Programs & Examples On #C2664

I want to convert std::string into a const wchar_t *

You can use the ATL text conversion macros to convert a narrow (char) string to a wide (wchar_t) one. For example, to convert a std::string:

#include <atlconv.h>
std::string str = "Hello, world!";
CA2W pszWide(str.c_str());

You can also specify a code page, so if your std::string contains UTF-8 chars you can use:

CA2W pszWide(str.c_str(), CP_UTF8);

Very useful but Windows only.

How to get the part of a file after the first line that matches a regular expression?

As a simple approximation you could use

grep -A100000 TERMINATE file

which greps for TERMINATE and outputs up to 100000 lines following that line.

From man page

-A NUM, --after-context=NUM

Print NUM lines of trailing context after matching lines. Places a line containing a group separator (--) between contiguous groups of matches. With the -o or --only-matching option, this has no effect and a warning is given.

how to remove new lines and returns from php string?

You need to place the \n in double quotes.
Inside single quotes it is treated as 2 characters '\' followed by 'n'

You need:

$str = str_replace("\n", '', $str);

A better alternative is to use PHP_EOL as:

$str = str_replace(PHP_EOL, '', $str);

'cout' was not declared in this scope

Put the following code before int main():

using namespace std;

And you will be able to use cout.

For example:

using namespace std;
int main(){
    char t = 'f';
    char *t1;
    char **t2;
    return 0;

Now take a moment and read up on what cout is and what is going on here:

Further, while its quick to do and it works, this is not exactly a good advice to simply add using namespace std; at the top of your code. For detailed correct approach, please read the answers to this related SO question.

How can I force Python's file.write() to use the same newline format in Windows as in Linux ("\r\n" vs. "\n")?

You can still use the textmode and force the linefeed-newline with the keyword argument newline

f = open("./foo",'w',newline='\n')

Tested with Python 3.4.2.

Edit: This does not work in Python 2.7.

Can I call an overloaded constructor from another constructor of the same class in C#?

No, You can't do that, the only place you can call the constructor from another constructor in C# is immediately after ":" after the constructor. for example

class foo
    public foo(){}
    public foo(string s ) { }
    public foo (string s1, string s2) : this(s1) {....}


How to export a Hive table into a CSV file?


hive --outputformat==csv2 -e "select * from YOUR_TABLE";

This worked for me

my hive version is "Hive"

How to resize the jQuery DatePicker control

The Jacob Tsui solution works perfect for me:

    showButtonPanel: true,
    dateFormat: "mm/dd/yy",
    beforeShow: function(){ 
        $(".ui-datepicker").css('font-size', 12)

jQuery show/hide not working

Use this

    $( '.expand' ).click(function() {
        $( '.img_display_content' ).show();

Event assigning always after Document Object Model loaded

scikit-learn random state in splitting dataset

The random_state is an integer value which implies the selection of a random combination of train and test. When you set the test_size as 1/4 the there is a set generated of permutation and combination of train and test and each combination has one state. Suppose you have a dataset---> [1,2,3,4]

Train   |  Test   | State
[1,2,3]    [4]      **0**
[1,3,4]    [2]      **1**
[4,2,3]    [1]      **2**
[2,4,1]    [3]      **3**

We need it because while param tuning of model same state will considered again and again. So that there won't be any inference with the accuracy.

But in case of Random forest there is also similar story but in a different way w.r.t the variables.

Animation fade in and out

This is Good Example for Fade In and Fade Out Animation with Alpha Effect

Animate Fade In Fade Out


check this answer may this help you

How to save/restore serializable object to/from file?

You'll need to serialize to something: that is, pick binary, or xml (for default serializers) or write custom serialization code to serialize to some other text form.

Once you've picked that, your serialization will (normally) call a Stream that is writing to some kind of file.

So, with your code, if I were using XML Serialization:

var path = @"C:\Test\myserializationtest.xml";
using(FileStream fs = new FileStream(path, FileMode.Create))
    XmlSerializer xSer = new XmlSerializer(typeof(SomeClass));

    xSer.Serialize(fs, serializableObject);

Then, to deserialize:

using(FileStream fs = new FileStream(path, FileMode.Open)) //double check that...
    XmlSerializer _xSer = new XmlSerializer(typeof(SomeClass));

    var myObject = _xSer.Deserialize(fs);

NOTE: This code hasn't been compiled, let alone run- there may be some errors. Also, this assumes completely out-of-the-box serialization/deserialization. If you need custom behavior, you'll need to do additional work.

PHP split alternative?

explode is an alternative. However, if you meant to split through a regular expression, the alternative is preg_split instead.

EC2 instance types's exact network performance?

Bandwidth is tiered by instance size, here's a comprehensive answer:

For t2/m3/c3/c4/r3/i2/d2 instances:

  • t2.nano = ??? (Based on the scaling factors, I'd expect 20-30 MBit/s)
  • t2.micro = ~70 MBit/s (qiita says 63 MBit/s) - t1.micro gets about ~100 Mbit/s
  • t2.small = ~125 MBit/s (t2, qiita says 127 MBit/s, cloudharmony says 125 Mbit/s with spikes to 200+ Mbit/s)
  • *.medium = t2.medium gets 250-300 MBit/s, m3.medium ~400 MBit/s
  • *.large = ~450-600 MBit/s (the most variation, see below)
  • *.xlarge = 700-900 MBit/s
  • *.2xlarge = ~1 GBit/s +- 10%
  • *.4xlarge = ~2 GBit/s +- 10%
  • *.8xlarge and marked specialty = 10 Gbit, expect ~8.5 GBit/s, requires enhanced networking & VPC for full throughput

m1 small, medium, and large instances tend to perform higher than expected. c1.medium is another freak, at 800 MBit/s.

I gathered this by combing dozens of sources doing benchmarks (primarily using iPerf & TCP connections). Credit to CloudHarmony & flux7 in particular for many of the benchmarks (note that those two links go to google searches showing the numerous individual benchmarks).

Caveats & Notes:

The large instance size has the most variation reported:

  • m1.large is ~800 Mbit/s (!!!)
  • t2.large = ~500 MBit/s
  • c3.large = ~500-570 Mbit/s (different results from different sources)
  • c4.large = ~520 MBit/s (I've confirmed this independently, by the way)
  • m3.large is better at ~700 MBit/s
  • m4.large is ~445 Mbit/s
  • r3.large is ~390 Mbit/s

Burstable (T2) instances appear to exhibit burstable networking performance too:

  • The CloudHarmony iperf benchmarks show initial transfers start at 1 GBit/s and then gradually drop to the sustained levels above after a few minutes. PDF links to reports below:

  • t2.small (PDF)

  • t2.medium (PDF)
  • t2.large (PDF)

Note that these are within the same region - if you're transferring across regions, real performance may be much slower. Even for the larger instances, I'm seeing numbers of a few hundred MBit/s.

How to check if bootstrap modal is open, so I can use jquery validate?

As a workaround I personally use a custom global flag to determine whether the modal has been opened or not and I reset it on ''

What difference is there between WebClient and HTTPWebRequest classes in .NET?

I know its too longtime to reply but just as an information purpose for future readers:



The WebRequest is an abstract base class. So you actually don't use it directly. You use it through it derived classes - HttpWebRequest and FileWebRequest.

You use Create method of WebRequest to create an instance of WebRequest. GetResponseStream returns data stream.

There are also FileWebRequest and FtpWebRequest classes that inherit from WebRequest. Normally, you would use WebRequest to, well, make a request and convert the return to either HttpWebRequest, FileWebRequest or FtpWebRequest, depend on your request. Below is an example:


var _request = (HttpWebRequest)WebRequest.Create("");
var _response = (HttpWebResponse)_request.GetResponse();



WebClient provides common operations to sending and receiving data from a resource identified by a URI. Simply, it’s a higher-level abstraction of HttpWebRequest. This ‘common operations’ is what differentiate WebClient from HttpWebRequest, as also shown in the sample below:


var _client = new WebClient();
var _stackContent = _client.DownloadString("");

There are also DownloadData and DownloadFile operations under WebClient instance. These common operations also simplify code of what we would normally do with HttpWebRequest. Using HttpWebRequest, we have to get the response of our request, instantiate StreamReader to read the response and finally, convert the result to whatever type we expect. With WebClient, we just simply call DownloadData, DownloadFile or DownloadString.

However, keep in mind that WebClient.DownloadString doesn’t consider the encoding of the resource you requesting. So, you would probably end up receiving weird characters if you don’t specify and encoding.

NOTE: Basically "WebClient takes few lines of code as compared to Webrequest"

nginx 502 bad gateway

I executed my localhost and the page displayed the 502 bad gateway message. This helped me:

  1. Edit /etc/php5/fpm/pool.d/www.conf
  2. Change listen = /var/run/php5-fpm.sock to listen =
  3. Ensure the location is set properly in nginx.conf.
  4. Run sudo service php5-fpm restart

Maybe it will help you.

Source from:

How to sort List of objects by some property

You can call Collections.sort() and pass in a Comparator which you need to write to compare different properties of the object.

How to get StackPanel's children to fill maximum space downward?

The reason that this is happening is because the stack panel measures every child element with positive infinity as the constraint for the axis that it is stacking elements along. The child controls have to return how big they want to be (positive infinity is not a valid return from the MeasureOverride in either axis) so they return the smallest size where everything will fit. They have no way of knowing how much space they really have to fill.

If your view doesn’t need to have a scrolling feature and the answer above doesn't suit your needs, I would suggest implement your own panel. You can probably derive straight from StackPanel and then all you will need to do is change the ArrangeOverride method so that it divides the remaining space up between its child elements (giving them each the same amount of extra space). Elements should render fine if they are given more space than they wanted, but if you give them less you will start to see glitches.

If you want to be able to scroll the whole thing then I am afraid things will be quite a bit more difficult, because the ScrollViewer gives you an infinite amount of space to work with which will put you in the same position as the child elements were originally. In this situation you might want to create a new property on your new panel which lets you specify the viewport size, you should be able to bind this to the ScrollViewer’s size. Ideally you would implement IScrollInfo, but that starts to get complicated if you are going to implement all of it properly.

Python: SyntaxError: keyword can't be an expression

It's python source parser failure on sum.up=False named argument as sum.up is not valid argument name (you can't use dots -- only alphanumerics and underscores in argument names).

Is there an advantage to use a Synchronized Method instead of a Synchronized Block?

I know this is an old question, but with my quick read of the responses here, I didn't really see anyone mention that at times a synchronized method may be the wrong lock.
From Java Concurrency In Practice (pg. 72):

public class ListHelper<E> {
  public List<E> list = Collections.syncrhonizedList(new ArrayList<>());

public syncrhonized boolean putIfAbsent(E x) {
 boolean absent = !list.contains(x);
if(absent) {
return absent;

The above code has the appearance of being thread-safe. However, in reality it is not. In this case the lock is obtained on the instance of the class. However, it is possible for the list to be modified by another thread not using that method. The correct approach would be to use

public boolean putIfAbsent(E x) {
 synchronized(list) {
  boolean absent = !list.contains(x);
  if(absent) {
  return absent;

The above code would block all threads trying to modify list from modifying the list until the synchronized block has completed.

What is difference between png8 and png24

There is only one PNG format, but it supports 5 color types.

PNG-8 refers to palette variant, which supports only 256 colors, but is usually smaller in size. PNG-8 can be a GIF substitute.

PNG-24 refers to true color variant, which supports more colors, but might be bigger. PNG-24 can be used instead of JPEG, if lossless image format is needed.

Any modern web browser will support both variants.

__FILE__ macro shows full path

A tweaked, even more "bloated" version of red1ynx's answer:

#define __FILENAME__ \
  (strchr(__FILE__, '\\') \
  ? ((strrchr(__FILE__, '\\') ? strrchr(__FILE__, '\\') + 1 : __FILE__)) \
  : ((strrchr(__FILE__, '/') ? strrchr(__FILE__, '/') + 1 : __FILE__)))

If we find backslashes, we split on backslashes. Otherwise, split on forward slash. Simple enough.

Just about any alternative would be cleaner (A C++ constexpr is really the gold standard here, in my opinion). However, this may be helpful if you're using some compiler where __BASE_FILE__ isn't available.

Drawing an image from a data URL to a canvas

Just to add to the other answers: In case you don't like the onload callback approach, you can "promisify" it like so:

let url = "data:image/gif;base64,R0lGODl...";
let img = new Image();
await new Promise(r => img.onload=r, img.src=url);
// now do something with img

What is the difference between Numpy's array() and asarray() functions?

asarray(x) is like array(x, copy=False)

Use asarray(x) when you want to ensure that x will be an array before any other operations are done. If x is already an array then no copy would be done. It would not cause a redundant performance hit.

Here is an example of a function that ensure x is converted into an array first.

def mysum(x):
    return np.asarray(x).sum()

Getting Textbox value in Javascript

Since you have master page and your control is in content place holder, Your control id will be generated different in client side. you need to do like...

var TestVar = document.getElementById('<%= txt_model_code.ClientID %>').value;

Javascript runs on client side and to get value you have to provide client id of your control

How can I use Guzzle to send a POST request in JSON?

This works for me with Guzzle 6.2 :

$gClient =  new \GuzzleHttp\Client(['base_uri' => '']);
$res = $gClient->post('ws/endpoint',

According to the documentation guzzle do the json_encode

Check if a value is within a range of numbers

I like Pointy's between function so I wrote a similar one that worked well for my scenario.

 * Checks if an integer is within ±x another integer.
 * @param {int} op - The integer in question
 * @param {int} target - The integer to compare to
 * @param {int} range - the range ±
function nearInt(op, target, range) {
    return op < target + range && op > target - range;

so if you wanted to see if x was within ±10 of y:

var x = 100;
var y = 115;
nearInt(x,y,10) = false

I'm using it for detecting a long-press on mobile:

//make sure they haven't moved too much during long press.
if (!nearInt(Last.x,Start.x,5) || !nearInt(Last.y, Start.y,5)) clearTimeout(t);

Error using eclipse for Android - No resource found that matches the given name

I had the same issue and tried most of the solutions mentioned above and they did not fix it.. At then end, I went to my .csproj file and viewed it in the text editor, I found that my xml file that I put in the /Drawable was not set to be AndroidResouces it was just of type Content.

Changing that to be of type AndroidResouces fixed the issue for me.

Using (Ana)conda within PyCharm

this might be repetitive. I was trying to use pycharm to run flask - had anaconda 3, pycharm 2019.1.1 and windows 10. Created a new conda environment - it threw errors. Followed these steps -

  1. Used the cmd to install python and flask after creating environment as suggested above.

  2. Followed this answer.

  3. As suggested above, went to Run -> Edit Configurations and changed the environment there as well as in (2).

Obviously kept the correct python interpreter (the one in the environment) everywhere.

JavaScript: Get image dimensions

Make a new Image

var img = new Image();

Set the src

img.src = your_src

Get the width and the height


How to check if a float value is a whole number

You can use a modulo operation for that.

if (n ** (1.0/3)) % 1 != 0:
    print("We have a decimal number here!")

jQuery if statement to check visibility

if visible.


if it's hidden.


How do I share a global variable between c files?

using extern <variable type> <variable name> in a header or another C file.

Sum values in a column based on date

Use pivot tables, it will definitely save you time. If you are using excel 2007+ use tables (structured references) to keep your table dynamic. However if you insist on using functions, go with Smandoli's suggestion. Again, if you are on 2007+ use SUMIFS, it's faster compared to SUMIF.

Getting an object array from an Angular service

Take a look at your code :

 getUsers(): Observable<User[]> {
        return Observable.create(observer => {
            this.http.get('').map(response => response.json();

and code from (BTW. really good tutorial, you should check it out)

 getHeroes(): Promise<Hero[]> {
    return this.http.get(this.heroesUrl)
               .then(response => response.json().data as Hero[])

The HttpService inside Angular2 already returns an observable, sou don't need to wrap another Observable around like you did here:

   return Observable.create(observer => {
        this.http.get('').map(response => response.json()

Try to follow the guide in link that I provided. You should be just fine when you study it carefully.


First of all WHERE you log the this.users variable? JavaScript isn't working that way. Your variable is undefined and it's fine, becuase of the code execution order!

Try to do it like this:

  getUsers(): void {
            .then(users => {
               this.users = users
               console.log('this.users=' + this.users);


See where the console.log(...) is!

Try to resign from toPromise() it's seems to be just for ppl with no RxJs background.

Catch another link: Build your service once again with RxJs observables.

Convert seconds to Hour:Minute:Second

Anyone whose looking for this in the future, this gives the format the initial poster asked for.

$init = 685;
$hours = floor($init / 3600);
if ($hrlength==1) {$hrs="0".$hours;}
else {$hrs=$hours;} 

$minutes = floor(($init / 60) % 60);
if ($minlength==1) {$mins="0".$minutes;}
else {$mins=$minutes;} 

$seconds = $init % 60;
if ($seclength==1) {$secs="0".$seconds;}
else {$secs=$seconds;} 

echo "$hrs:$mins:$secs";

How to get old Value with onchange() event in text box

I am not sure, but maybe this logic would work.

var d = 10;
var prevDate = "";
var x = 0;
var oldVal = "";
var func = function (d) {
    if (x == 0 && d != prevDate && prevDate == "") {
        oldVal = d;
        prevDate = d;
    else if (x == 1 && prevDate != d) {
        oldVal = prevDate;
        prevDate = d;
    x = 1;

Amazon S3 exception: "The specified key does not exist"

I also ran into this issue, but in my case I was inadvertently changing the internal state of my source object key when constructing the destination key:

  source_objects.each do |item|
    key = item.key.sub!(source_prefix, dest_prefix)
    item.copy_to(bucket: dest_bucket, key: key)

I'm new to Ruby and missed that sub! has side effects and sub should have been used instead.

JavaScript: Alert.Show(message) From ASP.NET Code-behind

And i think, the line:

string cleanMessage = message.Replace("'", "\'"); 

does not work, it must be:

string cleanMessage = message.Replace("'", "\\\'");

You need to mask the \ with a \ and the ' with another \.

C++ Vector of pointers

As far as I understand, you create a Movie class:

class Movie
  std::string _title;
  std::string _director;
  int         _year;
  int         _rating;
  std::vector<std::string> actors;

and having such class, you create a vector instance:

std::vector<Movie*> movies;

so, you can add any movie to your movies collection. Since you are creating a vector of pointers to movies, do not forget to free the resources allocated by your movie instances OR you could use some smart pointer to deallocate the movies automatically:

std::vector<shared_ptr<Movie>> movies;

Where can I get a list of Countries, States and Cities?

The UN maintains a list of countries and "states" / regions for economic trade. That DB is available here:

Show/Hide the console window of a C# console application

You could do the reversed and set the Application output type to: Windows Application. Then add this code to the beginning of the application.

[DllImport("kernel32.dll", EntryPoint = "GetStdHandle", SetLastError = true, CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
public static extern IntPtr GetStdHandle(int nStdHandle);

[DllImport("kernel32.dll", EntryPoint = "AllocConsole", SetLastError = true, CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
public static extern int AllocConsole();

private const int STD_OUTPUT_HANDLE = -11;
private const int MY_CODE_PAGE = 437;
private static bool showConsole = true; //Or false if you don't want to see the console

static void Main(string[] args)
    if (showConsole)
        IntPtr stdHandle = GetStdHandle(STD_OUTPUT_HANDLE);
        Microsoft.Win32.SafeHandles.SafeFileHandle safeFileHandle = new Microsoft.Win32.SafeHandles.SafeFileHandle(stdHandle, true);
        FileStream fileStream = new FileStream(safeFileHandle, FileAccess.Write);
        System.Text.Encoding encoding = System.Text.Encoding.GetEncoding(MY_CODE_PAGE);
        StreamWriter standardOutput = new StreamWriter(fileStream, encoding);
        standardOutput.AutoFlush = true;

    //Your application code

This code will show the Console if showConsole is true

Rename specific column(s) in pandas

How do I rename a specific column in pandas?

From v0.24+, to rename one (or more) columns at a time,

If you need to rename ALL columns at once,

  • DataFrame.set_axis() method with axis=1. Pass a list-like sequence. Options are available for in-place modification as well.

rename with axis=1

df = pd.DataFrame('x', columns=['y', 'gdp', 'cap'], index=range(5))

   y gdp cap
0  x   x   x
1  x   x   x
2  x   x   x
3  x   x   x
4  x   x   x

With 0.21+, you can now specify an axis parameter with rename:

df.rename({'gdp':'log(gdp)'}, axis=1)
# df.rename({'gdp':'log(gdp)'}, axis='columns')
   y log(gdp) cap
0  x        x   x
1  x        x   x
2  x        x   x
3  x        x   x
4  x        x   x

(Note that rename is not in-place by default, so you will need to assign the result back.)

This addition has been made to improve consistency with the rest of the API. The new axis argument is analogous to the columns parameter—they do the same thing.

df.rename(columns={'gdp': 'log(gdp)'})

   y log(gdp) cap
0  x        x   x
1  x        x   x
2  x        x   x
3  x        x   x
4  x        x   x

rename also accepts a callback that is called once for each column.

df.rename(lambda x: x[0], axis=1)
# df.rename(lambda x: x[0], axis='columns')

   y  g  c
0  x  x  x
1  x  x  x
2  x  x  x
3  x  x  x
4  x  x  x

For this specific scenario, you would want to use

df.rename(lambda x: 'log(gdp)' if x == 'gdp' else x, axis=1)


Similar to replace method of strings in python, pandas Index and Series (object dtype only) define a ("vectorized") str.replace method for string and regex-based replacement.

df.columns = df.columns.str.replace('gdp', 'log(gdp)')
   y log(gdp) cap
0  x        x   x
1  x        x   x
2  x        x   x
3  x        x   x
4  x        x   x

The advantage of this over the other methods is that str.replace supports regex (enabled by default). See the docs for more information.

Passing a list to set_axis with axis=1

Call set_axis with a list of header(s). The list must be equal in length to the columns/index size. set_axis mutates the original DataFrame by default, but you can specify inplace=False to return a modified copy.

df.set_axis(['cap', 'log(gdp)', 'y'], axis=1, inplace=False)
# df.set_axis(['cap', 'log(gdp)', 'y'], axis='columns', inplace=False)

  cap log(gdp)  y
0   x        x  x
1   x        x  x
2   x        x  x
3   x        x  x
4   x        x  x

Note: In future releases, inplace will default to True.

Method Chaining
Why choose set_axis when we already have an efficient way of assigning columns with df.columns = ...? As shown by Ted Petrou in this answer set_axis is useful when trying to chain methods.


# new for pandas 0.21+


# old way
df1 = df.some_method1()
df1.columns = columns

The former is more natural and free flowing syntax.

What is the difference between an IntentService and a Service?

Service is a base class of service implementation. Service runs on the application's main thread which may reduce the application performance. Thus, IntentService, which is a direct subclass of Service is available to make things easier.

The IntentService is used to perform a certain task in the background. Once done, the instance of IntentService terminates itself automatically. Examples for its usage would be to download a certain resource from the Internet.


  1. Service class uses the application's main thread, while IntentService creates a worker thread and uses that thread to run the service.
  2. IntentService creates a queue that passes one intent at a time to onHandleIntent(). Thus, implementing a multi-thread should be made by extending Service class directly. Service class needs a manual stop using stopSelf(). Meanwhile, IntentService automatically stops itself when it finishes execution.
  3. IntentService implements onBind() that returns null. This means that the IntentService can not be bound by default.
  4. IntentService implements onStartCommand() that sends Intent to queue and to onHandleIntent().

In brief, there are only two things to do to use IntentService. Firstly, to implement the constructor. And secondly, to implement onHandleIntent(). For other callback methods, the super is needed to be called so that it can be tracked properly.

ASP.NET Web API - PUT & DELETE Verbs Not Allowed - IIS 8

this worked for me on iis8 together with some of the other answers. My error was a 404.6 specifically

    <verbs applyToWebDAV="false">
       <add verb="DELETE" allowed="true" />

jQuery DatePicker with today as maxDate

If you're using bootstrap 3 date time picker, try this:

$('.selector').datetimepicker({ maxDate: $.now() });

Find first and last day for previous calendar month in SQL Server Reporting Services (VB.Net)

in C#:

new DateTime(DateTime.Now.Year, DateTime.Now.Month, 1).AddMonths(-1)
new DateTime(DateTime.Now.Year, DateTime.Now.Month, 1).AddDays(-1)

How to detect control+click in Javascript from an onclick div attribute?

pure javascript:

var ctrlKeyCode = 17;
var cntrlIsPressed = false;

document.addEventListener('keydown', function(event){
        cntrlIsPressed = true;

document.addEventListener('keyup', function(){
        cntrlIsPressed = true;

function selectMe(mouseButton)
            case 1:
                alert("Cntrl +  left click");
            case 2:
                alert("Cntrl + right click");

Correct way to work with vector of arrays


vector<vector<float>> vecArray; //both dimensions are open!

.append(), prepend(), .after() and .before()

There is a basic difference between .append() and .after() and .prepend() and .before().

.append() adds the parameter element inside the selector element's tag at the very end whereas the .after() adds the parameter element after the element's tag.

The vice-versa is for .prepend() and .before().


Replace part of a string in Python?

>>> stuff = "Big and small"
>>> stuff.replace(" and ","/")

jQuery UI Sortable, then write order into a database

This is my example.

You need to catch the order in the update event

    $( "#sortable" ).sortable({
    placeholder: "ui-state-highlight",
    update: function( event, ui ) {
        var sorted = $( "#sortable" ).sortable( "serialize", { key: "sort" } );
        $.post( "form/order.php",{ 'choices[]': sorted});

Vagrant stuck connection timeout retrying

I've found out that on MacOS with VirtualBox adding this to Vagrantfile will let you go further:

config.vm.provider 'virtualbox' do |vb|
  vb.customize ['modifyvm', :id, '--cableconnected1', 'on']

connecting to MySQL from the command line

See here


The options above means:

-u: username
-p: password (**no space between -p and the password text**)
-h: host
last one is name of the database that you wanted to connect. 

Look into the link, it's detailed there!

As already mentioned by Rick, you can avoid passing the password as the part of the command by not passing the password like this:


People editing this answer: PLEASE DONOT ADD A SPACE between -p and PASSWORD

How Do I Uninstall Yarn

I couldn't uninstall yarn on windows and I tried every single answer here, but every time I ran yarn -v, the command worked. But then I realized that there is another thing that can affect this.

If you on windows (not sure if this also happens in mac) and using nvm, one problem that can happen is that you have installed nvm without uninstalling npm, and the working yarn command is from your old yarn version from the old npm.

So what you need to do is follow this step from the nvm docs

You should also delete the existing npm install location (e.g. "C:\Users<user>\AppData\Roaming\npm"), so that the nvm install location will be correctly used instead. Backup the global npmrc config (e.g. C:\Users&lt;user>\AppData\Roaming\npm\etc\npmrc), if you have some important settings there, or copy the settings to the user config C:\Users&lt;user>.npmrc.

And to confirm that you problem is with the old npm, you will probably see the yarn.cmd file inside the C:\Users\<user>\AppData\Roaming\npm folder.

Spring CORS No 'Access-Control-Allow-Origin' header is present

I also had messages like No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:63342' is therefore not allowed access.

I had configured cors properly, but what was missing in webflux in RouterFuncion was accept and contenttype headers APPLICATION_JSON like in this piece of code:

RouterFunction<ServerResponse> routes() {
    return route(POST("/create")
                              .and(contentType(APPLICATION_JSON)), serverRequest -> create(serverRequest);

Force IE10 to run in IE10 Compatibility View?

You can try :

<meta http-equiv="X-UA-Compatible" content="IE=EmulateIE8" >

Just like you tried before, but caution:

It seems like the X-UA-Compatible tag has to be the first tag in the < head > section

If this conclusion is correct, then I believe it is undocumented in Microsoft’s blogs/msdn (and if it is documented, then it isn’t sticking out well enough from the docs). Ensuring that this was the first meta tag in the forced IE9 to switch to IE8 mode successfully

Node Version Manager (NVM) on Windows

Nvm can be used to manage various node version :

  • Step1: Download nvm for Windows

  • Step2: Choose

  • Step3: Unzip & click on installer.

  • Step4: Check if nvm properly installed, In new command prompt type nvm

  • Step5: Install node js using nvm : nvm install <version> : The version can be a node.js version or "latest" for the latest stable version

  • Step6: check node version - node -v

  • Step7(Optional)If you want to install another version of node js - Use STEP 5 with different version.

  • Step8: Check list node js version - nvm list

  • Step9: If you want to use specific node version do - nvm use <version>

How to get current formatted date dd/mm/yyyy in Javascript and append it to an input

   const monthNames = ["January", "February", "March", "April", "May", "June",
        "July", "August", "September", "October", "November", "December"];
    const dateObj = new Date();
    const month = monthNames[dateObj.getMonth()];
    const day = String(dateObj.getDate()).padStart(2, '0');
    const year = dateObj.getFullYear();
    const output = month  + '\n'+ day  + ',' + year;

    document.querySelector('.date').textContent = output; 

Do the parentheses after the type name make a difference with new?

The rules for new are analogous to what happens when you initialize an object with automatic storage duration (although, because of vexing parse, the syntax can be slightly different).

If I say:

int my_int; // default-initialize ? indeterminate (non-class type)

Then my_int has an indeterminate value, since it is a non-class type. Alternatively, I can value-initialize my_int (which, for non-class types, zero-initializes) like this:

int my_int{}; // value-initialize ? zero-initialize (non-class type)

(Of course, I can't use () because that would be a function declaration, but int() works the same as int{} to construct a temporary.)

Whereas, for class types:

Thing my_thing; // default-initialize ? default ctor (class type)
Thing my_thing{}; // value-initialize ? default-initialize ? default ctor (class type)

The default constructor is called to create a Thing, no exceptions.

So, the rules are more or less:

  • Is it a class type?
    • YES: The default constructor is called, regardless of whether it is value-initialized (with {}) or default-initialized (without {}). (There is some additional prior zeroing behavior with value-initialization, but the default constructor is always given the final say.)
    • NO: Were {} used?
      • YES: The object is value-initialized, which, for non-class types, more or less just zero-initializes.
      • NO: The object is default-initialized, which, for non-class types, leaves it with an indeterminate value (it effectively isn't initialized).

These rules translate precisely to new syntax, with the added rule that () can be substituted for {} because new is never parsed as a function declaration. So:

int* my_new_int = new int; // default-initialize ? indeterminate (non-class type)
Thing* my_new_thing = new Thing; // default-initialize ? default ctor (class type)
int* my_new_zeroed_int = new int(); // value-initialize ? zero-initialize (non-class type)
     my_new_zeroed_int = new int{}; // ditto
       my_new_thing = new Thing(); // value-initialize ? default-initialize ? default ctor (class type)

(This answer incorporates conceptual changes in C++11 that the top answer currently does not; notably, a new scalar or POD instance that would end up an with indeterminate value is now technically now default-initialized (which, for POD types, technically calls a trivial default constructor). While this does not cause much practical change in behavior, it does simplify the rules somewhat.)

Python socket.error: [Errno 111] Connection refused

The problem obviously was (as you figured it out) that port 36250 wasn't open on the server side at the time you tried to connect (hence connection refused). I can see the server was supposed to open this socket after receiving SEND command on another connection, but it apparently was "not opening [it] up in sync with the client side".

Well, the main reason would be there was no synchronisation whatsoever. Calling:

cs.send("SEND " + FILE)

would just place the data into a OS buffer; close would probably flush the data and push into the network, but it would almost certainly return before the data would reach the server. Adding sleep after close might mitigate the problem, but this is not synchronisation.

The correct solution would be to make sure the server has opened the connection. This would require server sending you some message back (for example OK, or better PORT 36250 to indicate where to connect). This would make sure the server is already listening.

The other thing is you must check the return values of send to make sure how many bytes was taken from your buffer. Or use sendall.

(Sorry for disturbing with this late answer, but I found this to be a high traffic question and I really didn't like the sleep idea in the comments section.)

Groovy executing shell commands

I find this more idiomatic:

def proc = "ls foo.txt doesnotexist.txt".execute()
assert == "foo.txt\n"
assert proc.err.text == "ls: doesnotexist.txt: No such file or directory\n"

As another post mentions, these are blocking calls, but since we want to work with the output, this may be necessary.

Printing the last column of a line in a file

One way using awk:

tail -f file.txt | awk '/A1/ { print $NF }'

Undo git update-index --assume-unchanged <file>

Adding to @adardesign's answer, if you want to reset all files that have been added to assume-unchanged list to no-assume-unchanged in one go, you can do the following:

git ls-files -v | grep '^h' | sed 's/^..//' | sed 's/\ /\\ /g' | xargs -I FILE git update-index --no-assume-unchanged FILE || true

This will just strip out the two characters output from grep i.e. "h ", then escape any spaces that may be present in file names, and finally || true will prevent the command to terminate prematurely in case some files in the loop has errors.

How to create a zip archive with PowerShell?

What about System.IO.Packaging.ZipPackage?

It would require .NET 3.0 or greater.

#Load some assemblys. (No line break!)
[System.Reflection.Assembly]::Load("WindowsBase, Version=, Culture=neutral, PublicKeyToken=31bf3856ad364e35")

#Create a zip file named "". (No line break!)
   [System.IO.FileMode]"OpenOrCreate", [System.IO.FileAccess]"ReadWrite")

#The files I want to add to my archive:
$files = @("/Penguins.jpg", "/Lighthouse.jpg")

#For each file you want to add, we must extract the bytes
#and add them to a part of the zip file.
ForEach ($file In $files)
   $partName=New-Object System.Uri($file, [System.UriKind]"Relative")
   #Create each part. (No line break!)
   $part=$ZipPackage.CreatePart($partName, "",
   $stream.Write($bytes, 0, $bytes.Length)

#Close the package when we're done.

via Anders Hesselbom

How to Import .bson file format on mongodb

If your access remotely you can do it

for bson:

mongorestore --host --port 27016 --ssl --username $user --password $password --authenticationDatabase $authdb -d test -c people "/home/${USER}/people.bson"

for bson compressed in .gz (gzip) format:

mongorestore --host --port 27016 --ssl --username $user --password $password --authenticationDatabase $authdb -d test -c people --gzip --dir "/home/${USER}/people.bson.gz"

single line comment in HTML

No, you have to close the comment with -->.

How to convert HTML to PDF using iTextSharp

I use the following code to create PDF

protected void CreatePDF(Stream stream)
            using (var document = new Document(PageSize.A4, 40, 40, 40, 30))
                var writer = PdfWriter.GetInstance(document, stream);
                writer.PageEvent = new ITextEvents();

                // instantiate custom tag processor and add to `HtmlPipelineContext`.
                var tagProcessorFactory = Tags.GetHtmlTagProcessorFactory();
                    new TableProcessor(),
                    new string[] { HTML.Tag.TABLE }

                //Register Fonts.
                XMLWorkerFontProvider fontProvider = new XMLWorkerFontProvider(XMLWorkerFontProvider.DONTLOOKFORFONTS);
                fontProvider.Register(HttpContext.Current.Server.MapPath("~/Content/Fonts/GothamRounded-Medium.ttf"), "Gotham Rounded Medium");
                CssAppliers cssAppliers = new CssAppliersImpl(fontProvider);

                var htmlPipelineContext = new HtmlPipelineContext(cssAppliers);

                var pdfWriterPipeline = new PdfWriterPipeline(document, writer);
                var htmlPipeline = new HtmlPipeline(htmlPipelineContext, pdfWriterPipeline);

                // get an ICssResolver and add the custom CSS
                var cssResolver = XMLWorkerHelper.GetInstance().GetDefaultCssResolver(true);
                cssResolver.AddCss(CSSSource, "utf-8", true);
                var cssResolverPipeline = new CssResolverPipeline(
                    cssResolver, htmlPipeline

                var worker = new XMLWorker(cssResolverPipeline, true);
                var parser = new XMLParser(worker);
                using (var stringReader = new StringReader(HTMLSource))
                    HttpContext.Current.Response.ContentType = "application /pdf";
                    if (base.View)
                        HttpContext.Current.Response.AddHeader("content-disposition", "inline;filename=\"" + OutputFileName + ".pdf\"");
                        HttpContext.Current.Response.AddHeader("content-disposition", "attachment;filename=\"" + OutputFileName + ".pdf\"");

How to convert an NSString into an NSNumber

Try this

NSNumber *yourNumber = [NSNumber numberWithLongLong:[yourString longLongValue]];

Note - I have used longLongValue as per my requirement. You can also use integerValue, longValue, or any other format depending upon your requirement.

Auto increment in phpmyadmin

(a)Simply click on your database, select your table. Click on 'Operations'. Under the 'table options' section change the AUTO_INCREMENT value to your desired value, in this case: 10000 the click 'Go'. (See the image attached)

(b)Alternatively, you can run a SQL command under the SQL tab after selecting your table. Simply type 'ALTER TABLE table_name AUTO_INCREMENT = 10000;' then click 'Go'. That's it!! SETTING AUTO INCREMENT VALUE image(a)


Get The Current Domain Name With Javascript (Not the path, etc.)

What about this function?


This will match only the domain name regardless if its a subdomain or a main domain

Include CSS and Javascript in my django template

Refer django docs on static files.


import os
CURRENT_PATH = os.path.abspath(os.path.dirname(__file__).decode('utf-8'))

MEDIA_ROOT = os.path.join(CURRENT_PATH, 'media')

MEDIA_URL = '/media/'

STATIC_ROOT = 'static/'

STATIC_URL = '/static/'

                    os.path.join(CURRENT_PATH, 'static'),

Then place your js and css files static folder in your project. Not in media folder.


from django.shortcuts import render_to_response, RequestContext

def view_name(request):
    #your stuff goes here
    return render_to_response('template.html', locals(), context_instance = RequestContext(request))

In template.html:

<link rel="stylesheet" type="text/css" href="{{ STATIC_URL }}css/style.css" />
<script type="text/javascript" src="{{ STATIC_URL }}js/jquery-1.8.3.min.js"></script>


from django.conf import settings
urlpatterns += patterns('',
    url(r'^media/(?P<path>.*)$', 'django.views.static.serve', {'document_root': settings.MEDIA_ROOT, 'show_indexes': True}),

Project file structure can be found here in imgbin.

How to comment in Vim's config files: ".vimrc"?

"This is a comment in vimrc. It does not have a closing quote 


Could not resolve all dependencies for configuration ':classpath'

I got the same problem. Just use File->INVALIDATE CACHES AND RESTART

iPhone: Setting Navigation Bar Title

There's one issue with using self.title = @"title";

If you're using Navigation Bar along with Tab bar, the above line also changes the label for the Tab Bar Item. To avoid this, use what @testing suggested

self.navigationItem.title = @"MyTitle";

Html- how to disable <a href>?


This will prevent the default action.

How to style a div to be a responsive square?

Another way is to use a transparent 1x1.png with width: 100%, height: auto in a div and absolutely positioned content within it:


    <img src="1x1px.png">


div {
    position: relative;
    width: 50%;

img {
    width: 100%;
    height: auto;

h1 {
    position: absolute;
    top: 10px;
    left: 10px;


Is embedding background image data into CSS as Base64 good or bad practice?

As far as I have researched,

Use : 1. When you are using an svg sprite. 2. When your images are of a lesser size (max 200mb).

Don't Use : 1. When you are bigger images. 2. Icons as svg's. As they are already good and gzipped after compression.

How can I make my website's background transparent without making the content (images & text) transparent too?

I would agree with @evillinux, It would be best to make your background image semi transparent so it supports < ie8

The other suggestions of using another div are also a great option, and it's the way to go if you want to do this in css. For example if the site had such features as selecting your own background color. I would suggest using a filter for older IE. eg:


Rails: Why "sudo" command is not recognized?

Sudo is a Unix specific command designed to allow a user to carry out administrative tasks with the appropriate permissions.

Windows does not have (need?) this.

Run the command with the sudo removed from the start.

"cannot be used as a function error"

#include "header.h"

int estimatedPopulation (int currentPopulation, float growthRate)
    return currentPopulation + currentPopulation * growthRate  / 100;

String isNullOrEmpty in Java?

public static boolean isNull(String str) {
        return str == null ? true : false;

    public static boolean isNullOrBlank(String param) {
        if (isNull(param) || param.trim().length() == 0) {
            return true;
        return false;

Error: «Could not load type MvcApplication»

This happened to me because I added Global.asax.cs (C# file) to a project so the file didn't get compiled and I had to use a .vb version of the file for it to work and get compiled.

How to convert 'binary string' to normal string in Python3?

If the answer from falsetru didn't work you could also try:

>>> b'a string'.decode('utf-8')
'a string'

How to print environment variables to the console in PowerShell?

Prefix the variable name with env:


For example, if you want to print the value of environment value "MINISHIFT_USERNAME", then command will be:


You can also enumerate all variables via the env drive:

Get-ChildItem env:

Type definition in object literal in TypeScript

In your code:

var obj = {
  myProp: string;

You are actually creating a object literal and assigning the variable string to the property myProp. Although very bad practice this would actually be valid TS code (don't use this!):

var string = 'A string';

var obj = {
  property: string

However, what you want is that the object literal is typed. This can be achieved in various ways:


interface myObj {
    property: string;

var obj: myObj = { property: "My string" };

Type alias:

type myObjType = {
    property: string

var obj: myObjType = { property: "My string" };

Object type literal:

var obj: { property: string; } = { property: "Mystring" };

Python 3 - Encode/Decode vs Bytes/Str

To add to add to the previous answer, there is even a fourth way that can be used

import codecs
encoded4 = codecs.encode(original, 'utf-8')

How to unescape a Java string literal in Java?

I know this question was old, but I wanted a solution that doesn't involve libraries outside those included JRE6 (i.e. Apache Commons is not acceptable), and I came up with a simple solution using the built-in


// ...

String literal = "\"Has \\\"\\\\\\\t\\\" & isn\\\'t \\\r\\\n on 1 line.\"";
StreamTokenizer parser = new StreamTokenizer(new StringReader(literal));
String result;
try {
  if (parser.ttype == '"') {
    result = parser.sval;
  else {
    result = "ERROR!";
catch (IOException e) {
  result = e.toString();


Has "\  " & isn't
 on 1 line.

Executing Javascript code "on the spot" in Chrome?

I'm not sure how far it will get you, but you can execute JavaScript one line at a time from the Developer Tool Console.

How does one sum only those rows in excel not filtered out?

If you aren't using an auto-filter (i.e. you have manually hidden rows), you will need to use the AGGREGATE function instead of SUBTOTAL.

ReactJS and images in public folder

You should use webpack here to make your life easier. Add below rule in your config:

const srcPath = path.join(__dirname, '..', 'publicfolder')

const rules = []

const includePaths = [
    // handle images
      test: /\.(png|gif|jpe?g|svg|ico)$/,
      include: includePaths,
      use: [{
        loader: 'file-loader',
        options: {
          name: 'images/[name]-[hash].[ext]'

After this, you can simply import the images into your react components:

import myImage from 'publicfolder/images/Image1.png'

Use myImage like below:

<div><img src={myImage}/></div>

or if the image is imported into local state of component

<div><img src={this.state.myImage}/></div> 

Checking whether the pip is installed?

pip list is a shell command. You should run it in your shell (bash/cmd), rather than invoke it from python interpreter.

pip does not provide a stable API. The only supported way of calling it is via subprocess, see docs and the code at the end of this answer.

However, if you want to just check if pip exists locally, without running it, and you are running Linux, I would suggest that you use bash's which command:

which pip

It should show you whether the command can be found in bash's PATH/aliases, and if it does, what does it actually execute.

If running pip is not an issue, you could just do:

python -m pip --version

If you really need to do it from a python script, you can always put the import statement into a try...except block:

    import pip
except ImportError:
    print("Pip not present.")

Or check what's the output of a pip --version using subprocess module:

subprocess.check_call([sys.executable, '-m', 'pip', '--version'])

GridView Hide Column by code

Here i am binding the gridview with dataset like this-

GVAnswer.DataSource = DS.Tables[0];

Then after

Then we count the number of rows like this in the for loop

for (int i = 0; i < GVAnswer.Rows.Count; i++)


Then after we find the header we want make visible false

GVAnswer.HeaderRow.Cells[2].Visible = false;

then after we make the visibility false of that particular cell.

The complete code is give like this

public void FillGVAnswer(int QuestionID) { try { OBJClsQuestionAnswer = new ClsQuestionAnswer(); DS = new DataSet(); DS = OBJClsQuestionAnswer.GetAnswers(QuestionID); GVAnswer.DataSource = DS.Tables[0]; GVAnswer.DataBind(); if (DS.Tables[0].Rows.Count > 0) { for (int i = 0; i < GVAnswer.Rows.Count; i++) { GVAnswer.HeaderRow.Cells[2].Visible = false; GVAnswer.HeaderRow.Cells[3].Visible = false; GVAnswer.HeaderRow.Cells[6].Visible = false; GVAnswer.HeaderRow.Cells[8].Visible = false; GVAnswer.HeaderRow.Cells[10].Visible = false; GVAnswer.HeaderRow.Cells[11].Visible = false; //GVAnswer.Rows[i].Cells[1].Visible = false; if (GVAnswer.Rows[i].Cells[4].Text == "T") { GVAnswer.Rows[i].Cells[4].Text = "Text"; } else { GVAnswer.Rows[i].Cells[4].Text = "Image"; } if (GVAnswer.Rows[i].Cells[5].Text == "View Image") { HtmlAnchor a = new HtmlAnchor(); a.HRef = "~/ImageHandler.aspx?ACT=AIMG&AID=" + GVAnswer.Rows[i].Cells[2].Text; a.Attributes.Add("rel", "lightbox"); a.InnerText = GVAnswer.Rows[i].Cells[5].Text; GVAnswer.Rows[i].Cells[5].Controls.Add(a); } if (GVAnswer.Rows[i].Cells[7].Text == "Yes") { j++; ViewState["CheckHasMulAns"] = j;// To Chek How Many answer Of a particulaer Question Is Right } GVAnswer.Rows[i].Cells[8].Visible = false; GVAnswer.Rows[i].Cells[3].Visible = false; GVAnswer.Rows[i].Cells[10].Visible = false; GVAnswer.Rows[i].Cells[6].Visible = false; GVAnswer.Rows[i].Cells[11].Visible = false; GVAnswer.Rows[i].Cells[2].Visible = false; } } } catch (Exception ex) { string err = ex.Message; if (ex.InnerException != null) { err = err + " :: Inner Exception :- " + ex.InnerException.Message; } string addInfo = "Error in getting Answers :: -> "; ClsExceptionPublisher objPub = new ClsExceptionPublisher(); objPub.Publish(err, addInfo); } }

AngularJS is rendering <br> as text not as a newline

You need to either use ng-bind-html-unsafe ... or you need to include the ngSanitize module and use ng-bind-html:

with ng-bind-html-unsafe

Use this if you trust the source of the HTML you're rendering it will render the raw output of whatever you put into it.

<div><h4>Categories</h4><span ng-bind-html-unsafe="q.CATEGORY"></span></div>

OR with ng-bind-html

Use this if you DON'T trust the source of the HTML (i.e. it's user input). It will sanitize the html to make sure it doesn't include things like script tags or other sources of potential security risks.

Make sure you include this:

<script src=""></script>

Then reference it in your application module:

var app = angular.module('myApp', ['ngSanitize']);

THEN use it:

<div><h4>Categories</h4><span ng-bind-html="q.CATEGORY"></span></div>

How can I bold the fonts of a specific row or cell in an Excel worksheet with C#?

this works for me, so try it :

Microsoft.Office.Interop.Excel.Range rng =(Microsoft.Office.Interop.Excel.Range)XcelApp.Cells[1, i];
rng.Font.Bold = true; 
rng.Interior.Color =System.Drawing.ColorTranslator.ToOle(System.Drawing.Color.Yellow);

How to NodeJS require inside TypeScript file?

Typescript will always complain when it is unable to find a symbol. The compiler comes together with a set of default definitions for window, document and such specified in a file called lib.d.ts. If I do a grep for require in this file I can find no definition of a function require. Hence, we have to tell the compiler ourselves that this function will exist at runtime using the declare syntax:

declare function require(name:string);
var sampleModule = require('modulename');

On my system, this compiles just fine.

Why is "throws Exception" necessary when calling a function?

package javaexception;

public class JavaException {
   void show() throws Exception
        throw new Exception("my.own.Exception");

void show2() throws Exception  // Why throws is necessary here ?

void show3() throws Exception  // Why throws is necessary here ?
public static void main(String[] args) {

   JavaException a = new JavaException();

   }catch(Exception e){

Only small changes in your program. What It seems to be misunderstood by many regarding the main issue, is whenever you throw exception you need to handle it, not necessary in the same place ( ex. show1,2,3 method in your program) but you must at first caller method inside the 'main'. in one word, there is 'throw', there must be 'catch/try', even if not same method where exception happens.

SSRS the definition of the report is invalid

This occurred for me due to changing the names of certain dataset fields within BIDS that were being referenced by parameters. I forgot to go into the parameters and reassign a default value (the default value of the parameter didn't automatically change to the newly renamed dataset field. Instead .

How create Date Object with values in java

I think the best way would be using a SimpleDateFormat object.

DateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
String dateString = "2014-02-11";
Date dateObject = sdf.parse(dateString); // Handle the ParseException here

Display the current date and time using HTML and Javascript with scrollable effects in hta application

Method 1:

With marquee tag.


<marquee behavior="scroll" bgcolor="yellow" loop="-1" width="30%">
      <font color="blue">
        Today's date is : 
         <span id="time"></span>


var today = new Date();

Fiddle demo here

Method 2:

Without marquee tag and with CSS.


<p class="marquee">
    <span id="dtText"></span>


.marquee {
   width: 350px;
   margin: 0 auto;
   white-space: nowrap;
   overflow: hidden;
   box-sizing: border-box;

.marquee span {
   display: inline-block;
   padding-left: 100%;
   text-indent: 0;
   animation: marquee 15s linear infinite;

.marquee span:hover {
    animation-play-state: paused

@keyframes marquee {
    0%   { transform: translate(0, 0); }
    100% { transform: translate(-100%, 0); }


var today = new Date();

Fiddle demo here

Which UUID version to use?

There are two different ways of generating a UUID.

If you just need a unique ID, you want a version 1 or version 4.

  • Version 1: This generates a unique ID based on a network card MAC address and a timer. These IDs are easy to predict (given one, I might be able to guess another one) and can be traced back to your network card. It's not recommended to create these.

  • Version 4: These are generated from random (or pseudo-random) numbers. If you just need to generate a UUID, this is probably what you want.

If you need to always generate the same UUID from a given name, you want a version 3 or version 5.

  • Version 3: This generates a unique ID from an MD5 hash of a namespace and name. If you need backwards compatibility (with another system that generates UUIDs from names), use this.

  • Version 5: This generates a unique ID from an SHA-1 hash of a namespace and name. This is the preferred version.

find files by extension, *.html under a folder in nodejs

I have looked at the above answers and have mixed together this version which works for me:

function getFilesFromPath(path, extension) {
    let files = fs.readdirSync( path );
    return files.filter( file => file.match(new RegExp(`.*\.(${extension})`, 'ig')));

console.log(getFilesFromPath("./testdata", ".txt"));

This test will return an array of filenames from the files found in the folder at the path ./testdata. Working on node version 8.11.3.

Smooth scrolling when clicking an anchor link

There is a css way of doing this using scroll-behavior. Add the following property.

    scroll-behavior: smooth;

And that is it. No JS required.

a {_x000D_
  display: inline-block;_x000D_
  width: 50px;_x000D_
  text-decoration: none;_x000D_
nav, scroll-container {_x000D_
  display: block;_x000D_
  margin: 0 auto;_x000D_
  text-align: center;_x000D_
nav {_x000D_
  width: 339px;_x000D_
  padding: 5px;_x000D_
  border: 1px solid black;_x000D_
scroll-container {_x000D_
  display: block;_x000D_
  width: 350px;_x000D_
  height: 200px;_x000D_
  overflow-y: scroll;_x000D_
  scroll-behavior: smooth;_x000D_
scroll-page {_x000D_
  display: flex;_x000D_
  align-items: center;_x000D_
  justify-content: center;_x000D_
  height: 100%;_x000D_
  font-size: 5em;_x000D_
  <a href="#page-1">1</a>_x000D_
  <a href="#page-2">2</a>_x000D_
  <a href="#page-3">3</a>_x000D_
  <scroll-page id="page-1">1</scroll-page>_x000D_
  <scroll-page id="page-2">2</scroll-page>_x000D_
  <scroll-page id="page-3">3</scroll-page>_x000D_

PS: please check the browser compatibility.

Excel compare two columns and highlight duplicates

Don't wana do soo much work guyss.. Just Press Ctr and select Colum one and Press Ctr and select colum two. Then click conditional formatting -> Highlight Cell Rules -> Equel To.

and thats it. your done. :)

How to read an http input stream

a complete code for reading from a webservice in two ways

public void buttonclick(View view) {
    // the name of your webservice where reactance is your method
    new GetMethodDemo().execute("");

public class GetMethodDemo extends AsyncTask<String, Void, String> {
    //see also: 
    //writing to see:
    String server_response;
    protected String doInBackground(String... strings) {
        URL url;
        HttpURLConnection urlConnection = null;
        try {
            url = new URL(strings[0]);
            urlConnection = (HttpURLConnection) url.openConnection();
            int responseCode = urlConnection.getResponseCode();
            if (responseCode == HttpURLConnection.HTTP_OK) {
                server_response = readStream(urlConnection.getInputStream());
                Log.v("CatalogClient", server_response);
        } catch (MalformedURLException e) {
        } catch (IOException e) {

        try {
            url = new URL(strings[0]);
            urlConnection = (HttpURLConnection) url.openConnection();
            BufferedReader in = new BufferedReader(new InputStreamReader(
            String inputLine;
            while ((inputLine = in.readLine()) != null)
            Log.v("bufferv ", server_response);
        } catch (MalformedURLException e) {
        } catch (IOException e) {
        return null;

    protected void onPostExecute(String s) {
        Log.e("Response", "" + server_response);
   //assume there is a field with id editText
        EditText editText = (EditText) findViewById(;

Block direct access to a file over http but allow php script access

That is how I prevented direct access from URL to my ini files. Paste the following code in .htaccess file on root. (no need to create extra folder)

<Files ~ "\.ini$">
  Order allow,deny
  Deny from all

my settings.ini file is on the root, and without this code is accessible

Comparing two maps

As long as you override equals() on each key and value contained in the map, then m1.equals(m2) should be reliable to check for maps equality.

The same result can be obtained also by comparing toString() of each map as you suggested, but using equals() is a more intuitive approach.

May not be your specific situation, but if you store arrays in the map, may be a little tricky, because they must be compared value by value, or using Arrays.equals(). More details about this see here.

Is it possible to append to innerHTML without destroying descendants' event listeners?

something.innerHTML += 'add whatever you want';

it worked for me. I added a button to an input text using this solution

MySQL - force not to use cache for testing speed of query

Another alternative that only affects the current connection:

SET SESSION query_cache_type=0;

Changing website favicon dynamically

A more modern approach:

const changeFavicon = link => {
  let $favicon = document.querySelector('link[rel="icon"]')
  // If a <link rel="icon"> element already exists,
  // change its href to the given link.
  if ($favicon !== null) {
    $favicon.href = link
  // Otherwise, create a new element and append it to <head>.
  } else {
    $favicon = document.createElement("link")
    $favicon.rel = "icon"
    $favicon.href = link

You can then use it like this:


Convert a list to a data frame

For a paralleled (multicore, multisession, etc) solution using purrr family of solutions, use:

library (furrr)
plan(multisession) # see below to see which other plan() is the more efficient
myTibble <- future_map_dfc(l, ~.x)

Where l is the list.

To benchmark the most efficient plan() you can use:

plan(sequential) # reference time
# plan(multisession) # benchamark plan() goes here. See ?plan().
myTibble <- future_map_dfc(l, ~.x)

Eclipse: How do I add the javax.servlet package to a project?

For me doesnt put jars to lib directory and set to Build path enought.

The right thing was add it to Deployment Assembly.

Original asnwer

PHP Warning: include_once() Failed opening '' for inclusion (include_path='.;C:\xampp\php\PEAR')

This should work if current file is located in same directory where initcontrols is:

$base_dir = realpath(dirname(__FILE__)  . $ds . '..') . $ds;
$file = "{$base_dir}initcontrols{$ds}header_myworks.php"; 
echo $plHeader;?>   

How to use Regular Expressions (Regex) in Microsoft Excel both in-cell and loops

Expanding on patszim's answer for those in a rush.

  1. Open Excel workbook.
  2. Alt+F11 to open VBA/Macros window.
  3. Add reference to regex under Tools then References
    ![Excel VBA Form add references
  4. and selecting Microsoft VBScript Regular Expression 5.5
    ![Excel VBA add regex reference
  5. Insert a new module (code needs to reside in the module otherwise it doesn't work).
    ![Excel VBA insert code module
  6. In the newly inserted module,
    ![Excel VBA insert code into module
  7. add the following code:

    Function RegxFunc(strInput As String, regexPattern As String) As String
        Dim regEx As New RegExp
        With regEx
            .Global = True
            .MultiLine = True
            .IgnoreCase = False
            .pattern = regexPattern
        End With
        If regEx.Test(strInput) Then
            Set matches = regEx.Execute(strInput)
            RegxFunc = matches(0).Value
            RegxFunc = "not matched"
        End If
    End Function
  8. The regex pattern is placed in one of the cells and absolute referencing is used on it. ![Excel regex function in-cell usage Function will be tied to workbook that its created in.
    If there's a need for it to be used in different workbooks, store the function in Personal.XLSB

How to write a stored procedure using phpmyadmin and how to use it through php?

I guess no one mentioned this so I will write it here. In phpMyAdmin 4.x, there is "Add Routine" link under "Routines" tab at the top row. This link opens a popup dialog where you can write your Stored procedure without worrying about delimiter or template.

enter image description here

Add Routine

enter image description here

Note that for simple test stored procedure, you may want to drop the default parameter which is already given or you can simply set it with a value.

Round up to Second Decimal Place in Python

The round funtion stated does not works for definate integers like :


but , works for :


Morever the decimals like 2.675 are rounded as 2.67 not 2.68.
Better use the other method provided above.

How to disable PHP Error reporting in CodeIgniter?

Here is the typical structure of new Codeigniter project:

- application/
- system/
- user_guide/
- index.php <- this is the file you need to change

I usually use this code in my CI index.php. Just change local_server_name to the name of your local webserver.

With this code you can deploy your site to your production server without changing index.php each time.

// Domain-based environment
if ($_SERVER['SERVER_NAME'] == 'local_server_name') {
    define('ENVIRONMENT', 'development');
} else {
    define('ENVIRONMENT', 'production');

 * Different environments will require different levels of error reporting.
 * By default development will show errors but testing and live will hide them.

if (defined('ENVIRONMENT')) {
    switch (ENVIRONMENT) {
        case 'development':
        case 'testing':
        case 'production':
            ini_set('display_errors', 0);  
            exit('The application environment is not set correctly.');

Undo a git stash

git stash list to list your stashed changes.

git stash show to see what n is in the below commands.

git stash apply to apply the most recent stash.

git stash apply stash@{n} to apply an older stash.

Path of currently executing powershell script

For PowerShell 3.0 users - following works for both modules and script files:

function Get-ScriptDirectory {
    Split-Path -parent $PSCommandPath

How do I append to a table in Lua

You are looking for the insert function, found in the table section of the main library.

foo = {}
table.insert(foo, "bar")
table.insert(foo, "baz")

(SC) DeleteService FAILED 1072

make sure the service is stopped, the services control panel is closed, and no open file handles are open by the service.

Also make sure ProcessExplorer is not running.

CSS: Responsive way to center a fluid div (without px width) while limiting the maximum width?

Centering both horizontally and vertically

Actually, having the height and width in percents makes centering it even easier. You just offset the left and top by half of the area not occupied by the div.

So if you height is 40%, 100% - 40% = 60%. So you want 30% above and below. Then top: 30% does the trick.

See the example here:

Centering only horizontally

Use inline-block. The other answer here will not work for IE 8 and below, however. You must use a CSS hack or conditional styles for that. Here is the hack version:

See the example here:

.inlineblock { 
    display: inline-block;
    zoom: 1;
    display*: inline; /* ie hack */


By using media queries you can combine two techniques to achive the effect you want. The only complication is height. You use a nested div to switch between % width and

@media (max-width: 1000px) {
@media (min-width: 1000px) {

Is there a simple way to increment a datetime object one month in Python?

Note: This answer shows how to achieve this using only the datetime and calendar standard library (stdlib) modules - which is what was explicitly asked for. The accepted answer shows how to better achieve this with one of the many dedicated non-stdlib libraries. If you can use non-stdlib libraries, by all means do so for these kinds of date/time manipulations!

How about this?

def add_one_month(orig_date):
    # advance year and month by one month
    new_year = orig_date.year
    new_month = orig_date.month + 1
    # note: in, months go from 1 to 12
    if new_month > 12:
        new_year += 1
        new_month -= 12

    new_day =
    # while day is out of range for month, reduce by one
    while True:
            new_date =, new_month, new_day)
        except ValueError as e:
            new_day -= 1

    return new_date


Improved version which:

  1. keeps the time information if given a datetime.datetime object
  2. doesn't use try/catch, instead using calendar.monthrange from the calendar module in the stdlib:
import datetime
import calendar

def add_one_month(orig_date):
    # advance year and month by one month
    new_year = orig_date.year
    new_month = orig_date.month + 1
    # note: in, months go from 1 to 12
    if new_month > 12:
        new_year += 1
        new_month -= 12

    last_day_of_month = calendar.monthrange(new_year, new_month)[1]
    new_day = min(, last_day_of_month)

    return orig_date.replace(year=new_year, month=new_month, day=new_day)

Filtering a list based on a list of booleans

You're looking for itertools.compress:

>>> from itertools import compress
>>> list_a = [1, 2, 4, 6]
>>> fil = [True, False, True, False]
>>> list(compress(list_a, fil))
[1, 4]

Timing comparisons(py3.x):

>>> list_a = [1, 2, 4, 6]
>>> fil = [True, False, True, False]
>>> %timeit list(compress(list_a, fil))
100000 loops, best of 3: 2.58 us per loop
>>> %timeit [i for (i, v) in zip(list_a, fil) if v]  #winner
100000 loops, best of 3: 1.98 us per loop

>>> list_a = [1, 2, 4, 6]*100
>>> fil = [True, False, True, False]*100
>>> %timeit list(compress(list_a, fil))              #winner
10000 loops, best of 3: 24.3 us per loop
>>> %timeit [i for (i, v) in zip(list_a, fil) if v]
10000 loops, best of 3: 82 us per loop

>>> list_a = [1, 2, 4, 6]*10000
>>> fil = [True, False, True, False]*10000
>>> %timeit list(compress(list_a, fil))              #winner
1000 loops, best of 3: 1.66 ms per loop
>>> %timeit [i for (i, v) in zip(list_a, fil) if v] 
100 loops, best of 3: 7.65 ms per loop

Don't use filter as a variable name, it is a built-in function.

Can I specify multiple users for myself in .gitconfig?

Windows Environment

Additional this can be modified from Git Extensions --> Settings --> Global Settings, if you have it installed in your systems.


Right Click on a folder/directory in Windows Environment to access these settings. enter image description here

Update : How to switch/maintain multiple settings in Version 2.49 How to switch/maintain multiple settings in Version 2.49

Android RecyclerView addition & removal of items

Here are some visual supplemental examples. See my fuller answer for examples of adding and removing a range.

Add single item

Add "Pig" at index 2.

Insert single item

String item = "Pig";
int insertIndex = 2;
data.add(insertIndex, item);

Remove single item

Remove "Pig" from the list.

Remove single item

int removeIndex = 2;

How to display multiple images in one figure correctly?

Here is my approach that you may try:

import numpy as np
import matplotlib.pyplot as plt

fig=plt.figure(figsize=(8, 8))
columns = 4
rows = 5
for i in range(1, columns*rows +1):
    img = np.random.randint(10, size=(h,w))
    fig.add_subplot(rows, columns, i)

The resulting image:


(Original answer date: Oct 7 '17 at 4:20)

Edit 1

Since this answer is popular beyond my expectation. And I see that a small change is needed to enable flexibility for the manipulation of the individual plots. So that I offer this new version to the original code. In essence, it provides:-

  1. access to individual axes of subplots
  2. possibility to plot more features on selected axes/subplot

New code:

import numpy as np
import matplotlib.pyplot as plt

w = 10
h = 10
fig = plt.figure(figsize=(9, 13))
columns = 4
rows = 5

# prep (x,y) for extra plotting
xs = np.linspace(0, 2*np.pi, 60)  # from 0 to 2pi
ys = np.abs(np.sin(xs))           # absolute of sine

# ax enables access to manipulate each of subplots
ax = []

for i in range(columns*rows):
    img = np.random.randint(10, size=(h,w))
    # create subplot and append to ax
    ax.append( fig.add_subplot(rows, columns, i+1) )
    ax[-1].set_title("ax:"+str(i))  # set title
    plt.imshow(img, alpha=0.25)

# do extra plots on selected axes/subplots
# note: index starts with 0
ax[2].plot(xs, 3*ys)
ax[19].plot(ys**2, xs)  # finally, render the plot

The resulting plot:

enter image description here

Edit 2

In the previous example, the code provides access to the sub-plots with single index, which is inconvenient when the figure has many rows/columns of sub-plots. Here is an alternative of it. The code below provides access to the sub-plots with [row_index][column_index], which is more suitable for manipulation of array of many sub-plots.

import matplotlib.pyplot as plt
import numpy as np

# settings
h, w = 10, 10        # for raster image
nrows, ncols = 5, 4  # array of sub-plots
figsize = [6, 8]     # figure size, inches

# prep (x,y) for extra plotting on selected sub-plots
xs = np.linspace(0, 2*np.pi, 60)  # from 0 to 2pi
ys = np.abs(np.sin(xs))           # absolute of sine

# create figure (fig), and array of axes (ax)
fig, ax = plt.subplots(nrows=nrows, ncols=ncols, figsize=figsize)

# plot simple raster image on each sub-plot
for i, axi in enumerate(ax.flat):
    # i runs from 0 to (nrows*ncols-1)
    # axi is equivalent with ax[rowid][colid]
    img = np.random.randint(10, size=(h,w))
    axi.imshow(img, alpha=0.25)
    # get indices of row/column
    rowid = i // ncols
    colid = i % ncols
    # write row/col indices as axes' title for identification
    axi.set_title("Row:"+str(rowid)+", Col:"+str(colid))

# one can access the axes by ax[row_id][col_id]
# do additional plotting on ax[row_id][col_id] of your choice
ax[0][2].plot(xs, 3*ys, color='red', linewidth=3)
ax[4][3].plot(ys**2, xs, color='green', linewidth=3)


The resulting plot:


From ND to 1D arrays

Although this isn't using the np array format, (to lazy to modify my code) this should do what you want... If, you truly want a column vector you will want to transpose the vector result. It all depends on how you are planning to use this.

def getVector(data_array,col):
    vector = []
    imax = len(data_array)
    for i in range(imax):
    return ( vector )
a = ([1,2,3], [4,5,6])
b = getVector(a,1)


So if you need to transpose, you can do something like this:

def transposeArray(data_array):
    # need to test if this is a 1D array 
    # can't do a len(data_array[0]) if it's 1D
    two_d = True
    if isinstance(data_array[0], list):
        dimx = len(data_array[0])
        dimx = 1
        two_d = False
    dimy = len(data_array)
    # init output transposed array
    data_array_t = [[0 for row in range(dimx)] for col in range(dimy)]
    # fill output transposed array
    for i in range(dimx):
        for j in range(dimy):
            if two_d:
                data_array_t[j][i] = data_array[i][j]
                data_array_t[j][i] = data_array[j]
    return data_array_t

Date difference in minutes in Python

there is also a sneak way with pandas:

pd.to_timedelta(x) - pd.to_timedelta(y)

How to test my servlet using JUnit

EDIT: Cactus is now a dead project:

You may want to look at cactus.

Project Description

Cactus is a simple test framework for unit testing server-side java code (Servlets, EJBs, Tag Libs, Filters, ...).

The intent of Cactus is to lower the cost of writing tests for server-side code. It uses JUnit and extends it.

Cactus implements an in-container strategy, meaning that tests are executed inside the container.

in_array() and multidimensional array

I was looking for a function that would let me search for both strings and arrays (as needle) in the array (haystack), so I added to the answer by @jwueller.

Here's my code:

 * Recursive in_array function
 * Searches recursively for needle in an array (haystack).
 * Works with both strings and arrays as needle.
 * Both needle's and haystack's keys are ignored, only values are compared.
 * Note: if needle is an array, all values in needle have to be found for it to
 * return true. If one value is not found, false is returned.
 * @param  mixed   $needle   The array or string to be found
 * @param  array   $haystack The array to be searched in
 * @param  boolean $strict   Use strict value & type validation (===) or just value
 * @return boolean           True if in array, false if not.
function in_array_r($needle, $haystack, $strict = false) {
     // array wrapper
    if (is_array($needle)) {
        foreach ($needle as $value) {
            if (in_array_r($value, $haystack, $strict) == false) {
                // an array value was not found, stop search, return false
                return false;
        // if the code reaches this point, all values in array have been found
        return true;

    // string handling
    foreach ($haystack as $item) {
        if (($strict ? $item === $needle : $item == $needle)
            || (is_array($item) && in_array_r($needle, $item, $strict))) {
            return true;
    return false;

Converting 24 hour time to 12 hour time w/ AM & PM using Javascript

date = date.replace(/[0-9]{1,2}(:[0-9]{2}){2}/, function (time) {
    var hms = time.split(':'),
        h = +hms[0],
        suffix = (h < 12) ? 'am' : 'pm';
    hms[0] = h % 12 || 12;        
    return hms.join(':') + suffix

edit: I forgot to deal with 12 o'clock am/pm. Fixed.

ssh-copy-id no identities found error

The simplest way is to:


cd ~/.ssh


Its very very simple.

In manual of "ss-keygen" explains:

"DESCRIPTION ssh-keygen generates, manages and converts authentication keys for ssh(1). ssh-keygen can create RSA keys for use by SSH protocol version 1 and DSA, ECDSA or RSA keys for use by SSH protocol version 2. The type of key to be generated is specified with the -t option. If invoked without any arguments, ssh-keygen will generate an RSA key for use in SSH protocol 2 connections."

Get int from String, also containing letters, in Java

The NumberFormat class will only parse the string until it reaches a non-parseable character:


will hence return 123.

How to get the first line of a file in a bash script?

This suffices and stores the first line of filename in the variable $line:

read -r line < filename

I also like awk for this:

awk 'NR==1 {print; exit}' file

To store the line itself, use the var=$(command) syntax. In this case, line=$(awk 'NR==1 {print; exit}' file).

Or even sed:

sed -n '1p' file

With the equivalent line=$(sed -n '1p' file).

See a sample when we feed the read with seq 10, that is, a sequence of numbers from 1 to 10:

$ read -r line < <(seq 10) 
$ echo "$line"

$ line=$(awk 'NR==1 {print; exit}' <(seq 10))
$ echo "$line"

Create MSI or setup project with Visual Studio 2012

Microsoft has listened to the cry for supporting installers (MSI) in Visual Studio and released the Visual Studio Installer Projects Extension. You can now create installers in Visual Studio 2013; download the extension here from the visualstudiogallery.

Finding duplicate values in MySQL

Try using this query:

SELECT name, COUNT(*) value_count FROM company_master GROUP BY name HAVING value_count > 1;

Twitter Bootstrap - full width navbar

I know I'm a bit late to the party, but I got around the issue by tweaking the CSS to have the width span 100%, and setting l/r margins to 0px;

    margin-left: 0px;
    margin-right: 0px;
    width: 100%;

In Laravel, the best way to pass different types of flash messages in the session

Simply return with the 'flag' that you want to be treated without using any additional user function. The Controller:

return \Redirect::back()->withSuccess( 'Message you want show in View' );

Notice that I used the 'Success' flag.

The View:

@if( Session::has( 'success' ))
     {{ Session::get( 'success' ) }}
@elseif( Session::has( 'warning' ))
     {{ Session::get( 'warning' ) }} <!-- here to 'withWarning()' -->

Yes, it really works!

Fast query runs slow in SSRS

I had the same problem, here is my description of the problem

"I created a store procedure which would generate 2200 Rows and would get executed in almost 2 seconds however after calling the store procedure from SSRS 2008 and run the report it actually never ran and ultimately I have to kill the BIDS (Business Intelligence development Studio) from task manager".

What I Tried: I tried running the SP from reportuser Login but SP was running normal for that user as well, I checked Profiler but nothing worked out.


Actually the problem is that even though SP is generating the result but SSRS engine is taking time to read these many rows and render it back. So I added WITH RECOMPILE option in SP and ran the report .. this is when miracle happened and my problem got resolve.

std::cin input with spaces?

Use :

getline(cin, input);

the function can be found in

#include <string>

How do I horizontally center an absolute positioned element inside a 100% width div?

If you want to align center on left attribute.
The same thing is for top alignment, you could use margin-top: (width/2 of your div), the concept is the same of left attribute.
It's important to set header element to position:relative.
try this:

#logo {


If you would like to not use calculations you can do this:

#logo {
  left: 0;
  right: 0;
  margin: 0 auto;


When and Why to use abstract classes/methods?

Typically one uses an abstract class to provide some incomplete functionality that will be fleshed out by concrete subclasses. It may provide methods that are used by its subclasses; it may also represent an intermediate node in the class hierarchy, to represent a common grouping of concrete subclasses, distinguishing them in some way from other subclasses of its superclass. Since an interface can't derive from a class, this is another situation where a class (abstract or otherwise) would be necessary, versus an interface.

A good rule of thumb is that only leaf nodes of a class hierarchy should ever be instantiated. Making non-leaf nodes abstract is an easy way of ensuring that.

How to check if array element exists or not in javascript?

Consider the array a:

var a ={'name1':1, 'name2':2}

If you want to check if 'name1' exists in a, simply test it with in:

if('name1' in a){
console.log('name1 exists in a')
console.log('name1 is not in a')

How to store a large (10 digits) integer?

A wrapper class java.lang.Long can store 10 digit easily.

   Long phoneNumber = 1234567890;

It can store more than that also.


public final class Long extends Number implements Comparable<Long> {
     * A constant holding the minimum value a {@code long} can
     * have, -2<sup>63</sup>.
    @Native public static final long MIN_VALUE = 0x8000000000000000L;

     * A constant holding the maximum value a {@code long} can
     * have, 2<sup>63</sup>-1.
    @Native public static final long MAX_VALUE = 0x7fffffffffffffffL;

This means it can store values of range 9,223,372,036,854,775,807 to -9,223,372,036,854,775,808.

C++ int to byte array

return ((byte[0]<<24)|(byte[1]<<16)|(byte[2]<<8)|(byte[3]));


Collections sort(List<T>,Comparator<? super T>) method example

To use Collections sort(List,Comparator) , you need to create a class that implements Comparator Interface, and code for the compare() in it, through Comparator Interface

You can do something like this:

class StudentComparator implements Comparator
    public int compare (Student s1 Student s2)
        // code to compare 2 students

To sort do this:

 Collections.sort(List,new StudentComparator())

UICollectionView Self Sizing Cells with Auto Layout

contentView anchor mystery:

In one bizarre case this

    contentView.translatesAutoresizingMaskIntoConstraints = false

would not work. Added four explicit anchors to the contentView and it worked.

class AnnoyingCell: UICollectionViewCell {
    @IBOutlet var word: UILabel!
    override init(frame: CGRect) {
        super.init(frame: frame); common() }
    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder); common() }
    private func common() {
        contentView.translatesAutoresizingMaskIntoConstraints = false
            contentView.leftAnchor.constraint(equalTo: leftAnchor),
            contentView.rightAnchor.constraint(equalTo: rightAnchor),
            contentView.topAnchor.constraint(equalTo: topAnchor),
            contentView.bottomAnchor.constraint(equalTo: bottomAnchor)

and as usual

    estimatedItemSize = UICollectionViewFlowLayout.automaticSize

in YourLayout: UICollectionViewFlowLayout

Who knows? Might help someone.


stumbled on to the tip there - never saw it anywhere else in all the 1000s articles on this.

Invoking a jQuery function after .each() has completed

I'm using something like this:

           $.each(yourArray, function (key, value) {
                // Do Something in loop here
          ).then(function () {
               // After loop ends.

Explicitly select items from a list or tuple

Maybe a list comprehension is in order:

L = ['a', 'b', 'c', 'd', 'e', 'f']
print [ L[index] for index in [1,3,5] ]


['b', 'd', 'f']

Is that what you are looking for?

in linux terminal, how do I show the folder's last modification date, taking its content into consideration?

If I could, I would vote for the answer by Paulo. I tested it and understood the concept. I can confirm it works. The find command can output many parameters. For example, add the following to the --printf clause:

%a for attributes in the octal format
%n for the file name including a complete path


find Desktop/ -exec stat \{} --printf="%y %n\n" \; | sort -n -r | head -1
2011-02-14 22:57:39.000000000 +0100 Desktop/new file

Let me raise this question as well: Does the author of this question want to solve his problem using Bash or PHP? That should be specified.

Installing Numpy on 64bit Windows 7 with Python 2.7.3

Download numpy-1.9.2+mkl-cp27-none-win32.whl from .

Copy the file to C:\Python27\Scripts

Run cmd from the above location and type

pip install numpy-1.9.2+mkl-cp27-none-win32.whl

You will hopefully get the below output:

Processing c:\python27\scripts\numpy-1.9.2+mkl-cp27-none-win32.whl
Installing collected packages: numpy
Successfully installed numpy-1.9.2

Hope that works for you.

Adding @oneleggedmule 's suggestion:

You can also run the following command in the cmd:

pip2.7 install numpy-1.9.2+mkl-cp27-none-win_amd64.whl

Basically, writing pip alone also works perfectly (as in the original answer). Writing the version 2.7 can also be done for the sake of clarity or specification.

count number of rows in a data frame in R based on group

The count() function in plyr does what you want:


count(mydf, "MONTH-YEAR")

How to make div follow scrolling smoothly with jQuery?

That code doesn't work very well i fixed it a little bit

var el = $('.caja-pago');
var elpos_original = el.offset().top;

     var elpos = el.offset().top;
     var windowpos = $(window).scrollTop();
     var finaldestination = windowpos;
     if(windowpos<elpos_original) {
         finaldestination = elpos_original;
     } else {

Error: Tablespace for table xxx exists. Please DISCARD the tablespace before IMPORT

A little late here but generally I've seen this problem occur when you get a 'tablespace full' error when running in a 'innodb_file_per_table' mode. Without going into too much detail (more here), the database server's tablespace is defined by the innodb_data_file_path setting and by default is rather small. Even made larger, the 'tablespace full' can still occur with larger queries and such (lots of non-table 'stuff' is stored in there, undo logs, caches, etc...).

Anyways, I found that if you look in the OS directory where the files-per-table are stored, /var/lib/mysql by default on OSX, /usr/local/var/mysql with homebrew iirc, you'll find an orphaned tablename.ibd file without it's normal companion tablename.frm file. If you move that .ibd file to a safe temporary location (just to be safe) that should fix the problem.

$ ls /var/lib/mysql

table3.idb <- problem table, no table3.frm

$ mkdir /tmp/mysql_orphans
$ mv /var/lib/mysql/table3.ibd /tmp/mysql_orphans/

One caveat though, make sure what ever is causing the problem originally, e.g. long running query, locked table, etc... has been cleared. Otherwise you just end up with another orphaned .ibd file when you try a second time.

UNIX nonblocking I/O: O_NONBLOCK vs. FIONBIO

Prior to standardization there was ioctl(...FIONBIO...) and fcntl(...O_NDELAY...), but these behaved inconsistently between systems, and even within the same system. For example, it was common for FIONBIO to work on sockets and O_NDELAY to work on ttys, with a lot of inconsistency for things like pipes, fifos, and devices. And if you didn't know what kind of file descriptor you had, you'd have to set both to be sure. But in addition, a non-blocking read with no data available was also indicated inconsistently; depending on the OS and the type of file descriptor the read may return 0, or -1 with errno EAGAIN, or -1 with errno EWOULDBLOCK. Even today, setting FIONBIO or O_NDELAY on Solaris causes a read with no data to return 0 on a tty or pipe, or -1 with errno EAGAIN on a socket. However 0 is ambiguous since it is also returned for EOF.

POSIX addressed this with the introduction of O_NONBLOCK, which has standardized behavior across different systems and file descriptor types. Because existing systems usually want to avoid any changes to behavior which might break backward compatibility, POSIX defined a new flag rather than mandating specific behavior for one of the others. Some systems like Linux treat all 3 the same, and also define EAGAIN and EWOULDBLOCK to the same value, but systems wishing to maintain some other legacy behavior for backward compatibility can do so when the older mechanisms are used.

New programs should use fcntl(...O_NONBLOCK...), as standardized by POSIX.

Is the Scala 2.8 collections library a case of "the longest suicide note in history"?

Is this going to put people off coming to Scala?

I don't think it is the main factor that will affect how popular Scala will become, because Scala has a lot of power and its syntax is not as foreign to a Java/C++/PHP programmer as Haskell, OCaml, SML, Lisps, etc..

But I do think Scala's popularity will plateau at less than where Java is today, because I also think the next mainstream language must be much simplified, and the only way I see to get there is pure immutability, i.e. declarative like HTML, but Turing complete. However, I am biased because I am developing such a language, but I only did so after ruling out over a several month study that Scala could not suffice for what I needed.

Is this going to give Scala a bad name in the commercial world as an academic plaything that only dedicated PhD students can understand? Are CTOs and heads of software going to get scared off?

I don't think Scala's reputation will suffer from the Haskell complex. But I think that some will put off learning it, because for most programmers, I don't yet see a use case that forces them to use Scala, and they will procrastinate learning about it. Perhaps the highly-scalable server side is the most compelling use case.

And, for the mainstream market, first learning Scala is not a "breath of fresh air", where one is writing programs immediately, such as first using HTML or Python. Scala tends to grow on you, after one learns all the details that one stumbles on from the start. However, maybe if I had read Programming in Scala from the start, my experience and opinion of the learning curve would have been different.

Was the library re-design a sensible idea?


If you're using Scala commercially, are you worried about this? Are you planning to adopt 2.8 immediately or wait to see what happens?

I am using Scala as the initial platform of my new language. I probably wouldn't be building code on Scala's collection library if I was using Scala commercially otherwise. I would create my own category theory based library, since the one time I looked, I found Scalaz's type signatures even more verbose and unwieldy than Scala's collection library. Part of that problem perhaps is Scala's way of implementing type classes, and that is a minor reason I am creating my own language.

I decided to write this answer, because I wanted to force myself to research and compare Scala's collection class design to the one I am doing for my language. Might as well share my thought process.

The 2.8 Scala collections use of a builder abstraction is a sound design principle. I want to explore two design tradeoffs below.

  1. WRITE-ONLY CODE: After writing this section, I read Carl Smotricz's comment which agrees with what I expect to be the tradeoff. James Strachan and davetron5000's comments concur that the meaning of That (it is not even That[B]) and the mechanism of the implicit is not easy to grasp intuitively. See my use of monoid in issue #2 below, which I think is much more explicit. Derek Mahar's comment is about writing Scala, but what about reading the Scala of others that is not "in the common cases".

    One criticism I have read about Scala, is that it is easier to write it, than read the code that others have written. And I find this to be occasionally true for various reasons (e.g. many ways to write a function, automatic closures, Unit for DSLs, etc), but I am undecided if this is major factor. Here the use of implicit function parameters has pluses and minuses. On the plus side, it reduces verbosity and automates selection of the builder object. In Odersky's example the conversion from a BitSet, i.e. Set[Int], to a Set[String] is implicit. The unfamiliar reader of the code might not readily know what the type of collection is, unless they can reason well about the all the potential invisible implicit builder candidates which might exist in the current package scope. Of course, the experienced programmer and the writer of the code will know that BitSet is limited to Int, thus a map to String has to convert to a different collection type. But which collection type? It isn't specified explicitly.

  2. AD-HOC COLLECTION DESIGN: After writing this section, I read Tony Morris's comment and realized I am making nearly the same point. Perhaps my more verbose exposition will make the point more clear.

    In "Fighting Bit Rot with Types" Odersky & Moors, two use cases are presented. They are the restriction of BitSet to Int elements, and Map to pair tuple elements, and are provided as the reason that the general element mapping function, A => B, must be able to build alternative destination collection types. However, afaik this is flawed from a category theory perspective. To be consistent in category theory and thus avoid corner cases, these collection types are functors, in which each morphism, A => B, must map between objects in the same functor category, List[A] => List[B], BitSet[A] => BitSet[B]. For example, an Option is a functor that can be viewed as a collection of sets of one Some( object ) and the None. There is no general map from Option's None, or List's Nil, to other functors which don't have an "empty" state.

    There is a tradeoff design choice made here. In the design for collections library of my new language, I chose to make everything a functor, which means if I implement a BitSet, it needs to support all element types, by using a non-bit field internal representation when presented with a non-integer type parameter, and that functionality is already in the Set which it inherits from in Scala. And Map in my design needs to map only its values, and it can provide a separate non-functor method for mapping its (key,value) pair tuples. One advantage is that each functor is then usually also an applicative and perhaps a monad too. Thus all functions between element types, e.g. A => B => C => D => ..., are automatically lifted to the functions between lifted applicative types, e.g. List[A] => List[B] => List[C] => List[D] => .... For mapping from a functor to another collection class, I offer a map overload which takes a monoid, e.g. Nil, None, 0, "", Array(), etc.. So the builder abstraction function is the append method of a monoid and is supplied explicitly as a necessary input parameter, thus with no invisible implicit conversions. (Tangent: this input parameter also enables appending to non-empty monoids, which Scala's map design can't do.) Such conversions are a map and a fold in the same iteration pass. Also I provide a traversable, in the category sense, "Applicative programming with effects" McBride & Patterson, which also enables map + fold in a single iteration pass from any traversable to any applicative, where most every collection class is both. Also the state monad is an applicative and thus is a fully generalized builder abstraction from any traversable.

    So afaics the Scala collections is "ad-hoc" in the sense that it is not grounded in category theory, and category theory is the essense of higher-level denotational semantics. Although Scala's implicit builders are at first appearance "more generalized" than a functor model + monoid builder + traversable -> applicative, they are afaik not proven to be consistent with any category, and thus we don't know what rules they follow in the most general sense and what the corner cases will be given they may not obey any category model. It is simply not true that adding more variables makes something more general, and this was one of huge benefits of category theory is it provides rules by which to maintain generality while lifting to higher-level semantics. A collection is a category.

    I read somewhere, I think it was Odersky, as another justification for the library design, is that programming in a pure functional style has the cost of limited recursion and speed where tail recursion isn't used. I haven't found it difficult to employ tail recursion in every case that I have encountered so far.

Additionally I am carrying in my mind an incomplete idea that some of Scala's tradeoffs are due to trying to be both an mutable and immutable language, unlike for example Haskell or the language I am developing. This concurs with Tony Morris's comment about for comprehensions. In my language, there are no loops and no mutable constructs. My language will sit on top of Scala (for now) and owes much to it, and this wouldn't be possible if Scala didn't have the general type system and mutability. That might not be true though, because I think Odersky & Moors ("Fighting Bit Rot with Types") are incorrect to state that Scala is the only OOP language with higher-kinds, because I verified (myself and via Bob Harper) that Standard ML has them. Also appears SML's type system may be equivalently flexible (since 1980s), which may not be readily appreciated because the syntax is not so much similar to Java (and C++/PHP) as Scala. In any case, this isn't a criticism of Scala, but rather an attempt to present an incomplete analysis of tradeoffs, which is I hope germane to the question. Scala and SML don't suffer from Haskell's inability to do diamond multiple inheritance, which is critical and I understand is why so many functions in the Haskell Prelude are repeated for different types.

How to Customize the time format for Python logging?

From the official documentation regarding the Formatter class:

The constructor takes two optional arguments: a message format string and a date format string.

So change

# create formatter
formatter = logging.Formatter("%(asctime)s;%(levelname)s;%(message)s")


# create formatter
formatter = logging.Formatter("%(asctime)s;%(levelname)s;%(message)s",
                              "%Y-%m-%d %H:%M:%S")

Text not wrapping in p tag

This is a little late for this question but others might benefit. I had a similar problem but had an added requirement for the text to correctly wrap in all device sizes. So in my case this worked. Need to setup the view port.

   white-space: normal;
    overflow-wrap: break-word;
    width: 96vw;

How to set Linux environment variables with Ansible

I did not have enough reputation to comment and hence am adding a new answer.
Gasek answer is quite correct. Just one thing: if you are updating the .bash_profile file or the /etc/profile, those changes would be reflected only after you do a new login. In case you want to set the env variable and then use it in subsequent tasks in the same playbook, consider adding those environment variables in the .bashrc file.
I guess the reason behind this is the login and the non-login shells.
Ansible, while executing different tasks, reads the parameters from a .bashrc file instead of the .bash_profile or the /etc/profile.

As an example, if I updated my path variable to include the custom binary in the .bash_profile file of the respective user and then did a source of the file. The next subsequent tasks won't recognize my command. However if you update in the .bashrc file, the command would work.

 - name: Adding the path in the bashrc files
   lineinfile: dest=/root/.bashrc line='export PATH=$PATH:path-to-mysql/bin' insertafter='EOF' regexp='export PATH=\$PATH:path-to-mysql/bin' state=present
-  - name: Source the bashrc file
   shell: source /root/.bashrc

 - name: Start the mysql client
   shell: mysql -e "show databases";

This would work, but had I done it using profile files the mysql -e "show databases" would have given an error.

- name: Adding the path in the Profile files
   lineinfile: dest=/root/.bash_profile line='export PATH=$PATH:{{install_path}}/{{mysql_folder_name}}/bin' insertafter='EOF' regexp='export PATH=\$PATH:{{install_path}}/{{mysql_folder_name}}/bin' state=present

 - name: Source the bash_profile file
   shell: source /root/.bash_profile

 - name: Start the mysql client
   shell: mysql -e "show databases";

This one won't work, if we have all these tasks in the same playbook.

How to check if a user likes my Facebook Page or URL using Facebook's API

You can use (PHP)

$isFan = file_get_contents("" . USER_TOKEN . "&page_id=" . FB_FANPAGE_ID);

That will return one of three:

  • string true string false json
  • formatted response of error if token
  • or page_id are not valid

I guess the only not-using-token way to achieve this is with the signed_request Jason Siffring just posted. My helper using PHP SDK:

function isFan(){
    global $facebook;
    $request = $facebook->getSignedRequest();
    return $request['page']['liked'];

How and when to use SLEEP() correctly in MySQL?

If you don't want to SELECT SLEEP(1);, you can also DO SLEEP(1); It's useful for those situations in procedures where you don't want to see output.



Field 'id' doesn't have a default value?

For me the issue got fixed when I changed

<id name="personID" column="person_id">
    <generator class="native"/>


<id name="personID" column="person_id">
    <generator class="increment"/>

in my Person.hbm.xml.

after that I re-encountered that same error for an another field(mobno). I tried restarting my IDE, recreating the database with previous back issue got eventually fixed when I re-create my tables using (without ENGINE=InnoDB DEFAULT CHARSET=latin1; and removing underscores in the field name)

CREATE TABLE `tbl_customers` (
  `pid` bigint(20) NOT NULL,
  `title` varchar(4) NOT NULL,
  `dob` varchar(10) NOT NULL,
  `address` varchar(100) NOT NULL,
  `country` varchar(4) DEFAULT NULL,
  `hometp` int(12) NOT NULL,
  `worktp` int(12) NOT NULL,
  `mobno` varchar(12) NOT NULL,
  `btcfrom` varchar(8) NOT NULL,
  `btcto` varchar(8) NOT NULL,
  `mmname` varchar(20) NOT NULL

instead of

CREATE TABLE `tbl_person` (
  `person_id` bigint(20) NOT NULL,
  `person_nic` int(10) NOT NULL,
  `first_name` varchar(20) NOT NULL,
  `sur_name` varchar(20) NOT NULL,
  `person_email` varchar(20) NOT NULL,
  `person_password` varchar(512) NOT NULL,
  `mobno` varchar(10) NOT NULL DEFAULT '1',
  `role` varchar(10) NOT NULL,
  `verified` int(1) DEFAULT NULL

I probably think this due to using ENGINE=InnoDB DEFAULT CHARSET=latin1; , because I once got the error org.hibernate.engine.jdbc.spi.SqlExceptionHelper - Unknown column 'mob_no' in 'field list' even though it was my previous column name, which even do not exist in my current table. Even after backing up the database(with modified column name, using InnoDB engine) I still got that same error with old field name. This probably due to caching in that Engine.

Increasing heap space in Eclipse: (java.lang.OutOfMemoryError)

What to do if i have to processed even more that 500000 records ?

There are a few ways, to increase the java heap size for your app where a few have suggested already. Your app need to remove the elements from your adddressMap as your app add new element into it and so you won't encounter oom if there are more records coming in. Look for producer-consumer if you are interested.

Multiline text in JLabel

Type the content (i.e., the "text" property field) inside a <html></html> tag. So you can use <br> or<P> to insert a newline.

For example:

String labelContent = "<html>Twinkle, twinkle, little star,<BR>How I wonder what you are.<BR>Up above the world so high,<BR>Like a diamond in the sky.</html>";

It will display as follows:

Twinkle, twinkle, little star,
How I wonder what you are.
Up above the world so high,
Like a diamond in the sky.

CSS3 opacity gradient?

You can do it in CSS, but there isn't much support in browsers other than modern versions of Chrome, Safari and Opera at the moment. Firefox currently only supports SVG masks. See the Caniuse results for more information.


p {
    color: red;
    -webkit-mask-image: -webkit-gradient(linear, left top, left bottom, 
    from(rgba(0,0,0,1)), to(rgba(0,0,0,0)));

The trick is to specify a mask that is itself a gradient that ends as invisible (thru alpha value)

See a demo with a solid background, but you can change this to whatever you want.


Notice also that all the usual image properties are available for mask-image

p  {_x000D_
  color: red;_x000D_
  font-size: 30px;_x000D_
  -webkit-mask-image: linear-gradient(to left, rgba(0,0,0,1), rgba(0,0,0,0)), linear-gradient(to right, rgba(0,0,0,1), rgba(0,0,0,0));_x000D_
  -webkit-mask-size: 100% 50%;_x000D_
  -webkit-mask-repeat: no-repeat;_x000D_
  -webkit-mask-position: left top, left bottom;_x000D_
div {_x000D_
    background-color: lightblue;_x000D_
<div><p>text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text </p></div>

Now, another approach is available, that is supported by Chrome, Firefox, Safari and Opera.

The idea is to use

mix-blend-mode: hard-light;

that gives transparency if the color is gray. Then, a grey overlay on the element creates the transparency

div {_x000D_
  background-color: lightblue;_x000D_
p {_x000D_
  color: red;_x000D_
  overflow: hidden;_x000D_
  position: relative;_x000D_
  width: 200px;_x000D_
  mix-blend-mode: hard-light;_x000D_
p::after {_x000D_
  position: absolute;_x000D_
  content: "";_x000D_
  left: 0px;_x000D_
  top: 0px;_x000D_
  height: 100%;_x000D_
  width: 100%;_x000D_
  background: linear-gradient(transparent, gray);_x000D_
  pointer-events: none;_x000D_
<div><p>text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text </p></div>
_x000D_ failed to connect to / (port 2468): connect failed: ECONNREFUSED (Connection refused)

Why this might have happened:

  1. The server couldn't send a response: Ensure that the backend is working properly at IP and port mentioned.
  2. SSL connections are being blocked: Fix this by importing SSL certificates

Less likely:

  1. Cookies not being sent
  2. Request timeout: Change request timeout

Meaning of .Cells(.Rows.Count,"A").End(xlUp).row


I think the first dot in the parenthesis should not be there, I mean, you should write it in this way:


Before the Cells, you can write your worksheet name, for example:

Worksheets("sheet1").Cells(Rows.Count, 2).End(xlUp).row

The worksheet name is not necessary when you operate on the same worksheet.

Remove last specific character in a string c#

When you have spaces at the end. you can use beliow.

ProcessStr = ProcessStr.Replace(" ", "");
Emails     = ProcessStr.TrimEnd(';');

Java logical operator short-circuiting

Logical OR :- returns true if at least one of the operands evaluate to true. Both operands are evaluated before apply the OR operator.

Short Circuit OR :- if left hand side operand returns true, it returns true without evaluating the right hand side operand.

How to convert a data frame column to numeric type?

df ist your dataframe. x is a column of df you want to convert


Axios having CORS issue

I had got the same CORS error while working on a Vue.js project. You can resolve this either by building a proxy server or another way would be to disable the security settings of your browser (eg, CHROME) for accessing cross origin apis (this is temporary solution & not the best way to solve the issue). Both these solutions had worked for me. The later solution does not require any mock server or a proxy server to be build. Both these solutions can be resolved at the front end.

You can disable the chrome security settings for accessing apis out of the origin by typing the below command on the terminal:

/Applications/Google\\ Chrome --user-data-dir="/tmp/chrome_dev_session" --disable-web-security

After running the above command on your terminal, a new chrome window with security settings disabled will open up. Now, run your program (npm run serve / npm run dev) again and this time you will not get any CORS error and would be able to GET request using axios.

Hope this helps!

What does __FILE__ mean in Ruby?

It is a reference to the current file name. In the file foo.rb, __FILE__ would be interpreted as "foo.rb".

Edit: Ruby 1.9.2 and 1.9.3 appear to behave a little differently from what Luke Bayes said in his comment. With these files:

# test.rb
puts __FILE__
require './dir2/test.rb'
# dir2/test.rb
puts __FILE__

Running ruby test.rb will output


Return back to MainActivity from another activity

I'm used it and worked perfectly...

startActivity(new Intent(getApplicationContext(),MainActivity.class).setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP)); 

because Finish() use for 2 activities, not for multiple activities

How to remove an appended element with Jquery and why bind or live is causing elements to repeat

Do you have multiple Radio Buttons on the page..

Because what I see is that you are assigning the events to all the radio button's on the page when you click on a radio button

In Git, how do I figure out what my current revision is?

What do you mean by "version number"? It is quite common to tag a commit with a version number and then use

$ git describe --tags

to identify the current HEAD w.r.t. any tags. If you mean you want to know the hash of the current HEAD, you probably want:

$ git rev-parse HEAD

or for the short revision hash:

$ git rev-parse --short HEAD

It is often sufficient to do:

$ cat .git/refs/heads/${branch-master}

but this is not reliable as the ref may be packed.

Where is the documentation for the values() method of Enum?

The method is implicitly defined (i.e. generated by the compiler).

From the JLS:

In addition, if E is the name of an enum type, then that type has the following implicitly declared static methods:

* Returns an array containing the constants of this enum 
* type, in the order they're declared.  This method may be
* used to iterate over the constants as follows:
*    for(E c : E.values())
*        System.out.println(c);
* @return an array containing the constants of this enum 
* type, in the order they're declared
public static E[] values();

* Returns the enum constant of this type with the specified
* name.
* The string must match exactly an identifier used to declare
* an enum constant in this type.  (Extraneous whitespace 
* characters are not permitted.)
* @return the enum constant with the specified name
* @throws IllegalArgumentException if this enum type has no
* constant with the specified name
public static E valueOf(String name);

Change remote repository credentials (authentication) on Intellij IDEA 14

For Mac users this could also be helpful:

Credentials are stored in Keychain You can just change them there.

Remove duplicate rows in MySQL

A solution that is simple to understand and works with no primary key:

1) add a new boolean column

alter table mytable add tokeep boolean;

2) add a constraint on the duplicated columns AND the new column

alter table mytable add constraint preventdupe unique (mycol1, mycol2, tokeep);

3) set the boolean column to true. This will succeed only on one of the duplicated rows because of the new constraint

update ignore mytable set tokeep = true;

4) delete rows that have not been marked as tokeep

delete from mytable where tokeep is null;

5) drop the added column

alter table mytable drop tokeep;

I suggest that you keep the constraint you added, so that new duplicates are prevented in the future.

changing visibility using javascript

If you just want to display it when you get a response add this to your loadpage()

function loadpage(page_request, containerid){
   if (page_request.readyState == 4 && page_request.status==200) { 
      var container = document.getElementById(containerid);
      container.innerHTML=page_request.responseText; = 'visible';
      // or = 'block';

but this depend entirely on how you hid the div in the first place

Javascript use variable as object name

If you already know the list of the possible varible names then try creating a new Object(iconObj) whose properties name are same as object names, Here in below example, iconLib variable will hold two string values , either 'ZondIcons' or 'MaterialIcons'. propertyName is the property of ZondIcons or MaterialsIcon object.

   const iconObj = {
  const objValue = iconObj[iconLib][propertyName]

How should I set the default proxy to use default credentials?

This is the new suggested method.


How to set up Automapper in ASP.NET Core

I am using AutoMapper 6.1.1 and Core 1.1.2.

First of all, define Profile classes inherited by Profile Class of Automapper. I Created IProfile interface which is empty, the purpose is only to find the classes of this type.

 public class UserProfile : Profile, IProfile
        public UserProfile()
            CreateMap<User, UserModel>();
            CreateMap<UserModel, User>();

Now create a separate class e.g Mappings

 public class Mappings
     public static void RegisterMappings()
       var all =
          .SelectMany(x => x.DefinedTypes)
          .Where(type => typeof(IProfile).GetTypeInfo().IsAssignableFrom(type.AsType()));

            foreach (var ti in all)
                var t = ti.AsType();
                if (t.Equals(typeof(IProfile)))
                    Mapper.Initialize(cfg =>
                        cfg.AddProfiles(t); // Initialise each Profile classe


Now in MVC Core web Project in Startup.cs file, in the constructor, call Mapping class which will initialize all mappings at the time of application loading.


Cannot lower case button text in android studio

in XML Code
add this line android:textAllCaps="false" like bellow code

       ** android:textAllCaps="false" ** />


in Java code (programmatically)
add this line to your button setAllCaps(false)

Button btn = (Button) findViewById(;

Build fails with "Command failed with a nonzero exit code"

In my case it was empty assets catalog, when I delete it everything was fine again.

Create Directory if it doesn't exist with Ruby

How about just Dir.mkdir('dir') rescue nil ?

Get full query string in C# ASP.NET

Just use Request.QueryString.ToString() to get full query string, like this:

string URL = ""+Request.Querystring.ToString();

Spring Resttemplate exception handling

Here is my POST method with HTTPS which returns a response body for any type of bad responses.

public String postHTTPSRequest(String url,String requestJson)
    //SSL Context
    CloseableHttpClient httpClient = HttpClients.custom().setSSLHostnameVerifier(new NoopHostnameVerifier()).build();
    HttpComponentsClientHttpRequestFactory requestFactory = new HttpComponentsClientHttpRequestFactory();
    //Initiate REST Template
    RestTemplate restTemplate = new RestTemplate(requestFactory);
    HttpHeaders headers = new HttpHeaders();
    //Send the Request and get the response.
    HttpEntity<String> entity = new HttpEntity<String>(requestJson,headers);
    ResponseEntity<String> response;
    String stringResponse = "";
    try {
        response = restTemplate.postForEntity(url, entity, String.class);
        stringResponse = response.getBody();
    catch (HttpClientErrorException e)
        stringResponse = e.getResponseBodyAsString();
    return stringResponse;

MySQL and GROUP_CONCAT() maximum length

The correct parameter to set the maximum length is:

SET @@group_concat_max_len = value_numeric;

value_numeric must be > 1024; by default the group_concat_max_len value is 1024.

How to get html table td cell value by JavaScript?



    <title>Search students by courses/professors</title>

    <script type="text/javascript">

    function ChangeColor(tableRow, highLight)
       if (highLight){
  = '00CCCC';

    else{ = 'white';

  function DoNav(theUrl)
  document.location.href = theUrl;


     <table id = "c" width="180" border="1" cellpadding="0" cellspacing="0">

            <% for (Course cs : courses){ %>

            <tr onmouseover="ChangeColor(this, true);" 
                onmouseout="ChangeColor(this, false);" 

                 <td name = "title" align = "center"><%= cs.getTitle() %></td>



I wrote the HTML table in JSP. Course is is a type. For example Course cs, cs= object of type Course which had 2 attributes: id, title. courses is an ArrayList of Course objects.

The HTML table displays all the courses titles in each cell. So the table has 1 column only: Course1 Course2 Course3 ...... Taking aside:


This means that after user selects a table cell, for example "Course2", the title of the course- "Course2" will travel to the page where the URL is directing the user: http://localhost:8080/Mydata/ComplexSearch/FoundS.jsp . "Course2" will arrive in FoundS.jsp page. The identifier of "Course2" is courseId. To declare the variable courseId, in which CourseX will be kept, you put a "?" after the URL and next to it the identifier. It works.

Rounding to 2 decimal places in SQL

Try using the COLUMN command with the FORMAT option for that:


How do I fix the "You don't have write permissions into the /usr/bin directory" error when installing Rails?

Using the -n /usr/local/bin flag does work, BUT I had to come back to this page every time I wanted to update a package again. So I figured out a permanent fix for this.

For those interested in fixing this permanently:

Create a ~/.gemrc file

vim .gemrc

With the following content:

   - ~/.gem/ruby
install: -n /usr/local/bin

Now you can run your command normally without the -n flag.


MySQL - How to select rows where value is in array?

Use the FIND_IN_SET function:

 WHERE FIND_IN_SET(3, t.ids) > 0

Watch multiple $scope attributes

Beginning with AngularJS 1.1.4 you can use $watchCollection:

$scope.$watchCollection('[item1, item2]', function(newValues, oldValues){
    // do stuff here
    // newValues and oldValues contain the new and respectively old value
    // of the observed collection array

Plunker example here

Documentation here

How do I set the background color of my main screen in Flutter?

I think you need to use MaterialApp widget and use theme and set primarySwatch with color that you want. look like below code,

import 'package:flutter/material.dart';

void main() {
  runApp(new MyApp());

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  Widget build(BuildContext context) {
    return new MaterialApp(
      title: 'Flutter Demo',
      theme: new ThemeData(
      home: new MyHomePage(title: 'Flutter Demo Home Page'),

Undefined Symbols for architecture x86_64: Compiling problems

There's no mystery here, the linker is telling you that you haven't defined the missing symbols, and you haven't.

Similarity::Similarity() or Similarity::~Similarity() are just missing and you have defined the others incorrectly,

void Similarity::readData(Scanner& inStream){


void readData(Scanner& inStream){

etc. etc.

The second one is a function called readData, only the first is the readData method of the Similarity class.

To be clear about this, in Similarity.h

void readData(Scanner& inStream);

but in Similarity.cpp

void Similarity::readData(Scanner& inStream){

Change border color on <select> HTML form

Replacing the border-color with outline-color should work.

Eloquent get only one column as an array

I came across this question and thought I would clarify that the lists() method of a eloquent builder object was depreciated in Laravel 5.2 and replaced with pluck().

// <= Laravel 5.1
Word_relation::where('word_one', $word_id)->lists('word_one')->toArray();
// >= Laravel 5.2
Word_relation::where('word_one', $word_id)->pluck('word_one')->toArray();

These methods can also be called on a Collection for example

// <= Laravel 5.1
  $collection = Word_relation::where('word_one', $word_id)->get();
  $array = $collection->lists('word_one');

// >= Laravel 5.2
  $collection = Word_relation::where('word_one', $word_id)->get();
  $array = $collection->pluck('word_one');

Repeat a task with a time delay?

Based on the above post concerning the ScheduledThreadPoolExecutor, I came up with a utility that suited my needs (wanted to fire a method every 3 seconds):

class MyActivity {
    private ScheduledThreadPoolExecutor mDialogDaemon;

    private void initDebugButtons() {
        Button btnSpawnDialogs = (Button)findViewById(;
        btnSpawnDialogs.setOnClickListener(new OnClickListener() {
            public void onClick(View view) {

    private void spawnDialogs() {
        if (mDialogDaemon != null) {
            mDialogDaemon = null;
        mDialogDaemon = new ScheduledThreadPoolExecutor(1);
        // This process will execute immediately, then execute every 3 seconds.
        mDialogDaemon.scheduleAtFixedRate(new Runnable() {
            public void run() {
                runOnUiThread(new Runnable() {
                    public void run() {
                        // Do something worthwhile
        }, 0L, 3000L, TimeUnit.MILLISECONDS);

In Android, how do I set margins in dp programmatically?

Simple Kotlin Extension Solutions

Set all/any side independently:

fun View.setMargin(left: Int? = null, top: Int? = null, right: Int? = null, bottom: Int? = null) {
    val params = (layoutParams as? MarginLayoutParams)
            left ?: params.leftMargin,
            top ?: params.topMargin,
            right ?: params.rightMargin,
            bottom ?: params.bottomMargin)
    layoutParams = params

myView.setMargin(10, 5, 10, 5)
// or just any subset
myView.setMargin(right = 10, bottom = 5)

Directly refer to a resource values:

fun View.setMarginRes(@DimenRes left: Int? = null, @DimenRes top: Int? = null, @DimenRes right: Int? = null, @DimenRes bottom: Int? = null) {
            if (left == null) null else resources.getDimensionPixelSize(left),
            if (top == null) null else resources.getDimensionPixelSize(top),
            if (right == null) null else resources.getDimensionPixelSize(right),
            if (bottom == null) null else resources.getDimensionPixelSize(bottom),

myView.setMarginRes(top = R.dimen.my_margin_res)

To directly set all sides equally as a property:

var View.margin: Int
    get() = throw UnsupportedOperationException("No getter for property")
    set(@Px margin) = setMargin(margin, margin, margin, margin)
myView.margin = 10 // px

// or as res
var View.marginRes: Int
    get() = throw UnsupportedOperationException("No getter for property")
    set(@DimenRes marginRes) {
        margin = resources.getDimensionPixelSize(marginRes)

myView.marginRes = R.dimen.my_margin_res

To directly set a specific side, you can create a property extension like this:

var View.leftMargin
    get() = marginLeft
    set(@Px leftMargin) = setMargin(left = leftMargin)

var View.leftMarginRes: Int
    get() = throw UnsupportedOperationException("No getter for property")
    set(@DimenRes leftMarginRes) {
        leftMargin = resources.getDimensionPixelSize(leftMarginRes)

This allows you to make horizontal or vertical variants as well:

var View.horizontalMargin
    get() = throw UnsupportedOperationException("No getter for property")
    set(@Px horizontalMargin) = setMargin(left = horizontalMargin, right = horizontalMargin)

var View.horizontalMarginRes: Int
    get() = throw UnsupportedOperationException("No getter for property")
    set(@DimenRes horizontalMarginRes) {
        horizontalMargin = resources.getDimensionPixelSize(horizontalMarginRes)

NOTE: If margin is failing to set, you may too soon before render, meaning params == null. Try wrapping the modification with{ margin = 10 }