Programs & Examples On #Eeepc

How to override during production in Spring-Boot?

The spring configuration precedence is as follows.

  1. ServletConfig init Parameter
  2. ServletContext init parameter
  3. JNDI attributes
  4. System.getProperties()

So your configuration will be overridden at the command-line if you wish to do that. But the recommendation is to avoid overriding, though you can use multiple profiles.

Send JSON data with jQuery

It gets serialized so that the URI can read the name value pairs in the POST request by default. You could try setting processData:false to your list of params. Not sure if that would help.

Importing large sql file to MySql via command line

+1 to @MartinNuc, you can run the mysql client in batch mode and then you won't see the long stream of "OK" lines.

The amount of time it takes to import a given SQL file depends on a lot of things. Not only the size of the file, but the type of statements in it, how powerful your server server is, and how many other things are running at the same time.

@MartinNuc says he can load 4GB of SQL in 4-5 minutes, but I have run 0.5 GB SQL files and had it take 45 minutes on a smaller server.

We can't really guess how long it will take to run your SQL script on your server.

Re your comment,

@MartinNuc is correct you can choose to make the mysql client print every statement. Or you could open a second session and run mysql> SHOW PROCESSLIST to see what's running. But you probably are more interested in a "percentage done" figure or an estimate for how long it will take to complete the remaining statements.

Sorry, there is no such feature. The mysql client doesn't know how long it will take to run later statements, or even how many there are. So it can't give a meaningful estimate for how much time it will take to complete.

simple custom event

Like has been mentioned already the progress field needs the keyword event

public event EventHandler<Progress> progress;

But I don't think that's where you actually want your event. I think you actually want the event in TestClass. How does the following look? (I've never actually tried setting up static events so I'm not sure if the following will compile or not, but I think this gives you an idea of the pattern you should be aiming for.)

public partial class Form1 : Form
    public Form1()
        TestClass.progress += SetStatus;

    private void SetStatus(object sender, Progress e)
        label1.Text = e.Status;

    private void button1_Click_1(object sender, EventArgs e)


public class TestClass
    public static event EventHandler<Progress> progress; 

    public static void Func()
        //time consuming code
        OnProgress(new Progress("current status"));
        // time consuming code
        OnProgress(new Progress("some new status"));            

    private static void OnProgress(EventArgs e) 
       if (progress != null)
          progress(this, e);

public class Progress : EventArgs
    public string Status { get; private set; }

    private Progress() {}

    public Progress(string status)
        Status = status;

Entity Framework Provider type could not be loaded?

Late to the party, but the top voted answers all seemed like hacks to me.

All I did was remove the following from my app.config in the test project. Worked.

    <defaultConnectionFactory type="System.Data.Entity.Infrastructure.LocalDbConnectionFactory, EntityFramework">
        <parameter value="mssqllocaldb" />
      <provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />

How do I convert a Python 3 byte-string variable into a regular string?

Call decode() on a bytes instance to get the text which it encodes.

str = bytes.decode()

Symfony2 and date_default_timezone_get() - It is not safe to rely on the system's timezone settings

Following up on sas's answer, PHP 5.4, Symfony 2.8, I had to use

ini_set('date.timezone','<whatever timezone string>');

instead of date_default_timezone_set. I also added a call to ini_set to the top of a custom web/config.php to get that check to succeed.

How to inspect FormData?

In certain cases, the use of :

for(var pair of formData.entries(){... 

is impossible.

I've used this code in replacement :

var outputLog = {}, iterator = myFormData.entries(), end = false;
while(end == false) {
   var item =;
   if(item.value!=undefined) {
       outputLog[item.value[0]] = item.value[1];
   } else if(item.done==true) {
       end = true;

It's not a very smart code, but it works...

Hope it's help.

Difference between datetime and timestamp in sqlserver?

According to the documentation, timestamp is a synonym for rowversion - it's automatically generated and guaranteed1 to be unique. datetime isn't - it's just a data type which handles dates and times, and can be client-specified on insert etc.

1 Assuming you use it properly, of course. See comments.

Cannot assign requested address - possible causes?

Okay, my problem wasn't the port, but the binding address. My server has an internal address ( and an external address (52.175.223.XX). When I tried connecting with:

$sock = @stream_socket_server('tcp://52.175.223.XX:123', $errNo, $errStr, STREAM_SERVER_BIND|STREAM_SERVER_LISTEN);

It failed because the local socket was and not the external 52.175.223.XX. You can checkout the local available interfaces with sudo ifconfig.

Get all variables sent with POST?

Why not this, it's easy:


Get lengths of a list in a jinja2 template

Alex' comment looks good but I was still confused with using range. The following worked for me while working on a for condition using length within range.

{% for i in range(0,(nums['list_users_response']['list_users_result']['users'])| length) %}
<li>    {{ nums['list_users_response']['list_users_result']['users'][i]['user_name'] }} </li>
{% endfor %}

Integer value in TextView

TextView tv = new TextView(this);



How to write a cron that will run a script every day at midnight?

Put this sentence in a crontab file: 0 0 * * * /usr/local/bin/python /opt/ > /var/log/cron.log 2>&1

jQuery slide left and show

This feature is included as part of jquery ui if you want to extend it with your own names you can use this.

  slideRightShow: function() {
    return this.each(function() {
        $(this).show('slide', {direction: 'right'}, 1000);
  slideLeftHide: function() {
    return this.each(function() {
      $(this).hide('slide', {direction: 'left'}, 1000);
  slideRightHide: function() {
    return this.each(function() {
      $(this).hide('slide', {direction: 'right'}, 1000);
  slideLeftShow: function() {
    return this.each(function() {
      $(this).show('slide', {direction: 'left'}, 1000);

you will need the following references

<script src=""></script>
<script src=""></script>
<script src=""></script>

Pass Model To Controller using Jquery/Ajax

Looks like your IndexPartial action method has an argument which is a complex object. If you are passing a a lot of data (complex object), It might be a good idea to convert your action method to a HttpPost action method and use jQuery post to post data to that. GET has limitation on the query string value.

public PartialViewResult IndexPartial(DashboardViewModel m)
   //May be you want to pass the posted model to the parial view?
   return PartialView("_IndexPartial");

Your script should be

var url = "@Url.Action("IndexPartial","YourControllerName")";

var model = { Name :"Shyju", Location:"Detroit"};

$.post(url, model, function(res){
   //res contains the markup returned by the partial view
   //You probably want to set that to some Div.

Assuming Name and Location are properties of your DashboardViewModel class and SomeDivToShowTheResult is the id of a div in your page where you want to load the content coming from the partialview.

Sending complex objects?

You can build more complex object in js if you want. Model binding will work as long as your structure matches with the viewmodel class

var model = { Name :"Shyju", 
              Interests : ["Code","Coffee","Stackoverflow"]

    type: "POST",
    data: JSON.stringify(model),
    url: url,
    contentType: "application/json"
}).done(function (res) {

For the above js model to be transformed to your method parameter, Your View Model should be like this.

public class DashboardViewModel
  public string Name {set;get;}
  public string Location {set;get;}
  public List<string> Interests {set;get;}

And in your action method, specify [FromBody]

public PartialViewResult IndexPartial([FromBody] DashboardViewModel m)
    return PartialView("_IndexPartial",m);

How to squash all git commits into one?

This worked best for me.

git rebase -X ours -i master

This will git will prefer your feature branch to master; avoiding the arduous merge edits. Your branch needs to be up to date with master.

           This resolves any number of heads, but the resulting tree of the merge is always that of the current
           branch head, effectively ignoring all changes from all other branches. It is meant to be used to
           supersede old development history of side branches. Note that this is different from the -Xours
           option to the recursive merge strategy.

How do I find the location of Python module sources?

Running python -v from the command line should tell you what is being imported and from where. This works for me on Windows and Mac OS X.

C:\>python -v
# installing zipimport hook
import zipimport # builtin
# installed zipimport hook
# C:\Python24\lib\site.pyc has bad mtime
import site # from C:\Python24\lib\
# wrote C:\Python24\lib\site.pyc
# C:\Python24\lib\os.pyc has bad mtime
import os # from C:\Python24\lib\
# wrote C:\Python24\lib\os.pyc
import nt # builtin
# C:\Python24\lib\ntpath.pyc has bad mtime

I'm not sure what those bad mtime's are on my install!

How do I get Maven to use the correct repositories?

By default, Maven will always look in the official Maven repository, which is

When Maven tries to build a project, it will look in your local repository (by default ~/.m2/repository but you can configure it by changing the <localRepository> value in your ~/.m2/settings.xml) to find any dependency, plugin or report defined in your pom.xml. If the adequate artifact is not found in your local repository, it will look in all external repositories configured, starting with the default one,

You can configure Maven to avoid this default repository by setting a mirror in your settings.xml file:

        <name>Our mirror for Maven repository</name>

This way, instead of contacting, Maven will contact your entreprise repository (http://the/server in this example).

If you want to add another repository, you can define a new one in your settings.xml file:


You can see the complete settings.xml model here.

Concerning the clean process, you can ask Maven to run it offline. In this case, Maven will not try to reach any external repositories:

mvn -o clean 

Regular Expressions and negating a whole character group

The regex [^ab] will match for example 'ab ab ab ab' but not 'ab', because it will match on the string ' a' or 'b '.

What language/scenario do you have? Can you subtract results from the original set, and just match ab?

If you are using GNU grep, and are parsing input, use the '-v' flag to invert your results, returning all non-matches. Other regex tools also have a 'return nonmatch' function, too.

If I understand correctly, you want everything except for those items which contain 'ab' anywhere.

How to center a table of the screen (vertically and horizontally)

Horizontal centering is easy. You just need to set both margins to "auto":

table {
  margin-left: auto;
  margin-right: auto;

Vertical centering usually is achieved by setting the parent element display type to table-cell and using vertical-align property. Assuming you have a <div class="wrapper"> around your table:

.wrapper {
  display: table-cell;
  vertical-align: middle;

More detailed information may be found on

If you need support for older versions of Internet Explorer (I do not know what works in what version of this strange and rarely used browser ;-) ) then you may want to search the web for more information, like: (just a first hit, which seems to mention IE)

conversion from infix to prefix

(a–b)/c*(d + e – f / g)

remember scanning the expression from leftmost to right most start on parenthesized terms follow the WHICH COMES FIRST rule... *, /, % are on the same level and higher than + and -.... so (a-b) = -bc prefix (a-b) = bc- for postfix another parenthesized term: (d + e - f / g) = do move the / first then plus '+' comes first before minus sigh '-' (remember they are on the same level..) (d + e - f / g) move / first (d + e - (/fg)) = prefix (d + e - (fg/)) = postfix followed by + then - ((+de) - (/fg)) = prefix ((de+) - (fg/)) = postfix

(-(+de)(/fg)) = prefix so the new expression is now -+de/fg (1) ((de+)(fg/)-) = postfix so the new expression is now de+fg/- (2)

(a–b)/c* hence

  1. (a-b)/c*(d + e – f / g) = -bc prefix [-ab]/c*[-+de/fg] ---> taken from (1) / c * do not move yet so '/' comes first before '*' because they on the same level, move '/' to the rightmost : /[-ab]c * [-+de/fg] then move '*' to the rightmost

    • / [-ab]c[-+de/fg] = remove the grouping symbols = */-abc-+de/fg --> Prefix
  2. (a-b)/c*(d + e – f / g) = bc- for postfix [ab-]/c*[de+fg/-]---> taken from (2) so '/' comes first before '' because they on the same level, move '/' to the leftmost: [ab-]c[de+fg/-]/ then move '' to the leftmost [ab-] c [de+fg/-]/ = remove the grouping symbols= a b - c d e + f g / - / * --> Postfix

What is [Serializable] and when should I use it?

What is it?

When you create an object in a .Net framework application, you don't need to think about how the data is stored in memory. Because the .Net Framework takes care of that for you. However, if you want to store the contents of an object to a file, send an object to another process or transmit it across the network, you do have to think about how the object is represented because you will need to convert to a different format. This conversion is called SERIALIZATION.

Uses for Serialization

Serialization allows the developer to save the state of an object and recreate it as needed, providing storage of objects as well as data exchange. Through serialization, a developer can perform actions like sending the object to a remote application by means of a Web Service, passing an object from one domain to another, passing an object through a firewall as an XML string, or maintaining security or user-specific information across applications.

Apply SerializableAttribute to a type to indicate that instances of this type can be serialized. Apply the SerializableAttribute even if the class also implements the ISerializable interface to control the serialization process.

All the public and private fields in a type that are marked by the SerializableAttribute are serialized by default, unless the type implements the ISerializable interface to override the serialization process. The default serialization process excludes fields that are marked with NonSerializedAttribute. If a field of a serializable type contains a pointer, a handle, or some other data structure that is specific to a particular environment, and cannot be meaningfully reconstituted in a different environment, then you might want to apply NonSerializedAttribute to that field.

See MSDN for more details.

Edit 1

Any reason to not mark something as serializable

When transferring or saving data, you need to send or save only the required data. So there will be less transfer delays and storage issues. So you can opt out unnecessary chunk of data when serializing.

GCC dump preprocessor defines

Late answer - I found the other answers useful - and wanted to add a bit extra.

How do I dump preprocessor macros coming from a particular header file?

echo "#include <sys/socket.h>" | gcc -E -dM -

or (thanks to @mymedia for the suggestion):

gcc -E -dM -include sys/socket.h - < /dev/null

In particular, I wanted to see what SOMAXCONN was defined to on my system. I know I could just open up the standard header file, but sometimes I have to search around a bit to find the header file locations. Instead I can just use this one-liner:

$ gcc -E -dM -include sys/socket.h - < /dev/null | grep SOMAXCONN
#define SOMAXCONN 128

Error 80040154 (Class not registered exception) when initializing VCProjectEngineObject (Microsoft.VisualStudio.VCProjectEngine.dll)

There are not many good reasons this would fail, especially the regsvr32 step. Run dumpbin /exports on that dll. If you don't see DllRegisterServer then you've got a corrupt install. It should have more side-effects, you wouldn't be able to build C/C++ projects anymore.

One standard failure mode is running this on a 64-bit operating system. This is 32-bit unmanaged code, you would indeed get the 'class not registered' exception. Project + Properties, Build tab, change Platform Target to x86.

Python: Random numbers into a list

Fix the indentation of the print statement

import random

for i in range (10):

print (my_randoms)

Dynamically updating css in Angular 2

You can also use hostbinding:

import { HostBinding } from '@angular/core';

export class HomeComponent {
    @HostBinding('style.width') width: Number;
    @HostBinding('style.height') height: Number;

Now when you change the width or height property from within the HomeComponent, this should affect the style attributes.

android get all contacts

Get contacts info , photo contacts , photo uri and convert to Class model

1). Sample for Class model :

    public class ContactModel {
        public String id;
        public String name;
        public String mobileNumber;
        public Bitmap photo;
        public Uri photoURI;

2). get Contacts and convert to Model

     public List<ContactModel> getContacts(Context ctx) {
        List<ContactModel> list = new ArrayList<>();
        ContentResolver contentResolver = ctx.getContentResolver();
        Cursor cursor = contentResolver.query(ContactsContract.Contacts.CONTENT_URI, null, null, null, null);
        if (cursor.getCount() > 0) {
            while (cursor.moveToNext()) {
                String id = cursor.getString(cursor.getColumnIndex(ContactsContract.Contacts._ID));
                if (cursor.getInt(cursor.getColumnIndex(ContactsContract.Contacts.HAS_PHONE_NUMBER)) > 0) {
                    Cursor cursorInfo = contentResolver.query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI, null,
                            ContactsContract.CommonDataKinds.Phone.CONTACT_ID + " = ?", new String[]{id}, null);
                    InputStream inputStream = ContactsContract.Contacts.openContactPhotoInputStream(ctx.getContentResolver(),
                            ContentUris.withAppendedId(ContactsContract.Contacts.CONTENT_URI, new Long(id)));

                    Uri person = ContentUris.withAppendedId(ContactsContract.Contacts.CONTENT_URI, new Long(id));
                    Uri pURI = Uri.withAppendedPath(person, ContactsContract.Contacts.Photo.CONTENT_DIRECTORY);

                    Bitmap photo = null;
                    if (inputStream != null) {
                        photo = BitmapFactory.decodeStream(inputStream);
                    while (cursorInfo.moveToNext()) {
                        ContactModel info = new ContactModel();
               = id;
               = cursor.getString(cursor.getColumnIndex(ContactsContract.Contacts.DISPLAY_NAME));
                        info.mobileNumber = cursorInfo.getString(cursorInfo.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));
               = photo;
                        info.photoURI= pURI;

        return list;

what does numpy ndarray shape do?

yourarray.shape or np.shape() or returns the shape of your ndarray as a tuple; And you can get the (number of) dimensions of your array using yourarray.ndim or np.ndim(). (i.e. it gives the n of the ndarray since all arrays in NumPy are just n-dimensional arrays (shortly called as ndarrays))

For a 1D array, the shape would be (n,) where n is the number of elements in your array.

For a 2D array, the shape would be (n,m) where n is the number of rows and m is the number of columns in your array.

Please note that in 1D case, the shape would simply be (n, ) instead of what you said as either (1, n) or (n, 1) for row and column vectors respectively.

This is to follow the convention that:

For 1D array, return a shape tuple with only 1 element   (i.e. (n,))
For 2D array, return a shape tuple with only 2 elements (i.e. (n,m))
For 3D array, return a shape tuple with only 3 elements (i.e. (n,m,k))
For 4D array, return a shape tuple with only 4 elements (i.e. (n,m,k,j))

and so on.

Also, please see the example below to see how np.shape() or behaves with 1D arrays and scalars:

# sample array
In [10]: u = np.arange(10)

# get its shape
In [11]: np.shape(u)    # u.shape
Out[11]: (10,)

# get array dimension using `np.ndim`
In [12]: np.ndim(u)
Out[12]: 1

In [13]: np.shape(np.mean(u))
Out[13]: ()       # empty tuple (to indicate that a scalar is a 0D array).

# check using `numpy.ndim`
In [14]: np.ndim(np.mean(u))
Out[14]: 0

P.S.: So, the shape tuple is consistent with our understanding of dimensions of space, at least mathematically.

switch case statement error: case expressions must be constant expression

Solution can be done be this way:

  1. Just assign the value to Integer
  2. Make variable to final


public static final int cameraRequestCode = 999;

Hope this will help you.

Convert an object to an XML string

This is my solution, for any list object you can use this code for convert to xml layout. KeyFather is your principal tag and KeySon is where start your Forech.

public string BuildXml<T>(ICollection<T> anyObject, string keyFather, string keySon)
        var settings = new XmlWriterSettings
            Indent = true
        PropertyDescriptorCollection props = TypeDescriptor.GetProperties(typeof(T));
        StringBuilder builder = new StringBuilder();
        using (XmlWriter writer = XmlWriter.Create(builder, settings))
            foreach (var objeto in anyObject)
                foreach (PropertyDescriptor item in props)
            return builder.ToString();

Type converting slices of interfaces

Here is the official explanation:

var dataSlice []int = foo()
var interfaceSlice []interface{} = make([]interface{}, len(dataSlice))
for i, d := range dataSlice {
    interfaceSlice[i] = d

How to create an empty file at the command line in Windows?

  • create a bat file with content echo '' > %1. (name the file as touch.bat)
  • add the folder to PATH variable.
  • you can use touch to create files. (Ex: touch temp.txt creates temp.txt file)

check this article for more information.

API vs. Webservice

another example: google map api vs google direction api web service, while the former serves (delivers) javascript file to the site (which can then be used as an api to make new functions) , the later is a Rest web service delivering data (in json or xml format), which can be processed (but not used in an api sense).

Naming convention - underscore in C++ and C# variables

_var has no meaning and only serves the purpose of making it easier to distinguish that the variable is a private member variable.

In C++, using the _var convention is bad form, because there are rules governing the use of the underscore in front of an identifier. _var is reserved as a global identifier, while _Var (underscore + capital letter) is reserved anytime. This is why in C++, you'll see people using the var_ convention instead.

How to add line breaks to an HTML textarea?

I have a textarea with id is #infoartist follow:

<textarea id="infoartist" ng-show="dForm" style="width: 100%;" placeholder="Tell your contacts and collectors about yourself."></textarea>

In javascript code, i'll get value of textarea and replace escaping new line (\n\r) by <br /> tag, such as:

var text = document.getElementById("infoartist").value;
text = text.replace(/\r?\n/g, '<br />');

So if you are using jquery (like me):

var text = $("#infoartist").val();
text = text.replace(/\r?\n/g, '<br />');

Hope it helped you. :-)

Formatting dates on X axis in ggplot2

Can you use date as a factor?

Yes, but you probably shouldn't.

...or should you use as.Date on a date column?


Which leads us to this:

df$Month <- as.Date(df$Month)
ggplot(df, aes(x = Month, y = AvgVisits)) + 
  geom_bar(stat = "identity") +
  theme_bw() +
  labs(x = "Month", y = "Average Visits per User") +
  scale_x_date(labels = date_format("%m-%Y"))

enter image description here

in which I've added stat = "identity" to your geom_bar call.

In addition, the message about the binwidth wasn't an error. An error will actually say "Error" in it, and similarly a warning will always say "Warning" in it. Otherwise it's just a message.

Are "while(true)" loops so bad?

I wouldn't say it's bad - but equally I would normally at least look for an alternative.

In situations where it's the first thing I write, I almost always at least try to refactor it into something clearer. Sometimes it can't be helped (or the alternative is to have a bool variable which does nothing meaningful except indicate the end of the loop, less clearly than a break statement) but it's worth at least trying.

As an example of where it's clearer to use break than a flag, consider:

while (true)
    int input = getSomeInput();
    if (testCondition(input))

Now let's force it to use a flag:

boolean running = true;
while (running)
    int input = getSomeInput();
    if (testCondition(input))
        running = false;

I view the latter as more complicated to read: it's got an extra else block, the actOnInput is more indented, and if you're trying to work out what happens when testCondition returns true, you need to look carefully through the rest of the block to check that there isn't something after the else block which would occur whether running has been set to false or not.

The break statement communicates the intent more clearly, and lets the rest of the block get on with what it needs to do without worrying about earlier conditions.

Note that this is exactly the same sort of argument that people have about multiple return statements in a method. For example, if I can work out the result of a method within the first few lines (e.g. because some input is null, or empty, or zero) I find it clearer to return that answer directly than to have a variable to store the result, then a whole block of other code, and finally a return statement.

Change default global installation directory for node.js modules in Windows?

The default global folder is C:\Users\{username}\AppData\Roaming\npm. You can create (if it doesn't exist) a .npmrc file in C:\Users\{username}\ and add prefix = "path\\to\\yourglobalfolder". Note that, in windows, the path should be separated by double back-slash.

SqlException: DB2 SQL error: SQLCODE: -302, SQLSTATE: 22001, SQLERRMC: null

To get the definition of the SQL codes, the easiest way is to use db2 cli!

at the unix or dos command prompt, just type

db2 "? SQL302"

this will give you the required explanation of the particular SQL code that you normally see in the java exception or your db2 sql output :)

hope this helped.

Run script with rc.local: script works, but not at boot

In this example of a rc.local script I use io redirection at the very first line of execution to my own log file:

#!/bin/sh -e
# rc.local
# This script is executed at the end of each multiuser runlevel.
# Make sure that the script will "exit 0" on success or any other
# value on error.
# In order to enable or disable this script just change the execution
# bits.
# By default this script does nothing.

exec 2> /tmp/rc.local.log  # send stderr from rc.local to a log file
exec 1>&2                      # send stdout to the same log file
set -x                         # tell sh to display commands before execution


exit 0

Git push error: "origin does not appear to be a git repository"

Your config file does not include any references to "origin" remote. That section looks like this:

[remote "origin"]
    url = [email protected]:repository.git
    fetch = +refs/heads/*:refs/remotes/origin/*

You need to add the remote using git remote add before you can use it.

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

If you have a version of find (such as GNU find) that supports -printf then there's no need to call stat repeatedly:

find /some/dir -printf "%T+\n" | sort -nr | head -n 1


find /some/dir -printf "%TY-%Tm-%Td %TT\n" | sort -nr | head -n 1

If you don't need recursion, though:

stat --printf="%y\n" *

javascript how to create a validation error message without using alert

I would strongly suggest you start using jQuery. Your code would look like:

$(function() {
    $('form[name="myform"]').submit(function(e) {
        var username = $('form[name="myform"] input[name="username"]').val();
        if ( username == '') {
            $('#errors').text('*Please enter a username*');

How do I hide an element on a click event anywhere outside of the element?

What you can also do is:

$(document).click(function (e)

  var container = $("div");

   if (! && container.has( === 0)



If your target is not a div then hide the div by checking its length is equal to zero.

How can I check if a string contains a character in C#?

here is an example what most of have done

using System;

class Program
    static void Main()
        Test("Dot Net Perls");
        Test("dot net perls");

    static void Test(string input)
        Console.Write("--- ");
        Console.WriteLine(" ---");
        // See if the string contains 'Net'
        bool contains = input.Contains("Net");
        // Write the result
        Console.Write("Contains 'Net': ");
        // See if the string contains 'perls' lowercase
        if (input.Contains("perls"))
            Console.WriteLine("Contains 'perls'");
        // See if the string contains 'Dot'
        if (!input.Contains("Dot"))
            Console.WriteLine("Doesn't Contain 'Dot'");

Trust Anchor not found for Android SSL Connection

Update based on latest Android documentation (March 2017):

When you get this type of error: Trust anchor for certification path not found.
        at org.apache.harmony.xnet.provider.jsse.OpenSSLSocketImpl.startHandshake(

the issue could be one of the following:

  1. The CA that issued the server certificate was unknown
  2. The server certificate wasn't signed by a CA, but was self signed
  3. The server configuration is missing an intermediate CA

The solution is to teach HttpsURLConnection to trust a specific set of CAs. How? Please check

Others who are using AsyncHTTPClient from library, please check Setup AsyncHttpClient to use HTTPS.

JNI converting jstring to char *

Here's a a couple of useful link that I found when I started with JNI

concerning your problem you can use this

JNIEXPORT void JNICALL Java_ClassName_MethodName(JNIEnv *env, jobject obj, jstring javaString)   
   const char *nativeString = env->GetStringUTFChars(javaString, 0);

   // use your string

   env->ReleaseStringUTFChars(javaString, nativeString);

Execute Shell Script after post build in Jenkins

You can also run arbitrary commands using the Groovy Post Build - and that will give you a lot of control over when they run and so forth. We use that to run a 'finger of blame' shell script in the case of failed or unstable builds.

if ( {
  item = hudson.model.Hudson.instance.getItem("PROJECTNAMEHERE")
  lastStableBuild = item.getLastStableBuild()
  lastStableDate = lastStableBuild.getTime()
  formattedLastStableDate = lastStableDate.format("MM/dd/yyyy h:mm:ss a")
  now = new Date()
  formattedNow = now.format("MM/dd/yyyy h:mm:ss a")
  command = ['/appframe/jenkins/appframework/fob.ksh', "${formattedLastStableDate}", "${formattedNow}"]
  manager.listener.logger.println "FOB Command: ${command}"
  manager.listener.logger.println command.execute().text

(Our command takes the last stable build date and the current time as parameters so it can go investigate who might have broken the build, but you could run whatever commands you like in a similar fashion)

Python sum() function with list parameter

In the last answer, you don't need to make a list from numbers; it is already a list:

numbers = [1, 2, 3]
numsum = sum(numbers)

Pandas: Subtracting two date columns and the result being an integer

You can divide column of dtype timedelta by np.timedelta64(1, 'D'), but output is not int, but float, because NaN values:

df_test['Difference'] = df_test['Difference'] / np.timedelta64(1, 'D')
print (df_test)
  First_Date Second Date  Difference
0 2016-02-09  2015-11-19        82.0
1 2016-01-06  2015-11-30        37.0
2        NaT  2015-12-04         NaN
3 2016-01-06  2015-12-08        29.0
4        NaT  2015-12-09         NaN
5 2016-01-07  2015-12-11        27.0
6        NaT  2015-12-12         NaN
7        NaT  2015-12-14         NaN
8 2016-01-06  2015-12-14        23.0
9        NaT  2015-12-15         NaN

Frequency conversion.

SOAP PHP fault parsing WSDL: failed to load external entity?

I had the same problem, I succeeded by adding:

new \SoapClient(URI WSDL OR NULL if non-WSDL mode, [
    'cache_wsdl' => WSDL_CACHE_NONE, 
    'proxy_host' => 'URL PROXY',
    'proxy_port' => 'PORT PROXY'

Hope this help :)

How to retrieve a file from a server via SFTP?

Another option is to consider looking at the JSch library. JSch seems to be the preferred library for a few large open source projects, including Eclipse, Ant and Apache Commons HttpClient, amongst others.

It supports both user/pass and certificate-based logins nicely, as well as all a whole host of other yummy SSH2 features.

Here's a simple remote file retrieve over SFTP. Error handling is left as an exercise for the reader :-)

JSch jsch = new JSch();

String knownHostsFilename = "/home/username/.ssh/known_hosts";
jsch.setKnownHosts( knownHostsFilename );

Session session = jsch.getSession( "remote-username", "remote-host" );    
  // "interactive" version
  // can selectively update specified known_hosts file 
  // need to implement UserInfo interface
  // MyUserInfo is a swing implementation provided in 
  //  examples/ in the JSch dist
  UserInfo ui = new MyUserInfo();

  // OR non-interactive version. Relies in host key being in known-hosts file
  session.setPassword( "remote-password" );


Channel channel = session.openChannel( "sftp" );

ChannelSftp sftpChannel = (ChannelSftp) channel;

sftpChannel.get("remote-file", "local-file" );
// OR
InputStream in = sftpChannel.get( "remote-file" );
  // process inputstream as needed


Bootstrap table without stripe / borders

Most examples seem to be too specific and/or bloated.

Here was my trimmed down solution using Bootstrap 4.0.0 (4.1 includes .table-borderless but still alpha)...

.table-borderless th{border:0;}
.table-borderless td{border:0;}

Similar to many proposed solutions, but minimal bytes

Note: Ended up here because I was viewing BS4.1 references and couldn't figure out why .table-borderless was not working with my 4.0 sources (eg: operator error, duh)

Select all occurrences of selected word in VSCode

In my MacOS case for some reason Cmd+Shift+L is not working while pressing the short cut on the keyboard (although it work just fine while clicking on this option in menu: Selection -> Select All Occurences). So for me pressing Cmd+FN+F2 did the trick (FN is for enabling "F2" obviously).

Btw, if you forget this shortcut just do right-click on the selection and see "Change All Occurrences" option

SSL Error: unable to get local issuer certificate

jww is right — you're referencing the wrong intermediate certificate.

As you have been issued with a SHA256 certificate, you will need the SHA256 intermediate. You can grab it from here:

How to add comments into a Xaml file in WPF?

I assume those XAML namespace declarations are in the parent tag of your control? You can't put comments inside of another tag. Other than that, the syntax you're using is correct.

<UserControl xmlns="...">
    <!-- Here's a valid comment. Notice it's outside the <UserControl> tag's braces -->

How can I rename a project folder from within Visual Studio?

Using Visual Studio 2019, I followed below steps to make the project name change successful:

  1. Close the solution
  2. Rename the project folder to match with new project name
  3. Open solution file in notepad++ kind of editor and edit the FilePath with new project name folder
  4. Open the solution and click No if it ask whether you want to open from source control
  5. Right click the project which you want renaming and click Properties then change below: Change Assembly Name, Default Assembly namespace and Assembly information with new name
  6. Open any of the file and move the file to new namespace which will be done by all files
  7. If you have app.config kind of files then make sure to move them also in new namespace
  8. Rebuild it which will work successfully

PHP: How to send HTTP response code?

With the header function. There is an example in the section on the first parameter it takes.

Print the address or pointer for value in C

I believe this would be most correct.

printf("%p", (void *)emp1);
printf("%p", (void *)*emp1);

printf() is a variadic function and must be passed arguments of the right types. The standard says %p takes void *.

c# search string in txt file

You have to use while since foreach does not know about index. Below is an example code.

int counter = 0;
string line;

Console.Write("Input your search text: ");
var text = Console.ReadLine();

System.IO.StreamReader file =
    new System.IO.StreamReader("SampleInput1.txt");

while ((line = file.ReadLine()) != null)
    if (line.Contains(text))


Console.WriteLine("Line number: {0}", counter);



How to programmatically round corners and set random background colors

I think the fastest way to do this is:

GradientDrawable gradientDrawable = new GradientDrawable(
            GradientDrawable.Orientation.TOP_BOTTOM, //set a gradient direction 
            new int[] {0xFF757775,0xFF151515}); //set the color of gradient
gradientDrawable.setCornerRadius(10f); //set corner radius

//Apply background to your view
View view = (RelativeLayout) findViewById( );
else view.setBackgroundDrawable(gradientDrawable);    

HTML5 Canvas background image

Theres a few ways you can do this. You can either add a background to the canvas you are currently working on, which if the canvas isn't going to be redrawn every loop is fine. Otherwise you can make a second canvas underneath your main canvas and draw the background to it. The final way is to just use a standard <img> element placed under the canvas. To draw a background onto the canvas element you can do something like the following:

Live Demo

var canvas = document.getElementById("canvas"),
    ctx = canvas.getContext("2d");

canvas.width = 903;
canvas.height = 657;

var background = new Image();
background.src = "";

// Make sure the image is loaded first otherwise nothing will draw.
background.onload = function(){

// Draw whatever else over top of it on the canvas.

What is the equivalent to getLastInsertId() in Cakephp?

This is interesting, I also stumbled upon this issue. What you asked perhaps how to get the last ID of a certain model regardless of it's state, whether it's just been inserted or not. To further understand what getInsertID does, we need to take a look at the source:

Link 1:

public function getInsertID() {
  return $this->_insertID

Yup, that's the only piece of code inside that function. It means that cakephp caches any last inserted ID, instead of retrieve it from the database. That's why you get nothing if you use that function when you haven't done any record creation on the model.

I made a small function to get the last ID of a certain table, but please note that this should not be used as a replacement of getLastID() or getLastInsertID(), since it has an entirely different purpose.

Add the function lastID() to the AppModel as shown below so that it can be used system wide. It has it's limit, which can't be used on model with composite primary key.

class AppModel extends Model {
  public function lastID() {
    $data = $this->find('first', 
        'order' => array($this->primaryKey . ' DESC'),
        'fields' => array($this->primaryKey)

    return $data[$this->name][$this->primaryKey];

Original Source : Class Model

One line ftp server in python

The answers above were all assuming your Python distribution would have some third-party libraries in order to achieve the "one liner python ftpd" goal, but that is not the case of what @zio was asking. Also, SimpleHTTPServer involves web broswer for downloading files, it's not quick enough.

Python can't do ftpd by itself, but you can use netcat, nc:

nc is basically a built-in tool from any UNIX-like systems (even embedded systems), so it's perfect for "quick and temporary way to transfer files".

Step 1, on the receiver side, run:

nc -l 12345 | tar -xf -

this will listen on port 12345, waiting for data.

Step 2, on the sender side:

tar -cf - ALL_FILES_YOU_WANT_TO_SEND ... | nc $RECEIVER_IP 12345

You can also put pv in the middle to monitor the progress of transferring:

tar -cf - ALL_FILES_YOU_WANT_TO_SEND ...| pv | nc $RECEIVER_IP 12345

After the transferring is finished, both sides of nc will quit automatically, and job done.

How to run a method every X seconds

    new CountDownTimer(120000, 1000) {

        public void onTick(long millisUntilFinished) {
            txtcounter.setText(" " + millisUntilFinished / 1000);


        public void onFinish() {

            txtcounter.setText(" TimeOut  ");
            Main2Activity.ShowPayment = false;



MVC which submit button has been pressed

Name both your submit buttons the same

<input name="submit" type="submit" id="submit" value="Save" />
<input name="submit" type="submit" id="process" value="Process" />

Then in your controller get the value of submit. Only the button clicked will pass its value.

public ActionResult Index(string submit)
    return View();

You can of course assess that value to perform different operations with a switch block.

public ActionResult Index(string submit)
    switch (submit)
        case "Save":
            // Do something
        case "Process":
            // Do something
            throw new Exception();

    return View();

C++ JSON Serialization

The jsoncons C++ header-only library also supports conversion between JSON text and C++ objects. Decode and encode are defined for all C++ classes that have json_type_traits defined. The standard library containers are already supported, and json_type_traits can be specialized for user types in the jsoncons namespace.

Below is an example:

#include <iostream>
#include <jsoncons/json.hpp>

namespace ns {
    enum class hiking_experience {beginner,intermediate,advanced};

    class hiking_reputon
        std::string rater_;
        hiking_experience assertion_;
        std::string rated_;
        double rating_;
        hiking_reputon(const std::string& rater,
                       hiking_experience assertion,
                       const std::string& rated,
                       double rating)
            : rater_(rater), assertion_(assertion), rated_(rated), rating_(rating)

        const std::string& rater() const {return rater_;}
        hiking_experience assertion() const {return assertion_;}
        const std::string& rated() const {return rated_;}
        double rating() const {return rating_;}

    class hiking_reputation
        std::string application_;
        std::vector<hiking_reputon> reputons_;
        hiking_reputation(const std::string& application, 
                          const std::vector<hiking_reputon>& reputons)
            : application_(application), 

        const std::string& application() const { return application_;}
        const std::vector<hiking_reputon>& reputons() const { return reputons_;}

} // namespace ns

// Declare the traits using convenience macros. Specify which data members need to be serialized.

JSONCONS_ENUM_TRAITS_DECL(ns::hiking_experience, beginner, intermediate, advanced)
JSONCONS_ALL_CTOR_GETTER_TRAITS(ns::hiking_reputon, rater, assertion, rated, rating)
JSONCONS_ALL_CTOR_GETTER_TRAITS(ns::hiking_reputation, application, reputons)

using namespace jsoncons; // for convenience

int main()

std::string data = R"(
       "application": "hiking",
       "reputons": [
           "rater": "HikingAsylum",
           "assertion": "advanced",
           "rated": "Marilyn C",
           "rating": 0.90

    // Decode the string of data into a c++ structure
    ns::hiking_reputation v = decode_json<ns::hiking_reputation>(data);

    // Iterate over reputons array value
    std::cout << "(1)\n";
    for (const auto& item : v.reputons())
        std::cout << item.rated() << ", " << item.rating() << "\n";

    // Encode the c++ structure into a string
    std::string s;
    encode_json<ns::hiking_reputation>(v, s, indenting::indent);
    std::cout << "(2)\n";
    std::cout << s << "\n";


Marilyn C, 0.9
    "application": "hiking",
    "reputons": [
            "assertion": "advanced",
            "rated": "Marilyn C",
            "rater": "HikingAsylum",
            "rating": 0.9

Change the background color in a twitter bootstrap modal?

If you want to change the background color of the backdrop for a specific modal, you can access the backdrop element in this way:


Then you can change any css property via .css jquery function. In particular, with background:


Note that $('#myModal') has to be initialized, otherwise $backdrop is going to be null. Same applies to bs.modal data element.

How to remove the border highlight on an input text element

Removing all focus styles is bad for accessibility and keyboard users in general. But outlines are ugly and providing a custom focussed style for every single interactive element can be a real pain.

So the best compromise I've found is to show the outline styles only when we detect that the user is using the keyboard to navigate. Basically, if the user presses TAB, we show the outlines and if he uses the mouse, we hide them.

It does not stop you from writing custom focus styles for some elements but at least it provides a good default.

This is how I do it:

// detect keyboard users_x000D_
const keyboardUserCssClass = "keyboardUser";_x000D_
function setIsKeyboardUser(isKeyboard) {_x000D_
  const { body } = document;_x000D_
  if (isKeyboard) {_x000D_
   body.classList.contains(keyboardUserCssClass) || body.classList.add(keyboardUserCssClass);_x000D_
  } else {_x000D_
// This is a quick hack to activate focus styles only when the user is_x000D_
// navigating with TAB key. This is the best compromise we've found to_x000D_
// keep nice design without sacrifying accessibility._x000D_
document.addEventListener("keydown", e => {_x000D_
  if (e.key === "Tab") {_x000D_
document.addEventListener("click", e => {_x000D_
  // Pressing ENTER on buttons triggers a click event with coordinates to 0_x000D_
  setIsKeyboardUser(!e.screenX && !e.screenY);_x000D_
document.addEventListener("mousedown", e => {_x000D_
body:not(.keyboardUser) *:focus {_x000D_
  outline: none;_x000D_
<p>By default, you'll see no outline. But press TAB key and you'll see focussed element</p>_x000D_
<button>This is a button</button>_x000D_
<a href="#">This is anchor link</a>_x000D_
<input type="checkbox" />_x000D_

Multiple input in JOptionPane.showInputDialog

this is my solution

JTextField username = new JTextField();
JTextField password = new JPasswordField();
Object[] message = {
    "Username:", username,
    "Password:", password

int option = JOptionPane.showConfirmDialog(null, message, "Login", JOptionPane.OK_CANCEL_OPTION);
if (option == JOptionPane.OK_OPTION) {
    if (username.getText().equals("h") && password.getText().equals("h")) {
        System.out.println("Login successful");
    } else {
        System.out.println("login failed");
} else {
    System.out.println("Login canceled");

How to unlock a file from someone else in Team Foundation Server

Based on stackptr answer I've created batch file UnlockOther.bat

@rem from
@rem tf undo {file path} /workspace:{workspace};{username

call "C:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\vcvarsall.bat" x86
@echo on
tf undo $/MyTfsProject/path/fileName.ext /workspace:CollegeMachine;CollegueName /login:MyLogin 

Catch KeyError in Python

Try print(e.message) this should be able to print your exception.

    connection = manager.connect("I2Cx")
except Exception, e:

How to make the Facebook Like Box responsive?

Colin's example for me clashed with the like button. So I adapted it to only target the Like Box.

.fb-like-box, .fb-like-box span, .fb-like-box span iframe[style] { width: 100% !important; }

Tested in most modern browsers.

How to get all subsets of a set? (powerset)

Perhaps the question is getting old, but I hope my code will help someone.

def powSet(set):
    if len(set) == 0:
       return [[]]
    return addtoAll(set[0],powSet(set[1:])) + powSet(set[1:])

def addtoAll(e, set):
   for c in set:
   return set

How can I make a list of installed packages in a certain virtualenv?

In my case the flask version was only visible under so I had to go to C:\Users\\AppData\Local\flask\venv\Scripts>pip freeze --local

Styling text input caret

It is enough to use color property alongside with -webkit-text-fill-color this way:

    input {_x000D_
        color: red; /* color of caret */_x000D_
        -webkit-text-fill-color: black; /* color of text */_x000D_
<input type="text"/>

Works in WebKit browsers (but not in iOS Safari, where is still used system color for caret) and also in Firefox.

The -webkit-text-fill-color CSS property specifies the fill color of characters of text. If this property is not set, the value of the color property is used. MDN

So this means we set text color with text-fill-color and caret color with standard color property. In unsupported browser, caret and text will have same color – color of the caret.

JSON Invalid UTF-8 middle byte

I had this problem inconsistently between different platforms, as I got JSON as String from Mapper and did the writing myself. Sometimes it went into file as ansi and other times correctly as UTF8. I switched to

mapper.writeValue(file, data);

letting Mapper do the file operations, and it started working fine.

Integration Testing POSTing an entire object to Spring MVC controller

I ran into the same issue a while ago and did solve it by using reflection with some help from Jackson.

First populate a map with all the fields on an Object. Then add those map entries as parameters to the MockHttpServletRequestBuilder.

In this way you can use any Object and you are passing it as request parameters. I'm sure there are other solutions out there but this one worked for us:

    public void testFormEdit() throws Exception {
                        addFormParameters(post(servletPath + tableRootUrl + "/" + POST_FORM_EDIT_URL).servletPath(servletPath)
                                .param("entityID", entityId), validEntity)).andDo(print()).andExpect(status().isOk())

    private MockHttpServletRequestBuilder addFormParameters(MockHttpServletRequestBuilder builder, Object object)
            throws IllegalAccessException, InvocationTargetException, NoSuchMethodException {

        SimpleDateFormat dateFormat = new SimpleDateFormat(applicationSettings.getApplicationDateFormat());

        Map<String, ?> propertyValues = getPropertyValues(object, dateFormat);

        for (Entry<String, ?> entry : propertyValues.entrySet()) {
                    Util.prepareDisplayValue(entry.getValue(), applicationSettings.getApplicationDateFormat()));

        return builder;

    private Map<String, ?> getPropertyValues(Object object, DateFormat dateFormat) {
        ObjectMapper mapper = new ObjectMapper();
        mapper.registerModule(new JodaModule());

        TypeReference<HashMap<String, ?>> typeRef = new TypeReference<HashMap<String, ?>>() {};

        Map<String, ?> returnValues = mapper.convertValue(object, typeRef);

        return returnValues;


default web page width - 1024px or 980px?

even there is no right or wrong answer for this question , but I personally prefer 960px width . since all modern monitors support at least 1024 × 768 pixel resolution. 960 is divisible by 2, 3, 4, 5, 6, 8, 10, 12, 15, 16, 20, 24, 30, 32, 40, 48, 60, 64, 80, 96, 120, 160, 192, 240, 320 and 480. This makes it a highly flexible base number to work with.

see this article that shows most popular screens resolutions 2013-2014 in US and UK :

Can I use conditional statements with EJS templates (in JMVC)?

For others that stumble on this, you can also use ejs params/props in conditional statements:

recipes.js File:

app.get("/recipes", function(req, res) {
    res.render("recipes.ejs", {
        recipes: recipes

recipes.ejs File:

<%if (recipes.length > 0) { %>
// Do something with more than 1 recipe
<% } %>

How to output messages to the Eclipse console when developing for Android

Rather than trying to output to the console, Log will output to LogCat which you can find in Eclipse by going to: Window->Show View->Other…->Android->LogCat

Have a look at the reference for Log.

The benefits of using LogCat are that you can print different colours depending on your log type, e.g.: Log.d prints blue, Log.e prints orange. Also you can filter by log tag, log message, process id and/or by application name. This is really useful when you just want to see your app's logs and keep the other system stuff separate.

Function to return only alpha-numeric characters from string?

Rather than preg_replace, you could always use PHP's filter functions using the filter_var() function with FILTER_SANITIZE_STRING.

Hiding table data using <div style="display:none">

Just apply the style attribute to the tr tag. In the case of multiple tr tags, you will have to apply the style to each element, or wrap them in a tbody tag:

  <tr><th>Test Table</th><tr>
  <tbody style="display:none">

Failed to execute 'postMessage' on 'DOMWindow': !== http://localhost:9000

Just wishing to avoid the console error, I solved this using a similar approach to Artur's earlier answer, following these steps:

  1. Downloaded the YouTube Iframe API (from to a local yt-api.js file.
  2. Removed the code which inserted the www-widgetapi.js script.
  3. Downloaded the www-widgetapi.js script (from to a local www-widgetapi.js file.
  4. Replaced the targetOrigin argument in the postMessage call which was causing the error in the console, with a "*" (indicating no preference - see
  5. Appended the modified www-widgetapi.js script to the end of the yt-api.js script.

This is not the greatest solution (patched local script to maintain, losing control of where messages are sent) but it solved my issue.

Please see the security warning about removing the targetOrigin URI stated here before using this solution -

Patched yt-api.js example

How to set app icon for Electron / Atom Shell App

Updated package.json:

"build": {
  "appId": "",
  "productName": "MyApp",
  "copyright": "Copyright © 2019 ${author}",
  "mac": {
    "icon": "./public/icons/mac/icon.icns",     <---------- set Mac Icons
    "category": ""
  "win": {
    "icon": "./public/icons/png/256x256.png" <---------- set Win Icon
  "files": [
    "./public/**/*",       <---------- need for get access to icons
  "directories": {
    "buildResources": "public" <---------- folder where placed icons

After build application you can see icons. This solution don't show icons in developer mode. I don't setup icons in new BrowserWindow().

Open Source Javascript PDF viewer

There are some guys at Mozilla working on implementing a PDF reader using HTML5 and JavaScript. It is called pdf.js and one of the developers just made an interesting blog post about the project.

"Error 404 Not Found" in Magento Admin Login Page

I have just copied and moved a Magento site to a local area so I could work on it offline and had the same problem.

But in the end I found out Magento was forcing a redirect from http to https and I didn't have a SSL setup. So this solved my problem

It pretty much says set web/secure/use_in_adminhtml value from 1 to 0 in the core_config_data to allow non-secure access to the admin area

UITableView example for Swift

The example below is an adaptation and simplification of a longer post from We ? Swift. This is what it will look like:

enter image description here

Create a New Project

It can be just the usual Single View Application.

Add the Code

Replace the ViewController.swift code with the following:

import UIKit
class ViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
    // Data model: These strings will be the data for the table view cells
    let animals: [String] = ["Horse", "Cow", "Camel", "Sheep", "Goat"]
    // cell reuse id (cells that scroll out of view can be reused)
    let cellReuseIdentifier = "cell"
    // don't forget to hook this up from the storyboard
    @IBOutlet var tableView: UITableView!
    override func viewDidLoad() {
        // Register the table view cell class and its reuse id
        self.tableView.register(UITableViewCell.self, forCellReuseIdentifier: cellReuseIdentifier)
        // (optional) include this line if you want to remove the extra empty cell divider lines
        // self.tableView.tableFooterView = UIView()

        // This view controller itself will provide the delegate methods and row data for the table view.
        tableView.delegate = self
        tableView.dataSource = self
    // number of rows in table view
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return self.animals.count
    // create a cell for each table view row
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        // create a new cell if needed or reuse an old one
        let cell:UITableViewCell = self.tableView.dequeueReusableCell(withIdentifier: cellReuseIdentifier) as UITableViewCell!
        // set the text from the data model
        cell.textLabel?.text = self.animals[indexPath.row]
        return cell
    // method to run when table view cell is tapped
    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        print("You tapped cell number \(indexPath.row).")

Read the in-code comments to see what is happening. The highlights are

  • The view controller adopts the UITableViewDelegate and UITableViewDataSource protocols.
  • The numberOfRowsInSection method determines how many rows there will be in the table view.
  • The cellForRowAtIndexPath method sets up each row.
  • The didSelectRowAtIndexPath method is called every time a row is tapped.

Add a Table View to the Storyboard

Drag a UITableView onto your View Controller. Use auto layout to pin the four sides.

enter image description here

Hook up the Outlets

Control drag from the Table View in IB to the tableView outlet in the code.


That's all. You should be able run your app now.

This answer was tested with Xcode 9 and Swift 4


Row Deletion

You only have to add a single method to the basic project above if you want to enable users to delete rows. See this basic example to learn how.

enter image description here

Row Spacing

If you would like to have spacing between your rows, see this supplemental example.

enter image description here

Custom cells

The default layout for the table view cells may not be what you need. Check out this example to help get you started making your own custom cells.

enter image description here

Dynamic Cell Height

Sometimes you don't want every cell to be the same height. Starting with iOS 8 it is easy to automatically set the height depending on the cell content. See this example for everything you need to get you started.

enter image description here

Further Reading

Collapse all methods in Visual Studio Code

The beauty of Visual Studio Code is

Ctrl + Shift + P

Hit it and search anything you want.

In your case, hit Ctrl + Shift + P and type fold all.

Possible to perform cross-database queries with PostgreSQL?

see [published 2017]

These days you also have the option to use

You can run SQL on that PrestoDB node and it will distribute the SQL query as required. It can connect to the same node twice for different databases, or it might be connecting to different nodes on different hosts.

It does not support:


So you should only use it for SELECT and JOIN needs. Connect directly to each database for the above needs. (It looks like you can also INSERT or UPDATE which is nice)

Client applications connect to PrestoDB primarily using JDBC, but other types of connection are possible including a Tableu compatible web API

This is an open source tool governed by the Linux Foundation and Presto Foundation.

The founding members of the Presto Foundation are: Facebook, Uber, Twitter, and Alibaba.

The current members are: Facebook, Uber, Twitter, Alibaba, Alluxio, Ahana, Upsolver, and Intel.

Understanding [TCP ACKed unseen segment] [TCP Previous segment not captured]

Another cause of "TCP ACKed Unseen" is the number of packets that may get dropped in a capture. If I run an unfiltered capture for all traffic on a busy interface, I will sometimes see a large number of 'dropped' packets after stopping tshark.

On the last capture I did when I saw this, I had 2893204 packets captured, but once I hit Ctrl-C, I got a 87581 packets dropped message. Thats a 3% loss, so when wireshark opens the capture, its likely to be missing packets and report "unseen" packets.

As I mentioned, I captured a really busy interface with no capture filter, so tshark had to sort all packets, when I use a capture filter to remove some of the noise, I no longer get the error.

Compare two DataFrames and output their differences side-by-side

import pandas as pd
import io

texts = ['''\
id   Name   score                    isEnrolled                        Comment
111  Jack   2.17                     True                 He was late to class
112  Nick   1.11                     False                           Graduated
113  Zoe    4.12                     True       ''',

id   Name   score                    isEnrolled                        Comment
111  Jack   2.17                     True                 He was late to class
112  Nick   1.21                     False                           Graduated
113  Zoe    4.12                     False                         On vacation''']

df1 = pd.read_fwf(io.StringIO(texts[0]), widths=[5,7,25,21,20])
df2 = pd.read_fwf(io.StringIO(texts[1]), widths=[5,7,25,21,20])
df = pd.concat([df1,df2]) 

#     id  Name  score isEnrolled               Comment
# 0  111  Jack   2.17       True  He was late to class
# 1  112  Nick   1.11      False             Graduated
# 2  113   Zoe   4.12       True                   NaN
# 0  111  Jack   2.17       True  He was late to class
# 1  112  Nick   1.21      False             Graduated
# 2  113   Zoe   4.12      False           On vacation

df.set_index(['id', 'Name'], inplace=True)
#           score isEnrolled               Comment
# id  Name                                        
# 111 Jack   2.17       True  He was late to class
# 112 Nick   1.11      False             Graduated
# 113 Zoe    4.12       True                   NaN
# 111 Jack   2.17       True  He was late to class
# 112 Nick   1.21      False             Graduated
# 113 Zoe    4.12      False           On vacation

def report_diff(x):
    return x[0] if x[0] == x[1] else '{} | {}'.format(*x)

changes = df.groupby(level=['id', 'Name']).agg(report_diff)


                score    isEnrolled               Comment
id  Name                                                 
111 Jack         2.17          True  He was late to class
112 Nick  1.11 | 1.21         False             Graduated
113 Zoe          4.12  True | False     nan | On vacation

Registry Key '...' has value '1.7', but '1.6' is required. Java 1.7 is Installed and the Registry is Pointing to it

In the START menu type "regedit" to open the Registry editor

Go to "HKEY_LOCAL_MACHINE" on the left-hand side registry explorer/tree menu

Click "SOFTWARE" within the "HKEY_LOCAL_MACHINE" registries

Click "JavaSoft" within the "SOFTWARE" registries

Click "Java Runtime Environment" within the "JavaSoft" list of registries here you can see different versions of installed java

Click "Java Runtime Environment"- On right hand side you will get 4-5 rows . Please select "CurrentVersion" and right Click( select modify option) Change version to "1.7"

Now the magic has been completed

How to count the NaN values in a column in pandas DataFrame

df.isnull().sum() will give the column-wise sum of missing values.

If you want to know the sum of missing values in a particular column then following code will work: df.column.isnull().sum()

Update data on a page without refreshing

You can read about jQuery Ajax from official jQuery Site:

If you don't want to use any click event then you can set timer for periodically update.

Below code may be help you just example.

function update() {
  $.get("response.php", function(data) {
    window.setTimeout(update, 10000);

Above function will call after every 10 seconds and get content from response.php and update in #some_div.

How to Resize a Bitmap in Android?

Someone asked how to keep aspect ratio in this situation:

Calculate the factor you are using for scaling and use it for both dimensions. Let´s say you want an image to be 20% of the screen in height

int scaleToUse = 20; // this will be our percentage
Bitmap bmp = BitmapFactory.decodeResource(
    context.getResources(), R.drawable.mypng);
int sizeY = screenResolution.y * scaleToUse / 100;
int sizeX = bmp.getWidth() * sizeY / bmp.getHeight();
Bitmap scaled = Bitmap.createScaledBitmap(bmp, sizeX, sizeY, false);

for getting the screen resolution you have this solution: Get screen dimensions in pixels

cannot import name patterns


from django.conf.urls.defaults import ... # is for django 1.3
from django.conf.urls  import ...         # is for django 1.4

I met this problem too.

How to plot a histogram using Matplotlib in Python with a list of data?

If you haven't installed matplotlib yet just try the command.

> pip install matplotlib

Library import

import matplotlib.pyplot as plot

The histogram data:

plot.hist(weightList,density=1, bins=20) 
plot.axis([50, 110, 0, 0.06]) 

Display histogram

And the output is like :

enter image description here

Add Class to Object on Page Load

I would recommend using jQuery with this function:


This will add the expand class to an element with id of about when the dom is ready on page load.

How to see query history in SQL Server Management Studio

If you want an history for the queries you executed through SMSS.

You may want to try SSMSPlus.

This feature does not exists out of the box in SSMS.

You'll need SSMS 18 or newer.

Disclaimer : I'm the author.

Attach the Java Source Code

To attach JDK source so that you refer to Java Source Code for code look-up which helps in learning the library implementation and sometimes in debugging, all you have to do is:

In your Eclipse Java Project > JRE Reference Library locate rt.jar. Right click and go to Properties:

Select "Java Source Attachment" on the right and to the left select "External Location" and click on "External File" Button and locate "" file in your $JAVA_HOME path in my case for my windows machine location is: C:/Program Files/Java/jdk1.7.0_45/

You are done now! Just Ctrl + click on any Java library Class in your project code to look-up the source code for the java class.

Android Studio update -Error:Could not run build action using Gradle distribution

I forced to use a proxy and also forced to add proxy setting on as these:


And also forced to close and open studio64.exe as administrator . Now its all seems greate

Event log says

8:21:39 AM Platform and Plugin Updates: The following components are ready to update: Android Support Repository, Google Repository, Intel x86 Emulator Accelerator (HAXM installer), Android SDK Platform-Tools 24, Google APIs Intel x86 Atom System Image, Android SDK Tools 25.1.7
8:21:40 AM Gradle sync started
8:22:03 AM Gradle sync completed
8:22:04 AM Executing tasks: [:app:generateDebugSources, :app:generateDebugAndroidTestSources, :app:prepareDebugUnitTestDependencies, :app:mockableAndroidJar]
8:22:25 AM Gradle build finished in 21s 607ms

I'm using android studio 2.1.2 downloaded as exe setup file. it has its Gradle ( I also forced to use custom install to address the Gradle )

Using a custom (ttf) font in CSS

You need to use the css-property font-face to declare your font. Have a look at this fancy site:


@font-face {
  font-family: MyHelvetica;
  src: local("Helvetica Neue Bold"),
  font-weight: bold;

See also: MDN @font-face

Facebook login "given URL not allowed by application configuration"

You can set up a developer application and set the url to Make sure to map to localhost on your hosts file

Works for me

Deleting multiple columns based on column names in Pandas

You can just pass the column names as a list with specifying the axis as 0 or 1

  • axis=1: Along the Rows
  • axis=0: Along the Columns
  • By default axis=0


How to declare an array of objects in C#

With LINQ, you can transform the array of uninitialized elements into the new collection of created objects with one line of code.

var houses = new GameObject[200].Select(h => new GameObject()).ToArray();

Actually, you can use any other source for this, even generated sequence of integers:

var houses = Enumerable.Repeat(0, 200).Select(h => new GameObject()).ToArray();

However, the first case seems to me more readable, although the type of original sequence is not important.

JQuery datepicker language

This is for the dutch people.

$.datepicker.regional['nl'] = {clearText: 'Effacer', clearStatus: '',
    closeText: 'sluiten', closeStatus: 'Onveranderd sluiten ',
    prevText: '<vorige', prevStatus: 'Zie de vorige maand',
    nextText: 'volgende>', nextStatus: 'Zie de volgende maand',
    currentText: 'Huidige', currentStatus: 'Bekijk de huidige maand',
    monthNames: ['januari','februari','maart','april','mei','juni',
    monthNamesShort: ['jan','feb','mrt','apr','mei','jun',
    monthStatus: 'Bekijk een andere maand', yearStatus: 'Bekijk nog een jaar',
    weekHeader: 'Sm', weekStatus: '',
    dayNames: ['zondag','maandag','dinsdag','woensdag','donderdag','vrijdag','zaterdag'],
    dayNamesShort: ['zo', 'ma','di','wo','do','vr','za'],
    dayNamesMin: ['zo', 'ma','di','wo','do','vr','za'],
    dayStatus: 'Gebruik DD als de eerste dag van de week', dateStatus: 'Kies DD, MM d',
    dateFormat: 'dd/mm/yy', firstDay: 1, 
    initStatus: 'Kies een datum', isRTL: false};

PHP date() with timezone?

Use the DateTime class instead, as it supports timezones. The DateTime equivalent of date() is DateTime::format.

An extremely helpful wrapper for DateTime is Carbon - definitely give it a look.

You'll want to store in the database as UTC and convert on the application level.

Android Paint: .measureText() vs .getTextBounds()

My experience with this is that getTextBounds will return that absolute minimal bounding rect that encapsulates the text, not necessarily the measured width used when rendering. I also want to say that measureText assumes one line.

In order to get accurate measuring results, you should use the StaticLayout to render the text and pull out the measurements.

For example:

String text = "text";
TextPaint textPaint = textView.getPaint();
int boundedWidth = 1000;

StaticLayout layout = new StaticLayout(text, textPaint, boundedWidth , Alignment.ALIGN_NORMAL, 1.0f, 0.0f, false);
int height = layout.getHeight();

How to Correctly handle Weak Self in Swift Blocks with Arguments

If self could be nil in the closure use [weak self].

If self will never be nil in the closure use [unowned self].

If it's crashing when you use [unowned self] I would guess that self is nil at some point in that closure, which is why you had to go with [weak self] instead.

I really liked the whole section from the manual on using strong, weak, and unowned in closures:

Note: I used the term closure instead of block which is the newer Swift term:

Difference between block (Objective C) and closure (Swift) in ios

Failed to read artifact descriptor for org.apache.maven.plugins:maven-source-plugin:jar:2.4

so I am assuming that this project you are doing in your private eclipse (not company provided eclipse where you work). The same problem I resolved just as below

quick fix : got to .m2 file --> create a backup of settings.xml --> remove settings.xml --> restart your eclipse.

How to check whether an object is a date?

Couldn't you just use

function getFormatedDate(date) {
    if (date.isValid()) {
       var month = date.GetMonth();

How can I make an entire HTML form "readonly"?

There's no fully compliant, official HTML way to do it, but a little javascript can go a long way. Another problem you'll run into is that disabled fields don't show up in the POST data

CSS3 Transition not working

For me, it was having display: none;

#spinner-success-text {
    display: none;
    transition: all 1s ease-in;
} {
    display: block;

Removing it, and using opacity instead, fixed the issue.

#spinner-success-text {
    opacity: 0;
    transition: all 1s ease-in;
} {
    opacity: 1;

How do I use the built in password reset/change views with my own templates

You can do the following:

  1. add to your urlpatterns (r'^/accounts/password/reset/$', password_reset)
  2. put your template in '/templates/registration/password_reset_form.html'
  3. make your app come before 'django.contrib.auth' in INSTALLED_APPS


When the templates are loaded, they are searched in your INSTALLED_APPS variable in . The order is dictated by the definition's rank in INSTALLED_APPS, so since your app come before 'django.contrib.auth' your template were loaded (reference:

Motivation of approach:

  1. I want be more dry and don't repeat for any view(defined by django) the template name (they are already defined in django)
  2. I want a smallest

Having both a Created and Last Updated timestamp columns in MySQL 4.0

If you do decide to have MySQL handle the update of timestamps, you can set up a trigger to update the field on insert.

CREATE TRIGGER <trigger_name> BEFORE INSERT ON <table_name> FOR EACH ROW SET NEW.<timestamp_field> = CURRENT_TIMESTAMP;

MySQL Reference:

How do I find the value of $CATALINA_HOME?

Tomcat can tell you in several ways. Here's the easiest:

 $ /path/to/ version
Using CATALINA_BASE:   /usr/local/apache-tomcat-7.0.29
Using CATALINA_HOME:   /usr/local/apache-tomcat-7.0.29
Using CATALINA_TMPDIR: /usr/local/apache-tomcat-7.0.29/temp
Using JRE_HOME:        /System/Library/Frameworks/JavaVM.framework/Versions/CurrentJDK/Home
Using CLASSPATH:       /usr/local/apache-tomcat-7.0.29/bin/bootstrap.jar:/usr/local/apache-tomcat-7.0.29/bin/tomcat-juli.jar
Server version: Apache Tomcat/7.0.29
Server built:   Jul 3 2012 11:31:52
Server number:
OS Name:        Mac OS X
OS Version:     10.7.4
Architecture:   x86_64
JVM Version:    1.6.0_33-b03-424-11M3720
JVM Vendor:     Apple Inc.

If you don't know where is (or it never gets called), you can usually find it via ps:

$ ps aux | grep catalina
chris            930   0.0  3.1  2987336 258328 s000  S    Wed01PM   2:29.43 /System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home/bin/java -Dnop -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager -Djava.library.path=/usr/local/apache-tomcat-7.0.29/lib -Djava.endorsed.dirs=/usr/local/apache-tomcat-7.0.29/endorsed -classpath /usr/local/apache-tomcat-7.0.29/bin/bootstrap.jar:/usr/local/apache-tomcat-7.0.29/bin/tomcat-juli.jar -Dcatalina.base=/Users/chris/blah/blah -Dcatalina.home=/usr/local/apache-tomcat-7.0.29 org.apache.catalina.startup.Bootstrap start

From the ps output, you can see both catalina.home and catalina.base. catalina.home is where the Tomcat base files are installed, and catalina.base is where the running configuration of Tomcat exists. These are often set to the same value unless you have configured your Tomcat for multiple (configuration) instances to be launched from a single Tomcat base install.

You can also interrogate the JVM directly if you can't find it in a ps listing:

$ jinfo -sysprops 930 | grep catalina
Attaching to process ID 930, please wait...
Debugger attached successfully.
Server compiler detected.
JVM version is 20.8-b03-424
catalina.base = /Users/chris/blah/blah
catalina.home = /usr/local/apache-tomcat-7.0.29

If you can't manage that, you can always try to write a JSP that dumps the values of the two system properties catalina.home and catalina.base.

Font size of TextView in Android application changes on changing font size from native settings

Actually, Settings font size affects only sizes in sp. So all You need to do - define textSize in dp instead of sp, then settings won't change text size in Your app.

Here's a link to the documentation: Dimensions

However please note that the expected behavior is that the fonts in all apps respect the user's preferences. There are many reasons a user might want to adjust the font sizes and some of them might even be medical - visually impaired users. Using dp instead of sp for text might lead to unwillingly discriminating against some of your app's users.



Error parsing yaml file: mapping values are not allowed here

I've seen this error in a similar situation to mentioned in Joe's answer:

description: Too high 5xx responses rate: {{ .Value }} > 0.05

We have a colon in description value. So, the problem is in missing quotes around description value. It can be resolved by adding quotes:

description: 'Too high 5xx responses rate: {{ .Value }} > 0.05'

How to use XPath contains() here?

You are only looking at the first li child in the query you have instead of looking for any li child element that may contain the text, 'Model'. What you need is a query like the following:

//ul[@class='featureList' and ./li[contains(.,'Model')]]

This query will give you the elements that have a class of featureList with one or more li children that contain the text, 'Model'.

node: command not found

The problem is that your PATH does not include the location of the node executable.

You can likely run node as "/usr/local/bin/node".

You can add that location to your path by running the following command to add a single line to your bashrc file:

echo 'export PATH=$PATH:/usr/local/bin' >> $HOME/.bashrc

Multiple argument IF statement - T-SQL

Your code is valid (with one exception). It is required to have code between BEGIN and END.


--do some work


print ''

I think maybe you saw "END and not "AND"

What is "pass-through authentication" in IIS 7?

Normally, IIS would use the process identity (the user account it is running the worker process as) to access protected resources like file system or network.

With passthrough authentication, IIS will attempt to use the actual identity of the user when accessing protected resources.

If the user is not authenticated, IIS will use the application pool identity instead. If pool identity is set to NetworkService or LocalSystem, the actual Windows account used is the computer account.

The IIS warning you see is not an error, it's just a warning. The actual check will be performed at execution time, and if it fails, it'll show up in the log.

Converting integer to string in Python

For someone who wants to convert int to string in specific digits, the below method is recommended.

month = "{0:04d}".format(localtime[1])

For more details, you can refer to Stack Overflow question Display number with leading zeros.

Differences between MySQL and SQL Server

Everything in MySQL seems to be done closer to the metal than in MSSQL, And the documentation treats it that way. Especially for optimization, you'll need to understand how indexes, system configuration, and the optimizer interact under various circumstances.

The "optimizer" is more a parser. In MSSQL your query plan is often a surprise (usually good, sometimes not). In MySQL, it pretty much does what you asked it to do, the way you expected it to. Which means you yourself need to have a deep understanding of the various ways it might be done.

Not built around a good TRANSACTION model (default MyISAM engine).

File-system setup is your problem.

All the database configuration is your problem - especially various cache sizes.

Sometimes it seems best to think of it as an ad-hoc, glorified isam. Codd and Date don't carry much weight here. They would say it with no embarrassment.

What is the C# version of's InputDialog?

Without adding a reference to Microsoft.VisualBasic:

// "dynamic" requires reference to Microsoft.CSharp
Type tScriptControl = Type.GetTypeFromProgID("ScriptControl");
dynamic oSC = Activator.CreateInstance(tScriptControl);

oSC.Language = "VBScript";
string sFunc = @"Function InBox(prompt, title, default) 
InBox = InputBox(prompt, title, default)    
End Function
dynamic Ret = oSC.Run("InBox", "?????", "????", "???");

See these for further information:
MsgBox in JScript
Input and MsgBox in JScript

.NET 2.0:

string sFunc = @"Function InBox(prompt, title, default) 
InBox = InputBox(prompt, title, default)    
End Function

Type tScriptControl = Type.GetTypeFromProgID("ScriptControl");
object oSC = Activator.CreateInstance(tScriptControl);

// System.Reflection.PropertyInfo pi = tScriptControl.GetProperty("Language", System.Reflection.BindingFlags.Instance | System.Reflection.BindingFlags.Static | System.Reflection.BindingFlags.CreateInstance| System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.SetProperty | System.Reflection.BindingFlags.IgnoreCase);
// pi.SetValue(oSC, "VBScript", null);

tScriptControl.InvokeMember("Language", System.Reflection.BindingFlags.SetProperty, null, oSC, new object[] { "VBScript" });
tScriptControl.InvokeMember("AddCode", System.Reflection.BindingFlags.InvokeMethod, null, oSC, new object[] { sFunc });
object ret = tScriptControl.InvokeMember("Run", System.Reflection.BindingFlags.InvokeMethod, null, oSC, new object[] { "InBox", "?????", "????", "???" });

How to use a variable inside a regular expression?

rx = r'\b(?<=\w){0}\b(?!\w)'.format(TEXTO)

Alternate table with new not null Column in existing table in SQL

FROM syscolumns sc
JOIN sysobjects so
ON =
WHERE so.Name = 'Table1'
AND sc.Name = 'Col1')

Table Naming Dilemma: Singular vs. Plural Names

I always thought that was a dumb convention. I use plural table names.

(I believe the rational behind that policy is that it make it easier for ORM code generators to produce object & collection classes, since it is easier to produce a plural name from a singular name than vice-versa)

C++ [Error] no matching function for call to

You are trying to call DeckOfCards::shuffle with a deckOfCards parameter:

deckOfCards cardDeck; // create DeckOfCards object
cardDeck.shuffle(cardDeck); // shuffle the cards in the deck

But the method takes a vector<Card>&:

void deckOfCards::shuffle(vector<Card>& deck)

The compiler error messages are quite clear on this. I'll paraphrase the compiler as it talks to you.


[Error] no matching function for call to 'deckOfCards::shuffle(deckOfCards&)'


Hey, pal. You're trying to call a function called shuffle which apparently takes a single parameter of type reference-to-deckOfCards, but there is no such function.


[Note] candidate is:

In file included from main.cpp

[Note] void deckOfCards::shuffle(std::vector&)


I mean, maybe you meant this other function called shuffle, but that one takes a reference-tovector<something>.


[Note] no known conversion for argument 1 from 'deckOfCards' to 'std::vector&'

Which I'd be happy to call if I knew how to convert from a deckOfCards to a vector; but I don't. So I won't.

Recursively find files with a specific extension

This q/a shows how to use find with regular expression: How to use regex with find command?

Pattern could be something like


How to avoid using Select in Excel VBA

Avoiding Select and Activate is the move that makes you a bit better VBA developer. In general, Select and Activate are used when a macro is recorded, thus the Parent worksheet or range is always considered the active one.

This is how you may avoid Select and Activate in the following cases:

Adding a new Worksheet and copying a cell on it:

From (code generated with macro recorder):

Sub Makro2()
    Sheets.Add After:=ActiveSheet
    Sheets("Tabelle1").Name = "NewName"
    ActiveCell.FormulaR1C1 = "12"
    Application.CutCopyMode = False
End Sub


Sub TestMe()
    Dim ws As Worksheet
    Set ws = Worksheets.Add
    With ws
        .Name = "NewName"
        .Range("B2") = 12
        .Range("B2").Copy Destination:=.Range("B3")
    End With
End Sub

When you want to copy range between worksheets:




Worksheets("Source").Columns("A:D").Copy Destination:=Worksheets("Target").Range("a1")

Using fancy named ranges

You may access them with [], which is really beautiful, compared to the other way. Check yourself:

Dim Months As Range
Dim MonthlySales As Range

Set Months = Range("Months")    
Set MonthlySales = Range("MonthlySales")

Set Months =[Months]
Set MonthlySales = [MonthlySales]

The example from above would look like this:

Worksheets("Source").Columns("A:D").Copy Destination:=Worksheets("Target").[A1]

Not copying values, but taking them

Usually, if you are willing to select, most probably you are copying something. If you are only interested in the values, this is a good option to avoid select:

Range("B1:B6").Value = Range("A1:A6").Value

Try always to reference the Worksheet as well

This is probably the most common mistake in . Whenever you copy ranges, sometimes the worksheet is not referenced and thus VBA considers the wrong sheet the ActiveWorksheet.

'This will work only if the 2. Worksheet is selected!
Public Sub TestMe()
    Dim rng As Range
    Set rng = Worksheets(2).Range(Cells(1, 1), Cells(2, 2)).Copy
End Sub

'This works always!
Public Sub TestMe2()
    Dim rng As Range
    With Worksheets(2)
        .Range(.Cells(1, 1), .Cells(2, 2)).Copy
    End With
End Sub

Can I really never use .Select or .Activate for anything?

  • A good example of when you could be justified in using .Activate and .Select is when you want make sure that a specific Worksheet is selected for visual reasons. E.g., that your Excel would always open with the cover worksheet selected first, disregarding which which was the ActiveSheet when the file was closed.

Thus, something like the code below is absolutely OK:

Private Sub Workbook_Open()
End Sub

Border length smaller than div width?

You can use a linear gradient:

div {_x000D_
    background-image: linear-gradient(to right, #000 1px, rgba(255,255,255,0) 1px), linear-gradient(to left, #000 0.1rem, rgba(255,255,255,0) 1px);_x000D_
 background-position: bottom;_x000D_
 background-size: 100% 25px;_x000D_
 background-repeat: no-repeat;_x000D_
    border-bottom: 1px solid #000;_x000D_
    border-top: 1px solid red;_x000D_

Disable and enable buttons in C#

button2.Enabled == true ;

should be

button2.Enabled = true ;

Why an inline "background-image" style doesn't work in Chrome 10 and Internet Explorer 8?

u must specify the width and height also

 <section class="bg-solid-light slideContainer strut-slide-0" style="background-image: url(; background-repeat: no-repeat;width: 100%;height: 100%;" >

(change) vs (ngModelChange) in angular

1 - (change) is bound to the HTML onchange event. The documentation about HTML onchange says the following :

Execute a JavaScript when a user changes the selected option of a <select> element

Source :

2 - As stated before, (ngModelChange) is bound to the model variable binded to your input.

So, my interpretation is :

  • (change) triggers when the user changes the input
  • (ngModelChange) triggers when the model changes, whether it's consecutive to a user action or not

jQuery.animate() with css class only, without explicit styles

Check out James Padolsey's animateToSelector

Intro: This jQuery plugin will allow you to animate any element to styles specified in your stylesheet. All you have to do is pass a selector and the plugin will look for that selector in your StyleSheet and will then apply it as an animation.

Access denied for user 'root'@'localhost' (using password: Yes) after password reset LINUX

You have to reset the password! steps for mac osx(tested and working) and ubuntu

Stop MySQL

$ sudo /usr/local/mysql/support-files/mysql.server stop

Start it in safe mode:

$ sudo mysqld_safe --skip-grant-tables

(above line is the whole command)

This will be an ongoing command until the process is finished so open another shell/terminal window, log in without a password:

$ mysql -u root

mysql> UPDATE mysql.user SET Password=PASSWORD('password') WHERE User='root';

Start MySQL

sudo /usr/local/mysql/support-files/mysql.server start

your new password is 'password'.

Could pandas use column as index?

You can set the column index using index_col parameter available while reading from spreadsheet in Pandas.

Here is my solution:

  1. Firstly, import pandas as pd: import pandas as pd

  2. Read in filename using pd.read_excel() (if you have your data in a spreadsheet) and set the index to 'Locality' by specifying the index_col parameter.

    df = pd.read_excel('testexcel.xlsx', index_col=0)

    At this stage if you get a 'no module named xlrd' error, install it using pip install xlrd.

  3. For visual inspection, read the dataframe using df.head() which will print the following output sc

  4. Now you can fetch the values of the desired columns of the dataframe and print it


How do I convert a String object into a Hash object?

I prefer to abuse ActiveSupport::JSON. Their approach is to convert the hash to yaml and then load it. Unfortunately the conversion to yaml isn't simple and you'd probably want to borrow it from AS if you don't have AS in your project already.

We also have to convert any symbols into regular string-keys as symbols aren't appropriate in JSON.

However, its unable to handle hashes that have a date string in them (our date strings end up not being surrounded by strings, which is where the big issue comes in):

string = '{'last_request_at' : 2011-12-28 23:00:00 UTC }' ActiveSupport::JSON.decode(string.gsub(/:([a-zA-z])/,'\\1').gsub('=>', ' : '))

Would result in an invalid JSON string error when it tries to parse the date value.

Would love any suggestions on how to handle this case

Finding the index of an item in a list

a = ["foo","bar","baz",'bar','any','much']

indexes = [index for index in range(len(a)) if a[index] == 'bar']

Disable all table constraints in Oracle

It is better to avoid writing out temporary spool files. Use a PL/SQL block. You can run this from SQL*Plus or put this thing into a package or procedure. The join to USER_TABLES is there to avoid view constraints.

It's unlikely that you really want to disable all constraints (including NOT NULL, primary keys, etc). You should think about putting constraint_type in the WHERE clause.

  FOR c IN
  (SELECT c.owner, c.table_name, c.constraint_name
   FROM user_constraints c, user_tables t
   WHERE c.table_name = t.table_name
   AND c.status = 'ENABLED'
   AND NOT (t.iot_type IS NOT NULL AND c.constraint_type = 'P')
   ORDER BY c.constraint_type DESC)
    dbms_utility.exec_ddl_statement('alter table "' || c.owner || '"."' || c.table_name || '" disable constraint ' || c.constraint_name);

Enabling the constraints again is a bit tricker - you need to enable primary key constraints before you can reference them in a foreign key constraint. This can be done using an ORDER BY on constraint_type. 'P' = primary key, 'R' = foreign key.

  FOR c IN
  (SELECT c.owner, c.table_name, c.constraint_name
   FROM user_constraints c, user_tables t
   WHERE c.table_name = t.table_name
   AND c.status = 'DISABLED'
   ORDER BY c.constraint_type)
    dbms_utility.exec_ddl_statement('alter table "' || c.owner || '"."' || c.table_name || '" enable constraint ' || c.constraint_name);

cin and getline skipping input

If you're using getline after cin >> something, you need to flush the newline out of the buffer in between.

My personal favourite for this if no characters past the newline are needed is cin.sync(). However, it is implementation defined, so it might not work the same way as it does for me. For something solid, use cin.ignore(). Or make use of std::ws to remove leading whitespace if desirable:

int a;

cin >> a;
cin.ignore (std::numeric_limits<std::streamsize>::max(), '\n'); 
//discard characters until newline is found

//my method: cin.sync(); //discard unread characters

string s;
getline (cin, s); //newline is gone, so this executes

//other method: getline(cin >> ws, s); //remove all leading whitespace

How to amend a commit without changing commit message (reusing the previous one)?

To extend on the accepted answer, you can also do:

git commit --amend --no-edit -a

to add the currently changed files.

Detecting the character encoding of an HTTP POST request

The Charset used in the POST will match that of the Charset specified in the HTML hosting the form. Hence if your form is sent using UTF-8 encoding that is the encoding used for the posted content. The URL encoding is applied after the values are converted to the set of octets for the character encoding.

Switch on Enum in Java

Article on Programming.Guide: Switch on enum

enum MyEnum { CONST_ONE, CONST_TWO }

class Test {
        public static void main(String[] args) {
            MyEnum e = MyEnum.CONST_ONE;

            switch (e) {
                case CONST_ONE: System.out.println(1); break;
                case CONST_TWO: System.out.println(2); break;

Switches for strings are implemented in Java 7.

Take a list of numbers and return the average

The input() function returns a string which may contain a "list of numbers". You should have understood that the numbers[2] operation returns the third element of an iterable. A string is an iterable, but an iterable of characters, which isn't what you want - you want to average the numbers in the input string.

So there are two things you have to do before you can get to the averaging shown by garyprice:

  1. convert the input string into something containing just the number strings (you don't want the spaces between the numbers)
  2. convert each number string into an integer

Hint for step 1: you have to split the input string into non-space substrings.

Step 2 (convert string to integer) should be easy to find with google.


import httplib ImportError: No module named httplib

If you use PyCharm, please change you 'Project Interpreter' to '2.7.x'

enter image description here

How do you get the file size in C#?

FileInfo.Length will do the trick (per MSDN it "[g]ets the size, in bytes, of the current file.") There is a nice page on MSDN on common I/O tasks.

What's the difference of $host and $http_host in Nginx

$host is a variable of the Core module.


This variable is equal to line Host in the header of request or name of the server processing the request if the Host header is not available.

This variable may have a different value from $http_host in such cases: 1) when the Host input header is absent or has an empty value, $host equals to the value of server_name directive; 2)when the value of Host contains port number, $host doesn't include that port number. $host's value is always lowercase since 0.8.17.

$http_host is also a variable of the same module but you won't find it with that name because it is defined generically as $http_HEADER (ref).


The value of the HTTP request header HEADER when converted to lowercase and with 'dashes' converted to 'underscores', e.g. $http_user_agent, $http_referer...;


  • $http_host equals always the HTTP_HOST request header.
  • $host equals $http_host, lowercase and without the port number (if present), except when HTTP_HOST is absent or is an empty value. In that case, $host equals the value of the server_name directive of the server which processed the request.

Add borders to cells in POI generated Excel File



Use XSSFCellStyle.BORDER_MEDIUM or XSSFBorderFormatting.BORDER_MEDIUM (both enums refer to the same value):

XSSFCellStyle cellStyle = workbook.createCellStyle();




Use setBorderColor(XSSFCellBorder.BorderSide.BOTTOM, XSSFColor) or setBottomBorderColor(XSSFColor) (equivalent for top, left, right):

XSSFCellStyle cellStyle = workbook.createCellStyle();
XSSFColor color = new XSSFColor(new java.awt.Color(128, 0, 128));



APT command line interface-like yes/no input?

For Python 3, I'm using this function:

def user_prompt(question: str) -> bool:
    """ Prompt the yes/no-*question* to the user. """
    from distutils.util import strtobool

    while True:
        user_input = input(question + " [y/n]: ")
            return bool(strtobool(user_input))
        except ValueError:
            print("Please use y/n or yes/no.\n")

The strtobool() function converts a string into a bool. If the string cant be parsed it will raise a ValueError.

In Python 3 raw_input() has been renamed to input().

As Geoff said, strtobool actually returns 0 or 1, therefore the result has to be cast to bool.

This is the implementation of strtobool, if you want special words to be recognized as true, you can copy the code and add your own cases.

def strtobool (val):
    """Convert a string representation of truth to true (1) or false (0).
    True values are 'y', 'yes', 't', 'true', 'on', and '1'; false values
    are 'n', 'no', 'f', 'false', 'off', and '0'.  Raises ValueError if
    'val' is anything else.
    val = val.lower()
    if val in ('y', 'yes', 't', 'true', 'on', '1'):
        return 1
    elif val in ('n', 'no', 'f', 'false', 'off', '0'):
        return 0
        raise ValueError("invalid truth value %r" % (val,))

How to escape comma and double quote at same time for CSV file?

You could also look at how Python writes Excel-compatible csv files.

I believe the default for Excel is to double-up for literal quote characters - that is, literal quotes " are written as "".

Soft keyboard open and close listener in an activity in Android

You can try it:

private void initKeyBoardListener() {
    // ??????????? ???????? ??????????. 
    // Threshold for minimal keyboard height.
    final int MIN_KEYBOARD_HEIGHT_PX = 150;
    // ???? ???????? ?????? view. 
    // Top-level window decor view.
    final View decorView = getWindow().getDecorView();
    // ???????????? ?????????? ?????????. Register global layout listener.
    decorView.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
        // ??????? ????????????? ?????? ????. 
        // Retrieve visible rectangle inside window.
        private final Rect windowVisibleDisplayFrame = new Rect();
        private int lastVisibleDecorViewHeight;

        public void onGlobalLayout() {
            final int visibleDecorViewHeight = windowVisibleDisplayFrame.height();

            if (lastVisibleDecorViewHeight != 0) {
                if (lastVisibleDecorViewHeight > visibleDecorViewHeight + MIN_KEYBOARD_HEIGHT_PX) {
                    Log.d("Pasha", "SHOW");
                } else if (lastVisibleDecorViewHeight + MIN_KEYBOARD_HEIGHT_PX < visibleDecorViewHeight) {
                    Log.d("Pasha", "HIDE");
            // ????????? ??????? ?????? view ?? ?????????? ??????.
            // Save current decor view height for the next call.
            lastVisibleDecorViewHeight = visibleDecorViewHeight;

Draw radius around a point in Google map

For a API v3 solution, refer to:

It creates circle around points and then show markers within and out of the range with different colors. They also calculate dynamic radius but in your case radius is fixed so may be less work.

Limit file format when using <input type="file">?

There is the accept attribute for the input tag. However, it is not reliable in any way. Browsers most likely treat it as a "suggestion", meaning the user will, depending on the file manager as well, have a pre-selection that only displays the desired types. They can still choose "all files" and upload any file they want.

For example:

    <input type="file" name="pic" id="pic" accept="image/gif, image/jpeg" />_x000D_

Read more in the HTML5 spec

Keep in mind that it is only to be used as a "help" for the user to find the right files. Every user can send any request he/she wants to your server. You always have to validated everything server-side.

So the answer is: no you cannot restrict, but you can set a pre-selection but you cannot rely on it.

Alternatively or additionally you can do something similar by checking the filename (value of the input field) with JavaScript, but this is nonsense because it provides no protection and also does not ease the selection for the user. It only potentially tricks a webmaster into thinking he/she is protected and opens a security hole. It can be a pain in the ass for users that have alternative file extensions (for example jpeg instead of jpg), uppercase, or no file extensions whatsoever (as is common on Linux systems).

Is it possible to register a http+domain-based URL Scheme for iPhone apps, like YouTube and Maps?

In seeking to fix the problem of pop-up, I discovered that Apple had a way around this concern.

Indeed, when you click on this link, if you installed the application, it is rerouted to it; otherwise, you will be redirected to the webpage, without any pop-up.

What is a typedef enum in Objective-C?

typedef enum {
} ShapeType;

then you can use it like :-

 ShapeType shape;


 enum {

now you can use it like:-

enum ShapeType shape;

How to run docker-compose up -d at system start up?

Use restart: always in your docker compose file.

Docker-compose up -d will launch container from images again. Use docker-compose start to start the stopped containers, it never launches new containers from images.

    restart: always   
    image: nginx   
      - "80:80"
      - "443:443"   links:
      - other_container:other_container

Also you can write the code up in the docker file so that it gets created first, if it has the dependency of other containers.

Position an element relative to its container

I know I am late but hope this helps.

Following are the values for the position property.

  • static
  • fixed
  • relative
  • absolute

position : static

This is default. It means the element will occur at a position that it normally would.

#myelem {
    position : static;

position : fixed

This will set the position of an element with respect to the browser window (viewport). A fixed positioned element will remain in its position even when the page scrolls.

(Ideal if you want scroll-to-top button at the bottom right corner of the page).

#myelem {
    position : fixed;
    bottom : 30px;
    right : 30px;

position : relative

To place an element at a new location relative to its original position.

#myelem {
    position : relative;
    left : 30px;
    top : 30px;

The above CSS will move the #myelem element 30px to the left and 30px from the top of its actual location.

position : absolute

If we want an element to be placed at an exact position in the page.

#myelem {
    position : absolute;
    top : 30px;
    left : 300px;

The above CSS will position #myelem element at a position 30px from top and 300px from the left in the page and it will scroll with the page.

And finally...

position relative + absolute

We can set the position property of a parent element to relative and then set the position property of the child element to absolute. This way we can position the child relative to the parent at an absolute position.

#container {
    position : relative;

#div-2 {
    position : absolute;
    top : 0;
    right : 0;

Absolute position of a child element w.r.t. a Relative positioned parent element.

We can see in the above image the #div-2 element is positioned at the top-right corner inside the #container element.

GitHub: You can find the HTML of the above image here and CSS here.

Hope this tutorial helps.

Running JAR file on Windows 10

How do I run an executable JAR file? If you have a jar file called Example.jar, follow these rules:

Open a notepad.exe.
Write : java -jar Example.jar.
Save it with the extension .bat.
Copy it to the directory which has the .jar file.
Double click it to run your .jar file.

Webpack.config how to just copy the index.html to the dist folder

I also found it easy and generic enough to put my index.html file in dist/ directory and add <script src='main.js'></script> to index.html to include my bundled webpack files. main.js seems to be default output name of our bundle if no other specified in webpack's conf file. I guess it's not good and long-term solution, but I hope it can help to understand how webpack works.

Javascript - check array for value

This should do it:

for (var i = 0; i < bank_holidays.length; i++) {
    if (bank_holidays[i] === '06/04/2012') {


Understanding CUDA grid dimensions, block dimensions and threads organization (simple explanation)

Suppose a 9800GT GPU:

  • it has 14 multiprocessors (SM)
  • each SM has 8 thread-processors (AKA stream-processors, SP or cores)
  • allows up to 512 threads per block
  • warpsize is 32 (which means each of the 14x8=112 thread-processors can schedule up to 32 threads)

A block cannot have more active threads than 512 therefore __syncthreads can only synchronize limited number of threads. i.e. If you execute the following with 600 threads:


then the kernel must run twice and the order of execution will be:

  1. func1 is executed for the first 512 threads
  2. func2 is executed for the first 512 threads
  3. func1 is executed for the remaining threads
  4. func2 is executed for the remaining threads


The main point is __syncthreads is a block-wide operation and it does not synchronize all threads.

I'm not sure about the exact number of threads that __syncthreads can synchronize, since you can create a block with more than 512 threads and let the warp handle the scheduling. To my understanding it's more accurate to say: func1 is executed at least for the first 512 threads.

Before I edited this answer (back in 2010) I measured 14x8x32 threads were synchronized using __syncthreads.

I would greatly appreciate if someone test this again for a more accurate piece of information.

Why dict.get(key) instead of dict[key]?

For what purpose is this function useful?

One particular usage is counting with a dictionary. Let's assume you want to count the number of occurrences of each element in a given list. The common way to do so is to make a dictionary where keys are elements and values are the number of occurrences.

fruits = ['apple', 'banana', 'peach', 'apple', 'pear']
d = {}
for fruit in fruits:
    if fruit not in d:
        d[fruit] = 0
    d[fruit] += 1

Using the .get() method, you can make this code more compact and clear:

for fruit in fruits:
    d[fruit] = d.get(fruit, 0) + 1

Invalid attempt to read when no data is present

I was having 2 values which could contain null values.

    Id = dr["Id"] as int? ?? default(int?);
    Alt =  dr["Alt"].ToString() as string ?? default(string);
    Name = dr["Name"].ToString()

resolved the issue

Decorators with parameters?

Here is a slightly modified version of t.dubrownik's answer. Why?

  1. As a general template, you should return the return value from the original function.
  2. This changes the name of the function, which could affect other decorators / code.

So use @functools.wraps():

from functools import wraps

def decorator(argument):
    def real_decorator(function):
        def wrapper(*args, **kwargs):
            retval = function(*args, **kwargs)
            return retval
        return wrapper
    return real_decorator

Convert a string into an int

You can also use like :

NSInteger getVal = [self.string integerValue];

How to run a function when the page is loaded?

window.onload will work like this:

function codeAddress() {_x000D_
window.onload = codeAddress;
<!DOCTYPE html>_x000D_
 <title>learning java script</title>_x000D_
 <script src="custom.js"></script>_x000D_
 <p id="test"></p>_x000D_

How to tell if a connection is dead in python

I translated the code sample in this blog post into Python: How to detect when the client closes the connection?, and it works well for me:

from ctypes import (
    CDLL, c_int, POINTER, Structure, c_void_p, c_size_t,
    c_short, c_ssize_t, c_char, ARRAY

__all__ = 'is_remote_alive',

class pollfd(Structure):
    _fields_ = (
        ('fd', c_int),
        ('events', c_short),
        ('revents', c_short),

MSG_PEEK = 0x02

EPOLLIN = 0x001
EPOLLPRI = 0x002

libc = CDLL(None)

recv = libc.recv
recv.restype = c_ssize_t
recv.argtypes = c_int, c_void_p, c_size_t, c_int

poll = libc.poll
poll.restype = c_int
poll.argtypes = POINTER(pollfd), c_int, c_int

class IsRemoteAlive:  # not needed, only for debugging
    def __init__(self, alive, msg):
        self.alive = alive
        self.msg = msg

    def __str__(self):
        return self.msg

    def __repr__(self):
        return 'IsRemoteClosed(%r,%r)' % (self.alive, self.msg)

    def __bool__(self):
        return self.alive

def is_remote_alive(fd):
    fileno = getattr(fd, 'fileno', None)
    if fileno is not None:
        if hasattr(fileno, '__call__'):
            fd = fileno()
            fd = fileno

    p = pollfd(fd=fd, events=EPOLLIN|EPOLLPRI|EPOLLRDNORM, revents=0)
    result = poll(p, 1, 0)
    if not result:
        return IsRemoteAlive(True, 'empty')

    buf = ARRAY(c_char, 1)()
    result = recv(fd, buf, len(buf), MSG_DONTWAIT|MSG_PEEK)
    if result > 0:
        return IsRemoteAlive(True, 'readable')
    elif result == 0:
        return IsRemoteAlive(False, 'closed')
        return IsRemoteAlive(False, 'errored')

Why does checking a variable against multiple values with `OR` only check the first value?

If you want case-insensitive comparison, use lower or upper:

if name.lower() == "jesse":

Implement Stack using Two Queues

#include "stdio.h"
#include "stdlib.h"

typedef struct {
    int *q;
    int size;
    int front;
    int rear;
} Queue;
typedef struct {
    Queue *q1;
    Queue *q2;
} Stack;

int queueIsEmpty(Queue *q) {
    if (q->front == -1 && q->rear == -1) {
        printf("\nQUEUE is EMPTY\n");
        return 1;
    return 0;
int queueIsFull(Queue *q) {
    if (q->rear == q->size-1) {
        return 1;
    return 0;
int queueTop(Queue *q) {
    if (queueIsEmpty(q)) {
        return -1;
    return q->q[q->front];
int queuePop(Queue *q) {
    if (queueIsEmpty(q)) {
        return -1;
    int item = q->q[q->front];
    if (q->front == q->rear) {
        q->front = q->rear = -1;
    else {
    return item;
void queuePush(Queue *q, int val) {
    if (queueIsFull(q)) {
        printf("\nQUEUE is FULL\n");
    if (queueIsEmpty(q)) {
    } else {
    q->q[q->rear] = val;
Queue *queueCreate(int maxSize) {
    Queue *q = (Queue*)malloc(sizeof(Queue));
    q->front = q->rear = -1;
    q->size = maxSize;
    q->q = (int*)malloc(sizeof(int)*maxSize);
    return q;
/* Create a stack */
void stackCreate(Stack *stack, int maxSize) {
    Stack **s = (Stack**) stack;
    *s = (Stack*)malloc(sizeof(Stack));
    (*s)->q1 = queueCreate(maxSize);
    (*s)->q2 = queueCreate(maxSize);

/* Push element x onto stack */
void stackPush(Stack *stack, int element) {
    Stack **s = (Stack**) stack;
    queuePush((*s)->q2, element);
    while (!queueIsEmpty((*s)->q1)) {
        int item = queuePop((*s)->q1);
        queuePush((*s)->q2, item);
    Queue *tmp = (*s)->q1;
    (*s)->q1 = (*s)->q2;
    (*s)->q2 = tmp;

/* Removes the element on top of the stack */
void stackPop(Stack *stack) {
    Stack **s = (Stack**) stack;

/* Get the top element */
int stackTop(Stack *stack) {
    Stack **s = (Stack**) stack;
    if (!queueIsEmpty((*s)->q1)) {
      return queueTop((*s)->q1);
    return -1;

/* Return whether the stack is empty */
bool stackEmpty(Stack *stack) {
    Stack **s = (Stack**) stack;
    if (queueIsEmpty((*s)->q1)) {
        return true;
    return false;

/* Destroy the stack */
void stackDestroy(Stack *stack) {
    Stack **s = (Stack**) stack;

int main()
  Stack *s = NULL;
  stackCreate((Stack*)&s, 10);
  stackPush((Stack*)&s, 44);
  printf("\n%d", stackTop((Stack*)&s));
  return 0;

How does the modulus operator work?

You can think of the modulus operator as giving you a remainder. count % 6 divides 6 out of count as many times as it can and gives you a remainder from 0 to 5 (These are all the possible remainders because you already divided out 6 as many times as you can). The elements of the array are all printed in the for loop, but every time the remainder is 5 (every 6th element), it outputs a newline character. This gives you 6 elements per line. For 5 elements per line, use

if (count % 5 == 4)

Setting the zoom level for a MKMapView

Based on @AdilSoomro's great answer. I have come up with this:

@interface MKMapView (ZoomLevel)
- (void)setCenterCoordinate:(CLLocationCoordinate2D)centerCoordinate

-(double) getZoomLevel;

@implementation MKMapView (ZoomLevel)

- (void)setCenterCoordinate:(CLLocationCoordinate2D)centerCoordinate
                  zoomLevel:(NSUInteger)zoomLevel animated:(BOOL)animated {
    MKCoordinateSpan span = MKCoordinateSpanMake(0, 360/pow(2, zoomLevel)*self.frame.size.width/256);
    [self setRegion:MKCoordinateRegionMake(centerCoordinate, span) animated:animated];

-(double) getZoomLevel {
    return log2(360 * ((self.frame.size.width/256) / self.region.span.longitudeDelta));


CSS table td width - fixed, not flexible

you also can try to use that:

table {
table td {
    width: 30px;
    overflow: hidden;
    text-overflow: ellipsis;

How to convert numbers between hexadecimal and decimal

If it's a really big hex string beyond the capacity of the normal integer:

For .NET 3.5, we can use BouncyCastle's BigInteger class:

String hex = "68c7b05d0000000002f8";
// results in "494809724602834812404472"
String decimal = new Org.BouncyCastle.Math.BigInteger(hex, 16).ToString();

.NET 4.0 has the BigInteger class.

Error:(1, 0) Plugin with id '' not found

Updated Answer (Dec. 2, 2020)

Latest Gradle: 6.5

Version check:

  • ./gradlew -v

How to update:

  • Set URL: ./gradlew wrapper --gradle-version=6.5 --distribution-type=all
  • Update: ./gradlew wrapper

Latest Android Gradle Plugin: 4.1.0

If you add the following code snippet to the top of your build.gradle file. Gradle will update the build tools.

buildscript {
    repositories {
        google() // For Gradle 4.0+
        maven { url '' } // For Gradle < 4.0

    dependencies {
        classpath ''

Read more here: and about version compatibility here: and

Original Answer

I had this same error, you need to make sure your Gradle version is compatible with your Android Gradle Plugin.

The latest version of Gradle is 2.0 but you need to use 1.12 in order to use the Android Gradle Plugin.

How to set menu to Toolbar in Android

protected void onCreate(Bundle savedInstanceState) {
    Toolbar toolbar;        
    toolbar = findViewById(;

    public boolean onCreateOptionsMenu(Menu menu) {
        MenuInflater inflater = getMenuInflater();
        return true;

    public boolean onOptionsItemSelected(MenuItem item) {
        int id = item.getItemId();
        if (id =={
            if (drawerLayout.isDrawerOpen(GravityCompat.END)) {
            } else {
        return super.onOptionsItemSelected(item);


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






         style="@style/TextAppearance.AppCompat.Widget.ActionBar.Title" />


How to animate RecyclerView items when they appear

I created animation from pbm's answer with little modification to make the aninmation run only once

in the other word the Animation appear with you scroll down only

private int lastPosition = -1;

private void setAnimation(View viewToAnimate, int position) {
    // If the bound view wasn't previously displayed on screen, it's animated
    if (position > lastPosition) {
        ScaleAnimation anim = new ScaleAnimation(0.0f, 1.0f, 0.0f, 1.0f, Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 0.5f);
        anim.setDuration(new Random().nextInt(501));//to make duration random number between [0,501)
        lastPosition = position;

and in onBindViewHolder call the function

public void onBindViewHolder(ViewHolder holder, int position) {

holder.getTextView().setText("some text");

// call Animation function
setAnimation(holder.itemView, position);            

jquery $(window).height() is returning the document height

Its really working if we use Doctype on our web page jquery(window) will return the viewport height else it will return the complete document height.

Define the following tag on the top of your web page: <!DOCTYPE html>

Android SQLite Example

The DBHelper class is what handles the opening and closing of sqlite databases as well sa creation and updating, and a decent article on how it all works is here. When I started android it was very useful (however I've been objective-c lately, and forgotten most of it to be any use.

How to convert .pfx file to keystore with private key?

Your PFX file should contain the private key within it. Export the private key and certificate directly from your PFX file (e.g. using OpenSSL) and import them into your Java keystore.


Further information:

  • Download OpenSSL for Windows here.
  • Export private key: openssl pkcs12 -in filename.pfx -nocerts -out key.pem
  • Export certificate: openssl pkcs12 -in filename.pfx -clcerts -nokeys -out cert.pem
  • Import private key and certificate into Java keystore using keytool.

VBA Check if variable is empty

I had a similar issue with an integer that could be legitimately assigned 0 in Access VBA. None of the above solutions worked for me.

At first I just used a boolean var and IF statement:

Dim i as integer, bol as boolean
   If bol = false then
      i = ValueIWantToAssign
      bol = True
   End If

In my case, my integer variable assignment was within a for loop and another IF statement, so I ended up using "Exit For" instead as it was more concise.

Like so:

Dim i as integer
   If ConditionIsMet Then
      i = ValueIWantToAssign
   Exit For
   End If

How to implement reCaptcha for ASP.NET MVC?

Step 1: Client site integration

Paste this snippet before the closing </head> tag on your HTML template:

<script src=''></script>

Paste this snippet at the end of the <form> where you want the reCAPTCHA widget to appear:

<div class="g-recaptcha" data-sitekey="your-site-key"></div>

Step 2: Server site integration

When your users submit the form where you integrated reCAPTCHA, you'll get as part of the payload a string with the name "g-recaptcha-response". In order to check whether Google has verified that user, send a POST request with these parameters:


secret : your secret key

response : The value of 'g-recaptcha-response'.

Now in action of your MVC app:

// return ActionResult if you want
    public string RecaptchaWork()
        // Get recaptcha value
        var r = Request.Params["g-recaptcha-response"];
        // ... validate null or empty value if you want
        // then
        // make a request to recaptcha api
        using (var wc = new WebClient())
            var validateString = string.Format(
               "your_secret_key",    // secret recaptcha key
               r); // recaptcha value
             // Get result of recaptcha
            var recaptcha_result = wc.DownloadString(validateString);
            // Just check if request make by user or bot
            if (recaptcha_result.ToLower().Contains("false"))
                 return "recaptcha false";
        // Do your work if request send from human :)

Relation between CommonJS, AMD and RequireJS?

RequireJS implements the AMD API (source).

CommonJS is a way of defining modules with the help of an exports object, that defines the module contents. Simply put, a CommonJS implementation might work like this:

// someModule.js
exports.doSomething = function() { return "foo"; };

var someModule = require('someModule'); // in the vein of node    
exports.doSomethingElse = function() { return someModule.doSomething() + "bar"; };

Basically, CommonJS specifies that you need to have a require() function to fetch dependencies, an exports variable to export module contents and a module identifier (which describes the location of the module in question in relation to this module) that is used to require the dependencies (source). CommonJS has various implementations, including Node.js, which you mentioned.

CommonJS was not particularly designed with browsers in mind, so it doesn't fit in the browser environment very well (I really have no source for this--it just says so everywhere, including the RequireJS site.) Apparently, this has something to do with asynchronous loading, etc.

On the other hand, RequireJS implements AMD, which is designed to suit the browser environment (source). Apparently, AMD started as a spinoff of the CommonJS Transport format and evolved into its own module definition API. Hence the similarities between the two. The new feature in AMD is the define() function that allows the module to declare its dependencies before being loaded. For example, the definition could be:

define('module/id/string', ['module', 'dependency', 'array'], 
function(module, factory function) {
  return ModuleContents;  

So, CommonJS and AMD are JavaScript module definition APIs that have different implementations, but both come from the same origins.

  • AMD is more suited for the browser, because it supports asynchronous loading of module dependencies.
  • RequireJS is an implementation of AMD, while at the same time trying to keep the spirit of CommonJS (mainly in the module identifiers).

To confuse you even more, RequireJS, while being an AMD implementation, offers a CommonJS wrapper so CommonJS modules can almost directly be imported for use with RequireJS.

define(function(require, exports, module) {
  var someModule = require('someModule'); // in the vein of node    
  exports.doSomethingElse = function() { return someModule.doSomething() + "bar"; };

I hope this helps to clarify things!

Error : Index was outside the bounds of the array.

You have declared an array that can store 8 elements not 9.

this.posStatus = new int[8]; 

It means postStatus will contain 8 elements from index 0 to 7.

Example of waitpid() in use?

Syntax of waitpid():

pid_t waitpid(pid_t pid, int *status, int options);

The value of pid can be:

  • < -1: Wait for any child process whose process group ID is equal to the absolute value of pid.
  • -1: Wait for any child process.
  • 0: Wait for any child process whose process group ID is equal to that of the calling process.
  • > 0: Wait for the child whose process ID is equal to the value of pid.

The value of options is an OR of zero or more of the following constants:

  • WNOHANG: Return immediately if no child has exited.
  • WUNTRACED: Also return if a child has stopped. Status for traced children which have stopped is provided even if this option is not specified.
  • WCONTINUED: Also return if a stopped child has been resumed by delivery of SIGCONT.

For more help, use man waitpid.

Is there a CSS selector for the first direct child only?

What you posted literally means "Find any divs that are inside of section divs and are the first child of their parent." The sub contains one tag that matches that description.

It is unclear to me whether you want both children of the main div or not. If so, use this:

div.section > div

If you only want the header, use this:

div.section > div:first-child

Using the > changes the description to: "Find any divs that are the direct descendents of section divs" which is what you want.

Please note that all major browsers support this method, except IE6. If IE6 support is mission-critical, you will have to add classes to the child divs and use that, instead. Otherwise, it's not worth caring about.


The default date format depends on the language setting for the database server. You can also change it per session, like:

set language french
select cast(getdate() as varchar(50))
févr 8 2013 9:45AM

how to set mongod --dbpath

First you will have a config file in /etc/mongodb.conf, therefore this sounds like a homebrew install which will use some more standardized paths. The whole /data/db/ thing is referenced in a lot of manual install documentation.

So basically from your log the server is not running, it's shutting down, so there is nothing for the shell to connect to. Seems like you have had some unclean shutdowns/restarts which has led to the inconsistency.

Clear the files in the journal /usr/local/var/mongodb/journal/ on your config.


sudo rm /var/lib/mongodb/mongod.lock

Just in case, even though that part looks clean. And then restart.

How to view hierarchical package structure in Eclipse package explorer

Here is representation of screen eclipse to make hierarachical.

enter image description here

What is the syntax for an inner join in LINQ to SQL?

try instead this,

var dealer = from d in Dealer
             join dc in DealerContact on d.DealerID equals dc.DealerID
             select d;