Programs & Examples On #Exim

Exim is a message transfer agent (MTA) for Unix systems, which routes and handles email.

Problem with SMTP authentication in PHP using PHPMailer, with Pear Mail works

that the OpenSSL extension enabled and the directory languages with "br"? first checks the data.

Add a new item to a dictionary in Python

It occurred to me that you may have actually be asking how to implement the + operator for dictionaries, the following seems to work:

>>> class Dict(dict):
...     def __add__(self, other):
...         copy = self.copy()
...         copy.update(other)
...         return copy
...     def __radd__(self, other):
...         copy = other.copy()
...         copy.update(self)
...         return copy
>>> default_data = Dict({'item1': 1, 'item2': 2})
>>> default_data + {'item3': 3}
{'item2': 2, 'item3': 3, 'item1': 1}
>>> {'test1': 1} + Dict(test2=2)
{'test1': 1, 'test2': 2}

Note that this is more overhead then using dict[key] = value or dict.update(), so I would recommend against using this solution unless you intend to create a new dictionary anyway.

Numpy, multiply array with scalar

Using .multiply() (ufunc multiply)

a_1 = np.array([1.0, 2.0, 3.0])
a_2 = np.array([[1., 2.], [3., 4.]])
b = 2.0 

# array([2., 4., 6.])
# array([[2., 4.],[6., 8.]])

Android DialogFragment vs Dialog

DialogFragment comes with the power of a dialog and a Fragment. Basically all the lifecycle events are managed very well with DialogFragment automatically, like change in screen configuration etc.

Adding value labels on a matplotlib bar chart

If you want to just label the data points above the bar, you could use plt.annotate()

My code:

import numpy as np
import matplotlib.pyplot as plt

n = [1,2,3,4,5,]
s = [i**2 for i in n]
line =,s)

for i in range(len(s)):
    plt.annotate(str(s[i]), xy=(n[i],s[i]), ha='center', va='bottom')

By specifying a horizontal and vertical alignment of 'center' and 'bottom' respectively one can get centered annotations.

a labelled bar chart

spacing between form fields

            <div class="form-group">
                <label for="nameLabel">Name</label>
                <input id="name" name="name" class="form-control" type="text" /> 
            <div class="form-group">
                <label for="PhoneLabel">Phone</label>
                <input id="phone" name="phone" class="form-control" type="text" /> 
            <div class="form-group">
                <label for="yearLabel">Year</label>
                <input id="year" name="year" class="form-control" type="text" />

Visual Studio Code pylint: Unable to import 'protorpc'

I got the same error on my vscode where I had a library installed and the code working when running from the terminal, but for some reason, the vscode pylint was not able to pick the installed package returning the infamous error:

Unable to import 'someLibrary.someModule' pylint(import-error)

The problem might arise due to the multiple Python installations. Basically you have installed a library/package on one, and vscode pylint is installed and running from another installation. For example, on macOS and many Linux distros, there are by default Python2 installed and when you install Python3 this might cause confusion. Also on windows the Chocolatey package manager might cause some mess and you end up with multiple Python installations. To figure it out if you are on a *nix machine (i.e., macOS, GNU/Linux, BSD...), use the which command, and if you are on Windows, use the where command to find the installed Python interpreters. For example, on *nix machines:

which python3

and on Windows

where python

then you may want to uninstall the ones you don't want. and the one you want to use check if the package causing above issue is installed by

python -c "import someLibrary"

if you get an error then you should install it by for example pip:

pip install someLibrary

then on vscode press ??P if you are on a mac and CtrlShiftP on other operating systems. Then type-select the >python: Select Interpreter option and select the one you know have the library installed. At this moment vscode might asks you to install pyling again, which you just go on with.

LINQ query to return a Dictionary<string, string>

Look at the ToLookup and/or ToDictionary extension methods.

Android - How to regenerate R class?

My problem was in Manifiest file. I have deleted launcher icons and did not reference the new ones on Manifiest :)

Recyclerview and handling different type of row inflation

You have to implement getItemViewType() method in RecyclerView.Adapter. By default onCreateViewHolder(ViewGroup parent, int viewType) implementation viewType of this method returns 0. Firstly you need view type of the item at position for the purposes of view recycling and for that you have to override getItemViewType() method in which you can pass viewType which will return your position of item. Code sample is given below

public MyViewholder onCreateViewHolder(ViewGroup parent, int viewType) {
    int listViewItemType = getItemViewType(viewType);
    switch (listViewItemType) {
         case 0: return new ViewHolder0(...);
         case 2: return new ViewHolder2(...);

public int getItemViewType(int position) {   
    return position;

// and in the similar way you can set data according 
// to view holder position by passing position in getItemViewType
public void onBindViewHolder(MyViewholder viewholder, int position) {
    int listViewItemType = getItemViewType(position);
    // ...

Is there a way to add/remove several classes in one single instruction with classList?

The new spread operator makes it even easier to apply multiple CSS classes as array:

const list = ['first', 'second', 'third'];

Java naming convention for static final variables

In my opinion a variable being "constant" is often an implementation detail and doesn't necessarily justify different naming conventions. It may help readability, but it may as well hurt it in some cases.

How to solve 'Redirect has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header'?

If you have control over your server, you can use PHP:

header('Access-Control-Allow-Origin: *');

The type or namespace name does not exist in the namespace 'System.Web.Mvc'

I have deleted System.Web.dll from Bin frolder of my site.

Docker remove <none> TAG images


Sharing the PowerShell command for windows lovers (just in case you don't have bash, grep or awk)

(docker images) -like '*<none>*' | ForEach-Object { 
  $imageid=($_ -split "\s+")[2]
  docker rmi -f $imageid

get all keys set in memcached

If you have PHP & PHP-memcached installed, you can run

$ php -r '$c = new Memcached(); $c->addServer("localhost", 11211); var_dump( $c->getAllKeys() );'

Install GD library and freetype on Linux

Things are pretty much simpler unless they are made confusing.

To Install GD library in Ubuntu

sudo apt-get install php5-gd

To Install Freetype in Ubuntu

sudo apt-get install libfreetype6-dev:i386

How to find out what the date was 5 days ago?

If you want a method in which you know the algorithm, or the functions mentioned in the previous answer aren't available: convert the date to Julian Day number (which is a way of counting days from January 1st, 4713 B.C), then subtract five, then convert back to calendar date (year, month, day). Sources of the algorithms for the two conversions is section 9 of or

What is the equivalent of ngShow and ngHide in Angular 2+?

According to Angular 1 documentation of ngShow and ngHide, both of these directive adds the css style display: none !important;, to the element according to the condition of that directive (for ngShow adds the css on false value, and for ngHide adds the css for true value).

We can achieve this behavior using Angular 2 directive ngClass:

/* style.css */
    display: none !important;

<!-- old angular1 ngShow -->
<div ng-show="ngShowVal"> I'm Angular1 ngShow... </div>

<!-- become new angular2 ngClass -->
<div [ngClass]="{ 'hide': !ngShowVal }"> I'm Angular2 ngShow... </div>

<!-- old angular2 ngHide -->
<div ng-hide="ngHideVal"> I'm Angular1 ngHide... </div>

<!-- become new angular2 ngClass -->
<div [ngClass]="{ 'hide': ngHideVal }"> I'm Angular2 ngHide... </div>

Notice that for show behavior in Angular2 we need to add ! (not) before the ngShowVal, and for hide behavior in Angular2 we don't need to add ! (not) before the ngHideVal.

How to use WPF Background Worker

I found this (WPF Multithreading: Using the BackgroundWorker and Reporting the Progress to the UI. link) to contain the rest of the details which are missing from @Andrew's answer.

The one thing I found very useful was that the worker thread couldn't access the MainWindow's controls (in it's own method), however when using a delegate inside the main windows event handler it was possible.

worker.RunWorkerCompleted += delegate(object s, RunWorkerCompletedEventArgs args)
    // Get a result from the asynchronous worker
    T t = (t)args.Result
    this.ExampleControl.Text = t.BlaBla;

Show a message box from a class in c#?

Try this:

System.Windows.Forms.MessageBox.Show("Here's a message!");

Benefits of using the conditional ?: (ternary) operator

I'd recommend limiting the use of the ternary(?:) operator to simple single line assignment if/else logic. Something resembling this pattern:

if(<boolCondition>) {
    <variable> = <value>;
else {
    <variable> = <anotherValue>;

Could be easily converted to:

<variable> = <boolCondition> ? <value> : <anotherValue>;

I would avoid using the ternary operator in situations that require if/else if/else, nested if/else, or if/else branch logic that results in the evaluation of multiple lines. Applying the ternary operator in these situations would likely result in unreadable, confusing, and unmanageable code. Hope this helps.

jquery fill dropdown with json data

In most of the companies they required a common functionality for multiple dropdownlist for all the pages. Just call the functions or pass your (DropDownID,JsonData,KeyValue,textValue)




        var data = [{"stateid" : "1","statename" : "Mumbai"},
                    {"stateid" : "2","statename" : "Panjab"},
                    {"stateid" : "3","statename" : "Pune"},
                     {"stateid" : "4","statename" : "Nagpur"},
                     {"stateid" : "5","statename" : "kanpur"}];

        var Did=document.getElementById("DLState");

        function GetData(Did,data,valkey,textkey){
          var str= "";
          for (var i = 0; i <data.length ; i++){


            str+= "<option value='" + data[i][valkey] + "'>" + data[i][textkey] + "</option>";

        };    </script>

  <select id="DLState">

How to obtain the chat_id of a private Telegram channel?

update #2 :

Found another one easiest way : Just send to @username_to_id_bot bot your invite link to your private channel, it will return it's ID. Simplest level : maximum! :)

ps. I am not a an owner of this bot.

ps2. To be sure in security, just revoke your old invitation link if it is matter for you after bot using.

Original post :

Make channel public cannot be done by user with exist at least 5 public groups/channels, so...problem not solved. Yes, you can revoke one of them, but for now, we cannot retrieve chat id other way.


Did anybody found solution for that case?


I found crazy solution :

  1. login under your account at web version of Telegram :
  2. Find your channel. See to your url, it should be like**1055587116**_11052224402541910257
  3. Grab "1055587116" from it, and add "-100" as a prefix.

So... your channel id will be "-1001055587116". Magic happen :)

Solution found here :

Trying to create a file in Android: open failed: EROFS (Read-only file system)

try using the permission of WRITE_EXTERNAL_STORAGE You should use that whether there is an external card or not.

This works well for me:

path = Environment.getExternalStoragePublicDirectory(
File file = new File(path, "/" + fname);

and places my files in the appropriate folder

SQL Query to fetch data from the last 30 days?

select status, timeplaced 
from orders 
where TIMEPLACED>'2017-06-12 00:00:00' 

How to remove space from string?

Try doing this in a shell:

var="  3918912k"
echo ${var//[[:blank:]]/}

That uses parameter expansion (it's a non feature)

[[:blank:]] is a POSIX regex class (remove spaces, tabs...), see

POST an array from an HTML form without javascript

You can also post multiple inputs with the same name and have them save into an array by adding empty square brackets to the input name like this:

<input type="text" name="comment[]" value="comment1"/>
<input type="text" name="comment[]" value="comment2"/>
<input type="text" name="comment[]" value="comment3"/>
<input type="text" name="comment[]" value="comment4"/>

If you use php:


you will get this:

Array ( [0] => 'comment1' [1] => 'comment2' [2] => 'comment3' [3] => 'comment4' )

accessing a file using [NSBundle mainBundle] pathForResource: ofType:inDirectory:

I was also having the same problem. The Solution i found is ( in xcode 4.x):

Go to : Target -> "Build Phases" -> "copy bundle Resources" Then add that particular file here. If that file is already added , delete it and add it again.

clean the project and RUN. It works. :)

What does the M stand for in C# Decimal literal notation?

M refers to the first non-ambiguous character in "decimal". If you don't add it the number will be treated as a double.

D is double.

mysqli::mysqli(): (HY000/2002): Can't connect to local MySQL server through socket 'MySQL' (2)

When you use just "localhost" the MySQL client library tries to use a Unix domain socket for the connection instead of a TCP/IP connection. The error is telling you that the socket, called MySQL, cannot be used to make the connection, probably because it does not exist (error number 2).

From the MySQL Documentation:

On Unix, MySQL programs treat the host name localhost specially, in a way that is likely different from what you expect compared to other network-based programs. For connections to localhost, MySQL programs attempt to connect to the local server by using a Unix socket file. This occurs even if a --port or -P option is given to specify a port number. To ensure that the client makes a TCP/IP connection to the local server, use --host or -h to specify a host name value of, or the IP address or name of the local server. You can also specify the connection protocol explicitly, even for localhost, by using the --protocol=TCP option.

There are a few ways to solve this problem.

  1. You can just use TCP/IP instead of the Unix socket. You would do this by using instead of localhost when you connect. The Unix socket might by faster and safer to use, though.
  2. You can change the socket in php.ini: open the MySQL configuration file my.cnf to find where MySQL creates the socket, and set PHP's mysqli.default_socket to that path. On my system it's /var/run/mysqld/mysqld.sock.
  3. Configure the socket directly in the PHP script when opening the connection. For example:

    $db = new MySQLi('localhost', 'kamil', '***', '', 0, 

Redis command to get all available keys?

KEYS pattern

Available since 1.0.0.

Time complexity: O(N) with N being the number of keys in the database, under the assumption that the key names in the database and the given pattern have limited length.

Returns all keys matching pattern.

Warning : This command is not recommended to use because it may ruin performance when it is executed against large databases instead of KEYS you can use SCAN or SETS.

Example of KEYS command to use :

redis> MSET firstname Jack lastname Stuntman age 35
redis> KEYS *name*
1) "lastname"
2) "firstname"
redis> KEYS a??
1) "age"
redis> KEYS *
1) "lastname"
2) "age"
3) "firstname"

Maximum number of threads in a .NET app?

I would recommend running ThreadPool.GetMaxThreads method in debug

ThreadPool.GetMaxThreads(out int workerThreadsCount, out int ioThreadsCount);

Docs and examples:

How to get Maven project version to the bash command line

I've recently developed the Release Candidate Maven plugin that solves this exact problem so that you don't have to resort to any hacky shell scripts and parsing the output of the maven-help-plugin.

For example, to print the version of your Maven project to a terminal, run:

mvn com.smartcodeltd:release-candidate-maven-plugin:LATEST:version

which gives output similar to maven-help-plugin:

[INFO] Detected version: '1.0.0-SNAPSHOT'
[INFO] ------------------------------------------------------------------------
[INFO] ------------------------------------------------------------------------

However, you can also specify an arbitrary output format (so that the version could be picked up from the log by a CI server such as TeamCity):

mvn com.smartcodeltd:release-candidate-maven-plugin:LATEST:version \
   -DoutputTemplate="##teamcity[setParameter name='env.PROJECT_VERSION' value='{{ version }}']"

Which results in:

[INFO] Detected version: '1.0.0-SNAPSHOT'
##teamcity[setParameter name='env.PROJECT_VERSION' value='1.0.0-SNAPSHOT']
[INFO] ------------------------------------------------------------------------
[INFO] ------------------------------------------------------------------------

To save the output to a file (so that a CI server such as Jenkins could use it):

mvn com.smartcodeltd:release-candidate-maven-plugin:LATEST:version \
   -DoutputTemplate="PROJECT_VERSION={{ version }}" \

The resulting file will look as follows:


On top of all the above, Release Candidate also allows you to set the version of your project (which is something you'd probably do on your CI server) based on the API version you've defined in your POM.

If you'd like to see an example of Release Candidate being used as part of the Maven lifecycle, have a look at the pom.xml of my other open-source project - Build Monitor for Jenkins.

Printing list elements on separated lines in Python

Use the splat operator(*)

By default, * operator prints list separated by space. Use sep operator to specify the delimiter

print(*sys.path, sep = "\n")

What is the official name for a credit card's 3 digit code?

It's got a number of names. Most likely you've heard it as either Card Security Code (CSC) or Card Verification Value (CVV).

Card Security Code

Creating a PHP header/footer

the simpler, the better.


if (empty($_SERVER['QUERY_STRING'])) { 
} else { 
if (is_readable($file)) { 
  include 'header.php';
} else { 
  header("HTTP/1.0 404 Not Found");


<a href="index.php">Main page</a><br>
<a href=?about>About</a><br>
<a href=?links>Links</a><br>

the actual static html pages stored in the txt folder in the page.htm format

How can I get the latest JRE / JDK as a zip file rather than EXE or MSI installer?

This link

helps you at least avoid the obnoxious preload installer getting straight to the SDK.

From there, I would install this in a throw-away VM, on your old crufty PC or elsewhere, then transfer the resulting

C:\Program Files (x86)\Java\jre7

(or similar) to your new machine, set the very few usual ENV variables, and there you ideally go, w/o all the marketing junk and potential tie-ins. Of course, also w/o the security from frequent automatic updates.

Where is SQLite database stored on disk?

There is no "standard place" for a sqlite database. The file's location is specified to the library, and may be in your home directory, in the invoking program's folder, or any other place.

If it helps, sqlite databases are, by convention, named with a .db file extension.

Error when trying to access XAMPP from a network

This answer is for XAMPP on Ubuntu.

The manual for installation and download is on (site official)

After to start XAMPP simply call this command:

sudo /opt/lampp/lampp start

You should now see something like this on your screen:

Starting XAMPP 1.8.1...
LAMPP: Starting Apache...
LAMPP: Starting MySQL...
LAMPP started.

If you have this

Starting XAMPP for Linux 1.8.1...                                                             
XAMPP: Another web server daemon is already running.                                          
XAMPP: Another MySQL daemon is already running.                                               
XAMPP: Starting ProFTPD...                                                                    
XAMPP for Linux started

. The solution is

sudo /etc/init.d/apache2 stop
sudo /etc/init.d/mysql stop

And the restast with sudo //opt/lampp/lampp restart

You to fix most of the security weaknesses simply call the following command:

/opt/lampp/lampp security

After the change this file

sudo kate //opt/lampp/etc/extra/httpd-xampp.conf

Find and replace on

# New XAMPP security concept
<LocationMatch "^/(?i:(?:xampp|security|licenses|phpmyadmin|webalizer|server-status|server-info))">
    Order deny,allow
    Deny from all
    Allow from ::1 
    Allow from all
    #   fc00::/7 \
    #   fe80::/10

    ErrorDocument 403 /error/XAMPP_FORBIDDEN.html.var

How to handle "Uncaught (in promise) DOMException: play() failed because the user didn't interact with the document first." on Desktop with Chrome 66?

The best solution i found out is to mute the video


<video loop muted autoplay id="videomain">
  <source src="videoname.mp4" type="video/mp4">

Python : Trying to POST form using requests

I was having problems here (i.e. sending form-data whilst uploading a file) until I used the following:

files = {'file': (filename, open(filepath, 'rb'), 'text/xml'),
         'Content-Disposition': 'form-data; name="file"; filename="' + filename + '"',
         'Content-Type': 'text/xml'}

That's the input that ended up working for me. In Chrome Dev Tools -> Network tab, I clicked the request I was interested in. In the Headers tab, there's a Form Data section, and it showed both the Content-Disposition and the Content-Type headers being set there.

I did NOT need to set headers in the actual command for this to succeed (including them actually caused it to fail)

NSURLConnection Using iOS Swift

An abbreviated version of your code worked for me,

class Remote: NSObject {

    var data = NSMutableData()

    func connect(query:NSString) {
        var url =  NSURL.URLWithString("")
        var request = NSURLRequest(URL: url)
        var conn = NSURLConnection(request: request, delegate: self, startImmediately: true)

     func connection(didReceiveResponse: NSURLConnection!, didReceiveResponse response: NSURLResponse!) {

    func connection(connection: NSURLConnection!, didReceiveData conData: NSData!) {

    func connectionDidFinishLoading(connection: NSURLConnection!) {

    deinit {

This is the code I used in the calling class,

class ViewController: UIViewController {

    var remote = Remote()

    @IBAction func downloadTest(sender : UIButton) {


You didn't specify in your question where you had this code,

var remote = Remote()

If var is a local variable, then the Remote class will be deallocated right after the connect(query:NSString) method finishes, but before the data returns. As you can see by my code, I usually implement reinit (or dealloc up to now) just to make sure when my instances go away. You should add that to your Remote class to see if that's your problem.

Spring-boot default profile for integration tests

Another programatically way to do that:

  import static org.springframework.core.env.AbstractEnvironment.DEFAULT_PROFILES_PROPERTY_NAME;

  public static void setupTest() {
    System.setProperty(DEFAULT_PROFILES_PROPERTY_NAME, "test");

It works great.

Set inputType for an EditText Programmatically?

For Kotlin:

    val password = EditText(this)
    password.inputType = InputType.TYPE_CLASS_TEXT or InputType.TYPE_TEXT_VARIATION_PASSWORD
    password.hint = "Password"

How do I call a non-static method from a static method in C#?

You just need to provide object reference . Please provide your class name in the position.

private static void data2()
    <classname> c1 = new <classname>();
    c1. data1();

Endless loop in C/C++

The problem with asking this question is that you'll get so many subjective answers that simply state "I prefer this...". Instead of making such pointless statements, I'll try to answer this question with facts and references, rather than personal opinions.

Through experience, we can probably start by excluding the do-while alternatives (and the goto), as they are not commonly used. I can't recall ever seeing them in live production code, written by professionals.

The while(1), while(true) and for(;;) are the 3 different versions commonly existing in real code. They are of course completely equivalent and results in the same machine code.


  • This is the original, canonical example of an eternal loop. In the ancient C bible The C Programming Language by Kernighan and Ritchie, we can read that:

    K&R 2nd ed 3.5:

    for (;;) {

    is an "infinite" loop, presumably to be broken by other means, such as a break or return. Whether to use while or for is largely a matter of personal preference.

    For a long while (but not forever), this book was regarded as canon and the very definition of the C language. Since K&R decided to show an example of for(;;), this would have been regarded as the most correct form at least up until the C standardization in 1990.

    However, K&R themselves already stated that it was a matter of preference.

    And today, K&R is a very questionable source to use as a canonical C reference. Not only is it outdated several times over (not addressing C99 nor C11), it also preaches programming practices that are often regarded as bad or blatantly dangerous in modern C programming.

    But despite K&R being a questionable source, this historical aspect seems to be the strongest argument in favour of the for(;;).

  • The argument against the for(;;) loop is that it is somewhat obscure and unreadable. To understand what the code does, you must know the following rule from the standard:

    ISO 9899:2011

    for ( clause-1 ; expression-2 ; expression-3 ) statement


    Both clause-1 and expression-3 can be omitted. An omitted expression-2 is replaced by a nonzero constant.

    Based on this text from the standard, I think most will agree that it is not only obscure, it is subtle as well, since the 1st and 3rd part of the for loop are treated differently than the 2nd, when omitted.


  • This is supposedly a more readable form than for(;;). However, it relies on another obscure, although well-known rule, namely that C treats all non-zero expressions as boolean logical true. Every C programmer is aware of that, so it is not likely a big issue.

  • There is one big, practical problem with this form, namely that compilers tend to give a warning for it: "condition is always true" or similar. That is a good warning, of a kind which you really don't want to disable, because it is useful for finding various bugs. For example a bug such as while(i = 1), when the programmer intended to write while(i == 1).

    Also, external static code analysers are likely to whine about "condition is always true".


  • To make while(1) even more readable, some use while(true) instead. The consensus among programmers seem to be that this is the most readable form.

  • However, this form has the same problem as while(1), as described above: "condition is always true" warnings.

  • When it comes to C, this form has another disadvantage, namely that it uses the macro true from stdbool.h. So in order to make this compile, we need to include a header file, which may or may not be inconvenient. In C++ this isn't an issue, since bool exists as a primitive data type and true is a language keyword.

  • Yet another disadvantage of this form is that it uses the C99 bool type, which is only available on modern compilers and not backwards compatible. Again, this is only an issue in C and not in C++.

So which form to use? Neither seems perfect. It is, as K&R already said back in the dark ages, a matter of personal preference.

Personally, I always use for(;;) just to avoid the compiler/analyser warnings frequently generated by the other forms. But perhaps more importantly because of this:

If even a C beginner knows that for(;;) means an eternal loop, then who are you trying to make the code more readable for?

I guess that's what it all really boils down to. If you find yourself trying to make your source code readable for non-programmers, who don't even know the fundamental parts of the programming language, then you are only wasting time. They should not be reading your code.

And since everyone who should be reading your code already knows what for(;;) means, there is no point in making it further readable - it is already as readable as it gets.

Run php function on button click

Do this:

<input type="button" name="test" id="test" value="RUN" /><br/>


function testfun()
   echo "Your test function on button click is working";

SQL Server equivalent to MySQL enum data type?

Found this interesting approach when I wanted to implement enums in SQL Server.

The approach mentioned below in the link is quite compelling, considering all your database enum needs could be satisfied with 2 central tables.

When or Why to use a "SET DEFINE OFF" in Oracle Database

Here is the example:

SQL> set define off;
SQL> select * from dual where dummy='&var';

no rows selected

SQL> set define on
SQL> /
Enter value for var: X
old   1: select * from dual where dummy='&var'
new   1: select * from dual where dummy='X'


With set define off, it took a row with &var value, prompted a user to enter a value for it and replaced &var with the entered value (in this case, X).

twitter bootstrap navbar fixed top overlapping site

As others have stated adding a padding-top to body works great. But when you make the screen narrower (to cell phone widths) there is a gap between the navbar and the body. Also, a crowded navbar can wrap to a multi-line bar, overwriting some of the content again.

This solved these kinds of issues for me

body { padding-top: 40px; }
@media screen and (max-width: 768px) {
    body { padding-top: 0px; }

This makes a 40px padding by default and 0px when under 768px width (which according to bootstrap's docs is the cell phone layout cutoff where the gap would be created)

"Bitmap too large to be uploaded into a texture"

Changing the image file to drawable-nodpi folder from drawable folder worked for me.

How can I delete derived data in Xcode 8?

The simplest and fastest way is the following (if you have not changed the defaults folder for DerivedData).

Open terminal and past the following:

rm -rf ~/Library/Developer/Xcode/DerivedData

Alternative to the HTML Bold tag

You can use following :

<p id="p1">Some Text here </p>
   font-weight: bold;


<Strong><p>Some text here </p></strong>


You can use <h1> tag which is somewhat similar to bold

Index (zero based) must be greater than or equal to zero

Change this line:

Aboutme.Text = String.Format("{0}", reader.GetString(0));

When to use If-else if-else over switch statements and vice versa

Switch statements are far easier to read and maintain, hands down. And are usually faster and less error prone.

Platform.runLater and Task in JavaFX

  • Platform.runLater: If you need to update a GUI component from a non-GUI thread, you can use that to put your update in a queue and it will be handled by the GUI thread as soon as possible.
  • Task implements the Worker interface which is used when you need to run a long task outside the GUI thread (to avoid freezing your application) but still need to interact with the GUI at some stage.

If you are familiar with Swing, the former is equivalent to SwingUtilities.invokeLater and the latter to the concept of SwingWorker.

The javadoc of Task gives many examples which should clarify how they can be used. You can also refer to the tutorial on concurrency.

How do I show the value of a #define at compile-time?

#define a <::BOOST_VERSION>
#include a
MSVC2015: fatal error C1083: Cannot open include file: '::106200': No such file or directory

Works even if preprocess to file is enabled, even if invalid tokens are present:

#define a <::'*/`#>
#include a
MSVC2015: fatal error C1083: Cannot open include file: '::'*/`#': No such file or directory
GCC4.x: warning: missing terminating ' character [-Winvalid-pp-token]
#define a <::'*/`#>

Jquery button click() function is not working

The click event is not bound to your new element, use a jQuery.on to handle the click.

how to convert 2d list to 2d numpy array?

I am using large data sets exported to a python file in the form

XVals1 = [.........] 
XVals2 = [.........] 

Each list is of identical length. I use

>>> a1 = np.array(SV.XVals1)

>>> a2 = np.array(SV.XVals2)


>>> A = np.matrix([a1,a2])

What is the difference between Set and List?

Set: A Set cannot have Duplicate elements in its collections. it is also an unordered collection. To access the data from Set, it is required to use Iterator only and index based retrieve is not possible for it. It is mainly used whenever required uniqueness collection.

List: A List can have duplicate elements, with the natural ordered as it is inserted. Thus, it can be retrieved data based on index or iterator. It is widely used to store collection which needs to access based on index.

How to make a launcher

They're examples provided by the Android team, if you've already loaded Samples, you can import Home screen replacement sample by following these steps.

File > New > Other >Android > Android Sample Project > Android x.x > Home > Finish

But if you do not have samples loaded, then download it using the below steps

Windows > Android SDK Manager > chooses "Sample for SDK" for SDK you need it > Install package > Accept License > Install

Awaiting multiple Tasks with different results

If you're using C# 7, you can use a handy wrapper method like this...

public static class TaskEx
    public static async Task<(T1, T2)> WhenAll<T1, T2>(Task<T1> task1, Task<T2> task2)
        return (await task1, await task2);
} enable convenient syntax like this when you want to wait on multiple tasks with different return types. You'd have to make multiple overloads for different numbers of tasks to await, of course.

var (someInt, someString) = await TaskEx.WhenAll(GetIntAsync(), GetStringAsync());

However, see Marc Gravell's answer for some optimizations around ValueTask and already-completed tasks if you intend to turn this example into something real.

How to assign the output of a Bash command to a variable?

In this specific case, note that bash has a variable called PWD that contains the current directory: $PWD is equivalent to `pwd`. (So do other shells, this is a standard feature.) So you can write your script like this:

until [ "$PWD" = "/" ]; do
  echo "$PWD"
  ls && cd .. && ls 

Note the use of double quotes around the variable references. They are necessary if the variable (here, the current directory) contains whitespace or wildcards (\[?*), because the shell splits the result of variable expansions into words and performs globbing on these words. Always double-quote variable expansions "$foo" and command substitutions "$(foo)" (unless you specifically know you have not to).

In the general case, as other answers have mentioned already:

  • You can't use whitespace around the equal sign in an assignment: var=value, not var = value
  • The $ means “take the value of this variable”, so you don't use it when assigning: var=value, not $var=value.

How to bind to a PasswordBox in MVVM

I used an authentication check followed by a sub called by a mediator class to the View (which also implements an authentication check) to write the password to the data class.

It's not a perfect solution; however, it remedied my problem of not being able to move the password.

Change the bullet color of list

I would recommend you to use background-image instead of default list.

.listStyle {
    list-style: none;
    background: url(image_path.jpg) no-repeat left center;
    padding-left: 30px;
    width: 20px;
    height: 20px;

Or, if you don't want to use background-image as bullet, there is an option to do it with pseudo element:

    list-style: none;
    margin: 0;
    padding: 0;
.liststyle:before {
    content: "• ";
    color: red; /* or whatever color you prefer */
    font-size: 20px;/* or whatever the bullet size you prefer */

how can I display tooltip or item information on mouse over?

The title attribute works on most HTML tags and is widely supported by modern browsers.

How do I get a decimal value when using the division operator in Python?

It's only dropping the fractional part after decimal. Have you tried : 4.0 / 100

C# Base64 String to JPEG Image

So with the code you have provided.

var bytes = Convert.FromBase64String(resizeImage.Content);
using (var imageFile = new FileStream(filePath, FileMode.Create))
    imageFile.Write(bytes ,0, bytes.Length);

Configure Flask dev server to be visible across the network

If your cool app has it's configuration loaded from an external file, like in the following example, then don't forget to update the corresponding config file with HOST="""HOST", "localhost"),"PORT", 9000)

CSS Outside Border

Try the outline property W3Schools - CSS Outline

Outline will not interfere with widths and lenghts of the elements/divs!

Please click the link I provided at the bottom to see working demos of the the different ways you can make borders, and inner/inline borders, even ones that do not disrupt the dimensions of the element! No need to add extra divs every time, as mentioned in another answer!

You can also combine borders with outlines, and if you like, box-shadows (also shown via link)

   <style type="text/css" ref="stylesheet">
      div {
        outline:1px solid black;

Usually by default, 'border:' puts the border on the outside of the width, measurement, adding to the overall dimensions, unless you use the 'inset' value:

div {border: inset solid 1px black};

But 'outline:' is an extra border outside of the border, and of course still adds extra width/length to the element.

Hope this helps

PS: I also was inspired to make this for you : Using borders, outlines, and box-shadows

How to call javascript function on page load in

Place this line before the closing script tag,writing from memory:

window.onload  = GetTimeZoneOffset;

i think the question is how to call the javascript function on pageload

How to check not in array element

I think everything that you need is array_key_exists:

if (!array_key_exists('id', $access_data['Privilege'])) {
                $this->Session->setFlash(__('Access Denied! You are not eligible to access this.'), 'flash_custom_success');
                return $this->redirect(array('controller' => 'Dashboard', 'action' => 'index'));

Get Last Part of URL PHP


$end = preg_replace( '%^(.+)/%', '', $url );

// if( ! $end ) no match.

This simply removes everything before the last slash, including it.

E: Unable to locate package mongodb-org

I had the same problems on Ubuntu 16.04 when I followed the steps posted on the official document.
Then I remove the text "[ arch=amd64,arm64 ]" in step2 and it works for me.

echo "deb xenial/mongodb-org/4.0 multiverse" | sudo tee /etc/apt/sources.list.d/mongodb-org-4.0.list   
apt-get install -y mongodb-org  

Generate random string/characters in JavaScript

I think this will work for you:

function makeid(length) {_x000D_
   var result           = '';_x000D_
   var characters       = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';_x000D_
   var charactersLength = characters.length;_x000D_
   for ( var i = 0; i < length; i++ ) {_x000D_
      result += characters.charAt(Math.floor(Math.random() * charactersLength));_x000D_
   return result;_x000D_

Find a file in python

If you are using Python on Ubuntu and you only want it to work on Ubuntu a substantially faster way is the use the terminal's locate program like this.

import subprocess

def find_files(file_name):
    command = ['locate', file_name]

    output = subprocess.Popen(command, stdout=subprocess.PIPE).communicate()[0]
    output = output.decode()

    search_results = output.split('\n')

    return search_results

search_results is a list of the absolute file paths. This is 10,000's of times faster than the methods above and for one search I've done it was ~72,000 times faster.

How do I concatenate multiple C++ strings on one line?

Something like this works for me

namespace detail {
    void concat_impl(std::ostream&) { /* do nothing */ }

    template<typename T, typename ...Args>
    void concat_impl(std::ostream& os, const T& t, Args&&... args)
        os << t;
        concat_impl(os, std::forward<Args>(args)...);
} /* namespace detail */

template<typename ...Args>
std::string concat(Args&&... args)
    std::ostringstream os;
    detail::concat_impl(os, std::forward<Args>(args)...);
    return os.str();
// ...
std::string s{"Hello World, "};
s = concat(s, myInt, niceToSeeYouString, myChar, myFoo);

Can a div have multiple classes (Twitter Bootstrap)

You can have multiple css class selectors:

For e.g.:

<div class="col-md-4 a-class-name">

but only a single id:

<div id = "btn1 btn">  <!-- this is wrong -->

Any way (or shortcut) to auto import the classes in IntelliJ IDEA like in Eclipse?

Not all at once. But you can press

Alt + Enter

People assume it only works when you are at the particular item. But it actually works for "next missing type". So if you keep pressing Alt + Enter, IDEA fixes one after another until all are fixed.

How to check if a date is in a given range?

You can try this:

//custom date for example
$d1 = new DateTime("2012-07-08");
$d2 = new DateTime("2012-07-11");
$d3 = new DateTime("2012-07-08");
$d4 = new DateTime("2012-07-15");

//create a date period object
$interval = new DateInterval('P1D');
$daterange = iterator_to_array(new DatePeriod($d1, $interval, $d2));
$daterange1 = iterator_to_array(new DatePeriod($d3, $interval, $d4));
array_map(function($v) use ($daterange1) { if(in_array($v, $daterange1)) print "Bingo!";}, $daterange);

How to fix HTTP 404 on Github Pages?

If you are sure that your structure is correct, just push an empty commit or update the index.html file with some space, it works!

Application Loader stuck at "Authenticating with the iTunes store" when uploading an iOS app

You have to agree to a new sign up in Application Loader. Select "Application Loader" under the "Xcode -> Open Developer Tool" menu (the first menu to the right of the Apple in the menu bar). Once you open Application Loader there will be a prompt to agree to new terms and then to login again into your iTunes account. After this any upload method will work.

Image of Application Loader on Xcode

How to use vagrant in a proxy environment?

Install proxyconf:

vagrant plugin install vagrant-proxyconf

Configure your Vagrantfile:

config.proxy.http     = "http://yourproxy:8080"
config.proxy.https    = "http://yourproxy:8080"
config.proxy.no_proxy = "localhost,"

Detect if the app was launched/opened from a push notification

M.Othman's answer is correct for apps that don't contain scene delegate For Scene Delegate Apps This worked for me on iOS 13

Here is the code for that should be written in will connect scene

if connectionOptions.notificationResponse == nil { 
//Not opened from push notification
} else {
  //Opened from push notification

Code for app delegate to support earlier versions didFinishLaunchingWithOptions

let notification = launchOptions?[UIApplication.LaunchOptionsKey.remoteNotification]
        if (notification != nil) {

            //Launched from push notification
        } else {

            //Launch from other source

JavaScript: Upload file

Pure JS

You can use fetch optionally with await-try-catch

let photo = document.getElementById("image-file").files[0];
let formData = new FormData();
formData.append("photo", photo);
fetch('/upload/image', {method: "POST", body: formData});

async function SavePhoto(inp) 
    let user = { name:'john', age:34 };
    let formData = new FormData();
    let photo = inp.files[0];      
    formData.append("photo", photo);
    formData.append("user", JSON.stringify(user)); 
    const ctrl = new AbortController()    // timeout
    setTimeout(() => ctrl.abort(), 5000);
    try {
       let r = await fetch('/upload/image', 
         {method: "POST", body: formData, signal: ctrl.signal}); 
       console.log('HTTP response code:',r.status); 
    } catch(e) {
       console.log('Huston we have problem...:', e);
<input id="image-file" type="file" onchange="SavePhoto(this)" >
Before selecting the file open chrome console > network tab to see the request details.
<small>Because in this example we send request to the response code will be 404 ofcourse...</small>

(in stack overflow snippets there is problem with error handling, however in <a href="">jsfiddle version</a> for 404 errors 4xx/5xx are <a href="">not throwing</a> at all but we can read response status which contains code)

Old school approach - xhr

let photo = document.getElementById("image-file").files[0];  // file from input
let req = new XMLHttpRequest();
let formData = new FormData();

formData.append("photo", photo);                       "POST", '/upload/image');

function SavePhoto(e) 
    let user = { name:'john', age:34 };
    let xhr = new XMLHttpRequest();
    let formData = new FormData();
    let photo = e.files[0];      
    formData.append("user", JSON.stringify(user));   
    formData.append("photo", photo);
    xhr.onreadystatechange = state => { console.log(xhr.status); } // err handling
    xhr.timeout = 5000;"POST", '/upload/image'); 
<input id="image-file" type="file" onchange="SavePhoto(this)" >
Choose file and open chrome console > network tab to see the request details.
<small>Because in this example we send request to the response code will be 404 ofcourse...</small>

(the stack overflow snippets, has some problem with error handling - the xhr.status is zero (instead of 404) which is similar to situation when we run script from file on <a href="">local disc</a> - so I provide also js fiddle version which shows proper http error code <a href="">here</a>)


  • In server side you can read original file name (and other info) which is automatically included to request by browser in filename formData parameter.
  • You do NOT need to set request header Content-Type to multipart/form-data - this will be set automatically by browser.
  • Instead of /upload/image you can use full address like http://.../upload/image.
  • If you want to send many files in single request use multiple attribute: <input multiple type=... />, and attach all chosen files to formData in similar way (e.g. photo2=...files[2];... formData.append("photo2", photo2);)
  • You can include additional data (json) to request e.g. let user = {name:'john', age:34} in this way: formData.append("user", JSON.stringify(user));
  • You can set timeout: for fetch using AbortController, for old approach by xhr.timeout= milisec
  • This solutions should work on all major browsers.

bodyParser is deprecated express 4

What is your opinion to use express-generator it will generate skeleton project to start with, without deprecated messages appeared in your log

run this command

npm install express-generator -g

Now, create new Express.js starter application by type this command in your Node projects folder.

express node-express-app

That command tell express to generate new Node.js application with the name node-express-app.

then Go to the newly created project directory, install npm packages and start the app using the command

cd node-express-app && npm install && npm start

Which sort algorithm works best on mostly sorted data?

Based on the highly scientific method of watching animated gifs I would say Insertion and Bubble sorts are good candidates.

How to call python script on excel vba?

Try this:

RetVal = Shell("<full path to python.exe> " & "<full path to your python script>")

Or if the python script is in the same folder as the workbook, then you can try :

RetVal = Shell("<full path to python.exe> " & ActiveWorkBook.Path & "\<python script name>")

All details within <> are to be given. <> - indicates changeable fields

I guess this should work. But then again, if your script is going to call other files which are in different folders, it can cause errors unless your script has properly handled it. Hope it helps.

Why is IoC / DI not common in Python?

IoC/DI is a design concept, but unfortunately it's often taken as a concept that applies to certain languages (or typing systems). I'd love to see dependency injection containers become far more popular in Python. There's Spring, but that's a super-framework and seems to be a direct port of the Java concepts without much consideration for "The Python Way."

Given Annotations in Python 3, I decided to have a crack at a full featured, but simple, dependency injection container: . It's based on some concepts from a .NET dependency injection container (which IMO is fantastic if you're ever playing in that space), but mutated with Python concepts.

Create an Array of Arraylists

You can create a class extending ArrayList

class IndividualList extends ArrayList<Individual> {


and then create the array

IndividualList[] group = new IndividualList[10];

What does "make oldconfig" do exactly in the Linux kernel makefile?


As mentioned by Ignacio, it updates your .config for you after you update the kernel source, e.g. with git pull.

It tries to keep your existing options.

Having a script for that is helpful because:

  • new options may have been added, or old ones removed

  • the kernel's Kconfig configuration format has options that:

    • imply one another via select
    • depend on another via depends

    Those option relationships make manual config resolution even harder.

Let's modify .config manually to understand how it resolves configurations

First generate a default configuration with:

make defconfig

Now edit the generated .config file manually to emulate a kernel update and run:

make oldconfig

to see what happens. Some conclusions:

  1. Lines of type:

    # CONFIG_XXX is not set

    are not mere comments, but actually indicate that the parameter is not set.

    For example, if we remove the line:

    # CONFIG_DEBUG_INFO is not set

    and run make oldconfig, it will ask us:

    Compile the kernel with debug info (DEBUG_INFO) [N/y/?] (NEW)

    When it is over, the .config file will be updated.

    If you change any character of the line, e.g. to # CONFIG_DEBUG_INFO, it does not count.

  2. Lines of type:

    # CONFIG_XXX is not set

    are always used for the negation of a property, although:


    is also understood as the negation.

    For example, if you remove # CONFIG_DEBUG_INFO is not set and answer:

    Compile the kernel with debug info (DEBUG_INFO) [N/y/?] (NEW)

    with N, then the output file contains:

    # CONFIG_DEBUG_INFO is not set

    and not:


    Also, if we manually modify the line to:


    and run make oldconfig, then the line gets modified to:

    # CONFIG_DEBUG_INFO is not set

    without oldconfig asking us.

  3. Configs whose dependencies are not met, do not appear on the .config. All others do.

    For example, set:


    and run make oldconfig. It will now ask us for: DEBUG_INFO_REDUCED, DEBUG_INFO_SPLIT, etc. configs.

    Those properties did not appear on the defconfig before.

    If we look under lib/Kconfig.debug where they are defined, we see that they depend on DEBUG_INFO:

        bool "Reduce debugging information"
        depends on DEBUG_INFO

    So when DEBUG_INFO was off, they did not show up at all.

  4. Configs which are selected by turned on configs are automatically set without asking the user.

    For example, if CONFIG_X86=y and we remove the line:


    and run make oldconfig, the line gets recreated without asking us, unlike DEBUG_INFO.

    This happens because arch/x86/Kconfig contains:

    config X86
        def_bool y

    and select forces that option to be true. See also:

  5. Configs whose constraints are not met are asked for.

    For example, defconfig had set:


    If we edit:


    and run make oldconfig, it will ask us:

    Tree-based hierarchical RCU fanout value (RCU_FANOUT) [32] (NEW)

    This is because RCU_FANOUT is defined at init/Kconfig as:

    config RCU_FANOUT
        int "Tree-based hierarchical RCU fanout value"
        range 2 64 if 64BIT
        range 2 32 if !64BIT

    Therefore, without 64BIT, the maximum value is 32, but we had 64 set on the .config, which would make it inconsistent.


make olddefconfig sets every option to their default value without asking interactively. It gets run automatically on make to ensure that the .config is consistent in case you've modified it manually like we did. See also:

make alldefconfig is like make olddefconfig, but it also accepts a config fragment to merge. This target is used by the script:

And if you want to automate the .config modification, that is not too simple: How do you non-interactively turn on features in a Linux kernel .config file?

Using Axios GET with Authorization Header in React-Native App

For anyone else that comes across this post and might find it useful... There is actually nothing wrong with my code. I made the mistake of requesting client_credentials type access code instead of password access code (#facepalms). FYI I am using urlencoded post hence the use of querystring.. So for those that may be looking for some example code.. here is my full request

Big thanks to @swapnil for trying to help me debug this.

   const data = {
      grant_type: USER_GRANT_TYPE,
      client_id: CLIENT_ID,
      client_secret: CLIENT_SECRET,
      scope: SCOPE_INT,
      username: DEMO_EMAIL,
      password: DEMO_PASSWORD
    };, Querystring.stringify(data))   
   .then(response => {
      USER_TOKEN =;
      console.log('userresponse ' +; 
   .catch((error) => {
      console.log('error ' + error);   

const AuthStr = 'Bearer '.concat(USER_TOKEN); 
axios.get(URL, { headers: { Authorization: AuthStr } })
 .then(response => {
     // If request is good...
 .catch((error) => {
     console.log('error ' + error);

node.js string.replace doesn't work?

Strings are always modelled as immutable (atleast in heigher level languages python/java/javascript/Scala/Objective-C).

So any string operations like concatenation, replacements always returns a new string which contains intended value, whereas the original string will still be same.

From inside of a Docker container, how do I connect to the localhost of the machine?

For macOS and Windows

Docker v 18.03 and above (since March 21st 2018)

Use your internal IP address or connect to the special DNS name host.docker.internal which will resolve to the internal IP address used by the host.

Linux support pending

MacOS with earlier versions of Docker

Docker for Mac v 17.12 to v 18.02

Same as above but use instead.

Docker for Mac v 17.06 to v 17.11

Same as above but use docker.for.mac.localhost instead.

Docker for Mac 17.05 and below

To access host machine from the docker container you must attach an IP alias to your network interface. You can bind whichever IP you want, just make sure you're not using it to anything else.

sudo ifconfig lo0 alias

Then make sure that you server is listening to the IP mentioned above or If it's listening on localhost it will not accept the connection.

Then just point your docker container to this IP and you can access the host machine!

To test you can run something like curl -X GET inside the container.

The alias will reset on every reboot so create a start-up script if necessary.

Solution and more documentation here:

How to convert the ^M linebreak to 'normal' linebreak in a file opened in vim?

On Linux and Mac OS, the following works,


where ^V^M means type Ctrl+V, then Ctrl+M.

Note: on Windows you probably want to use ^Q instead of ^V, since by default ^V is mapped to paste text.

Best way to store time (hh:mm) in a database

Just store a regular datetime and ignore everything else. Why spend extra time writing code that loads an int, manipulates it, and converts it into a datetime, when you could just load a datetime?

how to convert long date value to mm/dd/yyyy format

Try this example

 String[] formats = new String[] {
   "yyyy-MM-dd HH:mm",
   "yyyy-MM-dd HH:mmZ",
   "yyyy-MM-dd HH:mm:ss.SSSZ",
 for (String format : formats) {
   SimpleDateFormat sdf = new SimpleDateFormat(format, Locale.US);
   System.err.format("%30s %s\n", format, sdf.format(new Date(0)));
   System.err.format("%30s %s\n", format, sdf.format(new Date(0)));

and read this

fstream won't create a file

You should add fstream::out to open method like this:"test.txt",fstream::out);

More information about fstream flags, check out this link:

Are table names in MySQL case sensitive?

  1. Locate the file at /etc/mysql/my.cnf

  2. Edit the file by adding the following lines:

  3. sudo /etc/init.d/mysql restart

  4. Run mysqladmin -u root -p variables | grep table to check that lower_case_table_names is 1 now

You might need to recreate these tables to make it work.

Joining Multiple Tables - Oracle

While former answer is absolutely correct, I prefer using the JOIN ON syntax to be sure that I know how do I join and on what fields. It would look something like this:

SELECT bc.firstname, bc.lastname, b.title, TO_CHAR(bo.orderdate, 'MM/DD/YYYY') "Order         Date", p.publishername
FROM books b
JOIN book_customer bc ON bc.costumer_id = b.book_id
LEFT JOIN book_order bo ON bo.book_id = b.book_id
WHERE b.publishername = 'PRINTING IS US';

This syntax seperates completely the WHERE clause from the JOIN clause, making the statement more readable and easier for you to debug.

Android Center text on canvas

Use this in your paint properties:


access key and value of object using *ngFor

There's a real nice library that does this among other nice pipes. It's called ngx-pipes.

For example, keys pipe returns keys for an object, and values pipe returns values for an object:

keys pipe

<div *ngFor="let key of {foo: 1, bar: 2} | keys">{{key}}</div> 
<!-- Output: 'foo' and 'bar -->

values pipe

<div *ngFor="let value of {foo: 1, bar: 2} | values">{{value}}</div>
<!-- Output: 1 and 2 -->

No need to create your own custom pipe :)

Why do I get a "Null value was assigned to a property of primitive type setter of" error message when using HibernateCriteriaBuilder in Grails

According to this SO thread, the solution is to use the non-primitive wrapper types; e.g., Integer instead of int.

convert php date to mysql format

You are looking for the the MySQL functions FROM_UNIXTIME() and UNIX_TIMESTAMP().

Use them in your SQL, e.g.:

|            1311343579 |
1 row in set (0.00 sec)

mysql> SELECT FROM_UNIXTIME(1311343579);
| FROM_UNIXTIME(1311343579) |
| 2011-07-22 15:06:19       |
1 row in set (0.00 sec)

How do you check in python whether a string contains only numbers?

What about of float numbers, negatives numbers, etc.. All the examples before will be wrong.

Until now I got something like this, but I think it could be a lot better:


will return true only if there is one or no '.' in the string of digits.


will return false

String.replaceAll single backslashes with double backslashes

To avoid this sort of trouble, you can use replace (which takes a plain string) instead of replaceAll (which takes a regular expression). You will still need to escape backslashes, but not in the wild ways required with regular expressions.

Running a single test from unittest.TestCase via the command line

If you organize your test cases, that is, follow the same organization like the actual code and also use relative imports for modules in the same package, you can also use the following command format:

python -m unittest mypkg.tests.test_module.TestClass.test_method

# In your case, this would be:
python -m unittest testMyCase.MyCase.testItIsHot

Python 3 documentation for this: Command-Line Interface

Kotlin Ternary Conditional Operator

In Kotlin you can use ternary operation like this: val x = if(a) "add b" else "add c"

Unfamiliar symbol in algorithm: what does ? mean?

Can be read, "For all s such that s does not equal s[start]"

catch specific HTTP error in python

For Python 3.x

import urllib.request
from urllib.error import HTTPError
    urllib.request.urlretrieve(url, fullpath)
except urllib.error.HTTPError as err:

Bash loop ping successful

I use this Bash script to test the internet status every minute on OSX

#address=  # forced bad address for testing/debugging
address= #
internet=1             # default to internet is up

while true;
    # %a  Day of Week, textual
    # %b  Month, textual, abbreviated
    # %d  Day, numeric
    # %r  Timestamp AM/PM
    echo -n $(date +"%a, %b %d, %r") "-- " 
    ping -c 1 ${address} > /tmp/ping.$
    if [[ $? -ne 0 ]]; then
        if [[ ${internet} -eq 1 ]]; then   # edge trigger -- was up now down
            echo -n $(say "Internet down") # OSX Text-to-Speech
            echo -n "Internet DOWN"
            echo -n "... still down"
        if [[ ${internet} -eq 0 ]]; then     # edge trigger -- was down now up
            echo -n $(say "Internet back up") # OSX Text-To-Speech
    cat /tmp/ping.$ | head -2 | tail -1
    sleep 60 ; # sleep 60 seconds =1 min

How can I generate UUID in C#

I don't know about methods; however, the type to GUID can be done via:

Guid iid = System.Runtime.InteropServices.Marshal.GenerateGuidForType(typeof(IFoo));

What are the benefits of using C# vs F# or F# vs C#?

You're asking for a comparison between a procedural language and a functional language so I feel your question can be answered here: What is the difference between procedural programming and functional programming?

As to why MS created F# the answer is simply: Creating a functional language with access to the .Net library simply expanded their market base. And seeing how the syntax is nearly identical to OCaml, it really didn't require much effort on their part.

Can I add and remove elements of enumeration at runtime in Java

You could try to assign properties to the ENUM you're trying to create and statically contruct it by using a loaded properties file. Big hack, but it works :)

Callback functions in C++

Scott Meyers gives a nice example:

class GameCharacter;
int defaultHealthCalc(const GameCharacter& gc);

class GameCharacter
  typedef std::function<int (const GameCharacter&)> HealthCalcFunc;

  explicit GameCharacter(HealthCalcFunc hcf = defaultHealthCalc)
  : healthFunc(hcf)
  { }

  int healthValue() const { return healthFunc(*this); }

  HealthCalcFunc healthFunc;

I think the example says it all.

std::function<> is the "modern" way of writing C++ callbacks.

oracle varchar to number

If you want formated number then use

SELECT TO_CHAR(number, 'fmt')

SELECT TO_CHAR('123', 999.99)

Result 123.00

LINQ select one field from list of DTO objects to array

I think you're looking for;

  string[] skus = myLines.Select(x => x.Sku).ToArray();

However, if you're going to iterate over the sku's in subsequent code I recommend not using the ToArray() bit as it forces the queries execution prematurely and makes the applications performance worse. Instead you can just do;

  var skus = myLines.Select(x => x.Sku); // produce IEnumerable<string>

  foreach (string sku in skus) // forces execution of the query

Disable future dates after today in Jquery Ui Datepicker

Change maxDate to current date

maxDate: new Date()

It will set current date as maximum value.

I can pass a variable from a JSP scriptlet to JSTL but not from JSTL to a JSP scriptlet without an error

Scripts are raw java embedded in the page code, and if you declare variables in your scripts, then they become local variables embedded in the page.

In contrast, JSTL works entirely with scoped attributes, either at page, request or session scope. You need to rework your scriptlet to fish test out as an attribute:

<c:set var="test" value="test1"/>
  String resp = "abc";
  String test = pageContext.getAttribute("test");
  resp = resp + test;
  pageContext.setAttribute("resp", resp);
<c:out value="${resp}"/>

If you look at the docs for <c:set>, you'll see you can specify scope as page, request or session, and it defaults to page.

Better yet, don't use scriptlets at all: they make the baby jesus cry.

Android custom Row Item for ListView

Use a custom Listview.

You can also customize how row looks by having a custom background. activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android=""
 android:background="#0095FF"> //background color

<ListView android:id="@+id/list"


Define populateString() in MainActivity

 public class MainActivity extends Activity {

   String data_array[];
protected void onCreate(Bundle savedInstanceState) {
            data_array = populateString(); 
    ListView ll = (ListView) findViewById(;
    CustomAdapter cus = new CustomAdapter();

class CustomAdapter extends BaseAdapter
    LayoutInflater mInflater;

    public CustomAdapter()
        mInflater = (LayoutInflater) MainActivity.this.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    public int getCount() {
        // TODO Auto-generated method stub
        return data_array.length;//listview item count. 

    public Object getItem(int position) {
        // TODO Auto-generated method stub
        return position; 

    public long getItemId(int position) {
        // TODO Auto-generated method stub
        return 0;

    public View getView(int position, View convertView, ViewGroup parent) {
        // TODO Auto-generated method stub
        final ViewHolder vh;
        vh= new ViewHolder();

        if(convertView==null )
            convertView=mInflater.inflate(R.layout.row, parent,false);
                    //inflate custom layour
            vh.tv2= (TextView)convertView.findViewById(;

               //vh.tv2.setText("Position = "+position);
                           //set text of second textview based on position

        return convertView;

 class ViewHolder
    TextView tv1,tv2;


row.xml. Custom layout for each row.

<?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android=""
 android:orientation="vertical" >

    android:text="Header" />

    android:text="TextView" />


Inflate a custom layout. Use a view holder for smooth scrolling and performance. The talk is about listview performance by android developers.

enter image description here

Flash CS4 refuses to let go

Use a grep analog to find the strings oldnamespace and Jenine inside the files in your whole project folder. Then you'd know what step to do next.

C++ array initialization

Note that the '=' is optional in C++11 universal initialization syntax, and it is generally considered better style to write :

char myarray[ARRAY_SIZE] {0}

clear javascript console in Google Chrome


That is working

How to capture the screenshot of a specific element rather than entire page using Selenium Webdriver?

Here is a Python 3 version using Selenium webdriver and Pillow. This program captures the screenshot of the whole page and crop the element based on its location. The element image will be available as image.png. Firefox supports saving element image directly using element.screenshot_as_png('image_name').

from selenium import webdriver
from PIL import Image

driver = webdriver.Chrome()

element = driver.find_element_by_id("lst-ib")

location = element.location
size = element.size


x = location['x']
y = location['y']
w = size['width']
h = size['height']
width = x + w
height = y + h

im ='shot.png')
im = im.crop((int(x), int(y), int(width), int(height)))'image.png')


Now chrome also supports individual element screenshots. So you may directly capture the screenshot of the web element as given below.

from selenium import webdriver

driver = webdriver.Chrome()
image = driver.find_element_by_id("lst-ib").screenshot_as_png 
# or
# element = driver.find_element_by_id("lst-ib")
# element.screenshot_as_png("image.png")

Apply Calibri (Body) font to text

There is no such font as “Calibri (Body)”. You probably saw this string in Microsoft Word font selection menu, but it’s not a font name (see e.g. the explanation Font: +body (in W07)).

So use just font-family: Calibri or, better, font-family: Calibri, sans-serif. (There is no adequate backup font for Calibri, but the odds are that when Calibri is not available, the browser’s default sans-serif font suits your design better than the browser’s default font, which is most often a serif font.)

How to return a list of keys from a Hash Map?

Use the keySet() method to return a set with all the keys of a Map.

If you want to keep your Map ordered you can use a TreeMap.

Failed to create provisioning profile

After some time with the same disturbing error and after I write a unique Bundle Identifier and it didn't help, I searched the web and found here that my error was that I selected a virtual device and not an real device. The solution was:

1.I plugged my iPhone

2.I clicked on the button - set the active scheme. and there it was on the top - device iPhone. the error has gone.

enter image description here

How do I programmatically change file permissions?

Apache ant chmod (not very elegant, adding it for completeness) credit shared with @msorsky

    Chmod chmod = new Chmod();
    chmod.setProject(new Project());
    FileSet mySet = new FileSet();
    mySet.setDir(new File("/my/path"));
    chmod.setType(new FileDirBoth());

Plotting images side by side using matplotlib

As per matplotlib's suggestion for image grids:

import matplotlib.pyplot as plt
from mpl_toolkits.axes_grid1 import ImageGrid

fig = plt.figure(figsize=(4., 4.))
grid = ImageGrid(fig, 111,  # similar to subplot(111)
                 nrows_ncols=(2, 2),  # creates 2x2 grid of axes
                 axes_pad=0.1,  # pad between axes in inch.

for ax, im in zip(grid, image_data):
    # Iterating over the grid returns the Axes.

Converting Epoch time into the datetime

Try this:

>>> import time
>>> time.strftime("%Y-%m-%d %H:%M:%S", time.gmtime(1347517119))
'2012-09-12 23:18:39'

Also in MySQL, you can FROM_UNIXTIME like:


For your 2nd question, it is probably because getbbb_class.end_time is a string. You can convert it to numeric like: float(getbbb_class.end_time)

Append text using StreamWriter

using(StreamWriter writer = new StreamWriter("debug.txt", true))
  writer.WriteLine("whatever you text is");

The second "true" parameter tells it to append.

How can I split this comma-delimited string in Python?

How about a list?


It might help if you could explain what kind of info we are looking at. Maybe some background info also?


I had a thought you might want the info in groups of two?

then try:

re.split(r"\d*,\d*", mystring)

and also if you want them into tuples

[(pair[0], pair[1]) for match in re.split(r"\d*,\d*", mystring) for pair in match.split(",")]

in a more readable form:

mylist = []
for match in re.split(r"\d*,\d*", mystring):
    for pair in match.split(",")
        mylist.append((pair[0], pair[1]))

Get checkbox values using checkbox name using jquery

$('[name="CheckboxName"]:checked').each(function () {
    // do stuff

How to create and handle composite primary key in JPA

Key class:

@Access (AccessType.FIELD)
public class EntryKey implements Serializable {

    public EntryKey() {

    public EntryKey(final Long id, final Long version) { = id;
        this.version = version;

    public Long getId() {

    public void setId(Long id) { = id;

    public Long getVersion() {
        return this.version;

    public void setVersion(Long version) {
        this.version = version;

    public boolean equals(Object other) {
        if (this == other)
            return true;
        if (!(other instanceof EntryKey))
            return false;
        EntryKey castOther = (EntryKey) other;
        return id.equals( && version.equals(castOther.version);

    public int hashCode() {
        final int prime = 31;
        int hash = 17;
        hash = hash * prime +;
        hash = hash * prime + this.version.hashCode();
        return hash;

    @Column (name = "ID")
    private Long id;
    @Column (name = "VERSION")
    private Long operatorId;

Entity class:

@Table (name = "YOUR_TABLE_NAME")
public class Entry implements Serializable {

    public EntryKey getKey() {
        return this.key;

    public void setKey(EntryKey id) { = id;


    private EntryKey key;

How can I duplicate it with another Version?

You can detach entity which retrieved from provider, change the key of Entry and then persist it as a new entity.

How to solve error: "Clock skew detected"?

please try to do

make clean

(instead of make), then



Array to Collection: Optimized code

You can use:


Are the days of passing const std::string & as a parameter over?

I've copy/pasted the answer from this question here, and changed the names and spelling to fit this question.

Here is code to measure what is being asked:

#include <iostream>

struct string
    string() {}
    string(const string&) {std::cout << "string(const string&)\n";}
    string& operator=(const string&) {std::cout << "string& operator=(const string&)\n";return *this;}
#if (__has_feature(cxx_rvalue_references))
    string(string&&) {std::cout << "string(string&&)\n";}
    string& operator=(string&&) {std::cout << "string& operator=(string&&)\n";return *this;}


#if PROCESS == 1

do_something(string inval)
    // do stuff
    return inval;

#elif PROCESS == 2

do_something(const string& inval)
    string return_val = inval;
    // do stuff
    return return_val; 

#if (__has_feature(cxx_rvalue_references))

do_something(string&& inval)
    // do stuff
    return std::move(inval);



string source() {return string();}

int main()
    std::cout << "do_something with lvalue:\n\n";
    string x;
    string t = do_something(x);
#if (__has_feature(cxx_rvalue_references))
    std::cout << "\ndo_something with xvalue:\n\n";
    string u = do_something(std::move(x));
    std::cout << "\ndo_something with prvalue:\n\n";
    string v = do_something(source());

For me this outputs:

$ clang++ -std=c++11 -stdlib=libc++ -DPROCESS=1 test.cpp
$ a.out
do_something with lvalue:

string(const string&)

do_something with xvalue:


do_something with prvalue:

$ clang++ -std=c++11 -stdlib=libc++ -DPROCESS=2 test.cpp
$ a.out
do_something with lvalue:

string(const string&)

do_something with xvalue:


do_something with prvalue:


The table below summarizes my results (using clang -std=c++11). The first number is the number of copy constructions and the second number is the number of move constructions:

|    | lvalue | xvalue | prvalue |
| p1 |  1/1   |  0/2   |   0/1   |
| p2 |  1/0   |  0/1   |   0/1   |

The pass-by-value solution requires only one overload but costs an extra move construction when passing lvalues and xvalues. This may or may not be acceptable for any given situation. Both solutions have advantages and disadvantages.

react-router scroll to top on every transition

It is noteable that the onUpdate={() => window.scrollTo(0, 0)} method is outdated.

Here is a simple solution for react-router 4+.

const history = createBrowserHistory()

history.listen(_ => {
    window.scrollTo(0, 0)  

<Router history={history}>

How to increment a pointer address and pointer's value?

        1) Both ++ and * have same precedence(priority), so the associativity comes into picture.
        2) in this case Associativity is from **Right-Left**

        important table to remember in case of pointers and arrays: 

        operators           precedence        associativity

    1)  () , []                1               left-right
    2)  *  , identifier        2               right-left
    3)  <data type>            3               ----------

        let me give an example, this might help;

        char **str;
        str = (char **)malloc(sizeof(char*)*2); // allocate mem for 2 char*
        str[0]=(char *)malloc(sizeof(char)*10); // allocate mem for 10 char
        str[1]=(char *)malloc(sizeof(char)*10); // allocate mem for 10 char

        strcpy(str[0],"abcd");  // assigning value
        strcpy(str[1],"efgh");  // assigning value

            cout<<*str<<endl;   // printing the string
            *str++;             // incrementing the address(pointer)
                                // check above about the prcedence and associativity

Receiving "Attempted import error:" in react app

i had the same issue, but I just typed export on top and erased the default one on the bottom. Scroll down and check the comments.

import React, { Component } from "react";

export class Counter extends Component { // type this  
export default Counter; // this is eliminated  

Generate list of all possible permutations of a string

It's better to use backtracking

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

void swap(char *a, char *b) {
    char temp;
    temp = *a;
    *a = *b;
    *b = temp;

void print(char *a, int i, int n) {
    int j;
    if(i == n) {
        printf("%s\n", a);
    } else {
        for(j = i; j <= n; j++) {
            swap(a + i, a + j);
            print(a, i + 1, n);
            swap(a + i, a + j);

int main(void) {
    char a[100];
    print(a, 0, strlen(a) - 1);
    return 0;

How do I delete unpushed git commits?

If you want to move that commit to another branch, get the SHA of the commit in question

git rev-parse HEAD

Then switch the current branch

git checkout other-branch

And cherry-pick the commit to other-branch

git cherry-pick <sha-of-the-commit>

Is there a way to specify which pytest tests to run from a file?

My answer provides a ways to run a subset of test in different scenarios.

Run all tests in a project


Run tests in a Single Directory

To run all the tests from one directory, use the directory as a parameter to pytest:

pytest tests/my-directory

Run tests in a Single Test File/Module

To run a file full of tests, list the file with the relative path as a parameter to pytest:

pytest tests/my-directory/

Run a Single Test Function

To run a single test function, add :: and the test function name:

pytest -v tests/my-directory/

-v is used so you can see which function was run.

Run a Single Test Class

To run just a class, do like we did with functions and add ::, then the class name to the file parameter:

pytest -v tests/my-directory/

Run a Single Test Method of a Test Class

If you don't want to run all of a test class, just one method, just add another :: and the method name:

pytest -v tests/my-directory/

Run a Set of Tests Based on Test Name

The -k option enables you to pass in an expression to run tests that have certain names specified by the expression as a substring of the test name. It is possible to use and, or, and not to create complex expressions.

For example, to run all of the functions that have _raises in their name:

pytest -v -k _raises

Hashmap holding different data types as values for instance Integer, String and Object

Define a class to store your data first

public class YourDataClass {

    private String messageType;
    private Timestamp timestamp;
    private int count;
    private int version;

    // your get/setters

And then initialize your map:

Map<Integer, YourDataClass> map = new HashMap<Integer, YourDataClass>();

SET NAMES utf8 in MySQL?

Not only PDO. If sql answer like '????' symbols, preset of you charset (hope UTF-8) really recommended:

if (!$mysqli->set_charset("utf8")) 
 { printf("Can't set utf8: %s\n", $mysqli->error); }

or via procedure style mysqli_set_charset($db,"utf8")

Reading and writing to serial port in C on Linux

1) I'd add a /n after init. i.e. write( USB, "init\n", 5);

2) Double check the serial port configuration. Odds are something is incorrect in there. Just because you don't use ^Q/^S or hardware flow control doesn't mean the other side isn't expecting it.

3) Most likely: Add a "usleep(100000); after the write(). The file-descriptor is set not to block or wait, right? How long does it take to get a response back before you can call read? (It has to be received and buffered by the kernel, through system hardware interrupts, before you can read() it.) Have you considered using select() to wait for something to read()? Perhaps with a timeout?

Edited to Add:

Do you need the DTR/RTS lines? Hardware flow control that tells the other side to send the computer data? e.g.

int tmp, serialLines;

cout << "Dropping Reading DTR and RTS\n";
ioctl ( readFd, TIOCMGET, & serialLines );
serialLines &= ~TIOCM_DTR;
serialLines &= ~TIOCM_RTS;
ioctl ( readFd, TIOCMSET, & serialLines );
ioctl ( readFd, TIOCMGET, & tmp );
cout << "Reading DTR status: " << (tmp & TIOCM_DTR) << endl;
sleep (2);

cout << "Setting Reading DTR and RTS\n";
serialLines |= TIOCM_DTR;
serialLines |= TIOCM_RTS;
ioctl ( readFd, TIOCMSET, & serialLines );
ioctl ( readFd, TIOCMGET, & tmp );
cout << "Reading DTR status: " << (tmp & TIOCM_DTR) << endl;

Using the grep and cut delimiter command (in bash shell scripting UNIX) - and kind of "reversing" it?

You don't need to change the delimiter to display the right part of the string with cut.

The -f switch of the cut command is the n-TH element separated by your delimiter : :, so you can just type :

 grep puddle2_1557936 | cut -d ":" -f2

Another solutions (adapt it a bit) if you want fun :

Using :

grep -oP 'puddle2_1557936:\K.*' <<< 'puddle2_1557936:/home/rogers.williams/folderz/puddle2'                                                                        

or still with look around

grep -oP '(?<=puddle2_1557936:).*' <<< 'puddle2_1557936:/home/rogers.williams/folderz/puddle2'                                                                    

or with :

perl -lne '/puddle2_1557936:(.*)/ and print $1' <<< 'puddle2_1557936:/home/rogers.williams/folderz/puddle2'                                                      

or using (thanks to glenn jackman)

ruby -F: -ane '/puddle2_1557936/ and puts $F[1]' <<< 'puddle2_1557936:/home/rogers.williams/folderz/puddle2'

or with :

awk -F'puddle2_1557936:' '{print $2}'  <<< 'puddle2_1557936:/home/rogers.williams/folderz/puddle2'

or with :

python -c 'import sys; print(sys.argv[1].split("puddle2_1557936:")[1])' 'puddle2_1557936:/home/rogers.williams/folderz/puddle2'

or using only :

IFS=: read _ a <<< "puddle2_1557936:/home/rogers.williams/folderz/puddle2"
echo "$a"

or using in a :

var x = 'puddle2_1557936:/home/rogers.williams/folderz/puddle2'

or using in a :

php -r 'preg_match("/puddle2_1557936:(.*)/", $argv[1], $m); echo "$m[1]\n";' 'puddle2_1557936:/home/rogers.williams/folderz/puddle2' 

how to increase MaxReceivedMessageSize when calling a WCF from C#

Change the customBinding in the web.config to use larger defaults. I picked 2MB as it is a reasonable size. Of course setting it to 2GB (as your code suggests) will work but it does leave you more vulnerable to attacks. Pick a size that is larger than your largest request but isn't overly large.

Check this : Using Large Message Requests in Silverlight with WCF

       <behavior name="TestLargeWCF.Web.MyServiceBehavior">
         <serviceMetadata httpGetEnabled="true"/>
         <serviceDebug includeExceptionDetailInFaults="false"/>
       <binding name="customBinding0">
         <binaryMessageEncoding />
         <!-- Start change -->
         <httpTransport maxReceivedMessageSize="2097152"
         <!-- Stop change -->
   <serviceHostingEnvironment aspNetCompatibilityEnabled="true"/>
     <service behaviorConfiguration="Web.MyServiceBehavior" name="TestLargeWCF.Web.MyService">
       <endpoint address=""
       <endpoint address="mex"

Writing handler for UIAlertAction

Instead of self in your handler, put (alert: UIAlertAction!). This should make your code look like this

    alert.addAction(UIAlertAction(title: "Okay",
                          style: UIAlertActionStyle.Default,
                        handler: {(alert: UIAlertAction!) in println("Foo")}))

this is the proper way to define handlers in Swift.

As Brian pointed out below, there are also easier ways to define these handlers. Using his methods is discussed in the book, look at the section titled Closures

How to see indexes for a database or table in MySQL?

To see the index for a specific table use SHOW INDEX:

SHOW INDEX FROM yourtable;

To see indexes for all tables within a specific schema you can use the STATISTICS table from INFORMATION_SCHEMA:

WHERE TABLE_SCHEMA = 'your_schema';

Removing the where clause will show you all indexes in all schemas.

jQuery form input select by id

For example like this:

var value = $("#a").find("#b").val()

SQL Server : SUM() of multiple rows including where clauses

Try this:

   SUM(Amount) as TOTAL_COSTS
   EndDate IS NULL

CSS ''background-color" attribute not working on checkbox inside <div>

The Best solution to change background checkbox color

input[type=checkbox] {_x000D_
    margin-right: 5px;_x000D_
    cursor: pointer;_x000D_
    font-size: 14px;_x000D_
    width: 15px;_x000D_
    height: 12px;_x000D_
    position: relative;_x000D_
  input[type=checkbox]:after {_x000D_
    position: absolute;_x000D_
    width: 10px;_x000D_
    height: 15px;_x000D_
    top: 0;_x000D_
    content: " ";_x000D_
    background-color: #ff0000;_x000D_
    color: #fff;_x000D_
    display: inline-block;_x000D_
    visibility: visible;_x000D_
    padding: 0px 3px;_x000D_
    border-radius: 3px;_x000D_
  input[type=checkbox]:checked:after {_x000D_
   content: "?";_x000D_
   font-size: 12px;_x000D_
  <input type="checkbox" name="vehicle" value="Bike"> I have a bike<br>_x000D_
  <input type="checkbox" name="vehicle" value="Car" checked> I have a car<br>_x000D_
  <input type="checkbox" name="vehicle" value="Car" checked> I have a bus<br>

How to use a Bootstrap 3 glyphicon in an html select

To my knowledge the only way to achieve this in a native select would be to use the unicode representations of the font. You'll have to apply the glyphicon font to the select and as such can't mix it with other fonts. However, glyphicons include regular characters, so you can add text. Unfortunately setting the font for individual options doesn't seem to be possible.

<select class="form-control glyphicon">
    <option value="">&#x2212; &#x2212; &#x2212; Hello</option>
    <option value="glyphicon-list-alt">&#xe032; Text</option>

Here's a list of the icons with their unicode:

Converting A String To Hexadecimal In Java

Using Multiple Peoples help from multiple Threads..

I know this has been answered, but i would like to give a full encode & decode method for any others in my same situation..

Here's my Encoding & Decoding methods..

// Global Charset Encoding
public static Charset encodingType = StandardCharsets.UTF_8;

// Text To Hex
public static String textToHex(String text)
    byte[] buf = null;
    buf = text.getBytes(encodingType);
    char[] HEX_CHARS = "0123456789abcdef".toCharArray();
    char[] chars = new char[2 * buf.length];
    for (int i = 0; i < buf.length; ++i)
        chars[2 * i] = HEX_CHARS[(buf[i] & 0xF0) >>> 4];
        chars[2 * i + 1] = HEX_CHARS[buf[i] & 0x0F];
    return new String(chars);

// Hex To Text
public static String hexToText(String hex)
    int l = hex.length();
    byte[] data = new byte[l / 2];
    for (int i = 0; i < l; i += 2)
        data[i / 2] = (byte) ((Character.digit(hex.charAt(i), 16) << 4)
            + Character.digit(hex.charAt(i + 1), 16));
    String st = new String(data, encodingType);
    return st;

How do I use namespaces with TypeScript external modules?

Candy Cup Analogy

Version 1: A cup for every candy

Let's say you wrote some code like this:


export namespace A {
    export class Twix { ... }


export namespace A {
    export class PeanutButterCup { ... }


export namespace A {
     export class KitKat { ... }

You've created this setup: enter image description here

Each module (sheet of paper) gets its own cup named A. This is useless - you're not actually organizing your candy here, you're just adding an additional step (taking it out of the cup) between you and the treats.

Version 2: One cup in the global scope

If you weren't using modules, you might write code like this (note the lack of export declarations):


namespace A {
    export class Twix { ... }


namespace A {
    export class PeanutButterCup { ... }


namespace A {
     export class KitKat { ... }

This code creates a merged namespace A in the global scope:

enter image description here

This setup is useful, but doesn't apply in the case of modules (because modules don't pollute the global scope).

Version 3: Going cupless

Going back to the original example, the cups A, A, and A aren't doing you any favors. Instead, you could write the code as:


export class Twix { ... }


export class PeanutButterCup { ... }


export class KitKat { ... }

to create a picture that looks like this:

enter image description here

Much better!

Now, if you're still thinking about how much you really want to use namespace with your modules, read on...

These Aren't the Concepts You're Looking For

We need to go back to the origins of why namespaces exist in the first place and examine whether those reasons make sense for external modules.

Organization: Namespaces are handy for grouping together logically-related objects and types. For example, in C#, you're going to find all the collection types in System.Collections. By organizing our types into hierarchical namespaces, we provide a good "discovery" experience for users of those types.

Name Conflicts: Namespaces are important to avoid naming collisions. For example, you might have My.Application.Customer.AddForm and My.Application.Order.AddForm -- two types with the same name, but a different namespace. In a language where all identifiers exist in the same root scope and all assemblies load all types, it's critical to have everything be in a namespace.

Do those reasons make sense in external modules?

Organization: External modules are already present in a file system, necessarily. We have to resolve them by path and filename, so there's a logical organization scheme for us to use. We can have a /collections/generic/ folder with a list module in it.

Name Conflicts: This doesn't apply at all in external modules. Within a module, there's no plausible reason to have two objects with the same name. From the consumption side, the consumer of any given module gets to pick the name that they will use to refer to the module, so accidental naming conflicts are impossible.

Even if you don't believe that those reasons are adequately addressed by how modules work, the "solution" of trying to use namespaces in external modules doesn't even work.

Boxes in Boxes in Boxes

A story:

Your friend Bob calls you up. "I have a great new organization scheme in my house", he says, "come check it out!". Neat, let's go see what Bob has come up with.

You start in the kitchen and open up the pantry. There are 60 different boxes, each labelled "Pantry". You pick a box at random and open it. Inside is a single box labelled "Grains". You open up the "Grains" box and find a single box labelled "Pasta". You open the "Pasta" box and find a single box labelled "Penne". You open this box and find, as you expect, a bag of penne pasta.

Slightly confused, you pick up an adjacent box, also labelled "Pantry". Inside is a single box, again labelled "Grains". You open up the "Grains" box and, again, find a single box labelled "Pasta". You open the "Pasta" box and find a single box, this one is labelled "Rigatoni". You open this box and find... a bag of rigatoni pasta.

"It's great!" says Bob. "Everything is in a namespace!".

"But Bob..." you reply. "Your organization scheme is useless. You have to open up a bunch of boxes to get to anything, and it's not actually any more convenient to find anything than if you had just put everything in one box instead of three. In fact, since your pantry is already sorted shelf-by-shelf, you don't need the boxes at all. Why not just set the pasta on the shelf and pick it up when you need it?"

"You don't understand -- I need to make sure that no one else puts something that doesn't belong in the 'Pantry' namespace. And I've safely organized all my pasta into the Pantry.Grains.Pasta namespace so I can easily find it"

Bob is a very confused man.

Modules are Their Own Box

You've probably had something similar happen in real life: You order a few things on Amazon, and each item shows up in its own box, with a smaller box inside, with your item wrapped in its own packaging. Even if the interior boxes are similar, the shipments are not usefully "combined".

Going with the box analogy, the key observation is that external modules are their own box. It might be a very complex item with lots of functionality, but any given external module is its own box.

Guidance for External Modules

Now that we've figured out that we don't need to use 'namespaces', how should we organize our modules? Some guiding principles and examples follow.

Export as close to top-level as possible

  • If you're only exporting a single class or function, use export default:


export default class SomeType {
  constructor() { ... }


function getThing() { return 'thing'; }
export default getThing;


import t from './MyClass';
import f from './MyFunc';
var x = new t();

This is optimal for consumers. They can name your type whatever they want (t in this case) and don't have to do any extraneous dotting to find your objects.

  • If you're exporting multiple objects, put them all at top-level:


export class SomeType { ... }
export function someFunc() { ... }


import * as m from './MyThings';
var x = new m.SomeType();
var y = m.someFunc();
  • If you're exporting a large number of things, only then should you use the module/namespace keyword:


export namespace Animals {
  export class Dog { ... }
  export class Cat { ... }
export namespace Plants {
  export class Tree { ... }


import { Animals, Plants} from './MyLargeModule';
var x = new Animals.Dog();

Red Flags

All of the following are red flags for module structuring. Double-check that you're not trying to namespace your external modules if any of these apply to your files:

  • A file whose only top-level declaration is export module Foo { ... } (remove Foo and move everything 'up' a level)
  • A file that has a single export class or export function that isn't export default
  • Multiple files that have the same export module Foo { at top-level (don't think that these are going to combine into one Foo!)

Is either GET or POST more secure than the other?

Even if POST gives no real security benefit versus GET, for login forms or any other form with relatively sensitive information, make sure you are using POST as:

  1. The information POSTed will not be saved in the user's history.
  2. The sensitive information (password, etc.) sent in the form will not be visible later on in the URL bar (by using GET, it will be visible in the history and the URL bar).

Also, GET has a theorical limit of data. POST doesn't.

For real sensitive info, make sure to use SSL (HTTPS)

Remove IE10's "clear field" X button on certain inputs?

Style the ::-ms-clear pseudo-element for the box:

.someinput::-ms-clear {
    display: none;

Is it possible to program Android to act as physical USB keyboard?

I have some experience here as a user. The most obvious solution is via tcp/ip via a client/server model. Many of the tools out there like airkeyboard ( utilize this method for creating a keyboard/mouse replacement using a smartphone os. Note that there are some security issues that become apparent in the implementation. For instance, you must be logged in to utilize the server componenents.

Other cross platform tools (ie windows/mac controlling another windows/mac instance) utilize a similar approach. See synergy:

React-router v4 this.props.history.push(...) not working

Seems like an old question but still relevant.

I think it is a blocked update issue.

The main problem is the new URL (route) is supposed to be rendered by the same component(Costumers) as you are currently in (current URL).

So solution is rather simple, make the window url as a prop, so react has a chance to detect the prop change (therefore the url change), and act accordingly.

A nice usecase described in the official react blog called Recommendation: Fully uncontrolled component with a key.

So the solution is to change from render() { return( <ul>

to render() { return( <ul key={this.props.location.pathname}>

So whenever the location changed by react-router, the component got scrapped (by react) and a new one gets initiated with the right values (by react).

Oh, and pass the location as prop to the component(Costumers) where the redirect will happen if it is not passed already.

Hope it helps someone.

How do I remove a specific element from a JSONArray?

You can use reflection

A Chinese website provides a relevant solution:
If you don't understand Chinese, please try to read it with the translation software.

He provides this code for the old version:

public void JSONArray_remove(int index, JSONArray JSONArrayObject) throws Exception{
    if(index < 0)
    Field valuesField=JSONArray.class.getDeclaredField("values");
    List<Object> values=(List<Object>)valuesField.get(JSONArrayObject);
    if(index >= values.size())

CSS hide scroll bar if not needed

You can use both .content and .container to overflow:auto. Means if it's text is exceed automatically scroll will come x-axis and y-axis. (no need to give separete x-axis and y-axis commonly give overflow:auto)

.content {overflow:auto;}

How to insert text in a td with id, using JavaScript

There are several options... assuming you found your TD by var td = document.getElementyById('myTD_ID'); you can do:

  • td.innerHTML = "mytext";

  • td.textContent= "mytext";

  • td.innerText= "mytext"; - this one may not work outside IE? Not sure

  • Use firstChild or children array as previous poster noted.

If it's just the text that needs to be changed, textContent is faster and less prone to XSS attacks (

What are the minimum margins most printers can handle?

For every PostScript printer, one part of its driver is an ASCII file called PostScript Printer Description (PPD). PPDs are used in the CUPS printing system on Linux and Mac OS X as well even for non-PostScript printers.

Every PPD MUST, according to the PPD specification written by Adobe, contain definitions of a *ImageableArea (that's a PPD keyword) for each and every media sizes it can handle. That value is given for example as *ImageableArea Folio/8,25x13: "12 12 583 923" for one printer in this office here, and *ImageableArea Folio/8,25x13: "0 0 595 935" for the one sitting in the next room.

These figures mean "Lower left corner is at (12|12), upper right corner is at (583|923)" (where these figures are measured in points; 72pt == 1inch). Can you see that the first printer does print with a margin of 1/6 inch? -- Can you also see that the next one can even print borderless?

What you need to know is this: Even if the printer can do very small margins physically, if the PPD *ImageableArea is set to a wider margin, the print data generated by the driver and sent to the printer will be clipped according to the PPD setting -- not by the printer itself.

These days more and more models appear on the market which can indeed print edge-to-edge. This is especially true for office laser printers. (Don't know about devices for the home use market.) Sometimes you have to enable that borderless mode with a separate switch in the driver settings, sometimes also on the device itself (front panel, or web interface).

Older models, for example HP's, define in their PPDs their margines quite generously, just to be on the supposedly "safe side". Very often HP used 1/3, 1/2 inch or more (like "24 24 588 768" for Letter format). I remember having hacked HP PPDs and tuned them down to "6 6 606 786" (1/12 inch) before the physical boundaries of the device kicked in and enforced a real clipping of the page image.

Now, PCL and other language printers are not that much different in their margin capabilities from PostScript models.

But of course, when it comes to printing of PDF docs, here you can nearly always choose "print to fit" or similarly named options. Even for a file that itself does not use any margins. That "fit" is what the PDF viewer reads from the driver, and the viewer then scales down the page to the *ImageableArea.

SVN - Checksum mismatch while updating

In case you are using SVN 1.7+ there is a workaround described here.

Just to recap:

  1. Go to the folder with the file causing problems
  2. Execute command svn update --set-depth empty (note: this will delete your files, so make a copy first!)
  3. Execute command svn update --set-depth infinity

How to check is Apache2 is stopped in Ubuntu?

You can also type "top" and look at the list of running processes.

CSS Input with width: 100% goes outside parent's bound

I tried these solutions but never got a conclusive result. In the end I used proper semantic markup with a fieldset. It saved having to add any width calculations and any box-sizing.

It also allows you to set the form width as you require and the inputs remain within the padding you need for your edges.

In this example I have put a border on the form and fieldset and an opaque background on the legend and fieldset so you can see how they overlap and sit with each other.

    form {
      width: 300px;
      margin: 0 auto;
      border: 1px solid;
    fieldset {
      border: 0;
      margin: 0;
      padding: 0 20px 10px;
      border: 1px solid blue;
      background: rgba(0,0,0,.2);
    legend {
      background: rgba(0,0,0,.2);
      width: 100%;
      margin: 0 -20px;
      padding: 2px 20px;
      color: $col1;
      border: 0;
    button {
      width: 100%;
      margin: 0 0 10px;
      padding: 0 10px;
    input[type="password"] {
      line-height: 22px;
      font-size: 16px;
    button {
    line-height: 26px;
    font-size: 20px;
          <legend>Log in</legend>
          <p>You may need some content here, a message?</p>
          <input type="email" id="email" name="email" placeholder="Email" value=""/>
          <input type="password" id="password" name="password" placeholder="password" value=""/>
          <button type="submit">Login</button>

Inserting Image Into BLOB Oracle 10g

You cannot access a local directory from pl/sql. If you use bfile, you will setup a directory (create directory) on the server where Oracle is running where you will need to put your images.

If you want to insert a handful of images from your local machine, you'll need a client side app to do this. You can write your own, but I typically use Toad for this. In schema browser, click onto the table. Click the data tab, and hit + sign to add a row. Double click the BLOB column, and a wizard opens. The far left icon will load an image into the blob:

enter image description here

SQL Developer has a similar feature. See the "Load" link below:

enter image description here

If you need to pull images over the wire, you can do it using pl/sql, but its not straight forward. First, you'll need to setup ACL list access (for security reasons) to allow a user to pull over the wire. See this article for more on ACL setup.

Assuming ACL is complete, you'd pull the image like this:

    l_url varchar2(4000) := '';
    l_http_request   UTL_HTTP.req;
    l_http_response  UTL_HTTP.resp;
    l_raw RAW(2000);
    l_blob BLOB;
   -- Important: setup ACL access list first!

    DBMS_LOB.createtemporary(l_blob, FALSE);

    l_http_request  := UTL_HTTP.begin_request(l_url);
    l_http_response := UTL_HTTP.get_response(l_http_request);

  -- Copy the response into the BLOB.
      UTL_HTTP.read_raw(l_http_response, l_raw, 2000);
      DBMS_LOB.writeappend (l_blob, UTL_RAW.length(l_raw), l_raw);
    WHEN UTL_HTTP.end_of_body THEN

  insert into my_pics (pic_id, pic) values (102, l_blob);


Hope that helps.

Displaying all table names in php from MySQL database

The brackets that are commonly used in the mysql documentation for examples should be ommitted in a 'real' query.

It also doesn't appear that you're echoing the result of the mysql query anywhere. mysql_query returns a mysql resource on success. The php manual page also includes instructions on how to load the mysql result resource into an array for echoing and other manipulation.

Get and set position with jQuery .offset()

I recommend another option. jQuery UI has a new position feature that allows you to position elements relative to each other. For complete documentation and demo see:

Here's one way to position your elements using the position feature:

var options = {
    "my": "top left",
    "at": "top left",
    "of": ".layer1"

How to pass all arguments passed to my bash script to a function of mine?

The $@ variable expands to all command-line parameters separated by spaces. Here is an example.

abc "$@"

When using $@, you should (almost) always put it in double-quotes to avoid misparsing of arguments containing spaces or wildcards (see below). This works for multiple arguments. It is also portable to all POSIX-compliant shells.

It is also worth nothing that $0 (generally the script's name or path) is not in $@.

The Bash Reference Manual Special Parameters Section says that $@ expands to the positional parameters starting from one. When the expansion occurs within double quotes, each parameter expands to a separate word. That is "$@" is equivalent to "$1" "$2" "$3"....

Passing some arguments:

If you want to pass all but the first arguments, you can first use shift to "consume" the first argument and then pass "$@" to pass the remaining arguments to another command. In bash (and zsh and ksh, but not in plain POSIX shells like dash), you can do this without messing with the argument list using a variant of array slicing: "${@:3}" will get you the arguments starting with "$3". "${@:3:4}" will get you up to four arguments starting at "$3" (i.e. "$3" "$4" "$5" "$6"), if that many arguments were passed.

Things you probably don't want to do:

"$*" gives all of the arguments stuck together into a single string (separated by spaces, or whatever the first character of $IFS is). This looses the distinction between spaces within arguments and the spaces between arguments, so is generally a bad idea. Although it might be ok for printing the arguments, e.g. echo "$*", provided you don't care about preserving the space within/between distinction.

Assigning the arguments to a regular variable (as in args="$@") mashes all the arguments together just like "$*" does. If you want to store the arguments in a variable, use an array with args=("$@") (the parentheses make it an array), and then reference them as e.g. "${args[0]}" etc (note that bash array indexes start at 0, so $1 will be in args[0], etc).

Leaving off the double-quotes, with either $@ or $*, will try to split each argument up into separate words (based on whitespace or whatever's in $IFS), and also try to expand anything that looks like a filename wildcard into a list of matching filenames. This can have really weird effects, and should almost always be avoided.

Capture key press (or keydown) event on DIV element

Here example on plain JS:

document.querySelector('#myDiv').addEventListener('keyup', function (e) {_x000D_
#myDiv {_x000D_
  outline: none;_x000D_
<div _x000D_
  Press me and start typing_x000D_

How to set the value for Radio Buttons When edit?

When you populate your fields, you can check for the value:

<input type="radio" name="sex" value="Male" <?php echo ($sex=='Male')?'checked':'' ?>size="17">Male
<input type="radio" name="sex" value="Female" <?php echo ($sex=='Female')?'checked':'' ?> size="17">Female

Assuming that the value you return from your database is in the variable $sex

The checked property will preselect the value that match

How do I POST an array of objects with $.ajax (jQuery or Zepto)

edit: I guess it's now starting to be safe to use the native JSON.stringify() method, supported by most browsers (yes, even IE8+ if you're wondering).

As simple as:


You should encode you data in JSON before sending it, you can't just send an object like this as POST data.

I recommand using the jQuery json plugin to do so. You can then use something like this in jQuery:

$.post(_saveDeviceUrl, {
    data : $.toJSON(postData)
}, function(response){
    //Process your response here

Get array elements from index to end

The [:-1] removes the last element. Instead of




You can read up on Python slicing notation here: Explain Python's slice notation

NumPy slicing is an extension of that. The NumPy tutorial has some coverage: Indexing, Slicing and Iterating.

AWS Lambda import module error in python

Your package directories in your zip must be world readable too.

To identify if this is your problem (Linux) use:

find $ZIP_SOURCE -type d -not -perm /001 -printf %M\ "%p\n"

To fix use:

find $ZIP_SOURCE  -type d -not -perm /001 -exec chmod o+x {} \;

File readable is also a requirement. To identify if this is your problem use:

find $ZIP_SOURCE -type f -not -perm /004 -printf %M\ "%p\n"

To fix use:

find $ZIP_SOURCE  -type f -not -perm /004 -exec chmod o+r {} \;

If you had this problem and you are working in Linux, check that umask is appropriately set when creating or checking out of git your python packages e.g. put this in you packaging script or .bashrc:

umask 0002 

Cleanest way to toggle a boolean variable in Java?

The class BooleanUtils supportes the negation of a boolean. You find this class in commons-lang:commons-lang


Lodash .clone and .cloneDeep behaviors

Thanks to Gruff Bunny and Louis' comments, I found the source of the issue.

As I use Backbone.js too, I loaded a special build of Lodash compatible with Backbone and Underscore that disables some features. In this example:

var clone = _.clone(data, true);

data[1].values.d = 'x';

I just replaced the Underscore build with the Normal build in my Backbone application and the application is still working. So I can now use the Lodash .clone with the expected behaviour.

Edit 2018: the Underscore build doesn't seem to exist anymore. If you are reading this in 2018, you could be interested by this documentation (Backbone and Lodash).

How to set -source 1.7 in Android Studio and Gradle

You can change it in new Android studio version(0.8.X)

FIle-> Other Settings -> Default Settings -> Compiler (Expand it by clicking left arrow) -> Java Compiler -> You can change the Project bytecode version here

enter image description here

Python: How would you save a simple settings/config file?

Save and load a dictionary. You will have arbitrary keys, values and arbitrary number of key, values pairs.

onchange event on input type=range is not triggering in firefox while dragging

For a good cross-browser behavior, and understandable code, best is to use the onchange attribute in combination of a form:

function showVal(){
  valBox.innerHTML = inVal.value;
<form onchange="showVal()">
  <input type="range" min="5" max="10" step="1" id="inVal">

<span id="valBox"></span>

The same using oninput, the value is changed directly.

function showVal(){
  valBox.innerHTML = inVal.value;
<form oninput="showVal()">
  <input type="range" min="5" max="10" step="1" id="inVal">

<span id="valBox"></span>

Reverting single file in SVN to a particular revision

You want to do

svn merge -r [revision to revert from]:[revision to revert to] [path/filename]

Once you do that, you will have that revision of the file in a committable state. Commit the file.

Run a Command Prompt command from Desktop Shortcut

The solutions turned out to be very simple.

  1. Open text edit

  2. Write the command, save as .bat.

  3. Double click the file created and the command automatically starts running in command-prompt.

enter image description here

How do I make a composite key with SQL Server Management Studio?

create table myTable 
    Column1 int not null,
    Column2 int not null

    ADD  PRIMARY KEY (Column1,Column2)

How to clear cache of Eclipse Indigo

I think you can find the answer you want in these two posts. They are mentioning Flash Builder, but essentially, the talk is about its Eclipse base.

Clear improperly cached compile errors in FlexBuilder:

How to fix Flash Builder broken workspace:

ORA-01034: ORACLE not available ORA-27101: shared memory realm does not exist

I hit the same shared memory realm does not exist symptom (on Windows) but for a different reason. I had just installed Oracle (XE) and after some troubleshooting, established that my installation was corrupt due to the presence of an ORACLE_HOME environment property at the time I installed it.

If this is TLDR, skip to 'So to resolve:'!

My initial symptom was:

Message 850 not found; No message file for product=NETWORK, facility=NL

Apparently the Windows install reads the ORACLE_HOME from the registry and doesn't need (and certainly in my case shouldn't have...) an environment property.

Remove it, as follows:

  1. Edit the system environment settings (Windows key and start typing 'env' and you should see this option come up.
  2. Delete any User and System Environment Variables called ORACLE_HOME, if present. (make a note of their values, mainly out of interest, but may be of use if you want to put them back for some reason!)
  3. Restart your machine. Don't muck around with just a log off - restart your machine. The Windows Oracle install uses Windows services by default and your installation is currently very bad - it needs a restart.

Following the restart I was then able to get error messages other than 'No message file...' and could start looking at what the issue was. Setting the ORACLE_SID to XE and connecting @XE I got as far as the errors in this page, namely the following symptoms:

ORA-01034: ORACLE not available
ORA-27101: shared memory realm does not exist

Another symptom was: When launching the 'Get started' page it failed to connect, giving a not found error (if I recall correctly), despite the Windows listener & XE services being started. As noted in another answer, this could be due to the windows services not being started. In my case those services were started, so something else was misconfigured.

At this point, I figured maybe my install had just gone so badly wrong due to the presence of my bad ORACLE_HOME environment property that I should reinstall. (Previous reinstalls hadn't helped, but those had all been before I noticed the ORACLE_HOME system environment property (probably set up by me a year ago!).

So to resolve:

  1. Close any app looking at the Oraclexe install directory (editors/explorer/cmd prompts)
  2. A quick trip to Add/Remove programs and uninstall OracleXe
  3. Double-check you have no ORACLE_HOME environment property set anywhere, remember - Windows will use registry entries to get it.
  4. Restart (take no chances - we're in this for the long term!)
  5. Did you make sure there was no ORACLE_HOME property?
  6. Run the Oracle installer again (as local admin account if applicable)
  7. You should be able to rejoice in a working install. I did, at least!

How does Go update third-party packages?

Since the question mentioned third-party libraries and not all packages then you probably want to fall back to using wildcards.

A use case being: I just want to update all my packages that are obtained from the Github VCS, then you would just say:

go get -u // ('...' being the wildcard). 

This would go ahead and only update your github packages in the current $GOPATH

Same applies for within a VCS too, say you want to only upgrade all the packages from ogranizaiton A's repo's since as they have released a hotfix you depend on:

go get -u

Should IBOutlets be strong or weak under ARC?

Be aware, IBOutletCollection should be @property (strong, nonatomic).

How can I implement custom Action Bar with custom buttons in Android?

1 You can use a drawable

<menu xmlns:android="">
    <item android:id="@+id/menu_item1"
        android:showAsAction="ifRoom" />

2 Create a style for the action bar and use a custom background:

    <!-- the theme applied to the application or activity -->
    <style name="CustomActivityTheme" parent="@android:style/Theme.Holo">
        <item name="android:actionBarStyle">@style/MyActionBar</item>
        <!-- other activity and action bar styles here -->
    <!-- style for the action bar backgrounds -->
    <style name="MyActionBar" parent="@android:style/Widget.Holo.ActionBar">
        <item name="android:background">@drawable/background</item>
        <item name="android:backgroundStacked">@drawable/background</item>
        <item name="android:backgroundSplit">@drawable/split_background</item>

3 Style again android:actionBarDivider

The android documentation is very usefull for that.

Open Source HTML to PDF Renderer with Full CSS Support

This command line tool is the business!

It uses webkit rendering engine(used in safari and KDE), I tested it on some complex sites and it was by far better than any other tool.

Laravel - Session store not set on request

If Cas Bloem's answer does not apply (i.e. you've definitely got the web middleware on the applicable route), you might want to check the order of middlewares in your HTTP Kernel.

The default order in Kernel.php is this:

$middlewareGroups = [
    'web' => [

Note that VerifyCsrfToken comes after StartSession. If you've got these in a different order, the dependency between them can also lead to the Session store not set on request. exception.

C# How to change font of a label

Font.Name, Font.XYZProperty, etc are readonly as Font is an immutable object, so you need to specify a new Font object to replace it:

mainForm.lblName.Font = new Font("Arial", mainForm.lblName.Font.Size);

Check the constructor of the Font class for further options.

PHP Include for HTML?

Here is the step by step process to include php code in html file ( Tested )

If PHP is working there is only one step left to use PHP scripts in files with *.html or *.htm extensions as well. The magic word is ".htaccess". Please see the Wikipedia definition of .htaccess to learn more about it. According to Wikipedia it is "a directory-level configuration file that allows for decentralized management of web server configuration."

You can probably use such a .htaccess configuration file for your purpose. In our case you want the webserver to parse HTML files like PHP files.

First, create a blank text file and name it ".htaccess". You might ask yourself why the file name starts with a dot. On Unix-like systems this means it is a dot-file is a hidden file. (Note: If your operating system does not allow file names starting with a dot just name the file "xyz.htaccess" temporarily. As soon as you have uploaded it to your webserver in a later step you can rename the file online to ".htaccess") Next, open the file with a simple text editor like the "Editor" in MS Windows. Paste the following line into the file: AddType application/x-httpd-php .html .htm If this does not work, please remove the line above from your file and paste this alternative line into it, for PHP5: AddType application/x-httpd-php5 .html .htm Now upload the .htaccess file to the root directory of your webserver. Make sure that the name of the file is ".htaccess". Your webserver should now parse *.htm and *.html files like PHP files.

You can try if it works by creating a HTML-File like the following. Name it "php-in-html-test.htm", paste the following code into it and upload it to the root directory of your webserver:

    <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
 <TITLE>Use PHP in HTML files</TITLE>

    <?php echo "It works!"; ?>

Try to open the file in your browser by typing in: (once again, please replace by your own domain...) If your browser shows the phrase "It works!" everything works fine and you can use PHP in .*html and *.htm files from now on. However, if not, please try to use the alternative line in the .htaccess file as we showed above. If is still does not work please contact your hosting provider.

PHP validation/regex for URL

Use the filter_var() function to validate whether a string is URL or not:

var_dump(filter_var('', FILTER_VALIDATE_URL));

It is bad practice to use regular expressions when not necessary.

EDIT: Be careful, this solution is not unicode-safe and not XSS-safe. If you need a complex validation, maybe it's better to look somewhere else.

Largest and smallest number in an array

It is a long time. Maybe like this:

    public int smallestValue(int[] values)
        int smallest = int.MaxValue;

        for (int i = 0; i < values.Length; i++)
            smallest = (values[i] < smallest ? values[i] : smallest);

        return smallest;

    public static int largestvalue(int[] values)
        int largest = int.MinValue;

        for (int i = 0; i < values.Length; i++)
            largest = (values[i] > largest ? values[i] : largest);

        return largest;

remove attribute display:none; so the item will be visible

You should remove "style" attribute instead of "display" property :