true);
    curl_setopt($curlSession, CURLOPT_RETURNTRANSFER, true);

    $jsonData = json_decode(curl_exec($curlSession));

Incidentally, if you just want the raw JSON data, then simply remove the json_decode.

What programming language does facebook use?

Since nobody has mentioned it, I'd like to add that Facebook chat is written in Erlang.

MVC4 DataType.Date EditorFor won't display date value in Chrome, fine in Internet Explorer

When you decorate a model property with [DataType(DataType.Date)] the default template in ASP.NET MVC 4 generates an input field of type="date":

<input class="text-box single-line" 
       data-val-date="The field EstPurchaseDate must be a date."
       type="date" value="9/28/2012" />

Browsers that support HTML5 such Google Chrome render this input field with a date picker.

In order to correctly display the date, the value must be formatted as 2012-09-28. Quote from the specification:

value: A valid full-date as defined in [RFC 3339], with the additional qualification that the year component is four or more digits representing a number greater than 0.

You could enforce this format using the DisplayFormat attribute:

[DisplayFormat(DataFormatString = "{0:yyyy-MM-dd}", ApplyFormatInEditMode = true)]
public Nullable<System.DateTime> EstPurchaseDate { get; set; }

git visual diff between branches

For those of you on Windows using TortoiseGit, you can get a somewhat visual comparison through this rather obscure feature:

  1. Navigate to the folder you want to compare
  2. Hold down shift and right-click it
  3. Go to TortoiseGit -> Browse Reference
  4. Use ctrl to select two branches to compare
  5. Right-click your selection and click "Compare selected refs"


Keep only date part when using pandas.to_datetime

Converting to datetime64[D]:


Though re-assigning that to a DataFrame col will revert it back to [ns].

If you wanted actual

dt = pd.DatetimeIndex(df.dates)
dates = np.array([*date_tuple) for date_tuple in zip(dt.year, dt.month,])

How to calculate modulus of large numbers?

Just provide another implementation of Jason's answer by C.

After discussing with my classmates, based on Jason's explanation, I like the recursive version more if you don't care about the performance very much:

For example:


int mypow( int base, int pow, int mod ){
    if( pow == 0 ) return 1;
    if( pow % 2 == 0 ){
        int tmp = mypow( base, pow >> 1, mod );
        return tmp * tmp % mod;
        return base * mypow( base, pow - 1, mod ) % mod;

int main(){
    printf("%d", mypow(5,55,221));
    return 0;

Creating a JSON dynamically with each input value using jquery

same from above example - if you are just looking for json (not an array of object) just use

function getJsonDetails() {
      item = {}
      item ["token1"] = token1val;
      item ["token2"] = token1val;
      return item;

this output ll print as (a valid json)


Dealing with "Xerces hell" in Java/Maven?

You should debug first, to help identify your level of XML hell. In my opinion, the first step is to add

to the command line. If that works, then start excluding libraries. If not, then add


to the command-line.

What is @ModelAttribute in Spring MVC?

Annotation that binds a method parameter or method return value to a named model attribute, exposed to a web view.

public String add(@ModelAttribute("specified") Model model) {

How to create a button programmatically?

This works for me very well, #DynamicButtonEvent #IOS #Swift #Xcode

func setupButtonMap(){
    let mapButton = UIButton(type: .system)
    mapButton.setImage(#imageLiteral(resourceName: "CreateTrip").withRenderingMode(.alwaysOriginal), for: .normal)
    mapButton.frame = CGRect(x: 0, y: 0, width: 34, height: 34)
    mapButton.contentMode = .scaleAspectFit
    mapButton.backgroundColor = UIColor.clear
    mapButton.addTarget(self, action: #selector(ViewController.btnOpenMap(_:)), for: .touchUpInside)
    navigationItem.leftBarButtonItem = UIBarButtonItem(customView: mapButton)
@IBAction func btnOpenMap(_ sender: Any?) {

Convert a string to an enum in C#

Enum.Parse is your friend:

StatusEnum MyStatus = (StatusEnum)Enum.Parse(typeof(StatusEnum), "Active");

How to read text file in JavaScript

Yeah it is possible with FileReader, I have already done an example of this, here's the code:

<!DOCTYPE html>
    <title>Read File (via User Input selection)</title>
    <script type="text/javascript">
    var reader; //GLOBAL File Reader object for demo purpose only

     * Check for the various File API support.
    function checkFileAPI() {
        if (window.File && window.FileReader && window.FileList && window.Blob) {
            reader = new FileReader();
            return true; 
        } else {
            alert('The File APIs are not fully supported by your browser. Fallback required.');
            return false;

     * read text input
    function readText(filePath) {
        var output = ""; //placeholder for text output
        if(filePath.files && filePath.files[0]) {           
            reader.onload = function (e) {
                output =;
            };//end onload()
        }//end if html5 filelist support
        else if(ActiveXObject && filePath) { //fallback to IE 6-8 support via ActiveX
            try {
                reader = new ActiveXObject("Scripting.FileSystemObject");
                var file = reader.OpenTextFile(filePath, 1); //ActiveX File Object
                output = file.ReadAll(); //text contents of file
                file.Close(); //close file "input stream"
            } catch (e) {
                if (e.number == -2146827859) {
                    alert('Unable to access local files due to browser security settings. ' + 
                     'To overcome this, go to Tools->Internet Options->Security->Custom Level. ' + 
                     'Find the setting for "Initialize and script ActiveX controls not marked as safe" and change it to "Enable" or "Prompt"'); 
        else { //this is where you could fallback to Java Applet, Flash or similar
            return false;
        return true;

     * display content using a basic HTML replacement
    function displayContents(txt) {
        var el = document.getElementById('main'); 
        el.innerHTML = txt; //display output in DOM
<body onload="checkFileAPI();">
    <div id="container">    
        <input type="file" onchange='readText(this)' />
        <h3>Contents of the Text file:</h3>
        <div id="main">

It's also possible to do the same thing to support some older versions of IE (I think 6-8) using the ActiveX Object, I had some old code which does that too but its been a while so I'll have to dig it up I've found a solution similar to the one I used courtesy of Jacky Cui's blog and edited this answer (also cleaned up code a bit). Hope it helps.

Lastly, I just read some other answers that beat me to the draw, but as they suggest, you might be looking for code that lets you load a text file from the server (or device) where the JavaScript file is sitting. If that's the case then you want AJAX code to load the document dynamically which would be something as follows:

<!DOCTYPE html>
<head><meta charset="utf-8" />
<title>Read File (via AJAX)</title>
<script type="text/javascript">
var reader = new XMLHttpRequest() || new ActiveXObject('MSXML2.XMLHTTP');

function loadFile() {'get', 'test.txt', true); 
    reader.onreadystatechange = displayContents;

function displayContents() {
    if(reader.readyState==4) {
        var el = document.getElementById('main');
        el.innerHTML = reader.responseText;

<div id="container">
    <input type="button" value="test.txt"  onclick="loadFile()" />
    <div id="main">

'AND' vs '&&' as operator

Another nice example using if statements without = assignment operations.

if (true || true && false); // is the same as:
if (true || (true && false)); // TRUE


if (true || true AND false); // is the same as:
if ((true || true) && false); // FALSE

because AND has a lower precedence and thus || a higher precedence.

These are different in the cases of true, false, false and true, true, false. See for en elaborate example.

How to repair a serialized string which has been corrupted by an incorrect byte count length?

public function unserializeKeySkills($string) {
    $output = array();
    $string = trim(preg_replace('/\s\s+/', ' ',$string));
    $string = preg_replace_callback('!s:(\d+):"(.*?)";!', function($m) { return 's:'.strlen($m[2]).':"'.$m[2].'";'; }, utf8_encode( trim(preg_replace('/\s\s+/', ' ',$string)) ));
    try {
        $output =  unserialize($string);
    } catch (\Exception $e) {
        \Log::error("unserialize Data : " .print_r($string,true));
    return $output;

Message: Trying to access array offset on value of type null

This happens because $cOTLdata is not null but the index 'char_data' does not exist. Previous versions of PHP may have been less strict on such mistakes and silently swallowed the error / notice while 7.4 does not do this anymore.

To check whether the index exists or not you can use isset():


Which means the line should look something like this:

$len = isset($cOTLdata['char_data']) ? count($cOTLdata['char_data']) : 0;

Note I switched the then and else cases of the ternary operator since === null is essentially what isset already does (but in the positive case).

clear table jquery

I needed this:

$('#myTable tbody > tr').remove();

It deletes all rows except the header.

JQuery: dynamic height() with window resize()

I feel like there should be a no javascript solution, but how is this?

$(window).resize(function() {
    $('#content').height($(window).height() - 46);


Handling click events on a drawable within an EditText

This works fro me:) may this help you as well

edit_account_name.setOnTouchListener(new View.OnTouchListener() {
        public boolean onTouch(View v, MotionEvent event) {
            if (event.getAction() == MotionEvent.ACTION_DOWN) {
                if (event.getRawX() >= (edit_account_name.getRight())) {
                   return true;
            return false;

Set cURL to use local virtual hosts

Either use a real fully qualified domain name (like that pointing to or try editing the proper hosts file (usually /etc/hosts in *nix environments).

Automatically start a Windows Service on install

You can use the GetServices method of ServiceController class to get an array of all the services. Then, find your service by checking the ServiceName property of each service. When you've found your service, call the Start method to start it.

You should also check the Status property to see what state it is already in before calling start (it may be running, paused, stopped, etc..).

Make Error 127 when running trying to compile code

Error 127 means one of two things:

  1. file not found: the path you're using is incorrect. double check that the program is actually in your $PATH, or in this case, the relative path is correct -- remember that the current working directory for a random terminal might not be the same for the IDE you're using. it might be better to just use an absolute path instead.
  2. ldso is not found: you're using a pre-compiled binary and it wants an interpreter that isn't on your system. maybe you're using an x86_64 (64-bit) distro, but the prebuilt is for x86 (32-bit). you can determine whether this is the answer by opening a terminal and attempting to execute it directly. or by running file -L on /bin/sh (to get your default/native format) and on the compiler itself (to see what format it is).

if the problem is (2), then you can solve it in a few diff ways:

  1. get a better binary. talk to the vendor that gave you the toolchain and ask them for one that doesn't suck.
  2. see if your distro can install the multilib set of files. most x86_64 64-bit distros allow you to install x86 32-bit libraries in parallel.
  3. build your own cross-compiler using something like crosstool-ng.
  4. you could switch between an x86_64 & x86 install, but that seems a bit drastic ;).

File Upload In Angular?

I have used the following tool from priming with success. I have no skin in the game with primeNg, just passing on my suggestion.

Printing integer variable and string on same line in SQL

You can't combine a character string and numeric string. You need to convert the number to a string using either CONVERT or CAST.

For example:

print 'There are ' + cast(@Number as varchar) + ' alias combinations did not match a record'


print 'There are ' + convert(varchar,@Number) + ' alias combinations did not match a record'

fatal error: iostream.h no such file or directory

You should be using iostream without the .h.

Early implementations used the .h variants but the standard mandates the more modern style.

How can I declare a Boolean parameter in SQL statement?

SQL Server recognizes 'TRUE' and 'FALSE' as bit values. So, use a bit data type!

declare @var bit
set @var = 'true'
print @var

That returns 1.

What is a simple C or C++ TCP server and client example?

I've used Beej's Guide to Network Programming in the past. It's in C, not C++, but the examples are good. Go directly to section 6 for the simple client and server example programs.

What is the result of % in Python?

The % (modulo) operator yields the remainder from the division of the first argument by the second. The numeric arguments are first converted to a common type.

3 + 2 + 1 - 5 + 4 % 2 - 1 / 4 + 6 = 7

This is based on operator precedence.

Location of my.cnf file on macOS

You can check the file

/usr/local/bin/mysql.server and see from where my.conf is being read from.

Usually it is from /etc/my.cnf or ~/my.cnf or ~/.my.cnf

How do I add my bot to a channel?

Now all clients allow to do it, but it's not pretty simple.
In any Telegram client:

  1. Open Channel info (in app title)
  2. Choose Administrators
  3. Add Administrator
  4. There will be no bots in contact list, so you need to search for it. Enter your bot's username
  5. Clicking on it you make it as administrator.

enter image description here

Use "ENTER" key on softkeyboard instead of clicking button

may be you could add a attribute to your EditText like this:


SQL: Insert all records from one table to another table without specific the columns

You need to have at least the same number of columns and each column has to be defined in exactly the same way, i.e. a varchar column can't be inserted into an int column.

For bulk transfer, check the documentation for the SQL implementation you're using. There are often tools available to bulk transfer data from one table to another. For SqlServer 2005, for example, you could use the SQL Server Import and Export Wizard. Right-click on the database you're trying to move data around in and click Export to access it.

Resetting a multi-stage form with jQuery

I'm just an intermediate in PHP, and a bit lazy to dive into a new language like JQuery, but isn't the following a simple and elegant solution?

<input name="Submit1" type="submit" value="Get free quote" />
<input name="submitreset" type="submit" value="Reset" />

Can't see a reason why not have two submit buttons, just with different purposes. Then simply:

if ($_POST['submitreset']=="Reset") {
$_source = "--Choose language from--";
$_target = "--Choose language to--"; }

You just redefine your values back to whatever the default is supposed to be.

How to set Navigation Drawer to be opened from right to left

Add this code to manifest:

<application android:supportsRtl="true">

and then write this code on Oncreate:


It works for me. ;)

How to replace all strings to numbers contained in each string in Notepad++?

I have Notepad++ v6.8.8

Find: [([a-zA-Z])]

Replace: [\'\1\']

Will produce: $array[XYZ] => $array['XYZ']

What is the difference between .py and .pyc files?

.pyc contain the compiled bytecode of Python source files. The Python interpreter loads .pyc files before .py files, so if they're present, it can save some time by not having to re-compile the Python source code. You can get rid of them if you want, but they don't cause problems, they're not big, and they may save some time when running programs.

Delete everything in a MongoDB database


Add to python path mac os x

Setting the $PYTHONPATH environment variable does not seem to affect the Spyder IDE's iPython terminals on a Mac. However, Spyder's application menu contains a "PYTHONPATH manager." Adding my path here solved my problem. The "PYTHONPATH manager" is also persistent across application restarts.

This is specific to a Mac, because setting the PYTHONPATH environment variable on my Windows PC gives the expected behavior (modules are found) without using the PYTHONPATH manager in Spyder.

What is an efficient way to implement a singleton pattern in Java?

The best singleton pattern I've ever seen uses the Supplier interface.

  • It's generic and reusable
  • It supports lazy initialization
  • It's only synchronized until it has been initialized, then the blocking supplier is replaced with a non-blocking supplier.

See below:

public class Singleton<T> implements Supplier<T> {

    private boolean initialized;
    private Supplier<T> singletonSupplier;

    public Singleton(T singletonValue) {
        this.singletonSupplier = () -> singletonValue;

    public Singleton(Supplier<T> supplier) {
        this.singletonSupplier = () -> {
            // The initial supplier is temporary; it will be replaced after initialization
            synchronized (supplier) {
                if (!initialized) {
                    T singletonValue = supplier.get();
                    // Now that the singleton value has been initialized,
                    // replace the blocking supplier with a non-blocking supplier
                    singletonSupplier = () -> singletonValue;
                    initialized = true;
                return singletonSupplier.get();

    public T get() {
        return singletonSupplier.get();

Using .Select and .Where in a single LINQ statement

Did you add the Select() after the Where() or before?

You should add it after, because of the concurrency logic:

 1 Take the entire table  
 2 Filter it accordingly  
 3 Select only the ID's  
 4 Make them distinct.  

If you do a Select first, the Where clause can only contain the ID attribute because all other attributes have already been edited out.

Update: For clarity, this order of operators should work:

db.Items.Where(x=> x.userid == user_ID).Select(x=>x.Id).Distinct();

Probably want to add a .toList() at the end but that's optional :)

Simple Java Client/Server Program

this is client code

first run the server program then on another cmd run client program


public class frmclient 
 public static void main(String args[])throws Exception

          DataInputStream d=new DataInputStream(;
          System.out.print("\n1.fact\n2.Sum of digit\nEnter ur choice:");

           int ch=Integer.parseInt(d.readLine());
           System.out.print("\nEnter number:");
           int num=Integer.parseInt(d.readLine());

           Socket s=new Socket("localhost",1024);

           PrintStream ps=new PrintStream(s.getOutputStream());

          DataInputStream dis=new DataInputStream(s.getInputStream());
           String response=dis.readLine();

        catch(Exception ex)



this is sever side code

public class frmserver {

  public static void main(String args[])throws Exception


    ServerSocket ss=new ServerSocket(1024);
       System.out.print("\nWaiting for client.....");
       Socket s=ss.accept();

       DataInputStream d=new DataInputStream(s.getInputStream());

        int ch=Integer.parseInt(d.readLine());
       int num=Integer.parseInt(d.readLine());
         int result=0;

        PrintStream ps=new PrintStream(s.getOutputStream());
          case 1:result=fact(num);
          case 2:result=sum(num);

catch(Exception ex)


  public static int fact(int n)
  int ans=1;
    for(int i=n;i>0;i--)
    return ans;
  public static int sum(int n)
   String str=n+"";
   int ans=0;
    for(int i=0;i<str.length();i++)
      int tmp=Integer.parseInt(str.charAt(i)+"");
    return ans;

node.js: read a text file into an array. (Each line an item in the array.)

Using Node.js v8 or later has a new feature that converts normal function into an async function.


It's an awesome feature. Here's the example of parsing 10000 numbers from the txt file into an array, counting inversions using merge sort on the numbers.

// read from txt file
const util = require('util');
const fs = require('fs')
fs.readFileAsync = util.promisify(fs.readFile);
let result = []

const parseTxt = async (csvFile) => {
  let fields, obj
  const data = await fs.readFileAsync(csvFile)
  const str = data.toString()
  const lines = str.split('\r\n')
  // const lines = str
  console.log("lines", lines)
  // console.log("str", str) => {
    if(!line) {return null}
  return result
parseTxt('./count-inversion.txt').then(() => {
  console.log(mergeSort({arr: result, count: 0}))

Getting content/message from HttpResponseMessage

The quick answer I suggest is:


Sort table rows In Bootstrap

These examples are minified because StackOverflow has a maximum character limit and links to external code are discouraged since links can break.

There are multiple plugins if you look: Bootstrap Sortable, Bootstrap Table or DataTables.

Bootstrap 3 with DataTables Example: Bootstrap Docs & DataTables Docs

$(document).ready(function() {
<link href= rel=stylesheet><link href= rel=stylesheet><div class=container><h1>Bootstrap 3 DataTables</h1><table cellspacing=0 class="table table-bordered table-hover table-striped"id=example width=100%><thead><tr><th>Name<th>Position<th>Office<th>Salary<tbody><tr><td>Tiger Nixon<td>System Architect<td>Edinburgh<td>$320,800<tr><td>Garrett Winters<td>Accountant<td>Tokyo<td>$170,750<tr><td>Ashton Cox<td>Junior Technical Author<td>San Francisco<td>$86,000<tr><td>Cedric Kelly<td>Senior Javascript Developer<td>Edinburgh<td>$433,060<tr><td>Airi Satou<td>Accountant<td>Tokyo<td>$162,700<tr><td>Brielle Williamson<td>Integration Specialist<td>New York<td>$372,000<tr><td>Herrod Chandler<td>Sales Assistant<td>San Francisco<td>$137,500<tr><td>Rhona Davidson<td>Integration Specialist<td>Tokyo<td>$327,900<tr><td>Colleen Hurst<td>Javascript Developer<td>San Francisco<td>$205,500<tr><td>Sonya Frost<td>Software Engineer<td>Edinburgh<td>$103,600<tr><td>Jena Gaines<td>Office Manager<td>London<td>$90,560<tr><td>Quinn Flynn<td>Support Lead<td>Edinburgh<td>$342,000<tr><td>Charde Marshall<td>Regional Director<td>San Francisco<td>$470,600<tr><td>Haley Kennedy<td>Senior Marketing Designer<td>London<td>$313,500<tr><td>Tatyana Fitzpatrick<td>Regional Director<td>London<td>$385,750<tr><td>Michael Silva<td>Marketing Designer<td>London<td>$198,500<tr><td>Paul Byrd<td>Chief Financial Officer (CFO)<td>New York<td>$725,000<tr><td>Gloria Little<td>Systems Administrator<td>New York<td>$237,500<tr><td>Bradley Greer<td>Software Engineer<td>London<td>$132,000<tr><td>Dai Rios<td>Personnel Lead<td>Edinburgh<td>$217,500<tr><td>Jenette Caldwell<td>Development Lead<td>New York<td>$345,000<tr><td>Yuri Berry<td>Chief Marketing Officer (CMO)<td>New York<td>$675,000<tr><td>Caesar Vance<td>Pre-Sales Support<td>New York<td>$106,450<tr><td>Doris Wilder<td>Sales Assistant<td>Sidney<td>$85,600<tr><td>Angelica Ramos<td>Chief Executive Officer (CEO)<td>London<td>$1,200,000<tr><td>Gavin Joyce<td>Developer<td>Edinburgh<td>$92,575<tr><td>Jennifer Chang<td>Regional Director<td>Singapore<td>$357,650<tr><td>Brenden Wagner<td>Software Engineer<td>San Francisco<td>$206,850<tr><td>Fiona Green<td>Chief Operating Officer (COO)<td>San Francisco<td>$850,000<tr><td>Shou Itou<td>Regional Marketing<td>Tokyo<td>$163,000<tr><td>Michelle House<td>Integration Specialist<td>Sidney<td>$95,400<tr><td>Suki Burks<td>Developer<td>London<td>$114,500<tr><td>Prescott Bartlett<td>Technical Author<td>London<td>$145,000<tr><td>Gavin Cortez<td>Team Leader<td>San Francisco<td>$235,500<tr><td>Martena Mccray<td>Post-Sales support<td>Edinburgh<td>$324,050<tr><td>Unity Butler<td>Marketing Designer<td>San Francisco<td>$85,675<tr><td>Howard Hatfield<td>Office Manager<td>San Francisco<td>$164,500<tr><td>Hope Fuentes<td>Secretary<td>San Francisco<td>$109,850<tr><td>Vivian Harrell<td>Financial Controller<td>San Francisco<td>$452,500<tr><td>Timothy Mooney<td>Office Manager<td>London<td>$136,200<tr><td>Jackson Bradshaw<td>Director<td>New York<td>$645,750<tr><td>Olivia Liang<td>Support Engineer<td>Singapore<td>$234,500<tr><td>Bruno Nash<td>Software Engineer<td>London<td>$163,500<tr><td>Sakura Yamamoto<td>Support Engineer<td>Tokyo<td>$139,575<tr><td>Thor Walton<td>Developer<td>New York<td>$98,540<tr><td>Finn Camacho<td>Support Engineer<td>San Francisco<td>$87,500<tr><td>Serge Baldwin<td>Data Coordinator<td>Singapore<td>$138,575<tr><td>Zenaida Frank<td>Software Engineer<td>New York<td>$125,250<tr><td>Zorita Serrano<td>Software Engineer<td>San Francisco<td>$115,000<tr><td>Jennifer Acosta<td>Junior Javascript Developer<td>Edinburgh<td>$75,650<tr><td>Cara Stevens<td>Sales Assistant<td>New York<td>$145,600<tr><td>Hermione Butler<td>Regional Director<td>London<td>$356,250<tr><td>Lael Greer<td>Systems Administrator<td>London<td>$103,500<tr><td>Jonas Alexander<td>Developer<td>San Francisco<td>$86,500<tr><td>Shad Decker<td>Regional Director<td>Edinburgh<td>$183,000<tr><td>Michael Bruce<td>Javascript Developer<td>Singapore<td>$183,000<tr><td>Donna Snider<td>Customer Support<td>New York<td>$112,000</table></div><script src=></script><script src=></script><script src=></script>

Bootstrap 4 with DataTables Example: Bootstrap Docs & DataTables Docs

$(document).ready(function() {
<link href= rel=stylesheet><link href= rel=stylesheet><div class=container><h1>Bootstrap 4 DataTables</h1><table cellspacing=0 class="table table-bordered table-hover table-inverse table-striped"id=example width=100%><thead><tr><th>Name<th>Position<th>Office<th>Age<th>Start date<th>Salary<tfoot><tr><th>Name<th>Position<th>Office<th>Age<th>Start date<th>Salary<tbody><tr><td>Tiger Nixon<td>System Architect<td>Edinburgh<td>61<td>2011/04/25<td>$320,800<tr><td>Garrett Winters<td>Accountant<td>Tokyo<td>63<td>2011/07/25<td>$170,750<tr><td>Ashton Cox<td>Junior Technical Author<td>San Francisco<td>66<td>2009/01/12<td>$86,000<tr><td>Cedric Kelly<td>Senior Javascript Developer<td>Edinburgh<td>22<td>2012/03/29<td>$433,060<tr><td>Airi Satou<td>Accountant<td>Tokyo<td>33<td>2008/11/28<td>$162,700<tr><td>Brielle Williamson<td>Integration Specialist<td>New York<td>61<td>2012/12/02<td>$372,000<tr><td>Herrod Chandler<td>Sales Assistant<td>San Francisco<td>59<td>2012/08/06<td>$137,500<tr><td>Rhona Davidson<td>Integration Specialist<td>Tokyo<td>55<td>2010/10/14<td>$327,900<tr><td>Colleen Hurst<td>Javascript Developer<td>San Francisco<td>39<td>2009/09/15<td>$205,500<tr><td>Sonya Frost<td>Software Engineer<td>Edinburgh<td>23<td>2008/12/13<td>$103,600<tr><td>Jena Gaines<td>Office Manager<td>London<td>30<td>2008/12/19<td>$90,560<tr><td>Quinn Flynn<td>Support Lead<td>Edinburgh<td>22<td>2013/03/03<td>$342,000<tr><td>Charde Marshall<td>Regional Director<td>San Francisco<td>36<td>2008/10/16<td>$470,600<tr><td>Haley Kennedy<td>Senior Marketing Designer<td>London<td>43<td>2012/12/18<td>$313,500<tr><td>Tatyana Fitzpatrick<td>Regional Director<td>London<td>19<td>2010/03/17<td>$385,750<tr><td>Michael Silva<td>Marketing Designer<td>London<td>66<td>2012/11/27<td>$198,500<tr><td>Paul Byrd<td>Chief Financial Officer (CFO)<td>New York<td>64<td>2010/06/09<td>$725,000<tr><td>Gloria Little<td>Systems Administrator<td>New York<td>59<td>2009/04/10<td>$237,500<tr><td>Bradley Greer<td>Software Engineer<td>London<td>41<td>2012/10/13<td>$132,000<tr><td>Dai Rios<td>Personnel Lead<td>Edinburgh<td>35<td>2012/09/26<td>$217,500<tr><td>Jenette Caldwell<td>Development Lead<td>New York<td>30<td>2011/09/03<td>$345,000<tr><td>Yuri Berry<td>Chief Marketing Officer (CMO)<td>New York<td>40<td>2009/06/25<td>$675,000<tr><td>Caesar Vance<td>Pre-Sales Support<td>New York<td>21<td>2011/12/12<td>$106,450<tr><td>Doris Wilder<td>Sales Assistant<td>Sidney<td>23<td>2010/09/20<td>$85,600<tr><td>Angelica Ramos<td>Chief Executive Officer (CEO)<td>London<td>47<td>2009/10/09<td>$1,200,000<tr><td>Gavin Joyce<td>Developer<td>Edinburgh<td>42<td>2010/12/22<td>$92,575<tr><td>Jennifer Chang<td>Regional Director<td>Singapore<td>28<td>2010/11/14<td>$357,650<tr><td>Brenden Wagner<td>Software Engineer<td>San Francisco<td>28<td>2011/06/07<td>$206,850<tr><td>Fiona Green<td>Chief Operating Officer (COO)<td>San Francisco<td>48<td>2010/03/11<td>$850,000<tr><td>Shou Itou<td>Regional Marketing<td>Tokyo<td>20<td>2011/08/14<td>$163,000<tr><td>Michelle House<td>Integration Specialist<td>Sidney<td>37<td>2011/06/02<td>$95,400<tr><td>Suki Burks<td>Developer<td>London<td>53<td>2009/10/22<td>$114,500<tr><td>Prescott Bartlett<td>Technical Author<td>London<td>27<td>2011/05/07<td>$145,000<tr><td>Gavin Cortez<td>Team Leader<td>San Francisco<td>22<td>2008/10/26<td>$235,500<tr><td>Martena Mccray<td>Post-Sales support<td>Edinburgh<td>46<td>2011/03/09<td>$324,050<tr><td>Unity Butler<td>Marketing Designer<td>San Francisco<td>47<td>2009/12/09<td>$85,675<tr><td>Howard Hatfield<td>Office Manager<td>San Francisco<td>51<td>2008/12/16<td>$164,500<tr><td>Hope Fuentes<td>Secretary<td>San Francisco<td>41<td>2010/02/12<td>$109,850<tr><td>Vivian Harrell<td>Financial Controller<td>San Francisco<td>62<td>2009/02/14<td>$452,500<tr><td>Timothy Mooney<td>Office Manager<td>London<td>37<td>2008/12/11<td>$136,200<tr><td>Jackson Bradshaw<td>Director<td>New York<td>65<td>2008/09/26<td>$645,750<tr><td>Olivia Liang<td>Support Engineer<td>Singapore<td>64<td>2011/02/03<td>$234,500<tr><td>Bruno Nash<td>Software Engineer<td>London<td>38<td>2011/05/03<td>$163,500<tr><td>Sakura Yamamoto<td>Support Engineer<td>Tokyo<td>37<td>2009/08/19<td>$139,575<tr><td>Thor Walton<td>Developer<td>New York<td>61<td>2013/08/11<td>$98,540<tr><td>Finn Camacho<td>Support Engineer<td>San Francisco<td>47<td>2009/07/07<td>$87,500<tr><td>Serge Baldwin<td>Data Coordinator<td>Singapore<td>64<td>2012/04/09<td>$138,575<tr><td>Zenaida Frank<td>Software Engineer<td>New York<td>63<td>2010/01/04<td>$125,250<tr><td>Zorita Serrano<td>Software Engineer<td>San Francisco<td>56<td>2012/06/01<td>$115,000<tr><td>Jennifer Acosta<td>Junior Javascript Developer<td>Edinburgh<td>43<td>2013/02/01<td>$75,650<tr><td>Cara Stevens<td>Sales Assistant<td>New York<td>46<td>2011/12/06<td>$145,600<tr><td>Hermione Butler<td>Regional Director<td>London<td>47<td>2011/03/21<td>$356,250<tr><td>Lael Greer<td>Systems Administrator<td>London<td>21<td>2009/02/27<td>$103,500<tr><td>Jonas Alexander<td>Developer<td>San Francisco<td>30<td>2010/07/14<td>$86,500<tr><td>Shad Decker<td>Regional Director<td>Edinburgh<td>51<td>2008/11/13<td>$183,000<tr><td>Michael Bruce<td>Javascript Developer<td>Singapore<td>29<td>2011/06/27<td>$183,000<tr><td>Donna Snider<td>Customer Support<td>New York<td>27<td>2011/01/25<td>$112,000</table></div><script src=></script><script src=></script><script src=></script>

Bootstrap 3 with Bootstrap Table Example: Bootstrap Docs & Bootstrap Table Docs

<link href= rel=stylesheet><link href= rel=stylesheet><table data-sort-name=stargazers_count data-sort-order=desc data-toggle=table data-url=""><thead><tr><th data-field=name data-sortable=true>Name<th data-field=stargazers_count data-sortable=true>Stars<th data-field=forks_count data-sortable=true>Forks<th data-field=description data-sortable=true>Description</thead></table><script src=></script><script src=></script>

Bootstrap 3 with Bootstrap Sortable Example: Bootstrap Docs & Bootstrap Sortable Docs

function randomDate(t,e){return new Date(t.getTime()+Math.random()*(e.getTime()-t.getTime()))}function randomName(){return["Jack","Peter","Frank","Steven"][Math.floor(4*Math.random())]+" "+["White","Jackson","Sinatra","Spielberg"][Math.floor(4*Math.random())]}function newTableRow(){var t=moment(randomDate(new Date(2e3,0,1),new Date)).format("D.M.YYYY"),e=Math.round(Math.random()*Math.random()*100*100)/100,a=Math.round(Math.random()*Math.random()*100*100)/100,r=Math.round(Math.random()*Math.random()*100*100)/100;return"<tr><td>"+randomName()+"</td><td>"+e+"</td><td>"+a+"</td><td>"+r+"</td><td>"+Math.round(100*(e+a+r))/100+"</td><td data-dateformat='D-M-YYYY'>"+t+"</td></tr>"}function customSort(){alert("Custom sort.")}!function(t,e){"use strict";"function"==typeof define&&define.amd?define("tinysort",function(){return e}):t.tinysort=e}(this,function(){"use strict";function t(t,e){for(var a,r=t.length,o=r;o--;)e(t[a=r-o-1],a)}function e(t,e,a){for(var o in e)(a||t[o]===r)&&(t[o]=e[o]);return t}function a(t,e,a){u.push({prepare:t,sort:e,sortBy:a})}var r,o=!1,n=null,s=window,d=s.document,i=parseFloat,l=/(-?\d+\.?\d*)\s*$/g,c=/(\d+\.?\d*)\s*$/g,u=[],f=0,h=0,p=String.fromCharCode(4095),m={selector:n,order:"asc",attr:n,data:n,useVal:o,place:"org",returns:o,cases:o,natural:o,forceStrings:o,ignoreDashes:o,sortFunction:n,useFlex:o,emptyEnd:o};return s.Element&&function(t){t.matchesSelector=t.matchesSelector||t.mozMatchesSelector||t.msMatchesSelector||t.oMatchesSelector||t.webkitMatchesSelector||function(t){for(var e=this,a=(e.parentNode||e.document).querySelectorAll(t),r=-1;a[++r]&&a[r]!=e;);return!!a[r]}}(Element.prototype),e(a,{loop:t}),e(function(a,s){function v(t){var a=!!t.selector,r=a&&":"===t.selector[0],o=e(t||{},m);E.push(e({hasSelector:a,hasAttr:!(o.attr===n||""===o.attr),!==n,hasFilter:r,sortReturnNumber:"asc"===o.order?1:-1},o))}function b(t,e,a){for(var r=a(t.toString()),o=a(e.toString()),n=0;r[n]&&o[n];n++)if(r[n]!==o[n]){var s=Number(r[n]),d=Number(o[n]);return s==r[n]&&d==o[n]?s-d:r[n]>o[n]?1:-1}return r.length-o.length}function g(t){for(var e,a,r=[],o=0,n=-1,s=0;e=(a=t.charAt(o++)).charCodeAt(0);){var d=46==e||e>=48&&57>=e;d!==s&&(r[++n]="",s=d),r[n]+=a}return r}function w(){return Y.forEach(function(t){F.appendChild(t.elm)}),F}function S(t){var e=t.elm,a=d.createElement("div");return t.ghost=a,e.parentNode.insertBefore(a,e),t}function y(t,e){var a=t.ghost,r=a.parentNode;r.insertBefore(e,a),r.removeChild(a),delete t.ghost}function C(t,e){var a,r=t.elm;return e.selector&&(e.hasFilter?r.matchesSelector(e.selector)||(r=n):r=r.querySelector(e.selector)),e.hasAttr?a=r.getAttribute(e.attr):e.useVal?a=r.value||r.getAttribute("value"):e.hasData?a=r.getAttribute("data-",M(a)&&(e.cases||(a=a.toLowerCase()),a=a.replace(/\s+/g," ")),null===a&&(a=p),a}function M(t){return"string"==typeof t}M(a)&&(a=d.querySelectorAll(a)),0===a.length&&console.warn("No elements to sort");var x,N,F=d.createDocumentFragment(),D=[],Y=[],$=[],E=[],k=!0,A=a.length&&a[0].parentNode,T=A.rootNode!==document,R=a.length&&(s===r||!1!==s.useFlex)&&!T&&-1!==getComputedStyle(A,null).display.indexOf("flex");return function(){0===arguments.length?v({}):t(arguments,function(t){v(M(t)?{selector:t}:t)}),f=E.length}.apply(n,,1)),t(a,function(t,e){N?N!==t.parentNode&&(k=!1):N=t.parentNode;var a=E[0],r=a.hasFilter,o=a.selector,n=!o||r&&t.matchesSelector(o)||o&&t.querySelector(o)?Y:$,s={elm:t,pos:e,posn:n.length};D.push(s),n.push(s)}),x=Y.slice(0),Y.sort(function(e,a){var n=0;for(0!==h&&(h=0);0===n&&f>h;){var s=E[h],d=s.ignoreDashes?c:l;if(t(u,function(t){var e=t.prepare;e&&e(s)}),s.sortFunction)n=s.sortFunction(e,a);else if("rand"==s.order)n=Math.random()<.5?1:-1;else{var p=o,m=C(e,s),v=C(a,s),w=""===m||m===r,S=""===v||v===r;if(m===v)n=0;else if(s.emptyEnd&&(w||S))n=w&&S?0:w?1:-1;else{if(!s.forceStrings){var y=M(m)?m&&m.match(d):o,x=M(v)?v&&v.match(d):o;y&&x&&m.substr(0,m.length-y[0].length)==v.substr(0,v.length-x[0].length)&&(p=!o,m=i(y[0]),v=i(x[0]))}n=m===r||v===r?0:s.natural&&(isNaN(m)||isNaN(v))?b(m,v,g):v>m?-1:m>v?1:0}}t(u,function(t){var e=t.sort;e&&(n=e(s,p,m,v,n))}),0==(n*=s.sortReturnNumber)&&h++}return 0===n&&(n=e.pos>a.pos?1:-1),n}),function(){var t=Y.length===D.length;if(k&&t)R?Y.forEach(function(t,e){}):N?N.appendChild(w()):console.warn("parentNode has been removed");else{var e=E[0].place,a="start"===e,r="end"===e,o="first"===e,n="last"===e;if("org"===e)Y.forEach(S),Y.forEach(function(t,e){y(x[e],t.elm)});else if(a||r){var s=x[a?0:x.length-1],d=s&&s.elm.parentNode,i=d&&(a&&d.firstChild||d.lastChild);i&&(i!==s.elm&&(s={elm:i}),S(s),r&&d.appendChild(s.ghost),y(s,w()))}else(o||n)&&y(S(x[o?0:x.length-1]),w())}}(),{return t.elm})},{plugin:a,defaults:m})}()),function(t,e){"function"==typeof define&&define.amd?define(["jquery","tinysort","moment"],e):e(t.jQuery,t.tinysort,t.moment||void 0)}(this,function(t,e,a){var r,o,n,s=t(document);function d(e){var s=void 0!==a;r=e.sign?e.sign:"arrow","default"==e.customSort&&(e.customSort=c),o=e.customSort||o||c,n=e.emptyEnd,t("table.sortable").each(function(){var r=t(this),o=!0===e.applyLast;r.find("span.sign").remove(),r.find("> thead [colspan]").each(function(){for(var e=parseFloat(t(this).attr("colspan")),a=1;a<e;a++)t(this).after('<th class="colspan-compensate">')}),r.find("> thead [rowspan]").each(function(){for(var e=t(this),a=parseFloat(e.attr("rowspan")),r=1;r<a;r++){var o=e.parent("tr"),"tr"),s=o.children().index(e);n.children().eq(s).before('<th class="rowspan-compensate">')}}),r.find("> thead tr").each(function(e){t(this).find("th").each(function(a){var r=t(this);r.addClass("nosort").removeClass("up down"),r.attr("data-sortcolumn",a),r.attr("data-sortkey",a+"-"+e)})}),r.find("> thead .rowspan-compensate, .colspan-compensate").remove(),r.find("th").each(function(){var e=t(this);if(void 0!==e.attr("data-dateformat")&&s){var o=parseFloat(e.attr("data-sortcolumn"));r.find("td:nth-child("+(o+1)+")").each(function(){var r=t(this);r.attr("data-value",a(r.text(),e.attr("data-dateformat")).format("YYYY/MM/DD/HH/mm/ss"))})}else if(void 0!==e.attr("data-valueprovider")){o=parseFloat(e.attr("data-sortcolumn"));r.find("td:nth-child("+(o+1)+")").each(function(){var a=t(this);a.attr("data-value",new RegExp(e.attr("data-valueprovider")).exec(a.text())[0])})}}),r.find("td").each(function(){var e=t(this);void 0!==e.attr("data-dateformat")&&s?e.attr("data-value",a(e.text(),e.attr("data-dateformat")).format("YYYY/MM/DD/HH/mm/ss")):void 0!==e.attr("data-valueprovider")?e.attr("data-value",new RegExp(e.attr("data-valueprovider")).exec(e.text())[0]):void 0===e.attr("data-value")&&e.attr("data-value",e.text())});var n=l(r),d=n.bsSort;r.find('> thead th[data-defaultsort!="disabled"]').each(function(e){var a=t(this),r=a.closest("table.sortable");"sortTable",r);var s=a.attr("data-sortkey"),i=o?n.lastSort:-1;d[s]=o?d[s]:a.attr("data-defaultsort"),void 0!==d[s]&&o===(s===i)&&(d[s]="asc"===d[s]?"desc":"asc",u(a,r))})})}function i(e){var a=t(e),"sortTable")||a.closest("table.sortable");u(a,r)}function l(e){var"bootstrap-sortable-context");return void 0===a&&(a={bsSort:[],lastSort:void 0},e.find('> thead th[data-defaultsort!="disabled"]').each(function(e){var r=t(this),o=r.attr("data-sortkey");a.bsSort[o]=r.attr("data-defaultsort"),void 0!==a.bsSort[o]&&(a.lastSort=o)}),"bootstrap-sortable-context",a)),a}function c(t,a){e(t,a)}function u(e,a){a.trigger("before-sort");var s=parseFloat(e.attr("data-sortcolumn")),d=l(a),i=d.bsSort;if(e.attr("colspan")){var c=parseFloat("mainsort"))||0,f=parseFloat("sortkey").split("-").pop());if(a.find("> thead tr").length-1>f)return void u(a.find('[data-sortkey="'+(s+c)+"-"+(f+1)+'"]'),a);s+=c}var h=e.attr("data-defaultsign")||r;if(a.find("> thead th").each(function(){t(this).removeClass("up").removeClass("down").addClass("nosort")}),t.browser.mozilla){var p=a.find("> thead div.mozilla");void 0!==p&&(p.find(".sign").remove(),p.parent().html(p.html())),e.wrapInner('<div class="mozilla"></div>'),e.children().eq(0).append('<span class="sign '+h+'"></span>')}else a.find("> thead span.sign").remove(),e.append('<span class="sign '+h+'"></span>');var m=e.attr("data-sortkey"),v="desc"!==e.attr("data-firstsort")?"desc":"asc",b=i[m]||v;d.lastSort!==m&&void 0!==i[m]||(b="asc"===b?"desc":"asc"),i[m]=b,d.lastSort=m,"desc"===i[m]?(e.find("span.sign").addClass("up"),e.addClass("up").removeClass("down nosort")):e.addClass("down").removeClass("up nosort");var g=a.children("tbody").children("tr"),w=[];t(g.filter('[data-disablesort="true"]').get().reverse()).each(function(e,a){var r=t(a);w.push({index:g.index(r),row:r}),r.remove()});var S=g.not('[data-disablesort="true"]');if(0!=S.length){var y="asc"===i[m]&&n;o(S,{emptyEnd:y,selector:"td:nth-child("+(s+1)+")",order:i[m],data:"value"})}t(w.reverse()).each(function(t,e){0===e.index?a.children("tbody").prepend(e.row):a.children("tbody").children("tr").eq(e.index-1).after(e.row)}),a.find("> tbody > tr > td.sorted,> thead th.sorted").removeClass("sorted"),S.find("td:eq("+s+")").addClass("sorted"),e.addClass("sorted"),a.trigger("sorted")}if(t.bootstrapSortable=function(t){null==t?d({}):t.constructor===Boolean?d({applyLast:t}):void 0!==t.sortingHeader?i(t.sortingHeader):d(t)},s.on("click",'table.sortable>thead th[data-defaultsort!="disabled"]',function(t){i(this)}),!t.browser){t.browser={chrome:!1,mozilla:!1,opera:!1,msie:!1,safari:!1};var f=navigator.userAgent;t.each(t.browser,function(e){t.browser[e]=!!new RegExp(e,"i").test(f),t.browser.mozilla&&"mozilla"===e&&(t.browser.mozilla=!!new RegExp("firefox","i").test(f)),"safari"===e&&(t.browser.safari=!1)})}t(t.bootstrapSortable)}),function(){var t=$("table");t.append(newTableRow()),t.append(newTableRow()),$("button.add-row").on("click",function(){var e=$(this);t.append(newTableRow()),"sort")?$.bootstrapSortable(!0):$.bootstrapSortable(!1)}),$("button.change-sort").on("click",function(){$(this).data("custom")?$.bootstrapSortable(!0,void 0,customSort):$.bootstrapSortable(!0,void 0,"default")}),t.on("sorted",function(){alert("Table was sorted.")}),$("#event").on("change",function(){$(this).is(":checked")?t.on("sorted",function(){alert("Table was sorted.")})"sorted")}),$("input[name=sign]:radio").change(function(){$.bootstrapSortable(!0,$(this).val())})}();
table.sortable span.sign { display: block; position: absolute; top: 50%; right: 5px; font-size: 12px; margin-top: -10px; color: #bfbfc1; } table.sortable th:after { display: block; position: absolute; top: 50%; right: 5px; font-size: 12px; margin-top: -10px; color: #bfbfc1; } table.sortable th.arrow:after { content: ''; } table.sortable span.arrow, span.reversed, th.arrow.down:after, th.reversedarrow.down:after, th.arrow.up:after, th.reversedarrow.up:after { border-style: solid; border-width: 5px; font-size: 0; border-color: #ccc transparent transparent transparent; line-height: 0; height: 0; width: 0; margin-top: -2px; } table.sortable span.arrow.up, th.arrow.up:after { border-color: transparent transparent #ccc transparent; margin-top: -7px; } table.sortable span.reversed, th.reversedarrow.down:after { border-color: transparent transparent #ccc transparent; margin-top: -7px; } table.sortable span.reversed.up, th.reversedarrow.up:after { border-color: #ccc transparent transparent transparent; margin-top: -2px; } table.sortable, { content: "a .. z"; } table.sortable, { content: "z .. a"; } table.sortable, th.AZ.nosort:after, th._19.nosort:after, th.month.nosort:after { content: ".."; } table.sortable span.AZ:before, th.AZ.down:after { content: "A .. Z"; } table.sortable span.AZ.up:before, th.AZ.up:after { content: "Z .. A"; } table.sortable span._19:before, th._19.down:after { content: "1 .. 9"; } table.sortable span._19.up:before, th._19.up:after { content: "9 .. 1"; } table.sortable span.month:before, th.month.down:after { content: "jan .. dec"; } table.sortable span.month.up:before, th.month.up:after { content: "dec .. jan"; } table.sortable thead th:not([data-defaultsort=disabled]) { cursor: pointer; position: relative; top: 0; left: 0; } table.sortable thead th:hover:not([data-defaultsort=disabled]) { background: #efefef; } table.sortable thead th div.mozilla { position: relative; }
<link href= rel=stylesheet><link href= rel=stylesheet><div class=container><div class=hero-unit><h1>Bootstrap Sortable</h1></div><table class="sortable table table-bordered table-striped"><thead><tr><th style=width:20%;vertical-align:middle data-defaultsign=nospan class=az data-defaultsort=asc rowspan=2><i class="fa fa-fw fa-map-marker"></i>Name<th style=text-align:center colspan=4 data-mainsort=3>Results<th data-defaultsort=disabled><tr><th style=width:20% colspan=2 data-mainsort=1 data-firstsort=desc>Round 1<th style=width:20%>Round 2<th style=width:20%>Total<t

JavaScript Editor Plugin for Eclipse

JavaScript that allows for syntax checking


and autosuggestions for .js files in Eclipse?

  1. Use JSDoc more as JSDT has nice support for the standard, so you will get more suggestions for your own code.
  2. There is new TernIDE that provide additional hints for .js and AngulatJS .html. Get them together as Anide from

As Nodeclipse lead, I am always looking for what is available in Eclipse ecosystem. Nodeclipse site has even more links, and I am inviting to collaborate on the JavaScript tools on GitHub

cancelling a handler.postdelayed process

Here is a class providing a cancel method for a delayed action

public class DelayedAction {

private Handler _handler;
private Runnable _runnable;

 * Constructor
 * @param runnable The runnable
 * @param delay The delay (in milli sec) to wait before running the runnable
public DelayedAction(Runnable runnable, long delay) {
    _handler = new Handler(Looper.getMainLooper());
    _runnable = runnable;
    _handler.postDelayed(_runnable, delay);

 * Cancel a runnable
public void cancel() {
    if ( _handler == null || _runnable == null ) {

Plugin org.apache.maven.plugins:maven-clean-plugin:2.5 or one of its dependencies could not be resolved

Your debug output indicates that Clean is the first thing that it's trying to run, so I'm guessing it's failing to download any plugins from central.

First off, see if you can download the plugin jar directly in a web browser:

If that works then your web browser has connectivity to central but maven doesn't. That suggests to me that your web browser is using a proxy that maven isn't configured to use.

Maven proxy settings are described in depth here. To simplify that a little fill this out (replace the protocol/host/port with the values from your internet settings) and put it in the <settings> tag of your maven settings.xml file:


HTML5 Dynamically create Canvas

It happens because you call it before DOM has loaded. Firstly, create the element and add atrributes to it, then after DOM has loaded call it. In your case it should look like that:

var canvas = document.createElement('canvas');     = "CursorLayer";
canvas.width  = 1224;
canvas.height = 768;   = 8; = "absolute";   = "1px solid";
window.onload = function() {

Difference Between $.getJSON() and $.ajax() in jQuery


You don't need to specify that content-type on calls to MVC controller actions. The special "application/json; charset=utf-8" content-type is only necessary when calling ASP.NET AJAX "ScriptServices" and page methods. jQuery's default contentType of "application/x-www-form-urlencoded" is appropriate for requesting an MVC controller action.

More about that content-type here: JSON Hijacking and How ASP.NET AJAX 1.0 Avoids these Attacks


The data is correct as you have it. By passing jQuery a JSON object, as you have, it will be serialized as patientID=1 in the POST data. This standard form is how MVC expects the parameters.

You only have to enclose the parameters in quotes like "{ 'patientID' : 1 }" when you're using ASP.NET AJAX services. They expect a single string representing a JSON object to be parsed out, rather than the individual variables in the POST data.


It's not a problem in this specific case, but it's a good idea to get in the habit of quoting any string keys or values in your JSON object. If you inadvertently use a JavaScript reserved keyword as a key or value in the object, without quoting it, you'll run into a confusing-to-debug problem.

Conversely, you don't have to quote numeric or boolean values. It's always safe to use them directly in the object.

So, assuming you do want to POST instead of GET, your $.ajax() call might look like this:

  type: 'POST',
  url: '/Services/GetPatient',
  data: { 'patientID' : 1 },
  dataType: 'json',
  success: function(jsonData) {
  error: function() {
    alert('Error loading PatientID=' + id);

Using NSLog for debugging

Use NSLog() like this:

NSLog(@"The code runs through here!");

Or like this - with placeholders:

float aFloat = 5.34245;
NSLog(@"This is my float: %f \n\nAnd here again: %.2f", aFloat, aFloat);

In NSLog() you can use it like + (id)stringWithFormat:(NSString *)format, ...

float aFloat = 5.34245;
NSString *aString = [NSString stringWithFormat:@"This is my float: %f \n\nAnd here again: %.2f", aFloat, aFloat];

You can add other placeholders, too:

float aFloat = 5.34245;
int aInteger = 3;
NSString *aString = @"A string";
NSLog(@"This is my float: %f \n\nAnd here is my integer: %i \n\nAnd finally my string: %@", aFloat, aInteger, aString);

How to sort with a lambda?

Can the problem be with the "a.mProperty > b.mProperty" line? I've gotten the following code to work:

#include <algorithm>
#include <vector>
#include <iterator>
#include <iostream>
#include <sstream>

struct Foo
    Foo() : _i(0) {};

    int _i;

    friend std::ostream& operator<<(std::ostream& os, const Foo& f)
        os << f._i;
        return os;

typedef std::vector<Foo> VectorT;

std::string toString(const VectorT& v)
    std::stringstream ss;
    std::copy(v.begin(), v.end(), std::ostream_iterator<Foo>(ss, ", "));
    return ss.str();

int main()

    VectorT v(10);
    std::for_each(v.begin(), v.end(),
            [](Foo& f)
                f._i = rand() % 100;

    std::cout << "before sort: " << toString(v) << "\n";

    sort(v.begin(), v.end(),
            [](const Foo& a, const Foo& b)
                return a._i > b._i;

    std::cout << "after sort:  " << toString(v) << "\n";
    return 1;

The output is:

before sort: 83, 86, 77, 15, 93, 35, 86, 92, 49, 21,
after sort:  93, 92, 86, 86, 83, 77, 49, 35, 21, 15,

Connecting to via command line

Start session from terminal:

openssl s_client -connect -starttls smtp

The last line of the response should be "250 SMTPUTF8"

Initiate login

auth login

This should return "334 VXNlcm5hbWU6".

Type username

Type your username in base64 encoding (eg. echo -n 'your-username' | base64)

This should return "334 UGFzc3dvcmQ6"

Type password

Type your password in base64 encoding (eg. echo -n 'your-password' | base64)


You should see "235 2.7.0 Accepted" and you're are successfully logged in

Detecting value change of input[type=text] in jQuery

DON'T FORGET THE cut or select EVENTS!

The accepted answer is almost perfect, but it forgets about the cut and select events.

cut is fired when the user cuts text (CTRL + X or via right click)

select is fired when the user selects a browser-suggested option

You should add them too, as such:

$("#myTextBox").on("change paste keyup cut select", function() {
   //Do your function 

Load local javascript file in chrome for testing?

For security reasons, modern browsers won't load resource from locally running HTML files (files using file:// protocol in the address bar).

The easiest way to get a modern browser to load and run JavaScript files in local HTML files is to run a local web server.

If you don't want to go through the trouble of setting up a Node or Apache web server just to test your JavaScript, then I'd suggest you install Visual Studio Code and the Live Server extension.

Visual Studio Code

Visual Studio code is a source code editor for pretty much any programming language under the sun. It has built-in support for JavaScript, HTML, CSS, TypeScript, and almost any kind of language used for Web development.

Install Visual Studio Code

You can get the Visual Studio Code editor for your platform from It supports Windows, Linux, and Mac. I think it also works on your Surface Pro if that's your thing.

Add the Live Code Extension

After installing VS Code, you can add the Live Code code extension using the Extension panel (Ctrl+Shift+X in Windows) in Visual Studio Code.

Live Server Extension

After adding the extension, you should see a "Go Live" button in the bottom-right corner of the Visual Studio Code IDE (as shown in the above screenshot).

Open in Code

Open the root folder where your HTML and JavaScript files exist in Visual Studio Code and click the "Go Live" button. Optionally, you can right-click the HTML file in the Explorer (Ctrl+Shift+E) and select Open with Live Server from the pop-up menu that appears.

Open with Live Server

This should create a locally running web server and open the file or folder in your web browser. If your file paths are correct, your JavaScript files should also load and run correctly.


If for some reason, the page doesn't load in your favorite browser, check that the address and port number are correct. If the Live Server is running, it should display the port number in the bottom-right corner of the Visual Studio IDE. Make sure the address in your browser says<PORT>/index.html where <PORT> has the same number as shown in the status bar in Visual Studio Code.

How to build minified and uncompressed bundle with webpack?

You can format your webpack.config.js like this:

var debug = process.env.NODE_ENV !== "production";
var webpack = require('webpack');

module.exports = {
    context: __dirname,
    devtool: debug ? "inline-sourcemap" : null,
    entry: "./entry.js",
    output: {
        path: __dirname + "/dist",
        filename: "library.min.js"
    plugins: debug ? [] : [
        new webpack.optimize.DedupePlugin(),
        new webpack.optimize.OccurenceOrderPlugin(),
        new webpack.optimize.UglifyJsPlugin({ mangle: false, sourcemap: false }),

And then to build it unminified run (while in the project's main directory):

$ webpack

To build it minified run:

$ NODE_ENV=production webpack

Notes: Make sure that for the unminified version you change the output file name to library.js and for the minified library.min.js so they do not overwrite each other.

How can I declare optional function parameters in JavaScript?


With ES6, this is possible in exactly the manner you have described; a detailed description can be found in the documentation.

Old answer

Default parameters in JavaScript can be implemented in mainly two ways:

function myfunc(a, b)
    // use this if you specifically want to know if b was passed
    if (b === undefined) {
        // b was not passed
    // use this if you know that a truthy value comparison will be enough
    if (b) {
        // b was passed and has truthy value
    } else {
        // b was not passed or has falsy value
    // use this to set b to a default value (using truthy comparison)
    b = b || "default value";

The expression b || "default value" evaluates the value AND existence of b and returns the value of "default value" if b either doesn't exist or is falsy.

Alternative declaration:

function myfunc(a)
    var b;

    // use this to determine whether b was passed or not
    if (arguments.length == 1) {
        // b was not passed
    } else {
        b = arguments[1]; // take second argument

The special "array" arguments is available inside the function; it contains all the arguments, starting from index 0 to N - 1 (where N is the number of arguments passed).

This is typically used to support an unknown number of optional parameters (of the same type); however, stating the expected arguments is preferred!

Further considerations

Although undefined is not writable since ES5, some browsers are known to not enforce this. There are two alternatives you could use if you're worried about this:

b === void 0;
typeof b === 'undefined'; // also works for undeclared variables

How do I extend a class with c# extension methods?

They provide the capability to extend existing types by adding new methods with no modifications necessary to the type. Calling methods from objects of the extended type within an application using instance method syntax is known as ‘‘extending’’ methods. Extension methods are not instance members on the type. The key point to remember is that extension methods, defined as static methods, are in scope only when the namespace is explicitly imported into your application source code via the using directive. Even though extension methods are defined as static methods, they are still called using instance syntax.

Check the full example here,Methods_in_C_-sharp/201


class Extension
        static void Main(string[] args)
            string s = "sudhakar";

    public static class MyMathExtension

        public static int GetWordCount(this System.String mystring)
            return mystring.Length;

Setting up SSL on a local xampp/apache server

I did most of the suggested stuff here, still didnt work. Tried this and it worked: Open your XAMPP Control Panel, locate the Config button for the Apache module. Click on the Config button and Select PHP (php.ini). Open with any text editor and remove the semi-column before php_openssl. Save and Restart Apache. That should do!

How can I center a div within another div?

Use margin:0 auto; to the child div. Then you can center the child div inside the parent div.

What is the difference between =Empty and IsEmpty() in VBA (Excel)?

From the Help:
IsEmpty returns True if the variable is uninitialized, or is explicitly set to Empty; otherwise, it returns False. False is always returned if expression contains more than one variable.
IsEmpty only returns meaningful information for variants.

To check if a cell is empty, you can use cell(x,y) = "".
You might eventually save time by using Range("X:Y").SpecialCells(xlCellTypeBlanks) or xlCellTypeConstants or xlCellTypeFormulas

Copy row but with new id

depending on how many columns there are, you could just name the columns, sans the ID, and manually add an ID or, if it's in your table, a secondary ID (sid):

insert into PROG(date, level, Percent, sid) select date, level, Percent, 55 from PROG where sid = 31 Here, if sid 31 has more than one resultant row, all of them will be copied over to sid 55 and your auto iDs will still get auto-generated. for ID only: insert into PROG(date, level, Percent, ID) select date, level, Percent, 55 from PROG where ID = 31 where 55 is the next available ID in the table and ID 31 is the one you want to copy.

Delete all SYSTEM V shared memory and semaphores on UNIX-like systems

In addition to bvamos's answer, according to the documentation the use of sem is deprecated :

NAME ipcrm - remove a message queue, semaphore set or shared memory id SYNOPSIS ipcrm [ -M key | -m id | -Q key | -q id | -S key | -s id ] ... deprecated usage

ipcrm [ shm | msg | sem ] id ...

remove shared memory

us ipcrm -m to remove a shared memory segment by the id


set IPCS_M = ipcs -m | egrep "0x[0-9a-f]+ [0-9]+" | grep $USERNAME | cut -f2 -d" "

for id in $IPCS_M; do
  ipcrm -m $id;

or ipcrm -M to remove a shared memory segment by the key


set IPCS_M = ipcs -m | egrep "0x[0-9a-f]+ [0-9]+" | grep $USERNAME | cut -f1 -d" "

for id in $IPCS_M; do
  ipcrm -M $id;

remove message queues

us ipcrm -q to remove a shared memory segment by the id


set IPCS_Q = ipcs -q | egrep "0x[0-9a-f]+ [0-9]+" | grep $USERNAME | cut -f2 -d" "

for id in $IPCS_Q; do
  ipcrm -q $id;

or ipcrm -Q to remove a shared memory segment by the key


set IPCS_Q = ipcs -q | egrep "0x[0-9a-f]+ [0-9]+" | grep $USERNAME | cut -f1 -d" "

for id in $IPCS_Q; do
  ipcrm -Q $id;

remove semaphores

us ipcrm -s to remove a semaphore segment by the id


set IPCS_S = ipcs -s | egrep "0x[0-9a-f]+ [0-9]+" | grep $USERNAME | cut -f2 -d" "

for id in $IPCS_S; do
  ipcrm -s $id;

or ipcrm -S to remove a semaphore segment by the key


set IPCS_S = ipcs -s | egrep "0x[0-9a-f]+ [0-9]+" | grep $USERNAME | cut -f1 -d" "

for id in $IPCS_S; do
  ipcrm -S $id;

Single-threaded apartment - cannot instantiate ActiveX control

If you used [STAThread] to the main entry of your application and still get the error you may need to make a Thread-Safe call to the control... something like below. In my case with the same problem the following solution worked!

Private void YourFunc(..)
    if (this.InvokeRequired)
        Invoke(new MethodInvoker(delegate()
           // Call your method YourFunc(..);

How to open a file / browse dialog using javascript?

Here's is a way of doing it without any Javascript and it's also compatible with any browser.

EDIT: In Safari, the input gets disabled when hidden with display: none. A better approach would be to use position: fixed; top: -100em.

  Open file dialog
  <input type="file" style="position: fixed; top: -100em">

Also, if you prefer you can go the "correct way" by using for in the label pointing to the id of the input like this:

<label for="inputId">file dialog</label>
<input id="inputId" type="file" style="position: fixed; top: -100em">

rsync: difference between --size-only and --ignore-times

You are missing that rsync can also compare files by checksum.

--size-only means that rsync will skip files that match in size, even if the timestamps differ. This means it will synchronise fewer files than the default behaviour. It will miss any file with changes that don't affect the overall file size. If you have something that changes the dates on files without changing the files, and you don't want rsync to spend lots of time checksumming those files to discover they haven't changed, this is the option to use.

--ignore-times means that rsync will checksum every file, even if the timestamps and file sizes match. This means it will synchronise more files than the default behaviour. It will include changes to files even where the file size is the same and the modification date/time has been reset to the original value. Checksumming every file means it has to be entirely read from disk, which may be slow. Some build pipelines will reset timestamps to a specific date (like 1970-01-01) to ensure that the final build file is reproducible bit for bit, e.g. when packed into a tar file that saves the timestamps.

how to implement regions/code collapse in javascript

It works like a charm in PhpStorm

//#region My Region 1

//#region My Region 2

my regions

Creating a constant Dictionary in C#

There are precious few immutable collections in the current framework. I can think of one relatively pain-free option in .NET 3.5:

Use Enumerable.ToLookup() - the Lookup<,> class is immutable (but multi-valued on the rhs); you can do this from a Dictionary<,> quite easily:

    Dictionary<string, int> ids = new Dictionary<string, int> {
      {"abc",1}, {"def",2}, {"ghi",3}
    ILookup<string, int> lookup = ids.ToLookup(x => x.Key, x => x.Value);
    int i = lookup["def"].Single();

Jquery post, response in new window

I did it with an ajax post and then returned using a data url:

$(document).ready(function () {
    var exportClick = function () {
           url: "/api/test.php",
           type: "POST",
           dataType: "text",
           data: {
              action: "getCSV",
              filter: "name = 'smith'",
           success: function(data) {
              var w ='data:text/csv;charset=utf-8,' + encodeURIComponent(data));
           error: function () {
              alert('Problem getting data');

Sort divs in jQuery based on attribute 'data-sort'?

Use this function

   var result = $('div').sort(function (a, b) {

      var contentA =parseInt( $(a).data('sort'));
      var contentB =parseInt( $(b).data('sort'));
      return (contentA < contentB) ? -1 : (contentA > contentB) ? 1 : 0;


You can call this function just after adding new divs.

If you want to preserve javascript events within the divs, DO NOT USE html replace as in the above example. Instead use:

$(targetSelector).sort(function (a, b) {
    // ...

The response content cannot be parsed because the Internet Explorer engine is not available, or

To make it work without modifying your scripts:

I found a solution here:

The error is probably coming up because IE has not yet been launched for the first time, bringing up the window below. Launch it and get through that screen, and then the error message will not come up any more. No need to modify any scripts.

ie first launch window

How to get list of all installed packages along with version in composer?

If you only want to check version for only one, you can do

composer show -- twig/twig

Note that only installed packages are shown by default now, and installed option is now deprecated.

JavaScript error: "is not a function"

I also hit this error. In my case the root cause was async related (during a codebase refactor): An asynchronous function that builds the object to which the "not a function" function belongs was not awaited, and the subsequent attempt to invoke the function throws the error, example below:

const car = carFactory.getCar(); //throws TypeError: drive is not a function

The fix was:

const car = await carFactory.getCar();

Posting this incase it helps anyone else facing this error.

bash script use cut command at variable and store result at another variable

You can avoid the loop and cut etc by using:

awk -F ':' '{system("ping " $1);}' config.txt

However it would be better if you post a snippet of your config.txt

How can I control the speed that bootstrap carousel slides in items?

after including bootstrap.min.js or uncompressed one, you can just add interval as a parameter as below jQuery("#numbers").carousel({'interval':900 }); It works for me

Access denied for user 'root'@'localhost' while attempting to grant privileges. How do I grant privileges?

I run at this when I tried to add privileges to performance_schema, which is mysql bug (workaround to add --single-transaction).

Check if string is in a pandas dataframe

You should check the value of your line of code like adding checking length of it.

    print("Name Present")

Why is AJAX returning HTTP status code 0?

"Accidental" form submission was exactly the problem I was having. I just removed the FORM tags altogether and that seems to fix the problem. Thank you, everybody!

A KeyValuePair in Java

My favorite is

HashMap<Type1, Type2>

All you have to do is specify the datatype for the key for Type1 and the datatype for the value for Type2. It's the most common key-value object I've seen in Java.

What's the difference between "static" and "static inline" function?

From my experience with GCC I know that static and static inline differs in a way how compiler issue warnings about unused functions. More precisely when you declare static function and it isn't used in current translation unit then compiler produce warning about unused function, but you can inhibit that warning with changing it to static inline.

Thus I tend to think that static should be used in translation units and benefit from extra check compiler does to find unused functions. And static inline should be used in header files to provide functions that can be in-lined (due to absence of external linkage) without issuing warnings.

Unfortunately I cannot find any evidence for that logic. Even from GCC documentation I wasn't able to conclude that inline inhibits unused function warnings. I'd appreciate if someone will share links to description of that.

How to get date in BAT file

set datestr=%date%
set result=%datestr:/=-%
@echo %result%

How to remove an element slowly with jQuery?

I'm little late to the party, but for anyone like me that came from a Google search and didn't find the right answer. Don't get me wrong there are good answers here, but not exactly what I was looking for, without further ado, here is what I did:

$(document).ready(function() {
    var $deleteButton = $('.deleteItem');

    $deleteButton.on('click', function(event) {

      var $button = $(this);

      if(confirm('Are you sure about this ?')) {

        var $item = $button.closest('tr.item');

            .one('webkitAnimationEnd oanimationend msAnimationEnd animationend', function(e) {
 * Credit to Sara Soueidan
 * @link

.removed-item {
    -webkit-animation: removed-item-animation .6s cubic-bezier(.55,-0.04,.91,.94) forwards;
    -o-animation: removed-item-animation .6s cubic-bezier(.55,-0.04,.91,.94) forwards;
    animation: removed-item-animation .6s cubic-bezier(.55,-0.04,.91,.94) forwards

@keyframes removed-item-animation {
    from {
        opacity: 1;
        -webkit-transform: scale(1);
        -ms-transform: scale(1);
        -o-transform: scale(1);
        transform: scale(1)

    to {
        -webkit-transform: scale(0);
        -ms-transform: scale(0);
        -o-transform: scale(0);
        transform: scale(0);
        opacity: 0

@-webkit-keyframes removed-item-animation {
    from {
        opacity: 1;
        -webkit-transform: scale(1);
        transform: scale(1)

    to {
        -webkit-transform: scale(0);
        transform: scale(0);
        opacity: 0

@-o-keyframes removed-item-animation {
    from {
        opacity: 1;
        -o-transform: scale(1);
        transform: scale(1)

    to {
        -o-transform: scale(0);
        transform: scale(0);
        opacity: 0
<!DOCTYPE html>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width">
  <title>JS Bin</title>
  <link href="" rel="stylesheet"/>
  <table class="table table-striped table-bordered table-hover">
      <tr class="item">
        <td><button class="btn btn-danger deleteItem">Delete</button></td>
      <tr class="item">
        <td><button class="btn btn-danger deleteItem">Delete</button></td>
      <tr class="item">
        <td><button class="btn btn-danger deleteItem">Delete</button></td>
<script src=""></script>


OR is not supported with CASE Statement in SQL Server

  WHEN ebv.db_no = 22978 OR 
       ebv.db_no = 23218 OR
       ebv.db_no = 23219
  THEN 'WECS 9500' 
  ELSE 'WECS 9520' 
END as wecs_system 

npm ERR! network getaddrinfo ENOTFOUND

I also faced this error but I was not working behind a proxy server at the moment so using npm config set proxy=http://address:8080 couldn't help and ~/.npmrc didn't contain any proxy setting either. The solution in my case was just to restart my computer.

Waiting until two async blocks are executed before starting another block

Another GCD alternative is a barrier:

dispatch_queue_t queue = dispatch_queue_create("", DISPATCH_QUEUE_CONCURRENT);

dispatch_async(queue, ^{ 
    NSLog(@"start one!\n");  
    NSLog(@"end one!\n");

dispatch_async(queue, ^{  
    NSLog(@"start two!\n");  
    NSLog(@"end two!\n"); 

dispatch_barrier_async(queue, ^{  
    NSLog(@"Hi, I'm the final block!\n");  

Just create a concurrent queue, dispatch your two blocks, and then dispatch the final block with barrier, which will make it wait for the other two to finish.

int *array = new int[n]; what is this function actually doing?

It allocates that much space according to the value of n and pointer will point to the array i.e the 1st element of array

int *array = new int[n];

Figure out size of UILabel based on String in Swift

For multiline text this answer is not working correctly. You can build a different String extension by using UILabel

extension String {
func height(constraintedWidth width: CGFloat, font: UIFont) -> CGFloat {
    let label =  UILabel(frame: CGRect(x: 0, y: 0, width: width, height: .greatestFiniteMagnitude))
    label.numberOfLines = 0
    label.text = self
    label.font = font

    return label.frame.height

The UILabel gets a fixed width and the .numberOfLines is set to 0. By adding the text and calling .sizeToFit() it automatically adjusts to the correct height.

Code is written in Swift 3

WCF ServiceHost access rights

I am working on Windows Vista. Even i faced the same problem but when i tried to run VS 2008 with administrative privileges, the issue resolved and my service was up and running. :)

How to compile .c file with OpenSSL includes?

If the OpenSSL headers are in the openssl sub-directory of the current directory, use:

gcc -I. -o Opentest Opentest.c -lcrypto

The pre-processor looks to create a name such as "./openssl/ssl.h" from the "." in the -I option and the name specified in angle brackets. If you had specified the names in double quotes (#include "openssl/ssl.h"), you might never have needed to ask the question; the compiler on Unix usually searches for headers enclosed in double quotes in the current directory automatically, but it does not do so for headers enclosed in angle brackets (#include <openssl/ssl.h>). It is implementation defined behaviour.

You don't say where the OpenSSL libraries are - you might need to add an appropriate option and argument to specify that, such as '-L /opt/openssl/lib'.

What is the C# equivalent of friend?

Take a very common pattern. Class Factory makes Widgets. The Factory class needs to muck about with the internals, because, it is the Factory. Both are implemented in the same file and are, by design and desire and nature, tightly coupled classes -- in fact, Widget is really just an output type from factory.

In C++, make the Factory a friend of Widget class.

In C#, what can we do? The only decent solution that has occurred to me is to invent an interface, IWidget, which only exposes the public methods, and have the Factory return IWidget interfaces.

This involves a fair amount of tedium - exposing all the naturally public properties again in the interface.

How to get current time in milliseconds in PHP?

As other have stated, you can use microtime() to get millisecond precision on timestamps.

From your comments, you seem to want it as a high-precision UNIX Timestamp. Something like DateTime.Now.Ticks in the .NET world.

You may use the following function to do so:

function millitime() {
  $microtime = microtime();
  $comps = explode(' ', $microtime);

  // Note: Using a string here to prevent loss of precision
  // in case of "overflow" (PHP converts it to a double)
  return sprintf('%d%03d', $comps[1], $comps[0] * 1000);

Which Java library provides base64 encoding/decoding?

Java 9

Use the Java 8 solution. Note DatatypeConverter can still be used, but it is now within the java.xml.bind module which will need to be included.

module {
    requires java.xml.bind;

Java 8

Java 8 now provides java.util.Base64 for encoding and decoding base64.


byte[] message = "hello world".getBytes(StandardCharsets.UTF_8);
String encoded = Base64.getEncoder().encodeToString(message);
// => aGVsbG8gd29ybGQ=


byte[] decoded = Base64.getDecoder().decode("aGVsbG8gd29ybGQ=");
System.out.println(new String(decoded, StandardCharsets.UTF_8));
// => hello world

Java 6 and 7

Since Java 6 the lesser known class javax.xml.bind.DatatypeConverter can be used. This is part of the JRE, no extra libraries required.


byte[] message = "hello world".getBytes("UTF-8");
String encoded = DatatypeConverter.printBase64Binary(message);
// => aGVsbG8gd29ybGQ=  


byte[] decoded = DatatypeConverter.parseBase64Binary("aGVsbG8gd29ybGQ=");
System.out.println(new String(decoded, "UTF-8"));
// => hello world

Android Studio: Gradle: error: cannot find symbol variable

Open project in android studio click file and click Invalidate Caches/Restart

How to pattern match using regular expression in Scala?

First we should know that regular expression can separately be used. Here is an example:

import scala.util.matching.Regex
val pattern = "Scala".r // <=> val pattern = new Regex("Scala")
val str = "Scala is very cool"
val result = pattern findFirstIn str
result match {
  case Some(v) => println(v)
  case _ =>
} // output: Scala

Second we should notice that combining regular expression with pattern matching would be very powerful. Here is a simple example.

val date = """(\d\d\d\d)-(\d\d)-(\d\d)""".r
"2014-11-20" match {
  case date(year, month, day) => "hello"
} // output: hello

In fact, regular expression itself is already very powerful; the only thing we need to do is to make it more powerful by Scala. Here are more examples in Scala Document:

JPA and Hibernate - Criteria vs. JPQL or HQL

Criteria is an object-oriented API, while HQL means string concatenation. That means all of the benefits of object-orientedness apply:

  1. All else being equal, the OO version is somewhat less prone to error. Any old string could get appended into the HQL query, whereas only valid Criteria objects can make it into a Criteria tree. Effectively, the Criteria classes are more constrained.
  2. With auto-complete, the OO is more discoverable (and thus easier to use, for me at least). You don't necessarily need to remember which parts of the query go where; the IDE can help you
  3. You also don't need to remember the particulars of the syntax (like which symbols go where). All you need to know is how to call methods and create objects.

Since HQL is very much like SQL (which most devs know very well already) then these "don't have to remember" arguments don't carry as much weight. If HQL was more different, then this would be more importatnt.

How do I set <table> border width with CSS?

The reason it didn't work is that despite setting the border-width and the border-color you didn't specify the border-style:

<table style="border-width:1px;border-color:black;border-style:solid;">

JS Fiddle demo.

It's usually better to define the styles in the stylesheet (so that all elements are styled without having to find, and change, every element's style attribute):

table {
    border-color: #000;
    border-width: 1px;
    border-style: solid;
    /* or, of course,
    border: 1px solid #000;

JS Fiddle demo (Or using shorthand border notation).

Creation timestamp and last update timestamp with Hibernate and MySQL

You might consider storing the time as a DateTime, and in UTC. I typically use DateTime instead of Timestamp because of the fact that MySql converts dates to UTC and back to local time when storing and retrieving the data. I'd rather keep any of that kind of logic in one place (Business layer). I'm sure there are other situations where using Timestamp is preferable though.

How to execute a function when page has fully loaded?

The onload property of the GlobalEventHandlers mixin is an event handler for the load event of a Window, XMLHttpRequest, element, etc., which fires when the resource has loaded.

So basically javascript already has onload method on window which get executed which page fully loaded including images...

You can do something:

var spinner = true;

window.onload = function() {
  //whatever you like to do now, for example hide the spinner in this case
  spinner = false;

How to delete the top 1000 rows from a table using Sql Server 2008?

It is fast. Try it:


Replace YourTABLE by table name, XX by a number, for example 1000, pk is the name of the primary key field of your table.

Why does this CSS margin-top style not work?

I guess setting the position property of the #inner div to relative may also help achieve the effect. But anyways I tried the original code pasted in the Question on IE9 and latest Google Chrome and they already give the desirable effect without any modifications.

How can I generate a unique ID in Python?

Perhaps uuid.uuid4() might do the job. See uuid for more information.

How do I change Bootstrap 3 column order on mobile layout?

This is quite easy with jQuery using insertAfter() or insertBefore():

<div class="left">content</div>
<div class="right">sidebar</div>


If you want to to set o condition for mobile devices you can make it like this:

  var $iW = $(window).innerWidth();
  if ($iW < 992){


Can't connect to docker from docker-compose

I've had the same symptoms.

Only diff that it happened only during docker-compose build docker ps worked. Happened with version 2.x as well as 3.x. Restarted docker service, then the machine... Even re-installed docker + docker-compose.

Tried everything but nothing helped.

Finally I tried building the Dockerfile "manually" by using docker build.

Apparently I had a permission issue on a file/folder inside the Docker context. It was trying to read the context when starting the build and failed with a proper error message. However this error message did not propagate to docker-compose which only shows Couldn't connect to Docker daemon at http+unix://var/run/docker.sock - is it running?

Having found that the solution was simply adding the file/folder to the .dockerignore file since it wasn't needed for the build. Another solution might have been to chown or chmod it.

Anyway maybe this could help someone coming across the same issue that really has nothing to do with docker and the misleading error message being displayed.

How to change a PG column to NULLABLE TRUE?

From the fine manual:


There's no need to specify the type when you're just changing the nullability.

How to get temporary folder for current user

I have this same requirement - we want to put logs in a specific root directory that should exist within the environment.

public static readonly string DefaultLogFilePath = Environment.GetFolderPath(Environment.SpecialFolder.UserProfile);

If I want to combine this with a sub-directory, I should be able to use Path.Combine( ... ).

The GetFolderPath method has an overload for special folder options which allows you to control whether the specified path be created or simply verified.

ExpressJS How to structure an application?

This may be of interest:

Hierarchical node.js configuration with files, environment variables, command-line arguments, and atomic object merging.

Session 'app': Error Launching activity

OK already so many possible solutions for this problem, if none of those works then try this.

I faced this problem when I first uninstalled my app then tried reinstalling from ADB. But then after trying these many solutions, I realized that uninstalling app nowadays does not really uninstall it. It just disables it for few days so that it can be enabled in case you change your mind.

Now I am not sure whether its done by LG or Native Android Nougat.

I just went in Settings-> apps-> my-app and uninstalled it completely. After that from Android studio I am able to install the app again properly without this error.

PHP compare time

Simple way to compare time is :

$time = date('H:i:s',strtotime("11 PM"));
if($time < date('H:i:s')){
     // your code

Convert JS object to JSON string

Just use JSON.stringify to do such conversion - however remember that fields which have undefined value will not be included into json

var j={"name":"binchen", "remember":undefined, "age": null };_x000D_
var s=JSON.stringify(j);_x000D_

The field remember 'disappear' from output json

Angular 2 : No NgModule metadata found

In my case, I had defined a couple of (private) static methods in one of my components and was using them in the same component.

Setting up connection string in ASP.NET to SQL SERVER

You can also use external configuration file to specify connection strings section, and refer that file in application configuration file like in web.config

Like the in web.config file:

    <connectionStrings configSource="connections.config"/>  

The external configuration connections.config file will contains connections section

  <add name="Name"   
   connectionString="Valid Connection String;" />  


Modifying contents of external configuration file will not restart the application (as does by default with any change in application configuration files)

Invalid attempt to read when no data is present

You have to call dr.Read() before attempting to read any data. That method will return false if there is nothing to read.

How to Decode Json object in laravel and apply foreach loop on that in laravel

your string is NOT a valid json to start with.

a valid json will be,

    "area": [
            "area": "kothrud"
            "area": "katraj"

if you do a json_decode, it will yield,

stdClass Object
    [area] => Array
            [0] => stdClass Object
                    [area] => kothrud

            [1] => stdClass Object
                    [area] => katraj



Update: to use

$string = '

    "area": [
            "area": "kothrud"
            "area": "katraj"

            $area = json_decode($string, true);

            foreach($area['area'] as $i => $v)
                echo $v['area'].'<br/>';



Update #2:

for that true:

When TRUE, returned objects will be converted into associative arrays. for more information, click here

Can scripts be inserted with innerHTML?

You can also wrap your <script> like this and it will get executed:

<your target node>.innerHTML = '<iframe srcdoc="<script>alert(top.document.title);</script>"></iframe>';

Please note: The scope inside srcdoc refers to the iframe, so you have to use top like in the example above to access the parent document.

Controlling number of decimal digits in print output in R

One more solution able to control the how many decimal digits to print out based on needs (if you don't want to print redundant zero(s))

For example, if you have a vector as elements and would like to get sum of it

elements <- c(-1e-05, -2e-04, -3e-03, -4e-02, -5e-01, -6e+00, -7e+01, -8e+02)
## -876.5432

Apparently, the last digital as 1 been truncated, the ideal result should be -876.54321, but if set as fixed printing decimal option, e.g sprintf("%.10f", sum(elements)), redundant zero(s) generate as -876.5432100000

Following the tutorial here: printing decimal numbers, if able to identify how many decimal digits in the certain numeric number, like here in -876.54321, there are 5 decimal digits need to print, then we can set up a parameter for format function as below:

decimal_length <- 5
formatC(sum(elements), format = "f", digits = decimal_length)
## -876.54321

We can change the decimal_length based on each time query, so it can satisfy different decimal printing requirement.

Sum of Numbers C++

The loop is great; it's what's inside the loop that's wrong. You need a variable named sum, and at each step, add i+1 to sum. At the end of the loop, sum will have the right value, so print it.

How to escape strings in SQL Server using PHP?

addslashes() isn't fully adequate, but PHP's mssql package doesn't provide any decent alternative. The ugly but fully general solution is encoding the data as a hex bytestring, i.e.

$unpacked = unpack('H*hex', $data);
    INSERT INTO sometable (somecolumn)
    VALUES (0x' . $unpacked['hex'] . ')

Abstracted, that would be:

function mssql_escape($data) {
        return $data;
    $unpacked = unpack('H*hex', $data);
    return '0x' . $unpacked['hex'];

    INSERT INTO sometable (somecolumn)
    VALUES (' . mssql_escape($somevalue) . ')

mysql_error() equivalent is mssql_get_last_message().

Tomcat startup logs - SEVERE: Error filterStart how to get a stack trace?

if anyone is getting error like SEVERE: Error filterStart Apr 29, 2013 4:49:20 PM org.apache.catalina.core.StandardContext startInternal SEVERE: Context [/TraceMW] startup failed due to previous errors

then please check whether your tomcat/lib directory contains cors-filter-1.5.jar or not. if you dot have u will get above error and ur application will not be available.

So, i just managed to copy the jar file from other tomcat folder and i didnt get the above mentioned error later.

How to import an existing project from GitHub into Android Studio

You can directly import github projects into Android Studio. File -> New -> Project from Version Control -> GitHub. Then enter your github username and password.Select the repository and hit clone.

The github repo will be created as a new project in android studio.

How to change a particular element of a C++ STL vector

at and operator[] both return a reference to the indexed element, so you can simply use: = -1;


l[4] = -1;

How to sort an array in descending order in Ruby

I see that we have (beside others) basically two options:

a.sort_by { |h| -h[:bar] }


a.sort_by { |h| h[:bar] }.reverse

While both ways give you the same result when your sorting key is unique, keep in mind that the reverse way will reverse the order of keys that are equal.


a = [{foo: 1, bar: 1},{foo: 2,bar: 1}]
a.sort_by {|h| -h[:bar]}
 => [{:foo=>1, :bar=>1}, {:foo=>2, :bar=>1}]
a.sort_by {|h| h[:bar]}.reverse
 => [{:foo=>2, :bar=>1}, {:foo=>1, :bar=>1}]

While you often don't need to care about this, sometimes you do. To avoid such behavior you could introduce a second sorting key (that for sure needs to be unique at least for all items that have the same sorting key):

a.sort_by {|h| [-h[:bar],-h[:foo]]}
 => [{:foo=>2, :bar=>1}, {:foo=>1, :bar=>1}]
a.sort_by {|h| [h[:bar],h[:foo]]}.reverse
 => [{:foo=>2, :bar=>1}, {:foo=>1, :bar=>1}]

How do I use shell variables in an awk script?

You could pass in the command-line option -v with a variable name (v) and a value (=) of the environment variable ("${v}"):

% awk -vv="${v}" 'BEGIN { print v }'

Or to make it clearer (with far fewer vs):

% environment_variable=123test
% awk -vawk_variable="${environment_variable}" 'BEGIN { print awk_variable }'

Microsoft Advertising SDK doesn't deliverer ads

I only use MicrosoftAdvertising.Mobile and Microsoft.Advertising.Mobile.UI and I am served ads. The SDK should only add the DLLs not reference itself.

Note: You need to explicitly set width and height Make sure the phone dialer, and web browser capabilities are enabled

Followup note: Make sure that after you've removed the SDK DLL, that the xmlns references are not still pointing to it. The best route to take here is

  1. Remove the XAML for the ad
  2. Remove the xmlns declaration (usually at the top of the page, but sometimes will be declared in the ad itself)
  3. Remove the bad DLL (the one ending in .SDK )
  4. Do a Clean and then Build (clean out anything remaining from the DLL)
  5. Add the xmlns reference (actual reference is below)
  6. Add the ad to the page (example below)

Here is the xmlns reference:


Then the ad itself:

<AdNamespace:AdControl x:Name="myAd" Height="80" Width="480"                    AdUnitId="yourAdUnitIdHere" ApplicationId="yourIdHere"/> 

What is the difference between require() and library()?

My initial theory about the difference was that library loads the packages whether it is already loaded or not, i.e. it might reload an already loaded package, while require just checks that it is loaded, or loads it if it isn't (thus the use in functions that rely on a certain package). The documentation refutes this, however, and explicitly states that neither function will reload an already loaded package.

Compiler warning - suggest parentheses around assignment used as truth value

While that particular idiom is common, even more common is for people to use = when they mean ==. The convention when you really mean the = is to use an extra layer of parentheses:

while ((list = list->next)) { // yes, it's an assignment

changing source on html5 video tag

Modernizr worked like a charm for me.

What I did is that I didn't use <source>. Somehow this screwed things up, since the video only worked the first time load() was called. Instead I used the source attribute inside the video tag -> <video src="blabla.webm" /> and used Modernizr to determine what format the browser supported.

var v = new Array();

v[0] = [
v[1] = [
v[2] = [

function changeVid(n){
    var video = document.getElementById('video');

    if( && {
        video.setAttribute("src", v[n][0]);
    } else if( && {
        video.setAttribute("src", v[n][1]);
    } else if( && {
        video.setAttribute("src", v[n][2]);


Hopefully this will help you :)

If you don't want to use Modernizr , you can always use CanPlayType().

ProgressDialog spinning circle

Just change from ProgressDialog to ProgressBar in a layout:


<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android=""

        android:layout_height="match_parent" >
        //Your content here

            android:indeterminateDrawable="@drawable/progress" >


public class YourActivity extends Activity{

private ProgressBar bar;

protected void onCreate(Bundle savedInstanceState) {
    bar = (ProgressBar) this.findViewById(;
    new ProgressTask().execute();
private class ProgressTask extends AsyncTask <Void,Void,Void>{
    protected void onPreExecute(){

    protected Void doInBackground(Void... arg0) {   
           //my stuff is here

    protected void onPostExecute(Void result) {

drawable/progress.xml This is a custom ProgressBar that i use to change the default colors.

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

    Duration = 1 means that one rotation will be done in 1 second. leave it.
    If you want to speed up the rotation, increase duration value. 
    in example 1080 shows three times faster revolution. 
    make the value multiply of 360, or the ring animates clunky 
<rotate xmlns:android=""
    android:toDegrees="360" >

        android:useLevel="false" >
            android:width="48dip" />

            android:useLevel="false" />


An unhandled exception was generated during the execution of the current web request

In my case, I created a new project and when I ran it the first time, it gave me the following error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

So my solution was to go to the Package Manager Console inside the Visual Studio and run:Update-Package

Problem solved!!

How to call a function within class?

Since these are member functions, call it as a member function on the instance, self.

def isNear(self, p):

How to position background image in bottom right corner? (CSS)

for more exactly positioning:

      background-position: bottom 5px right 7px;

Change Activity's theme programmatically

I have used this code to implement dark worked fine for me...You can use it in a switch on....listener...

//setting up Night Mode...
//Store current mode in a sharedprefernce to retrieve on restarting app
            editor.putBoolean("NightMode", true);
//restart all the activities to apply changed mode...
                    .addNextIntent(new Intent(getActivity(), MainActivity.class))

How can I remove a substring from a given String?

This works good for me.

String hi = "Hello World!"
String no_o = hi.replaceAll("o", "");

or you can use

String no_o = hi.replace("o", "");

How to add a linked source folder in Android Studio?

While sourceSets allows you to include entire directory structures, there's no way to exclude parts of it in Android Studio (as of version 1.2), as described here: Android Studio Exclude Class from build?

Until Android Studio gets updated to support include/exclude directives for Android sources, Symlinks work quite well. If you're using Windows, native tools such as junction or mklink can accomplish the equivalent of Un*x symlinks. CygWin can also create these with a little coersion. See: Git Symlinks in Windows and How to make symbolic link with cygwin in Windows 7

How to update and order by using ms sql

As stated in comments below, you can use also the SET ROWCOUNT clause, but just for SQL Server 2014 and older.


UPDATE messages
SET status = 10 
WHERE status = 0 


More info:

Or with a temp table

INSERT @t (id)
FROM messages
WHERE status = 0
ORDER BY priority DESC

UPDATE messages
SET status = 10

how to query LIST using linq

Well, the code you've given is invalid to start with - List is a generic type, and it has an Add method instead of add etc.

But you could do something like:

List<Person> list = new List<Person>
    new person{ID=1,Name="jhon",salary=2500},
    new person{ID=2,Name="Sena",salary=1500},
    new person{ID=3,Name="Max",salary=5500}.
    new person{ID=4,Name="Gen",salary=3500}

// The "Where" LINQ operator filters a sequence
var highEarners = list.Where(p => p.salary > 3000);

foreach (var person in highEarners)

If you want to learn details of what all the LINQ operators do, and how they can be implemented in LINQ to Objects, you might be interested in my Edulinq blog series.

"detached entity passed to persist error" with JPA/EJB code


Let's say you have two entities Album and Photo. Album contains many photos, so it's a one to many relationship.

Album class

public class Album {
    Integer albumId;

    String albumName;

    Set<Photo> photos = new HashSet<Photo>();

Photo class

public class Photo{
    Integer photo_id;

    String photoName;

    Album album;


What you have to do before persist or merge is to set the Album reference in each photos.

        Album myAlbum = new Album();
        Photo photo1 = new Photo();
        Photo photo2 = new Photo();


That is how to attach the related entity before you persist or merge.

java: run a function after a specific number of seconds

Example of using javax.swing.Timer

Timer timer = new Timer(3000, new ActionListener() {
  public void actionPerformed(ActionEvent arg0) {
    // Code to be executed
timer.setRepeats(false); // Only execute once
timer.start(); // Go go go!

This code will only be executed once, and the execution happens in 3000 ms (3 seconds).

As camickr mentions, you should lookup "How to Use Swing Timers" for a short introduction.

How can I search (case-insensitive) in a column using LIKE wildcard?

This is the example of a simple LIKE query:

SELECT * FROM <table> WHERE <key> LIKE '%<searchpattern>%'

Now, case-insensitive using LOWER() func:

SELECT * FROM <table> WHERE LOWER(<key>) LIKE LOWER('%<searchpattern>%')

How to sync with a remote Git repository?

You need to add the original repository (the one that you forked) as a remote.

git remote add github (clone url for the orignal repository)

Then you need to bring in the changes to your local repository

git fetch github

Now you will have all the branches of the original repository in your local one. For example, the master branch will be github/master. With these branches you can do what you will. Merge them into your branches etc

SQL Server Express 2008 Install Side-by-side w/ SQL 2005 Express Fails

I also had to remove the SMSS before it would get past that step.

Node.js check if path is file or directory

The answers above check if a filesystem contains a path that is a file or directory. But it doesn't identify if a given path alone is a file or directory.

The answer is to identify directory-based paths using "/." like --> "/c/dos/run/." <-- trailing period.

Like a path of a directory or file that has not been written yet. Or a path from a different computer. Or a path where both a file and directory of the same name exists.

// /tmp/
// |- dozen.path
// |- dozen.path/.
//    |- eggs.txt
// "/tmp/dozen.path" !== "/tmp/dozen.path/"
// Very few fs allow this. But still. Don't trust the filesystem alone!

// Converts the non-standard "path-ends-in-slash" to the standard "path-is-identified-by current "." or previous ".." directory symbol.
function tryGetPath(pathItem) {
    const isPosix = pathItem.includes("/");
    if ((isPosix && pathItem.endsWith("/")) ||
        (!isPosix && pathItem.endsWith("\\"))) {
        pathItem = pathItem + ".";
    return pathItem;
// If a path ends with a current directory identifier, it is a path! /c/dos/run/. and c:\dos\run\.
function isDirectory(pathItem) {
    const isPosix = pathItem.includes("/");
    if (pathItem === "." || pathItem ==- "..") {
        pathItem = (isPosix ? "./" : ".\\") + pathItem;
    return (isPosix ? pathItem.endsWith("/.") || pathItem.endsWith("/..") : pathItem.endsWith("\\.") || pathItem.endsWith("\\.."));
// If a path is not a directory, and it isn't empty, it must be a file
function isFile(pathItem) {
    if (pathItem === "") {
        return false;
    return !isDirectory(pathItem);

Node version: v11.10.0 - Feb 2019

Last thought: Why even hit the filesystem?

Delete all objects in a list

Here's how you delete every item from a list.

del c[:]

Here's how you delete the first two items from a list.

del c[:2]

Here's how you delete a single item from a list (a in your case), assuming c is a list.

del c[0]

How to get certain commit from GitHub project

Try the following command sequence:

$ git fetch origin <copy/past commit sha1 here>
$ git checkout FETCH_HEAD
$ git push origin master

Cannot truncate table because it is being referenced by a FOREIGN KEY constraint?

use the following command after deletion of all rows in that table by using delete statement

delete from tablename

DBCC CHECKIDENT ('tablename', RESEED, 0)

EDIT: Corrected syntax for SQL Server

1052: Column 'id' in field list is ambiguous

You would do that by providing a fully qualified name, e.g.:

SELECT as id, name, section FROM tbl_names, tbl_section WHERE =

Which would give you the id of tbl_names

JavaScript variable assignments from tuples

This "tuple" feature it is called destructuring in EcmaScript2015 and is soon to be supported by up to date browsers. For the time being, only Firefox and Chrome support it.

But hey, you can use a transpiler.

The code would look as nice as python:

let tuple = ["Bob", 24]
let [name, age] = tuple


How to load a resource from WEB-INF directory of a web archive

The problem I had accessing the sqlite db file I created in my java (jersey) server had solely to due with path. Some of the docs say the jdbc connect url should look like "jdbc:sqlite://path-to-file/sample.db". I thought the double-slash was part of a htt protocol-style path and would map properly when deployed, but in actuality, it's an absolute or relative path. So, when I placed the file at the root of the WebContent folder (tomcat project), a uri like this worked "jdbc:sqlite:sample.db".

The one thing that was throwing me was that when I was stepping through the debugger, I received a message that said "opening db: ... permission denied". I thought it was a matter of file system permissions or perhaps sql user permissions. After finding out that SQLite doesn't have the concept of roles/permissions like MySQL, etc, I did eventually change the file permissions before I came to what I believe was the correct solution, but I think it was just a bad message (i.e. permission denied, instead of File not found).

Hope this helps someone.

PHP - Failed to open stream : No such file or directory

Samba Shares

If you have a Linux test server and you work from a Windows Client, the Samba share interferes with the chmod command. So, even if you use:

chmod -R 777 myfolder

on the Linux side it is fully possible that the Unix Group\www-data still doesn't have write access. One working solution if your share is set up that Windows admins are mapped to root: From Windows, open the Permissions, disable Inheritance for your folder with copy, and then grant full access for www-data.

How can I install the VS2017 version of msbuild on a build server without installing the IDE?

The Visual Studio Build tools are a different download than the IDE. They appear to be a pretty small subset, and they're called Build Tools for Visual Studio 2019 (download).

You can use the GUI to do the installation, or you can script the installation of msbuild:

vs_buildtools.exe --add Microsoft.VisualStudio.Workload.MSBuildTools --quiet

Microsoft.VisualStudio.Workload.MSBuildTools is a "wrapper" ID for the three subcomponents you need:

  • Microsoft.Component.MSBuild
  • Microsoft.VisualStudio.Component.CoreBuildTools
  • Microsoft.VisualStudio.Component.Roslyn.Compiler

You can find documentation about the other available CLI switches here.

The build tools installation is much quicker than the full IDE. In my test, it took 5-10 seconds. With --quiet there is no progress indicator other than a brief cursor change. If the installation was successful, you should be able to see the build tools in %programfiles(x86)%\Microsoft Visual Studio\2019\BuildTools\MSBuild\Current\Bin.

If you don't see them there, try running without --quiet to see any error messages that may occur during installation.

How do I simulate placeholder functionality on input date field?

The input[type="date"] DOMElement only takes the following value: YYYY-MM-DD, any other format or text with be skipped.

Live Demo


<input type="text" placeholder="bingo" />
<input type="date" placeholder="2013-01-25" />

Pure JavaScript

window.onload = function () {
    /* Grab all elements with a placeholder attribute */
    var element = document.querySelectorAll('[placeholder]');

    /* Loop through each found elements */
    for (var i in element) {
        /* If the element is a DOMElement and has the nodeName "INPUT" */
        if (element[i].nodeType == 1 && element[i].nodeName == "INPUT") {

            /* We change the value of the element to its placeholder attr value */
            element[i].value = element[i].getAttribute('placeholder');
            /* We change its color to a light gray */
            element[i].style.color = "#777";

            /* When the input is selected/clicked on */
            element[i].onfocus = function (event) {
                /* If the value within it is the placeholder, we clear it */
                if (this.value == this.getAttribute('placeholder')) {
                    this.value = "";
                    /* Setting default text color */
           = "#000";

            /* We the input is left */
            element[i].onblur = function (event) {
                /* If the field is empty, we set its value to the placeholder */
                if (this.value == "") {
                    this.value = this.getAttribute('placeholder');
           = "#777";

Performance review

In this exact case, with 2 input elements, Pure JavaScript is ~40% ± 10% faster.

With 32 input elements, the difference remains the same (~43% ± 10% faster for Pure JS).

You must add a reference to assembly 'netstandard, Version=

Although this is an old thread, I had the same issue today, last week I updated some NuGet packages and although the MVC website worked OK on my dev machine when I published to the testing server it failed.

I read numerous posts but none worked. I finally compared the DLL's in my local bin to those in the testing server and found that the netstandard.dll was not uploaded, once uploaded the website worked OK, not sure why VS2017 web deploy did not publish the DLL.

Just something to look out for in case none of the above work for you.

How do I compile a .c file on my Mac?

You will need to install the Apple Developer Tools. Once you have done that, the easiest thing is to either use the Xcode IDE or use gcc, or nowadays better cc (the clang LLVM compiler), from the command line.

According to Apple's site, the latest version of Xcode (3.2.1) only runs on Snow Leopard (10.6) so if you have an earlier version of OS X you will need to use an older version of Xcode. Your Mac should have come with a Developer Tools DVD which will contain a version that should run on your system. Also, the Apple Developer Tools site still has older versions available for download. Xcode 3.1.4 should run on Leopard (10.5).

Install IPA with iTunes 12

Since iTunes 12.7 doesn't have "Application" section so it can't be done. As a workaround I've found this answer.

I simply installed "Apple Configurator 2". Than:

  1. Run application
  2. Connect device
  3. Unlock device
  4. Drag IPA file to visualisation of device in "Apple Configurator 2"
  5. Confirm action

I didn't had to "sign in" as described in on linked question answers

Android, canvas: How do I clear (delete contents of) a canvas (= bitmaps), living in a surfaceView?

Try to remove the view at onPause() of an activity and add onRestart()

LayoutYouAddedYourView.addView(YourCustomView); LayoutYouAddedYourView.removeView(YourCustomView);

The moment you add your view, onDraw() method would get called.

YourCustomView, is a class which extends the View class.

Open soft keyboard programmatically

In your manifest file, try adding the following to the <activity> that you want to show the keyboard when the activity starts:


This should cause the keyboard to become visible when the activity starts.

For more options, checkout the documentation.

How to upload, display and save images using node.js and express

First of all, you should make an HTML form containing a file input element. You also need to set the form's enctype attribute to multipart/form-data:

<form method="post" enctype="multipart/form-data" action="/upload">
    <input type="file" name="file">
    <input type="submit" value="Submit">

Assuming the form is defined in index.html stored in a directory named public relative to where your script is located, you can serve it this way:

const http = require("http");
const path = require("path");
const fs = require("fs");

const express = require("express");

const app = express();
const httpServer = http.createServer(app);

const PORT = process.env.PORT || 3000;

httpServer.listen(PORT, () => {
  console.log(`Server is listening on port ${PORT}`);

// put the HTML file containing your form in a directory named "public" (relative to where this script is located)
app.get("/", express.static(path.join(__dirname, "./public")));

Once that's done, users will be able to upload files to your server via that form. But to reassemble the uploaded file in your application, you'll need to parse the request body (as multipart form data).

In Express 3.x you could use express.bodyParser middleware to handle multipart forms but as of Express 4.x, there's no body parser bundled with the framework. Luckily, you can choose from one of the many available multipart/form-data parsers out there. Here, I'll be using multer:

You need to define a route to handle form posts:

const multer = require("multer");

const handleError = (err, res) => {
    .end("Oops! Something went wrong!");

const upload = multer({
  dest: "/path/to/temporary/directory/to/store/uploaded/files"
  // you might also want to set some limits:
  upload.single("file" /* name attribute of <file> element in your form */),
  (req, res) => {
    const tempPath = req.file.path;
    const targetPath = path.join(__dirname, "./uploads/image.png");

    if (path.extname(req.file.originalname).toLowerCase() === ".png") {
      fs.rename(tempPath, targetPath, err => {
        if (err) return handleError(err, res);

          .end("File uploaded!");
    } else {
      fs.unlink(tempPath, err => {
        if (err) return handleError(err, res);

          .end("Only .png files are allowed!");

In the example above, .png files posted to /upload will be saved to uploaded directory relative to where the script is located.

In order to show the uploaded image, assuming you already have an HTML page containing an img element:

<img src="/image.png" />

you can define another route in your express app and use res.sendFile to serve the stored image:

app.get("/image.png", (req, res) => {
  res.sendFile(path.join(__dirname, "./uploads/image.png"));

Sending websocket ping/pong frame from browser

There is no Javascript API to send ping frames or receive pong frames. This is either supported by your browser, or not. There is also no API to enable, configure or detect whether the browser supports and is using ping/pong frames. There was discussion about creating a Javascript ping/pong API for this. There is a possibility that pings may be configurable/detectable in the future, but it is unlikely that Javascript will be able to directly send and receive ping/pong frames.

However, if you control both the client and server code, then you can easily add ping/pong support at a higher level. You will need some sort of message type header/metadata in your message if you don't have that already, but that's pretty simple. Unless you are planning on sending pings hundreds of times per second or have thousands of simultaneous clients, the overhead is going to be pretty minimal to do it yourself.

In TensorFlow, what is the difference between and Tensor.eval()?

The FAQ session on tensor flow has an answer to exactly the same question. I will just go ahead and leave it here:

If t is a Tensor object, t.eval() is shorthand for (where sess is the current default session. The two following snippets of code are equivalent:

sess = tf.Session()
c = tf.constant(5.0)

c = tf.constant(5.0)
with tf.Session():
  print c.eval()

In the second example, the session acts as a context manager, which has the effect of installing it as the default session for the lifetime of the with block. The context manager approach can lead to more concise code for simple use cases (like unit tests); if your code deals with multiple graphs and sessions, it may be more straightforward to explicit calls to

I'd recommend that you at least skim throughout the whole FAQ, as it might clarify a lot of things.

Concatenate a NumPy array to another NumPy array

If I understand your question, here's one way. Say you have:

a = [4.1, 6.21, 1.0]

so here's some code...

def array_in_array(scalarlist):
    return [(x,) for x in scalarlist]

Which leads to:

In [72]: a = [4.1, 6.21, 1.0]

In [73]: a
Out[73]: [4.1, 6.21, 1.0]

In [74]: def array_in_array(scalarlist):
   ....:     return [(x,) for x in scalarlist]

In [75]: b = array_in_array(a)

In [76]: b
Out[76]: [(4.1,), (6.21,), (1.0,)]