SyntaxFix

Programs & Examples On #Optionparser

Global environment variables in a shell script

source myscript.sh is also feasible.

Description for linux command source:

source is a Unix command that evaluates the file following the command, 
as a list of commands, executed in the current context

Check if a key is down?

Ended up here to check if there was something builtin to the browser already, but it seems there isn't. This is my solution (very similar to Robert's answer):

"use strict";

const is_key_down = (() => {
    const state = {};

    window.addEventListener('keyup', (e) => state[e.key] = false);
    window.addEventListener('keydown', (e) => state[e.key] = true);

    return (key) => state.hasOwnProperty(key) && state[key] || false;
})();

You can then check if a key is pressed with is_key_down('ArrowLeft').

what is difference between success and .done() method of $.ajax

success only fires if the AJAX call is successful, i.e. ultimately returns a HTTP 200 status. error fires if it fails and complete when the request finishes, regardless of success.

In jQuery 1.8 on the jqXHR object (returned by $.ajax) success was replaced with done, error with fail and complete with always.

However you should still be able to initialise the AJAX request with the old syntax. So these do similar things:

// set success action before making the request
$.ajax({
  url: '...',
  success: function(){
    alert('AJAX successful');
  }
});

// set success action just after starting the request
var jqxhr = $.ajax( "..." )
  .done(function() { alert("success"); });

This change is for compatibility with jQuery 1.5's deferred object. Deferred (and now Promise, which has full native browser support in Chrome and FX) allow you to chain asynchronous actions:

$.ajax("parent").
    done(function(p) { return $.ajax("child/" + p.id); }).
    done(someOtherDeferredFunction).
    done(function(c) { alert("success: " + c.name); });

This chain of functions is easier to maintain than a nested pyramid of callbacks you get with success.

However, please note that done is now deprecated in favour of the Promise syntax that uses then instead:

$.ajax("parent").
    then(function(p) { return $.ajax("child/" + p.id); }).
    then(someOtherDeferredFunction).
    then(function(c) { alert("success: " + c.name); }).
    catch(function(err) { alert("error: " + err.message); });

This is worth adopting because async and await extend promises improved syntax (and error handling):

try {
    var p = await $.ajax("parent");
    var x = await $.ajax("child/" + p.id);
    var c = await someOtherDeferredFunction(x);
    alert("success: " + c.name);
}
catch(err) { 
    alert("error: " + err.message); 
}

Error :- java runtime environment JRE or java development kit must be available in order to run eclipse

I got the same error after a Java version update. I just edited the line after "-vm" in the eclipse.ini file, which was pointing to the older and no more existing jre path, and everything worked fine.

The cause of "bad magic number" error when loading a workspace and how to avoid it?

The magic number comes from UNIX-type systems where the first few bytes of a file held a marker indicating the file type.

This error indicates you are trying to load a non-valid file type into R. For some reason, R no longer recognizes this file as an R workspace file.

Image.open() cannot identify image file - Python?

I had a same issue.

from PIL import Image

instead of

import Image

fixed the issue

HTML embed autoplay="false", but still plays automatically

the below codes helped me with the same problem. Let me know if it helped. 

<!DOCTYPE html>
<html>
<body>


<audio controls>

<source src="YOUR AUDIO FILE" type="audio/mpeg">
Your browser does not support the audio element.
</audio>



</body>
</html>

React.js: Set innerHTML vs dangerouslySetInnerHTML

Based on (dangerouslySetInnerHTML).

It's a prop that does exactly what you want. However they name it to convey that it should be use with caution

Add button to navigationbar programmatically

Try this.It work for me. Add button to navigation bar programmatically, Also we set image to navigation bar button,

Below is Code:-

  UIBarButtonItem *Savebtn=[[UIBarButtonItem alloc]initWithImage:
  [[UIImage imageNamed:@"bt_save.png"]imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal] 
  style:UIBarButtonItemStylePlain target:self action:@selector(SaveButtonClicked)];
  self.navigationItem.rightBarButtonItem=Savebtn;

  -(void)SaveButtonClicked
  {
    // Add save button code.
  }

Find specific string in a text file with VBS script

I'd recommend using a regular expressions instead of string operations for this:

Set fso = CreateObject("Scripting.FileSystemObject")

filename = "C:\VBS\filediprova.txt"

newtext = vbLf & "<tr><td><a href=""..."">Beginning_of_DD_TC5</a></td></tr>"

Set re = New RegExp
re.Pattern = "(\n.*?Test Case \d)"
re.Global  = False
re.IgnoreCase = True

text = f.OpenTextFile(filename).ReadAll
f.OpenTextFile(filename, 2).Write re.Replace(text, newText & "$1")

The regular expression will match a line feed (\n) followed by a line containing the string Test Case followed by a number (\d), and the replacement will prepend that with the text you want to insert (variable newtext). Setting re.Global = False makes the replacement stop after the first match.

If the line breaks in your text file are encoded as CR-LF (carriage return + line feed) you'll have to change \n into \r\n and vbLf into vbCrLf.

If you have to modify several text files, you could do it in a loop like this:

For Each f In fso.GetFolder("C:\VBS").Files
  If LCase(fso.GetExtensionName(f.Name)) = "txt" Then
    text = f.OpenAsTextStream.ReadAll
    f.OpenAsTextStream(2).Write re.Replace(text, newText & "$1")
  End If
Next

How does Zalgo text work?

The text uses combining characters, also known as combining marks. See section 2.11 of Combining Characters in the Unicode Standard (PDF).

In Unicode, character rendering does not use a simple character cell model where each glyph fits into a box with given height. Combining marks may be rendered above, below, or inside a base character

So you can easily construct a character sequence, consisting of a base character and “combining above” marks, of any length, to reach any desired visual height, assuming that the rendering software conforms to the Unicode rendering model. Such a sequence has no meaning of course, and even a monkey could produce it (e.g., given a keyboard with suitable driver).

And you can mix “combining above” and “combining below” marks.

The sample text in the question starts with:

Call asynchronous method in constructor?

Try to replace this:

myLongList.ItemsSource = writings;

with this

Dispatcher.BeginInvoke(() => myLongList.ItemsSource = writings);

Ubuntu: OpenJDK 8 - Unable to locate package

UPDATE: installation without root privileges below

I advise you to not install packages manually on ubuntu system if there is already a (semi-official) repository able to solve your problem. Further, use Oracle JDK for development, just to avoid (very sporadic) compatibility issues (i've tried many years ago, it's surely better now).

Add the webupd8 repo to your system:

sudo add-apt-repository ppa:webupd8team/java
sudo apt-get update

Install your preferred version of jdk (versions from java-6 to java-9 available):

sudo apt-get install oracle-java8-installer

You can also install multiple version of jdk, mixing openjdk and oracle versions. Then you can use the command update-java-alternatives to switch between installed version:

# list available jdk
update-java-alternatives --list

# use jdk7
sudo update-java-alternatives --set java-7-oracle

# use jdk8
sudo update-java-alternatives --set java-8-oracle

Requirements

If you get add-apt-repository: command not found be sure to have software-properties-common installed:

sudo apt-get install software-properties-common

If you're using an older version Ubuntu:

sudo apt-get install python-software-properties

JDK installation without root privileges

If you haven't administrator rights on your target machine your simplest bet is to use sdkman to install the zulu certified openjdk:

curl -s "https://get.sdkman.io" | bash
source "$HOME/.sdkman/bin/sdkman-init.sh"
sdk install java

NOTE: sdkman allow to install also the official Oracle JDK, although it's not a the default option. View available versions with:

sdk ls java

Install the chosen version with:

sdk install java <version>

For example:

sdk install java 9.0.1-oracle

Glossary of commands

  • sudo <command> [command_arguments]: execute a command with the superuser privilege.

  • add-apt-repository <PPA_id>: Ubuntu (just like every Debian derivatives and generally speaking every Linux distribution) has a main repository of packages that handle things like package dependencies and updating. In Ubuntu is possible to extend the main repository using a PPA (Personal Package Archive) that usually contains packages not available in the system (just like oracle jdk) or updated versions of available ones (example: LibreOffice 5 in LTS is available only through this PPA).

  • apt-get [install|update|upgrade|purge|...]: it's "the" command-line package handler used to manipulate the state of every repository on the system (installing / updating / upgrading can be viewed as an alteration of the repository current state).

In our case: with the command sudo add-apt-repository ppa:webupd8team/java we inform the system that the next repository update must retrieve packages information also from webupd8 repo.

With sudo apt-get update we actually update the system repository (all this operations requires superuser privileges, so we prepend sudo to the commands).

sudo apt-get install oracle-java8-installer

  • update-java-alternatives (a specific java version of update-alternatives): in Ubuntu several packages provides the same functionality (browse the internet, compile mails, edit a text file or provides java/javac executables...). To allows the system to choose the user favourites tool given a specific task a mechanism using symlinks under /etc/alternatives/ is used. Try to update the jdk as indicated above (switch between java 7 and java 8) and view how change the output of this command:

    ls -l /etc/alternatives/java*

In our case: sudo update-java-alternatives --set java-8-oracle update symlinks under /etc/alternatives to point to java-8-oracle executables.

Extras:

  • man <command>: start using man to read a really well written and detailed help on (almost) every shell command and its options (every command i mention in this little answer has a man page, try man update-java-alternatives).

  • apt-cache search <search_key>: query the APT cache to search for a package related with the search_key provided (can be the package name or some word in package description).

  • apt-cache show <package>: provides APT information for a specific package (package version, installed or not, description).

setting min date in jquery datepicker

basically if you already specify the year range there is no need to use mindate and maxdate if only year is required

Get only the Date part of DateTime in mssql

We can use this method:

CONVERT(VARCHAR(10), GETDATE(), 120)

Last parameter changes the format to only to get time or date in specific formats.

MySQL - Operand should contain 1 column(s)

 
(SELECT users.username AS posted_by,
users.id AS posted_by_id
FROM users
WHERE users.id = posts.posted_by)

Here you using sub-query but this sub-query must return only one column. Separate it otherwise it will shows error.

How to resize JLabel ImageIcon?

Try this :

ImageIcon imageIcon = new ImageIcon("./img/imageName.png"); // load the image to a imageIcon
Image image = imageIcon.getImage(); // transform it 
Image newimg = image.getScaledInstance(120, 120,  java.awt.Image.SCALE_SMOOTH); // scale it the smooth way  
imageIcon = new ImageIcon(newimg);  // transform it back

(found it here)

Java String to JSON conversion

You are getting NullPointerException as the "output" is null when the while loop ends. You can collect the output in some buffer and then use it, something like this-

    StringBuilder buffer = new StringBuilder();
    String output;
    System.out.println("Output from Server .... \n");
    while ((output = br.readLine()) != null) {
        System.out.println(output);
        buffer.append(output);
    }
    output = buffer.toString(); // now you have the output
    conn.disconnect();

Example JavaScript code to parse CSV data

csvToArray v1.3

A compact (645 bytes), but compliant function to convert a CSV string into a 2D array, conforming to the RFC4180 standard.

https://code.google.com/archive/p/csv-to-array/downloads

Common Usage: jQuery

 $.ajax({
        url: "test.csv",
        dataType: 'text',
        cache: false
 }).done(function(csvAsString){
        csvAsArray=csvAsString.csvToArray();
 });

Common usage: JavaScript

csvAsArray = csvAsString.csvToArray();

Override field separator

csvAsArray = csvAsString.csvToArray("|");

Override record separator

csvAsArray = csvAsString.csvToArray("", "#");

Override Skip Header

csvAsArray = csvAsString.csvToArray("", "", 1);

Override all

csvAsArray = csvAsString.csvToArray("|", "#", 1);

How to execute multiple commands in a single line

Googling gives me this:

Command A & Command B

Execute Command A, then execute Command B (no evaluation of anything)

Command A | Command B

Execute Command A, and redirect all its output into the input of Command B

Command A && Command B

Execute Command A, evaluate the errorlevel after running and if the exit code (errorlevel) is 0, only then execute Command B

Command A || Command B

Execute Command A, evaluate the exit code of this command and if it's anything but 0, only then execute Command B

Change URL parameters

Another variation on Sujoy's answer. Just changed the variable names & added a namespace wrapper:

window.MyNamespace = window.MyNamespace  || {};
window.MyNamespace.Uri = window.MyNamespace.Uri || {};

(function (ns) {

    ns.SetQueryStringParameter = function(url, parameterName, parameterValue) {

        var otherQueryStringParameters = "";

        var urlParts = url.split("?");

        var baseUrl = urlParts[0];
        var queryString = urlParts[1];

        var itemSeparator = "";
        if (queryString) {

            var queryStringParts = queryString.split("&");

            for (var i = 0; i < queryStringParts.length; i++){

                if(queryStringParts[i].split('=')[0] != parameterName){

                    otherQueryStringParameters += itemSeparator + queryStringParts[i];
                    itemSeparator = "&";
                }
            }
        }

        var newQueryStringParameter = itemSeparator + parameterName + "=" + parameterValue;

        return baseUrl + "?" + otherQueryStringParameters + newQueryStringParameter;
    };

})(window.MyNamespace.Uri);

Useage is now:

var changedUrl = MyNamespace.Uri.SetQueryStringParameter(originalUrl, "CarType", "Ford");

What is a JavaBean exactly?

Just a little background/update on the bean concept. Many other answers actually have the what but not so much why of them.

They were invented early on in Java as part of building GUIs. They followed patterns that were easy for tools to pull apart letting them create a properties panel so you could edit the attributes of the Bean. In general, the Bean properties represented a control on the screen (Think x,y,width,height,text,..)

You can also think of it as a strongly typed data structure.

Over time these became useful for lots of tools that used the same type of access (For example, Hibernate to persist data structures to the database)

As the tools evolved, they moved more towards annotations and away from pulling apart the setter/getter names. Now most systems don't require beans, they can take any plain old Java object with annotated properties to tell them how to manipulate them.

Now I see beans as annotated property balls--they are really only useful for the annotations they carry.

Beans themselves are not a healthy pattern. They destroy encapsulation by their nature since they expose all their properties to external manipulation and as they are used there is a tendency (by no means a requirement) to create code to manipulate the bean externally instead of creating code inside the bean (violates "don't ask an object for its values, ask an object to do something for you"). Using annotated POJOs with minimal getters and no setters is much more OO restoring encapsulation and with the possibility of immutability.

By the way, as all this stuff was happening someone extended the concept to something called Enterprise Java Beans. These are... different. and they are complicated enough that many people felt they didn't understand the entire Bean concept and stopped using the term. This is, I think, why you generally hear beans referred to as POJOs (since every Java object is a POJO this is technically OK, but when you hear someone say POJO they are most often thinking about something that follows the bean pattern)

How to draw an empty plot?

There is an interest in your solution that plot.new() hasn't though: in the empty plot you "draw" you can write text at specified coordinates with text(x = ..., y = ..., your_text).

PermissionError: [Errno 13] in python

For me, I was writing to a file that is opened in Excel.

Making custom right-click context menus for my web-app

You can watch this tutorial: http://www.youtube.com/watch?v=iDyEfKWCzhg Make sure the context menu is hidden at first and has a position of absolute. This will ensure that there won't be multiple context menu and useless creation of context menu. The link to the page is placed in the description of the YouTube video.

$(document).bind("contextmenu", function(event){
$("#contextmenu").css({"top": event.pageY +  "px", "left": event.pageX +  "px"}).show();
});
$(document).bind("click", function(){
$("#contextmenu").hide();
});

Why does CreateProcess give error 193 (%1 is not a valid Win32 app)

Your Button2Click and Button3Click functions pass klad.xls and smimime.txt. These files most likely aren't actual executables indeed.

In order to open arbitrary files using the application associated with them, use ShellExecute

curl: (6) Could not resolve host: google.com; Name or service not known

Issues were:

  1. IPV6 enabled
  2. Wrong DNS server

Here is how I fixed it:

IPV6 Disabling

  • Open Terminal
  • Type su and enter to log in as the super user
  • Enter the root password
  • Type cd /etc/modprobe.d/ to change directory to /etc/modprobe.d/
  • Type vi disableipv6.conf to create a new file there
  • Press Esc + i to insert data to file
  • Type install ipv6 /bin/true on the file to avoid loading IPV6 related modules
  • Type Esc + : and then wq for save and exit
  • Type reboot to restart fedora
  • After reboot open terminal and type lsmod | grep ipv6
  • If no result, it means you properly disabled IPV6

Add Google DNS server

  • Open Terminal
  • Type su and enter to log in as the super user
  • Enter the root password
  • Type cat /etc/resolv.conf to check what DNS server your Fedora using. Mostly this will be your Modem IP address.
  • Now we have to Find a powerful DNS server. Luckily there is a open DNS server maintain by Google.
  • Go to this page and find out what are the "Google Public DNS IP addresses"
  • Today those are 8.8.8.8 and 8.8.4.4. But in future those may change.
  • Type vi /etc/resolv.conf to edit the resolv.conf file
  • Press Esc + i for insert data to file
  • Comment all the things in the file by inserting # at the begin of the each line. Do not delete anything because can be useful in future.

  • Type below two lines in the file

    nameserver 8.8.8.8
    nameserver 8.8.4.4

    -Type Esc + : and then wq for save and exit

  • Now you are done and everything works fine (Not necessary to restart).
  • But every time when you restart the computer your /etc/resolv.conf will be replaced by default. So I'll let you find a way to avoid that.

Here is my blog post about this: http://codeketchup.blogspot.sg/2014/07/how-to-fix-curl-6-could-not-resolve.html

Why can't I inherit static classes?

Citation from here:

This is actually by design. There seems to be no good reason to inherit a static class. It has public static members that you can always access via the class name itself. The only reasons I have seen for inheriting static stuff have been bad ones, such as saving a couple of characters of typing.

There may be reason to consider mechanisms to bring static members directly into scope (and we will in fact consider this after the Orcas product cycle), but static class inheritance is not the way to go: It is the wrong mechanism to use, and works only for static members that happen to reside in a static class.

(Mads Torgersen, C# Language PM)

Other opinions from channel9

Inheritance in .NET works only on instance base. Static methods are defined on the type level not on the instance level. That is why overriding doesn't work with static methods/properties/events...

Static methods are only held once in memory. There is no virtual table etc. that is created for them.

If you invoke an instance method in .NET, you always give it the current instance. This is hidden by the .NET runtime, but it happens. Each instance method has as first argument a pointer (reference) to the object that the method is run on. This doesn't happen with static methods (as they are defined on type level). How should the compiler decide to select the method to invoke?

(littleguru)

And as a valuable idea, littleguru has a partial "workaround" for this issue: the Singleton pattern.

Java Compare Two List's object values?

I found a very basic example of List comparison at List Compare This example verifies the size first and then checks the availability of the particular element of one list in another.

WebApi's {"message":"an error has occurred"} on IIS7, not in IIS Express

My swagger XML file was not deployed into \bin:

GlobalConfiguration.Configuration
  .EnableSwagger(c =>
  {
    c.SingleApiVersion("v1", "SwaggerDemoApi");
    c.IncludeXmlComments(string.Format(@"{0}\bin\SwaggerDemoApi.XML", 
                         System.AppDomain.CurrentDomain.BaseDirectory));
    c.DescribeAllEnumsAsStrings();
  })

http://wmpratt.com/swagger-and-asp-net-web-api-part-1/

enter image description here

It had to be set in the Release Configuration as well as in the Debug Configuration.

How to secure RESTful web services?

There's another, very secure method. It's client certificates. Know how servers present an SSL Cert when you contact them on https? Well servers can request a cert from a client so they know the client is who they say they are. Clients generate certs and give them to you over a secure channel (like coming into your office with a USB key - preferably a non-trojaned USB key).

You load the public key of the cert client certificates (and their signer's certificate(s), if necessary) into your web server, and the web server won't accept connections from anyone except the people who have the corresponding private keys for the certs it knows about. It runs on the HTTPS layer, so you may even be able to completely skip application-level authentication like OAuth (depending on your requirements). You can abstract a layer away and create a local Certificate Authority and sign Cert Requests from clients, allowing you to skip the 'make them come into the office' and 'load certs onto the server' steps.

Pain the neck? Absolutely. Good for everything? Nope. Very secure? Yup.

It does rely on clients keeping their certificates safe however (they can't post their private keys online), and it's usually used when you sell a service to clients rather then letting anyone register and connect.

Anyway, it may not be the solution you're looking for (it probably isn't to be honest), but it's another option.

Visual Studio Code pylint: Unable to import 'protorpc'

I had same problem for pyodbc , I had two version of python on my Ubuntu (python3.8 and python3.9), problem was: package installed on python3.8 location but my interpreter was for python3.9. i installed python3.8 interpreter in command palette and it fixed.

How do I post button value to PHP?

As Josh has stated above, you want to give each one the same name (letter, button, etc.) and all of them work. Then you want to surround all of these with a form tag:

<form name="myLetters" action="yourScript.php" method="POST">
<!-- Enter your values here with the following syntax: -->
<input type="radio" name="letter" value="A" /> A
<!-- Then add a submit value & close your form -->
<input type="submit" name="submit" value="Choose Letter!" />
</form>

Then, in the PHP script "yourScript.php" as defined by the action attribute, you can use:

$_POST['letter']

To get the value chosen.

How to check whether an object is a date?

Inspired by this answer, this solution works in my case(I needed to check whether the value recieved from API is a date or not):

!isNaN(Date.parse(new Date(YourVariable)))

This way, if it is some random string coming from a client, or any other object, you can find out if it is a Date-like object.

expected assignment or function call: no-unused-expressions ReactJS

In my case, I got the error on the setState line:

increment(){
  this.setState(state => {
    count: state.count + 1
  });
}

I changed it to this, now it works

increment(){
  this.setState(state => {
    const count = state.count + 1

    return {
      count
    };
  });
}

What browsers support HTML5 WebSocket API?

Client side

  • Hixie-75:
    • Chrome 4.0 + 5.0
    • Safari 5.0.0
  • HyBi-00/Hixie-76:
  • HyBi-07+:
  • HyBi-10:
    • Chrome 14.0 + 15.0
    • Firefox 7.0 + 8.0 + 9.0 + 10.0 - prefixed: MozWebSocket
    • IE 10 (from Windows 8 developer preview)
  • HyBi-17/RFC 6455
    • Chrome 16
    • Firefox 11
    • Opera 12.10 / Opera Mobile 12.1

Any browser with Flash can support WebSocket using the web-socket-js shim/polyfill.

See caniuse for the current status of WebSockets support in desktop and mobile browsers.

See the test reports from the WS testsuite included in Autobahn WebSockets for feature/protocol conformance tests.

Server side

It depends on which language you use.

In Java/Java EE:

Some other Java implementations:

In C#:

In PHP:

In Python:

In C:

In Node.js:

  • Socket.io : Socket.io also has serverside ports for Python, Java, Google GO, Rack
  • sockjs : sockjs also has serverside ports for Python, Java, Erlang and Lua
  • WebSocket-Node - Pure JavaScript Client & Server implementation of HyBi-10.

Vert.x (also known as Node.x) : A node like polyglot implementation running on a Java 7 JVM and based on Netty with :

  • Support for Ruby(JRuby), Java, Groovy, Javascript(Rhino/Nashorn), Scala, ...
  • True threading. (unlike Node.js)
  • Understands multiple network protocols out of the box including: TCP, SSL, UDP, HTTP, HTTPS, Websockets, SockJS as fallback for WebSockets

Pusher.com is a Websocket cloud service accessible through a REST API.

DotCloud cloud platform supports Websockets, and Java (Jetty Servlet Container), NodeJS, Python, Ruby, PHP and Perl programming languages.

Openshift cloud platform supports websockets, and Java (Jboss, Spring, Tomcat & Vertx), PHP (ZendServer & CodeIgniter), Ruby (ROR), Node.js, Python (Django & Flask) plateforms.

For other language implementations, see the Wikipedia article for more information.

The RFC for Websockets : RFC6455

How to remove unused imports in Intellij IDEA on commit?

You can check checkbox in the commit dialog.

enter image description here

You can use settings to automatically optimize imports since 11.1 and above.

enter image description here

PHP Warning: Unknown: failed to open stream

It is a SELinux blocking issue, Linux prevented httpd access. Here is the solution:

# restorecon '/var/www/html/wiki/index.php'
# restorecon -R '/var/www/html/wiki/index.php'
# /sbin/restorecon '/var/www/html/wiki/index.php'

How to loop through a checkboxlist and to find what's checked and not checked?

I think the best way to do this is to use CheckedItems:

 foreach (DataRowView objDataRowView in CheckBoxList.CheckedItems)
 {
     // use objDataRowView as you wish                
 }

XmlDocument - load from string?

 
XmlDocument doc = new XmlDocument();
doc.LoadXml(str);

Where str is your XML string. See the MSDN article for more info.

What is the difference between SessionState and ViewState?

Usage: If you're going to store information that you want to access on different web pages, you can use SessionState

If you want to store information that you want to access from the same page, then you can use Viewstate

Storage The Viewstate is stored within the page itself (in encrypted text), while the Sessionstate is stored in the server.

The SessionState will clear in the following conditions

  1. Cleared by programmer
  2. Cleared by user
  3. Timeout

What is the difference between char s[] and char *s?

Given the declarations

char *s0 = "hello world";
char s1[] = "hello world";

assume the following hypothetical memory map:

                    0x01  0x02  0x03  0x04
        0x00008000: 'h'   'e'   'l'   'l'
        0x00008004: 'o'   ' '   'w'   'o'
        0x00008008: 'r'   'l'   'd'   0x00
        ...
s0:     0x00010000: 0x00  0x00  0x80  0x00
s1:     0x00010004: 'h'   'e'   'l'   'l'
        0x00010008: 'o'   ' '   'w'   'o'
        0x0001000C: 'r'   'l'   'd'   0x00

The string literal "hello world" is a 12-element array of char (const char in C++) with static storage duration, meaning that the memory for it is allocated when the program starts up and remains allocated until the program terminates. Attempting to modify the contents of a string literal invokes undefined behavior.

The line

char *s0 = "hello world";

defines s0 as a pointer to char with auto storage duration (meaning the variable s0 only exists for the scope in which it is declared) and copies the address of the string literal (0x00008000 in this example) to it. Note that since s0 points to a string literal, it should not be used as an argument to any function that would try to modify it (e.g., strtok(), strcat(), strcpy(), etc.).

The line

char s1[] = "hello world";

defines s1 as a 12-element array of char (length is taken from the string literal) with auto storage duration and copies the contents of the literal to the array. As you can see from the memory map, we have two copies of the string "hello world"; the difference is that you can modify the string contained in s1.

s0 and s1 are interchangeable in most contexts; here are the exceptions:

sizeof s0 == sizeof (char*)
sizeof s1 == 12

type of &s0 == char **
type of &s1 == char (*)[12] // pointer to a 12-element array of char

You can reassign the variable s0 to point to a different string literal or to another variable. You cannot reassign the variable s1 to point to a different array.

Postgresql tables exists, but getting "relation does not exist" when querying

The error can be caused by access restrictions. Solution:

GRANT ALL PRIVILEGES ON DATABASE my_database TO my_user;

Accessing UI (Main) Thread safely in WPF

Use [Dispatcher.Invoke(DispatcherPriority, Delegate)] to change the UI from another thread or from background.

Step 1. Use the following namespaces

using System.Windows;
using System.Threading;
using System.Windows.Threading;

Step 2. Put the following line where you need to update UI

Application.Current.Dispatcher.Invoke(DispatcherPriority.Background, new ThreadStart(delegate
{
    //Update UI here
}));

Syntax

[BrowsableAttribute(false)]
public object Invoke(
  DispatcherPriority priority,
  Delegate method
)

Parameters

priority

Type: System.Windows.Threading.DispatcherPriority

The priority, relative to the other pending operations in the Dispatcher event queue, the specified method is invoked.

method

Type: System.Delegate

A delegate to a method that takes no arguments, which is pushed onto the Dispatcher event queue.

Return Value

Type: System.Object

The return value from the delegate being invoked or null if the delegate has no return value.

Version Information

Available since .NET Framework 3.0

CSS: Creating textured backgrounds

You should try slicing the image if possible into a smaller piece which could be repeated. I have sliced that image to a 101x101px image.

BG Tile

CSS:

body{
  background-image: url(SO_texture_bg.jpg);
  background-repeat:repeat;
}

But in some cases, we wouldn't be able to slice the image to a smaller one. In that case, I would use the whole image. But you could also use the CSS3 methods like what Mustafa Kamal had mentioned.

Wish you good luck.

How to pass table value parameters to stored procedure from .net code

Use this code to create suitable parameter from your type:

private SqlParameter GenerateTypedParameter(string name, object typedParameter)
{
    DataTable dt = new DataTable();

    var properties = typedParameter.GetType().GetProperties().ToList();
    properties.ForEach(p =>
    {
        dt.Columns.Add(p.Name, Nullable.GetUnderlyingType(p.PropertyType) ?? p.PropertyType);
    });
    var row = dt.NewRow();
    properties.ForEach(p => { row[p.Name] = (p.GetValue(typedParameter) ?? DBNull.Value); });
    dt.Rows.Add(row);

    return new SqlParameter
    {
        Direction = ParameterDirection.Input,
        ParameterName = name,
        Value = dt,
        SqlDbType = SqlDbType.Structured
    };
}

Django: List field in model?

You can flatten the list and then store the values to a CommaSeparatedIntegerField. When you read back from the database, just group the values back into threes.

Disclaimer: according to database normalization theory, it is better not to store collections in single fields; instead you would be encouraged to store the values in those triplets in their own fields and link them via foreign keys. In the real world, though, sometimes that is too cumbersome/slow.

XPath query to get nth instance of an element

This seems to work:

/descendant::input[@id="search_query"][2]

I go this from "XSLT 2.0 and XPath 2.0 Programmer's Reference, 4th Edition" by Michael Kay.

There is also a note in the "Abbreviated Syntax" section of the XML Path Language specification http://www.w3.org/TR/xpath/#path-abbrev that provided a clue.

Python SQL query string formatting

Using 'sqlparse' library we can format the sqls.

>>> import sqlparse
>>> raw = 'select * from foo; select * from bar;'
>>> print(sqlparse.format(raw, reindent=True, keyword_case='upper'))
SELECT *
FROM foo;

SELECT *
FROM bar;

Ref: https://pypi.org/project/sqlparse/

Python Matplotlib figure title overlaps axes label when using twiny

I'm not sure whether it is a new feature in later versions of matplotlib, but at least for 1.3.1, this is simply:

plt.title(figure_title, y=1.08)

This also works for plt.suptitle(), but not (yet) for plt.xlabel(), etc.

Wait for async task to finish

This will never work, because the JS VM has moved on from that async_call and returned the value, which you haven't set yet.

Don't try to fight what is natural and built-in the language behaviour. You should use a callback technique or a promise.

function f(input, callback) {
    var value;

    // Assume the async call always succeed
    async_call(input, function(result) { callback(result) };

}

The other option is to use a promise, have a look at Q. This way you return a promise, and then you attach a then listener to it, which is basically the same as a callback. When the promise resolves, the then will trigger.

How to unzip a file in Powershell?

In PowerShell v5+, there is an Expand-Archive command (as well as Compress-Archive) built in:

Expand-Archive c:\a.zip -DestinationPath c:\a

How to get an input text value in JavaScript

The reason that this doesn't work is because the variable doesn't change with the textbox. When it initially runs the code it gets the value of the textbox, but afterwards it isn't ever called again. However, when you define the variable in the function, every time that you call the function the variable updates. Then it alerts the variable which is now equal to the textbox's input.

How to square or raise to a power (elementwise) a 2D numpy array?

The fastest way is to do a*a or a**2 or np.square(a) whereas np.power(a, 2) showed to be considerably slower.

np.power() allows you to use different exponents for each element if instead of 2 you pass another array of exponents. From the comments of @GarethRees I just learned that this function will give you different results than a**2 or a*a, which become important in cases where you have small tolerances.

I've timed some examples using NumPy 1.9.0 MKL 64 bit, and the results are shown below:

In [29]: a = np.random.random((1000, 1000))

In [30]: timeit a*a
100 loops, best of 3: 2.78 ms per loop

In [31]: timeit a**2
100 loops, best of 3: 2.77 ms per loop

In [32]: timeit np.power(a, 2)
10 loops, best of 3: 71.3 ms per loop

How to add `style=display:"block"` to an element using jQuery?

If you need to add multiple then you can do it like this:

$('#element').css({
    'margin-left': '5px',
    'margin-bottom': '-4px',
    //... and so on
});

As a good practice I would also put the property name between quotes to allow the dash since most styles have a dash in them. If it was 'display', then quotes are optional but if you have a dash, it will not work without the quotes. Anyways, to make it simple: always enclose them in quotes.

Creating a UICollectionView programmatically

 
    #pragma mark -
    #pragma mark - UICollectionView Datasource and Delegates

    -(NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView
    {
        return 1;
    }

    -(NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
    {
        return Arr_AllCulturalButtler.count;
    }

    -(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
    {
        static NSString *coll=@"FromCulturalbutlerCollectionViewCell";
        FromCulturalbutlerCollectionViewCell *cell=[collectionView dequeueReusableCellWithReuseIdentifier:coll forIndexPath:indexPath];
        cell.lbl_categoryname.text=[[Arr_AllCulturalButtler objectAtIndex:indexPath.row] Category_name];
        cell.lbl_date.text=[[Arr_AllCulturalButtler objectAtIndex:indexPath.row] event_Start_date];
        cell.lbl_location.text=[[Arr_AllCulturalButtler objectAtIndex:indexPath.row] Location_name];
        [cell.Img_Event setImageWithURL:[APPDELEGATE getURLForMediumSizeImage:[(EventObj *)[Arr_AllCulturalButtler objectAtIndex:indexPath.row] Event_image_name]] placeholderImage:nil usingActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
        cell.button_Bookmark.selected=[[Arr_AllCulturalButtler objectAtIndex:indexPath.row] Event_is_bookmarked];
        [cell.button_Bookmark addTarget:self action:@selector(btn_bookmarkClicked:) forControlEvents:UIControlEventTouchUpInside];
        cell.button_Bookmark.tag=indexPath.row;


        return cell;
    }
    - (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath
    {

        [self performSegueWithIdentifier:SEGUE_CULTURALBUTLER_KULTURELLIS_DETAIL sender:self];
    }

// stroy board navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    if ([segue.identifier isEqualToString:@"Overview_Register"])
    {
        WDRegisterViewController *obj=(WDRegisterViewController *)[segue destinationViewController];
        obj.str_Title=@"Edit Profile";
        obj.isRegister=NO;
    }
}

            [self performSegueWithIdentifier:@"Overview_Measure" sender:nil];



    UIStoryboard *sb = [UIStoryboard storyboardWithName:@"Main" bundle:nil];
    WDPeekViewController *Peek = (WDPeekViewController *)[sb instantiateViewControllerWithIdentifier:@"WDPeekViewController"];
 [self.navigationController pushViewController:tabBarController animated:YES];

How can I verify if an AD account is locked?

I found also this list of property flags: How to use the UserAccountControl flags

SCRIPT  0x0001  1
ACCOUNTDISABLE  0x0002  2
HOMEDIR_REQUIRED    0x0008  8
LOCKOUT 0x0010  16
PASSWD_NOTREQD  0x0020  32
PASSWD_CANT_CHANGE 0x0040   64
ENCRYPTED_TEXT_PWD_ALLOWED  0x0080  128
TEMP_DUPLICATE_ACCOUNT  0x0100  256
NORMAL_ACCOUNT  0x0200  512
INTERDOMAIN_TRUST_ACCOUNT   0x0800  2048
WORKSTATION_TRUST_ACCOUNT   0x1000  4096
SERVER_TRUST_ACCOUNT    0x2000  8192
DONT_EXPIRE_PASSWORD    0x10000 65536
MNS_LOGON_ACCOUNT   0x20000 131072
SMARTCARD_REQUIRED  0x40000 262144
TRUSTED_FOR_DELEGATION  0x80000 524288
NOT_DELEGATED   0x100000    1048576
USE_DES_KEY_ONLY    0x200000    2097152
DONT_REQ_PREAUTH    0x400000    4194304
PASSWORD_EXPIRED    0x800000    8388608
TRUSTED_TO_AUTH_FOR_DELEGATION  0x1000000   16777216
PARTIAL_SECRETS_ACCOUNT 0x04000000      67108864

You must make a binary-AND of property userAccountControl with 0x002. In order to get all locked (i.e. disabled) accounts you can filter on this:

(&(objectClass=user)(userAccountControl:1.2.840.113556.1.4.803:=2))

For operator 1.2.840.113556.1.4.803 see LDAP Matching Rules

What is the difference between signed and unsigned variables?

Unsigned variables can only be positive numbers, because they lack the ability to indicate that they are negative.

This ability is called the 'sign' or 'signing bit'.

A side effect is that without a signing bit, they have one more bit that can be used to represent the number, doubling the maximum number it can represent.

How can I make a list of lists in R?

Using your example::

list1 <- list()
list1[1] = 1
list1[2] = 2
list2 <- list()
list2[1] = 'a'
list2[2] = 'b'
list_all <- list(list1, list2)

Use '[[' to retrieve an element of a list:

b = list_all[[1]]
 b
[[1]]
[1] 1

[[2]]
[1] 2

class(b)
[1] "list"

How to use lodash to find and return an object from Array?

You can use the following

import { find } from 'lodash'

Then to return the entire object (not only its key or value) from the list with the following:

let match = find(savedViews, { 'ID': 'id to match'});

Can I invoke an instance method on a Ruby module without including it?

Firstly, I'd recommend breaking the module up into the useful things you need. But you can always create a class extending that for your invocation:

module UsefulThings
  def a
    puts "aaay"
  end
  def b
    puts "beee"
  end
end

def test
  ob = Class.new.send(:include, UsefulThings).new
  ob.a
end

test

Create stacked barplot where each stack is scaled to sum to 100%

prop.table is a nice friendly way of obtaining proportions of tables.

m <- matrix(1:4,2)

 m
     [,1] [,2]
[1,]    1    3
[2,]    2    4

Leaving margin blank gives you proportions of the whole table

 prop.table(m, margin=NULL)
     [,1] [,2]
[1,]  0.1  0.3
[2,]  0.2  0.4

Giving it 1 gives you row proportions

 prop.table(m, 1)
      [,1]      [,2]
[1,] 0.2500000 0.7500000
[2,] 0.3333333 0.6666667

And 2 is column proportions

 prop.table(m, 2)
          [,1]      [,2]
[1,] 0.3333333 0.4285714
[2,] 0.6666667 0.5714286

How to iterate through range of Dates in Java?

You can write a class like it(implementing iterator interface) and iterate over it . 

public class DateIterator implements Iterator<Date>, Iterable<Date>
{

 private Calendar end = Calendar.getInstance();
 private Calendar current = Calendar.getInstance();

 public DateIterator(Date start, Date end)
 {
     this.end.setTime(end);
     this.end.add(Calendar.DATE, -1);
     this.current.setTime(start);
     this.current.add(Calendar.DATE, -1);
 }

 @Override
 public boolean hasNext()
 {
     return !current.after(end);
 }

 @Override
 public Date next()
 {
     current.add(Calendar.DATE, 1);
     return current.getTime();
 }

 @Override
 public void remove()
 {
     throw new UnsupportedOperationException(
        "Cannot remove");
 }

 @Override
 public Iterator<Date> iterator()
 {
     return this;
 }
}

and use it like :

Iterator<Date> dateIterator = new DateIterator(startDate, endDate);
while(dateIterator.hasNext()){
      Date selectedDate = dateIterator .next();

}

100% width Twitter Bootstrap 3 template

This is the complete basic structure for 100% width layout in Bootstrap v3.0.0. You shouldn't wrap your <div class="row"> with container class. Cause container class will take lots of margin and this will not provide you full screen (100% width) layout where bootstrap has removed container-fluid class from their mobile-first version v3.0.0.

So just start writing <div class="row"> without container class and you are ready to go with 100% width layout.

<!DOCTYPE html>
<html>
  <head>
    <title>Bootstrap Basic 100% width Structure</title>
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <!-- Bootstrap -->
    <link rel="stylesheet" href="http://netdna.bootstrapcdn.com/bootstrap/3.0.0/css/bootstrap.min.css">

<!-- HTML5 shim and Respond.js IE8 support of HTML5 elements and media queries -->
<!--[if lt IE 9]>
  <script src="http://getbootstrap.com/assets/js/html5shiv.js"></script>
  <script src="http://getbootstrap.com/assets/js/respond.min.js"></script>
<![endif]-->
<style>
    .red{
        background-color: red;
    }
    .green{
        background-color: green;
    }
</style>
</head>
<body>
    <div class="row">
        <div class="col-md-3 red">Test content</div>
        <div class="col-md-9 green">Another Content</div>
    </div>
    <!-- jQuery (necessary for Bootstrap's JavaScript plugins) -->
    <script src="//code.jquery.com/jquery.js"></script>
    <!-- Include all compiled plugins (below), or include individual files as needed -->
    <script src="http://netdna.bootstrapcdn.com/bootstrap/3.0.0/js/bootstrap.min.js"></script>
</body>
</html>

To see the result by yourself I have created a bootply. See the live output there. http://bootply.com/82136 And the complete basic bootstrap 3 100% width layout I have created a gist. you can use that. Get the gist from here

Reply me if you need more further assistance. Thanks.

Pods stuck in Terminating status

In my case the --force option didn't quite work. I could still see the pod ! It was stuck in Terminating/Unknown mode. So after running 

kubectl delete pods <pod> -n redis --grace-period=0 --force

I ran

kubectl patch pod <pod> -p '{"metadata":{"finalizers":null}}'

Make the first character Uppercase in CSS

 
<script type="text/javascript">
     $(document).ready(function() {
     var asdf = $('.capsf').text();

    $('.capsf').text(asdf.toLowerCase());
     });
     </script>
<div style="text-transform: capitalize;"  class="capsf">sd GJHGJ GJHgjh gh hghhjk ku</div>

How to check if an element does NOT have a specific class?

I don't know why, but the accepted answer didn't work for me. Instead this worked:

if ($(this).hasClass("test") !== false) {}

Move SQL Server 2008 database files to a new folder location

You forgot to mention the name of your database (is it "my"?).

ALTER DATABASE my SET SINGLE_USER WITH ROLLBACK IMMEDIATE;

ALTER DATABASE my SET OFFLINE;

ALTER DATABASE my MODIFY FILE 
(
   Name = my_Data,
   Filename = 'D:\DATA\my.MDF'
);

ALTER DATABASE my MODIFY FILE 
(
   Name = my_Log, 
   Filename = 'D:\DATA\my_1.LDF'
);

Now here you must manually move the files from their current location to D:\Data\ (and remember to rename them manually if you changed them in the MODIFY FILE command) ... then you can bring the database back online:

ALTER DATABASE my SET ONLINE;

ALTER DATABASE my SET MULTI_USER;

This assumes that the SQL Server service account has sufficient privileges on the D:\Data\ folder. If not you will receive errors at the SET ONLINE command.

Is there a difference between using a dict literal and a dict constructor?

I think you have pointed out the most obvious difference. Apart from that,

the first doesn't need to lookup dict which should make it a tiny bit faster

the second looks up dict in locals() and then globals() and the finds the builtin, so you can switch the behaviour by defining a local called dict for example although I can't think of anywhere this would be a good idea apart from maybe when debugging

Appending an id to a list if not already present in a string

A more pythonic way, without using set is as follows:

lst = [1, 2, 3, 4]
lst.append(3) if 3 not in lst else lst

How do you append rows to a table using jQuery?

I always use this code below for more readable

$('table').append([
'<tr>',
    '<td>My Item 1</td>',
    '<td>My Item 2</td>',
    '<td>My Item 3</td>',
    '<td>My Item 4</td>',
'</tr>'
].join(''));

or if it have tbody 

$('table').find('tbody').append([
'<tr>',
    '<td>My Item 1</td>',
    '<td>My Item 2</td>',
    '<td>My Item 3</td>',
    '<td>My Item 4</td>',
'</tr>'
].join(''));

Angular - How to apply [ngStyle] conditions

You can use an inline if inside your ngStyle:

[ngStyle]="styleOne?{'background-color': 'red'} : {'background-color': 'blue'}"

A batter way in my opinion is to store your background color inside a variable and then set the background-color as the variable value:

[style.background-color]="myColorVaraible"

Programmatically go back to the previous fragment in the backstack

To make that fragment come again, just add that fragment to backstack which you want to come on back pressed, Eg:

button.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        Fragment fragment = new LoginFragment();
        //replacing the fragment
        if (fragment != null) {
            FragmentTransaction ft = ((FragmentActivity)getContext()).getSupportFragmentManager().beginTransaction();
            ft.replace(R.id.content_frame, fragment);
            ft.addToBackStack("SignupFragment");
            ft.commit();
        }
    }
});

In the above case, I am opening LoginFragment when Button button is pressed, right now the user is in SignupFragment. So if addToBackStack(TAG) is called, where TAG = "SignupFragment", then when back button is pressed in LoginFragment, we come back to SignUpFragment.

Happy Coding!

Maintain the aspect ratio of a div with CSS

As stated in here on w3schools.com and somewhat reiterated in this accepted answer, padding values as percentages (emphasis mine):

Specifies the padding in percent of the width of the containing element

Ergo, a correct example of a responsive DIV that keeps a 16:9 aspect ratio is as follows:

CSS

.parent {
    position: relative;
    width: 100%;
}
.child {
    position: relative;
    padding-bottom: calc(100% * 9 / 16);
}
.child > div {
    position: absolute;
    top: 0;
    bottom: 0;
    left: 0;
    right: 0;
}

HTML

<div class="parent">
    <div class="child">
        <div>Aspect is kept when resizing</div>
    </div>
</div>

Demo on JSFiddle

Is it better to use C void arguments "void foo(void)" or not "void foo()"?

C99 quotes

This answer aims to quote and explain the relevant parts of the C99 N1256 standard draft.

Definition of declarator

The term declarator will come up a lot, so let's understand it.

From the language grammar, we find that the following underline characters are declarators:

int f(int x, int y);
    ^^^^^^^^^^^^^^^

int f(int x, int y) { return x + y; }
    ^^^^^^^^^^^^^^^

int f();
    ^^^

int f(x, y) int x; int y; { return x + y; }
    ^^^^^^^

Declarators are part of both function declarations and definitions.

There are 2 types of declarators:

  • parameter type list
  • identifier list

Parameter type list

Declarations look like:

int f(int x, int y);

Definitions look like:

int f(int x, int y) { return x + y; }

It is called parameter type list because we must give the type of each parameter.

Identifier list

Definitions look like:

int f(x, y)
    int x;
    int y;
{ return x + y; }

Declarations look like:

int g();

We cannot declare a function with a non-empty identifier list:

int g(x, y);

because 6.7.5.3 "Function declarators (including prototypes)" says:

3 An identifier list in a function declarator that is not part of a definition of that function shall be empty.

It is called identifier list because we only give the identifiers x and y on f(x, y), types come after.

This is an older method, and shouldn't be used anymore. 6.11.6 Function declarators says:

1 The use of function declarators with empty parentheses (not prototype-format parameter type declarators) is an obsolescent feature.

and the Introduction explains what is an obsolescent feature:

Certain features are obsolescent, which means that they may be considered for withdrawal in future revisions of this International Standard. They are retained because of their widespread use, but their use in new implementations (for implementation features) or new programs (for language [6.11] or library features [7.26]) is discouraged

f() vs f(void) for declarations

When you write just:

void f();

it is necessarily an identifier list declaration, because 6.7.5 "Declarators" says defines the grammar as:

direct-declarator:
    [...]
    direct-declarator ( parameter-type-list )
    direct-declarator ( identifier-list_opt )

so only the identifier-list version can be empty because it is optional (_opt).

direct-declarator is the only grammar node that defines the parenthesis (...) part of the declarator.

So how do we disambiguate and use the better parameter type list without parameters? 6.7.5.3 Function declarators (including prototypes) says:

10 The special case of an unnamed parameter of type void as the only item in the list specifies that the function has no parameters.

So:

void f(void);

is the way.

This is a magic syntax explicitly allowed, since we cannot use a void type argument in any other way:

void f(void v);
void f(int i, void);
void f(void, int);

What can happen if I use an f() declaration?

Maybe the code will compile just fine: 6.7.5.3 Function declarators (including prototypes):

14 The empty list in a function declarator that is not part of a definition of that function specifies that no information about the number or types of the parameters is supplied.

So you can get away with:

void f();
void f(int x) {}

Other times, UB can creep up (and if you are lucky the compiler will tell you), and you will have a hard time figuring out why:

void f();
void f(float x) {}

See: Why does an empty declaration work for definitions with int arguments but not for float arguments?

f() and f(void) for definitions

f() {}

vs

f(void) {}

are similar, but not identical.

6.7.5.3 Function declarators (including prototypes) says:

14 An empty list in a function declarator that is part of a definition of that function specifies that the function has no parameters.

which looks similar to the description of f(void).

But still... it seems that:

int f() { return 0; }
int main(void) { f(1); }

is conforming undefined behavior, while:

int f(void) { return 0; }
int main(void) { f(1); }

is non conforming as discussed at: Why does gcc allow arguments to be passed to a function defined to be with no arguments?

TODO understand exactly why. Has to do with being a prototype or not. Define prototype.

Change a HTML5 input's placeholder color with CSS

In addition to toscho's answer I've noticed some webkit inconsistencies between Chrome 9-10 and Safari 5 with the CSS properties supported that are worth noting.

Specifically Chrome 9 and 10 do not support background-color, border, text-decoration and text-transform when styling the placeholder.

The full cross-browser comparison is here.

How do I create ColorStateList programmatically?

Here's an example of how to create a ColorList programmatically in Kotlin:

val colorList = ColorStateList(
        arrayOf(
                intArrayOf(-android.R.attr.state_enabled),  // Disabled
                intArrayOf(android.R.attr.state_enabled)    // Enabled
        ),
        intArrayOf(
                Color.BLACK,     // The color for the Disabled state
                Color.RED        // The color for the Enabled state
        )
)

Android, How can I Convert String to Date?

It could be a good idea to be careful with the Locale upon which c.getTime().toString(); depends.

One idea is to store the time in seconds (e.g. UNIX time). As an int you can easily compare it, and then you just convert it to string when displaying it to the user.

TypeError: Cannot read property "0" from undefined

For me, the problem was I was using a package that isn't included in package.json nor installed.

import { ToastrService } from 'ngx-toastr';

So when the compiler tried to compile this, it threw an error.

(I installed it locally, and when running a build on an external server the error was thrown)

How can I convince IE to simply display application/json rather than offer to download it?

I just had the same issue with an XMLHttpRequest. The site functions flawlessly in Chrome and FF, and in dozens upon dozens of Internet Explorer browsers in production. This ONE machine (the one our company is setting up to be a demo machine, of course) decided that it was going to prompt to save the json response to an ajax request.

The accepted regedit solution below fixed it. Thanks.

PHP expects T_PAAMAYIM_NEKUDOTAYIM?

It’s the double colon operator :: (see list of parser tokens).

How to delete file from public folder in laravel 5.1

this method worked for me
First, put the line below at the beginning of your controller: 

use File;

below namespace in your php file Second: 

 $destinationPath = 'your_path';
 File::delete($destinationPath.'/your_file');

$destinationPath --> the folder inside folder public.

Regular expression to stop at first match

 
import regex
text = 'ask her to call Mary back when she comes back'                           
p = r'(?i)(?s)call(.*?)back'
for match in regex.finditer(p, str(text)):
    print (match.group(1))

Output: Mary

DELETE_FAILED_INTERNAL_ERROR Error while Installing APK

This worked for my xiaomi redmii note 4 after allowing developer options and allowing USB debugging go to settings-> developer options-> uncheck Turn on MIUI optimization Restart your device and now install the app.

How to redirect 'print' output to a file using python?

Don't use print, use logging

You can change sys.stdout to point to a file, but this is a pretty clunky and inflexible way to handle this problem. Instead of using print, use the logging module.

With logging, you can print just like you would to stdout, or you can also write the output to a file. You can even use the different message levels (critical, error, warning, info, debug) to, for example, only print major issues to the console, but still log minor code actions to a file.

A simple example

Import logging, get the logger, and set the processing level:

import logging
logger = logging.getLogger()
logger.setLevel(logging.DEBUG) # process everything, even if everything isn't printed

If you want to print to stdout:

ch = logging.StreamHandler()
ch.setLevel(logging.INFO) # or any other level
logger.addHandler(ch)

If you want to also write to a file (if you only want to write to a file skip the last section):

fh = logging.FileHandler('myLog.log')
fh.setLevel(logging.DEBUG) # or any level you want
logger.addHandler(fh)

Then, wherever you would use print use one of the logger methods:

# print(foo)
logger.debug(foo)

# print('finishing processing')
logger.info('finishing processing')

# print('Something may be wrong')
logger.warning('Something may be wrong')

# print('Something is going really bad')
logger.error('Something is going really bad')

To learn more about using more advanced logging features, read the excellent logging tutorial in the Python docs.

Convert xlsx to csv in Linux with command line

Using the Gnumeric spreadsheet application which comes which a commandline utility called ssconvert is indeed super simple:

find . -name '*.xlsx' -exec ssconvert -T Gnumeric_stf:stf_csv {} \;

and you're done!

Datatable to html Table

From this link

using System;
using System.Collections.Generic;
using System.Data;
using System.Globalization;
using System.Text;
using System.Xml;

namespace ClientUtil
{
public class DataTableUtil
{

public static string DataTableToXmlString(DataTable dtData)
{
if (dtData == null || dtData.Columns.Count == 0)
return (string) null;
DataColumn[] primaryKey = dtData.PrimaryKey;
StringBuilder stringBuilder = new StringBuilder();
stringBuilder.Append(“<TABLE>”);
stringBuilder.Append(“<TR>”);
foreach (DataColumn dataColumn in (InternalDataCollectionBase) dtData.Columns)
{
if (DataTableUtil.IsPrimaryKey(dataColumn.ColumnName, primaryKey))
stringBuilder.Append(“<TH IsPK=’true’ ColType='”).Append(Convert.ToString(dataColumn.DataType == typeof (object) ? (object) typeof (string) : (object) dataColumn.DataType)).Append(“‘>”).Append(dataColumn.ColumnName.Replace(“&”, “”)).Append(“</TH>”);
else
stringBuilder.Append(“<TH IsPK=’false’ ColType='”).Append(Convert.ToString(dataColumn.DataType == typeof (object) ? (object) typeof (string) : (object) dataColumn.DataType)).Append(“‘>”).Append(dataColumn.ColumnName.Replace(“&”, “”)).Append(“</TH>”);
}
stringBuilder.Append(“</TR>”);
int num1 = 0;
foreach (DataRow dataRow in (InternalDataCollectionBase) dtData.Rows)
{
stringBuilder.Append(“<TR>”);
int num2 = 0;
foreach (DataColumn dataColumn in (InternalDataCollectionBase) dtData.Columns)
{
string str = Convert.IsDBNull(dataRow[dataColumn.ColumnName]) ? (string) null : Convert.ToString(dataRow[dataColumn.ColumnName]).Replace(“<“, “&lt;”).Replace(“>”, “&gt;”).Replace(“\””, “&quot;”).Replace(“‘”, “&apos;”).Replace(“&”, “&amp;”);
if (!string.IsNullOrEmpty(str))
stringBuilder.Append(“<TD>”).Append(str).Append(“</TD>”);
else
stringBuilder.Append(“<TD>”).Append(“</TD>”);
++num2;
}
stringBuilder.Append(“</TR>”);
++num1;
}
stringBuilder.Append(“</TABLE>”);
return ((object) stringBuilder).ToString();
}

protected static bool IsPrimaryKey(string ColumnName, DataColumn[] PKs)
{
if (PKs == null || string.IsNullOrEmpty(ColumnName))
return false;
foreach (DataColumn dataColumn in PKs)
{
if (dataColumn.ColumnName.ToLower().Trim() == ColumnName.ToLower().Trim())
return true;
}
return false;
}

public static DataTable XmlStringToDataTable(string XmlData)
{
DataTable dataTable = (DataTable) null;
IList<DataColumn> list = (IList<DataColumn>) new List<DataColumn>();
if (string.IsNullOrEmpty(XmlData))
return (DataTable) null;
XmlDocument xmlDocument1 = new XmlDocument();
xmlDocument1.PreserveWhitespace = true;
XmlDocument xmlDocument2 = xmlDocument1;
xmlDocument2.LoadXml(XmlData);
XmlNode xmlNode1 = xmlDocument2.SelectSingleNode(“/TABLE”);
if (xmlNode1 != null)
{
dataTable = new DataTable();
int num = 0;
foreach (XmlNode xmlNode2 in xmlNode1.SelectNodes(“TR”))
{
if (num == 0)
{
foreach (XmlNode xmlNode3 in xmlNode2.SelectNodes(“TH”))
{
bool result = false;
string str = xmlNode3.Attributes[“IsPK”].Value;
if (!string.IsNullOrEmpty(str))
{
if (!bool.TryParse(str, out result))
result = false;
}
else
result = false;
Type type = Type.GetType(xmlNode3.Attributes[“ColType”].Value);
DataColumn column = new DataColumn(xmlNode3.InnerText, type);
if (result)
list.Add(column);
if (!dataTable.Columns.Contains(column.ColumnName))
dataTable.Columns.Add(column);
}
if (list.Count > 0)
{
DataColumn[] dataColumnArray = new DataColumn[list.Count];
for (int index = 0; index < list.Count; ++index)
dataColumnArray[index] = list[index];
dataTable.PrimaryKey = dataColumnArray;
}
}
else
{
DataRow row = dataTable.NewRow();
int index = 0;
foreach (XmlNode xmlNode3 in xmlNode2.SelectNodes(“TD”))
{
Type dataType = dataTable.Columns[index].DataType;
string s = xmlNode3.InnerText;
if (!string.IsNullOrEmpty(s))
{
try
{
s = s.Replace(“&lt;”, “<“);
s = s.Replace(“&gt;”, “>”);
s = s.Replace(“&quot;”, “\””);
s = s.Replace(“&apos;”, “‘”);
s = s.Replace(“&amp;”, “&”);
row[index] = Convert.ChangeType((object) s, dataType);
}
catch
{
if (dataType == typeof (DateTime))
row[index] = (object) DateTime.ParseExact(s, “yyyyMMdd”, (IFormatProvider) CultureInfo.InvariantCulture);
}
}
else
row[index] = Convert.DBNull;
++index;
}
dataTable.Rows.Add(row);
}
++num;
}
}
return dataTable;
}
}
}

How to use absolute path in twig functions

For Symfony 2.7 and newer

See this answer here.

1st working option

{{ app.request.scheme ~'://' ~ app.request.httpHost ~ asset('bundles/acmedemo/images/search.png') }}

2nd working option - preferred

Just made a quick test with a clean new Symfony copy. There is also another option which combines scheme and httpHost:

{{ app.request.getSchemeAndHttpHost() ~ asset('bundles/acmedemo/images/search.png') }}
{# outputs #}
{# http://localhost/Symfony/web/bundles/acmedemo/css/demo.css  #}

Http Servlet request lose params from POST body after read it once

The method getContentAsByteArray() of the Spring class ContentCachingRequestWrapper reads the body multiple times, but the methods getInputStream() and getReader() of the same class do not read the body multiple times:

"This class caches the request body by consuming the InputStream. If we read the InputStream in one of the filters, then other subsequent filters in the filter chain can't read it anymore. Because of this limitation, this class is not suitable in all situations."

In my case more general solution that solved this problem was to add following three classes to my Spring boot project (and the required dependencies to the pom file):

CachedBodyHttpServletRequest.java:

public class CachedBodyHttpServletRequest extends HttpServletRequestWrapper {

    private byte[] cachedBody;

    public CachedBodyHttpServletRequest(HttpServletRequest request) throws IOException {
        super(request);
        InputStream requestInputStream = request.getInputStream();
        this.cachedBody = StreamUtils.copyToByteArray(requestInputStream);
    }

    @Override
    public ServletInputStream getInputStream() throws IOException {
        return new CachedBodyServletInputStream(this.cachedBody);
    }

    @Override
    public BufferedReader getReader() throws IOException {
        // Create a reader from cachedContent
        // and return it
        ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(this.cachedBody);
        return new BufferedReader(new InputStreamReader(byteArrayInputStream));
    }
}

CachedBodyServletInputStream.java:

public class CachedBodyServletInputStream extends ServletInputStream {

    private InputStream cachedBodyInputStream;

    public CachedBodyServletInputStream(byte[] cachedBody) {
        this.cachedBodyInputStream = new ByteArrayInputStream(cachedBody);
    }

    @Override
    public boolean isFinished() {
        try {
            return cachedBodyInputStream.available() == 0;
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return false;
    }

    @Override
    public boolean isReady() {
        return true;
    }

    @Override
    public void setReadListener(ReadListener readListener) {
        throw new UnsupportedOperationException();
    }

    @Override
    public int read() throws IOException {
        return cachedBodyInputStream.read();
    }
}

ContentCachingFilter.java:

@Order(value = Ordered.HIGHEST_PRECEDENCE)
@Component
@WebFilter(filterName = "ContentCachingFilter", urlPatterns = "/*")
public class ContentCachingFilter extends OncePerRequestFilter {

    @Override
    protected void doFilterInternal(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, FilterChain filterChain) throws ServletException, IOException {
        System.out.println("IN  ContentCachingFilter ");
        CachedBodyHttpServletRequest cachedBodyHttpServletRequest = new CachedBodyHttpServletRequest(httpServletRequest);
        filterChain.doFilter(cachedBodyHttpServletRequest, httpServletResponse);
    }
}

I also added the following dependencies to pom:

<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-webmvc</artifactId>
    <version>5.2.0.RELEASE</version>
</dependency>
<dependency>
    <groupId>javax.servlet</groupId>
    <artifactId>javax.servlet-api</artifactId>
    <version>4.0.1</version>
</dependency>
<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.10.0</version>
</dependency>

A tuturial and full source code is located here: https://www.baeldung.com/spring-reading-httpservletrequest-multiple-times

Plot 3D data in R

Not sure why the code above did not work for the library rgl, but the following link has a great example with the same library. Run the code in R and you will obtain a beautiful 3d plot that you can turn around in all angles.

http://statisticsr.blogspot.de/2008/10/some-r-functions.html

########################################################################
## another example of 3d plot from my personal reserach, use rgl library
########################################################################
# 3D visualization device system

library(rgl);
data(volcano)
dim(volcano)

peak.height <- volcano;
ppm.index <- (1:nrow(volcano));
sample.index <- (1:ncol(volcano));

zlim <- range(peak.height)
zlen <- zlim[2] - zlim[1] + 1
colorlut <- terrain.colors(zlen) # height color lookup table
col <- colorlut[(peak.height-zlim[1]+1)] # assign colors to heights for each point
open3d()

ppm.index1 <- ppm.index*zlim[2]/max(ppm.index);
sample.index1 <- sample.index*zlim[2]/max(sample.index)

title.name <- paste("plot3d ", "volcano", sep = "");
surface3d(ppm.index1, sample.index1, peak.height, color=col, back="lines", main = title.name);
grid3d(c("x", "y+", "z"), n =20)

sample.name <- paste("col.", 1:ncol(volcano), sep="");
sample.label <- as.integer(seq(1, length(sample.name), length = 5));

axis3d('y+',at = sample.index1[sample.label], sample.name[sample.label], cex = 0.3);
axis3d('y',at = sample.index1[sample.label], sample.name[sample.label], cex = 0.3)
axis3d('z',pos=c(0, 0, NA))

ppm.label <- as.integer(seq(1, length(ppm.index), length = 10));
axes3d('x', at=c(ppm.index1[ppm.label], 0, 0), abs(round(ppm.index[ppm.label], 2)), cex = 0.3);

title3d(main = title.name, sub = "test", xlab = "ppm", ylab = "samples", zlab = "peak")
rgl.bringtotop();

The SELECT permission was denied on the object 'sysobjects', database 'mssqlsystemresource', schema 'sys'

In my case, my site was hosted on shared hosting and there was a resource over usage not even relating to my database, thus my database was locked down, the hosting panel was Plesk

How to present a simple alert message in java?

Call "setWarningMsg()" Method and pass the text that you want to show.

exm:- setWarningMsg("thank you for using java");


public static void setWarningMsg(String text){
    Toolkit.getDefaultToolkit().beep();
    JOptionPane optionPane = new JOptionPane(text,JOptionPane.WARNING_MESSAGE);
    JDialog dialog = optionPane.createDialog("Warning!");
    dialog.setAlwaysOnTop(true);
    dialog.setVisible(true);
}

Or Just use 

JOptionPane optionPane = new JOptionPane("thank you for using java",JOptionPane.WARNING_MESSAGE);
JDialog dialog = optionPane.createDialog("Warning!");
dialog.setAlwaysOnTop(true); // to show top of all other application
dialog.setVisible(true); // to visible the dialog

You can use JOptionPane. (WARNING_MESSAGE or INFORMATION_MESSAGE or ERROR_MESSAGE)

Logo image and H1 heading on the same line

If your image is part of the logo why not do this:

<h1><img src="img/logo.png" alt="logo" /> My website name</h1>

Use CSS to style it better.

And it is also best practice to make your logo a hyperlink that take the user back to the home page.

So you could do:

<h1 id="logo"><a href="/"><img src="img/logo.png" alt="logo" /> My website name</a></h1>

Git clone particular version of remote repository

uploadpack.allowReachableSHA1InWant

Since Git 2.5.0 this configuration variable can be enabled on the server, here the GitHub feature request and the GitHub commit enabling this feature.

Bitbucket Server enabled it since version 5.5+.

Usage:

# Make remote with 4 commits, and local with just one.
mkdir server
cd server
git init
touch 1
git add 1
git commit -m 1
git clone ./ ../local
for i in {2..4}; do
    touch "$i"
    git add "$i"
    git commit -m "$i"
done

# Before last commit.
SHA3="$(git log --format='%H' --skip=1 -n1)"
# Last commit.
SHA4="$(git log --format='%H' -n1)"

# Failing control without feature.
cd ../local
# Does not give an error, but does not fetch either.
git fetch origin "$SHA3"
# Error.
git checkout "$SHA3"

# Enable the feature.
cd ../server
git config uploadpack.allowReachableSHA1InWant true

# Now it works.
cd ../local
git fetch origin "$SHA3"
git checkout "$SHA3"
# Error.
git checkout "$SHA4"

Android Studio Stuck at Gradle Download on create new project

Invalidate Caches and Restart

It worked for me.

How to get all selected values of a multiple select box?

Same as the earlier answer but using underscore.js.

function getSelectValues(select) {
    return _.map(_.filter(select.options, function(opt) { 
        return opt.selected; }), function(opt) { 
            return opt.value || opt.text; });
}

How does "cat << EOF" work in bash?

Worth noting that here docs work in bash loops too. This example shows how-to get the column list of table: 

export postgres_db_name='my_db'
export table_name='my_table_name'

# start copy 
while read -r c; do test -z "$c" || echo $table_name.$c , ; done < <(cat << EOF | psql -t -q -d $postgres_db_name -v table_name="${table_name:-}"
SELECT column_name
FROM information_schema.columns
WHERE 1=1
AND table_schema = 'public'
AND table_name   =:'table_name'  ;
EOF
)
# stop copy , now paste straight into the bash shell ...

output: 
my_table_name.guid ,
my_table_name.id ,
my_table_name.level ,
my_table_name.seq ,

or even without the new line 

while read -r c; do test -z "$c" || echo $table_name.$c , | perl -ne 
's/\n//gm;print' ; done < <(cat << EOF | psql -t -q -d $postgres_db_name -v table_name="${table_name:-}"
 SELECT column_name
 FROM information_schema.columns
 WHERE 1=1
 AND table_schema = 'public'
 AND table_name   =:'table_name'  ;
 EOF
 )

 # output: daily_issues.guid ,daily_issues.id ,daily_issues.level ,daily_issues.seq ,daily_issues.prio ,daily_issues.weight ,daily_issues.status ,daily_issues.category ,daily_issues.name ,daily_issues.description ,daily_issues.type ,daily_issues.owner

How to install older version of node.js on Windows?

run:

npm install -g [email protected]

- or whatever version you want after the @ symbol (This works as of 2019)

IE9 jQuery AJAX with CORS returns "Access is denied"

Note -- Note

do not use "http://www.domain.xxx" or "http://localhost/" or "IP >> 127.0.0.1" for URL in ajax. only use path(directory) and page name without address.

false state:

var AJAXobj = createAjax();
AJAXobj.onreadystatechange = handlesAJAXcheck;
AJAXobj.open('POST', 'http://www.example.com/dir/getSecurityCode.php', true);
AJAXobj.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded; charset=UTF-8');
AJAXobj.send(pack);

true state:

var AJAXobj = createAjax();
AJAXobj.onreadystatechange = handlesAJAXcheck;
AJAXobj.open('POST', 'dir/getSecurityCode.php', true);   // <<--- note
AJAXobj.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded; charset=UTF-8');
AJAXobj.send(pack);

Converting JSON to XML in Java

For json to xml use the following Jackson example:

final String str = "{\"name\":\"JSON\",\"integer\":1,\"double\":2.0,\"boolean\":true,\"nested\":{\"id\":42},\"array\":[1,2,3]}";
ObjectMapper jsonMapper = new ObjectMapper();
JsonNode node = jsonMapper.readValue(str, JsonNode.class);
XmlMapper xmlMapper = new XmlMapper();
        xmlMapper.configure(SerializationFeature.INDENT_OUTPUT, true);
        xmlMapper.configure(ToXmlGenerator.Feature.WRITE_XML_DECLARATION, true);
        xmlMapper.configure(ToXmlGenerator.Feature.WRITE_XML_1_1, true);
StringWriter w = new StringWriter();
xmlMapper.writeValue(w, node);
System.out.println(w.toString());

Prints:

<?xml version='1.1' encoding='UTF-8'?>
<ObjectNode>
  <name>JSON</name>
  <integer>1</integer>
  <double>2.0</double>
  <boolean>true</boolean>
  <nested>
    <id>42</id>
  </nested>
  <array>1</array>
  <array>2</array>
  <array>3</array>
</ObjectNode>

To convert it back (xml to json) take a look at this answer https://stackoverflow.com/a/62468955/1485527 .

How to print a two dimensional array?

How about trying this?

public static void main (String [] args)
{
   int [] [] listTwo = new int [5][5];
    // 2 Dimensional array 
    int x = 0;
    int y = 0;
    while (x < 5) {
        listTwo[x][y] = (int)(Math.random()*10);

        while (y <5){
            listTwo [x] [y] = (int)(Math.random()*10);
            System.out.print(listTwo[x][y]+" | ");
            y++;                
        }
        System.out.println("");
        y=0;
        x++;
    }
}

How to validate phone number using PHP?

I depends heavily on which number formats you aim to support, and how strict you want to enforce number grouping, use of whitespace and other separators etc....

Take a look at this similar question to get some ideas.

Then there is E.164 which is a numbering standard recommendation from ITU-T

ZIP file content type for HTTP request

 
.zip    application/zip, application/octet-stream

jQuery click events firing multiple times

To make sure a click only actions once use this:

$(".bet").unbind().click(function() {
    //Stuff
});

How to get a Fragment to remove itself, i.e. its equivalent of finish()?

In the Activity/AppCompatActivity:

@Override
public void onBackPressed() {
    if (mDrawerLayout.isDrawerOpen(GravityCompat.START)) {
        // if you want to handle DrawerLayout
        mDrawerLayout.closeDrawer(GravityCompat.START);
    } else {
        if (getFragmentManager().getBackStackEntryCount() == 0) {
            super.onBackPressed();
        } else {
            getFragmentManager().popBackStack();
        }
    }
}

and then call in the fragment:

getActivity().onBackPressed();

or like stated in other answers, call this in the fragment:

getActivity().getSupportFragmentManager().beginTransaction().remove(this).commit();

How to show math equations in general github's markdown(not github's blog)

Markdown supports inline HTML. Inline HTML can be used for both quick and simple inline equations and, with and external tool, more complex rendering.

Quick and Simple Inline

For quick and simple inline items use HTML ampersand entity codes. An example that combines this idea with subscript text in markdown is: h?(x) = ?o x + ?1x, the code for which follows.

    h<sub>&theta;</sub>(x) = &theta;<sub>o</sub> x + &theta;<sub>1</sub>x

HTML ampersand entity codes for common math symbols can be found here. Codes for Greek letters here.

While this approach has limitations it works in practically all markdown and does not require any external libraries.

Complex Scalable Inline Rendering with LaTeX and Codecogs

If your needs are greater use an external LaTeX renderer like CodeCogs. Create an equation with CodeCogs editor. Choose svg for rendering and HTML for the embed code. Svg renders well on resize. HTML allows LaTeX to be easily read when you are looking at the source. Copy the embed code from the bottom of the page and paste it into your markdown.

<img src="https://latex.codecogs.com/svg.latex?\Large&space;x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}" title="\Large x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}" />

Expressed in markdown becomes

![\Large x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}](https://latex.codecogs.com/svg.latex?\Large&space;x=\frac{-b\pm\sqrt{b^2-4ac}}{2a})

\Large x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}

This combines this answer and this answer.

GitHub support only somtimes worked using the above raw html syntax for readable LaTeX for me. If the above does not work for you another option is to instead choose URL Encoded rendering and use that output to manually create a link like:

\Large x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}

![\Large x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}](https://latex.codecogs.com/svg.latex?x%3D%5Cfrac%7B-b%5Cpm%5Csqrt%7Bb%5E2-4ac%7D%7D%7B2a%7D)

This manually incorporates LaTex in the alt image text and uses an encoded URL for rendering on GitHub.

Multi-line Rendering

If you need multi-line rendering check out this answer.

How to Create Multiple Where Clause Query Using Laravel Eloquent?

The whereColumn method can be passed an array of multiple conditions. These conditions will be joined using the and operator.

Example:

$users = DB::table('users')
            ->whereColumn([
                ['first_name', '=', 'last_name'],
                ['updated_at', '>', 'created_at']
            ])->get();

$users = User::whereColumn([
                ['first_name', '=', 'last_name'],
                ['updated_at', '>', 'created_at']
            ])->get();

For more information check this section of the documentation https://laravel.com/docs/5.4/queries#where-clauses

How can I use Timer (formerly NSTimer) in Swift?

In Swift 3 something like this with @objc:

func startTimerForResendingCode() {
    let timerIntervalForResendingCode = TimeInterval(60)
    Timer.scheduledTimer(timeInterval: timerIntervalForResendingCode,
                         target: self,
                         selector: #selector(timerEndedUp),
                         userInfo: nil,
                         repeats: false)
}




@objc func timerEndedUp() {
    output?.timerHasFinishedAndCodeMayBeResended()
}

Oracle client ORA-12541: TNS:no listener

According to oracle online documentation

ORA-12541: TNS:no listener

Cause: The connection request could not be completed because the listener is not running.

Action: Ensure that the supplied destination address matches one of the addresses used by 
the listener - compare the TNSNAMES.ORA entry with the appropriate LISTENER.ORA file (or  
TNSNAV.ORA if the connection is to go by way of an Interchange). Start the listener on 
the remote machine.

How can I check file size in Python?

There is a bitshift trick I use if I want to to convert from bytes to any other unit. If you do a right shift by 10 you basically shift it by an order (multiple).

Example: 5GB are 5368709120 bytes

print (5368709120 >> 10)  # 5242880 kilobytes (kB)
print (5368709120 >> 20 ) # 5120 megabytes (MB)
print (5368709120 >> 30 ) # 5 gigabytes (GB)

How to deploy a war file in JBoss AS 7?

Just copy war file to standalone/deployments/ folder, it should deploy it automatically. It'll also create your_app_name.deployed file, when your application is deployed. Also be sure that you start server with bin/standalone.sh script.

How can I get around MySQL Errcode 13 with SELECT INTO OUTFILE?

You can do this : 

mysql -u USERNAME --password=PASSWORD --database=DATABASE --execute='SELECT `FIELD`, `FIELD` FROM `TABLE` LIMIT 0, 10000 ' -X > file.xml

Create JPA EntityManager without persistence.xml configuration file

Yes you can without using any xml file using spring like this inside a @Configuration class (or its equivalent spring config xml):

@Bean
public LocalContainerEntityManagerFactoryBean emf(){
    properties.put("javax.persistence.jdbc.driver", dbDriverClassName);
    properties.put("javax.persistence.jdbc.url", dbConnectionURL);
    properties.put("javax.persistence.jdbc.user", dbUser); //if needed

    LocalContainerEntityManagerFactoryBean emf = new LocalContainerEntityManagerFactoryBean();
    emf.setPersistenceProviderClass(org.eclipse.persistence.jpa.PersistenceProvider.class); //If your using eclipse or change it to whatever you're using
    emf.setPackagesToScan("com.yourpkg"); //The packages to search for Entities, line required to avoid looking into the persistence.xml
    emf.setPersistenceUnitName(SysConstants.SysConfigPU);
    emf.setJpaPropertyMap(properties);
    emf.setLoadTimeWeaver(new ReflectiveLoadTimeWeaver()); //required unless you know what your doing
    return emf;
}

How to change line-ending settings

If you want to convert back the file formats which have been changed to UNIX Format from PC format.

(1)You need to reinstall tortoise GIT and in the "Line Ending Conversion" Section make sure that you have selected "Check out as is - Check in as is"option.

(2)and keep the remaining configurations as it is.

(3)once installation is done

(4)write all the file extensions which are converted to UNIX format into a text file (extensions.txt).

ex:*.dsp
   *.dsw

(5) copy the file into your clone Run the following command in GITBASH

while read -r a;
do
find . -type f -name "$a" -exec dos2unix {} \;
done<extension.txt

How to correctly set Http Request Header in Angular 2

Angular 4 >

You can either choose to set the headers manually, or make an HTTP interceptor that automatically sets header(s) every time a request is being made.

Manually

Setting a header:

http
  .post('/api/items/add', body, {
    headers: new HttpHeaders().set('Authorization', 'my-auth-token'),
  })
  .subscribe();

Setting headers:

this.http
.post('api/items/add', body, {
  headers: new HttpHeaders({
    'Authorization': 'my-auth-token',
    'x-header': 'x-value'
  })
}).subscribe()

Local variable (immutable instantiate again)

let headers = new HttpHeaders().set('header-name', 'header-value');
headers = headers.set('header-name-2', 'header-value-2');

this.http
  .post('api/items/add', body, { headers: headers })
  .subscribe()

The HttpHeaders class is immutable, so every set() returns a new instance and applies the changes.

From the Angular docs.

HTTP interceptor

A major feature of @angular/common/http is interception, the ability to declare interceptors which sit in between your application and the backend. When your application makes a request, interceptors transform it before sending it to the server, and the interceptors can transform the response on its way back before your application sees it. This is useful for everything from authentication to logging.

From the Angular docs.

Make sure you use @angular/common/http throughout your application. That way your requests will be catched by the interceptor.

Step 1, create the service:

import * as lskeys from './../localstorage.items';
import { Observable } from 'rxjs/Observable';
import { Injectable } from '@angular/core';
import { HttpEvent, HttpInterceptor, HttpHandler, HttpRequest, HttpHeaders } from '@angular/common/http';

@Injectable()
export class HeaderInterceptor implements HttpInterceptor {

    intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
        if (true) { // e.g. if token exists, otherwise use incomming request.
            return next.handle(req.clone({
                setHeaders: {
                    'AuthenticationToken': localStorage.getItem('TOKEN'),
                    'Tenant': localStorage.getItem('TENANT')
                }
            }));
        }
        else {
            return next.handle(req);
        }
    }
}

Step 2, add it to your module:

providers: [
    {
      provide: HTTP_INTERCEPTORS,
      useClass: HeaderInterceptor,
      multi: true // Add this line when using multiple interceptors.
    },
    // ...
  ]

Useful links:

Xcode 4 - "Archive" is greyed out?

see the picture. but I have to type enough chars to post the picture.:)

enter image description here

How to hide command output in Bash

 
.SILENT:

Type " .SILENT: " in the beginning of your script without colons.

UPDATE with CASE and IN - Oracle

You said that budgetpost is alphanumeric. That means it is looking for comparisons against strings. You should try enclosing your parameters in single quotes (and you are missing the final THEN in the Case expression).

UPDATE tab1   
SET budgpost_gr1=   CASE  
                        WHEN (budgpost in ('1001','1012','50055'))  THEN 'BP_GR_A'   
                        WHEN (budgpost in ('5','10','98','0'))  THEN 'BP_GR_B'  
                        WHEN (budgpost in ('11','876','7976','67465')) THEN 'What?'
                        ELSE 'Missing' 
                        END

AngularJS - How can I do a redirect with a full page load?

Try this

$window.location.href="#page-name";
$window.location.reload();

Semi-transparent color layer over background-image?

I've used this as a way to both apply colour tints as well as gradients to images to make dynamic overlaying text easier to style for legibility when you can't control image colour profiles. You don't have to worry about z-index.

HTML

<div class="background-image"></div>

SASS

.background-image {
  background: url('../img/bg/diagonalnoise.png') repeat;
  &:before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(248, 247, 216, 0.7);
  }
}

CSS

.background-image {
  background: url('../img/bg/diagonalnoise.png') repeat;
}

.background-image:before {
    content: '';
    position: absolute;
    top: 0;
    bottom: 0;
    right: 0;
    left: 0;
    background: rgba(248, 247, 216, 0.7);
  }

Hope it helps

The remote certificate is invalid according to the validation procedure

Even shorter version of the solution from Dominic Zukiewicz:

ServicePointManager.ServerCertificateValidationCallback += (o, c, ch, er) => true;

But this means that you will trust all certificates. For a service that isn't just run locally, something a bit smarter will be needed. In the first instance you could use this code to just test whether it solves your problem.

Parameterize an SQL IN clause

If we have strings stored inside the IN clause with the comma(,) delimited, we can use the charindex function to get the values. If you use .NET, then you can map with SqlParameters.

DDL Script:

CREATE TABLE Tags
    ([ID] int, [Name] varchar(20))
;

INSERT INTO Tags
    ([ID], [Name])
VALUES
    (1, 'ruby'),
    (2, 'rails'),
    (3, 'scruffy'),
    (4, 'rubyonrails')
;

T-SQL:

DECLARE @Param nvarchar(max)

SET @Param = 'ruby,rails,scruffy,rubyonrails'

SELECT * FROM Tags
WHERE CharIndex(Name,@Param)>0

You can use the above statement in your .NET code and map the parameter with SqlParameter.

Fiddler demo

EDIT: Create the table called SelectedTags using the following script.

DDL Script:

Create table SelectedTags
(Name nvarchar(20));

INSERT INTO SelectedTags values ('ruby'),('rails')

T-SQL:

DECLARE @list nvarchar(max)
SELECT @list=coalesce(@list+',','')+st.Name FROM SelectedTags st

SELECT * FROM Tags
WHERE CharIndex(Name,@Param)>0

How to increase number of threads in tomcat thread pool?

From Tomcat Documentation

maxConnections When this number has been reached, the server will accept, but not process, one further connection. once the limit has been reached, the operating system may still accept connections based on the acceptCount setting. (The maximum queue length for incoming connection requests when all possible request processing threads are in use. Any requests received when the queue is full will be refused. The default value is 100.) For BIO the default is the value of maxThreads unless an Executor is used in which case the default will be the value of maxThreads from the executor. For NIO and NIO2 the default is 10000. For APR/native, the default is 8192. Note that for APR/native on Windows, the configured value will be reduced to the highest multiple of 1024 that is less than or equal to maxConnections. This is done for performance reasons.

maxThreads
The maximum number of request processing threads to be created by this Connector, which therefore determines the maximum number of simultaneous requests that can be handled. If not specified, this attribute is set to 200. If an executor is associated with this connector, this attribute is ignored as the connector will execute tasks using the executor rather than an internal thread pool.

Replacing a 32-bit loop counter with 64-bit introduces crazy performance deviations with _mm_popcnt_u64 on Intel CPUs

This is not an answer, but it's hard to read if I put results in comment.

I get these results with a Mac Pro (Westmere 6-Cores Xeon 3.33 GHz). I compiled it with clang -O3 -msse4 -lstdc++ a.cpp -o a (-O2 get same result).

clang with uint64_t size=atol(argv[1])<<20;

unsigned    41950110000 0.811198 sec    12.9263 GB/s
uint64_t    41950110000 0.622884 sec    16.8342 GB/s

clang with uint64_t size=1<<20;

unsigned    41950110000 0.623406 sec    16.8201 GB/s
uint64_t    41950110000 0.623685 sec    16.8126 GB/s

I also tried to:

  1. Reverse the test order, the result is the same so it rules out the cache factor.
  2. Have the for statement in reverse: for (uint64_t i=size/8;i>0;i-=4). This gives the same result and proves the compile is smart enough to not divide size by 8 every iteration (as expected).

Here is my wild guess:

The speed factor comes in three parts:

  • code cache: uint64_t version has larger code size, but this does not have an effect on my Xeon CPU. This makes the 64-bit version slower.

  • Instructions used. Note not only the loop count, but the buffer is accessed with a 32-bit and 64-bit index on the two versions. Accessing a pointer with a 64-bit offset requests a dedicated 64-bit register and addressing, while you can use immediate for a 32-bit offset. This may make the 32-bit version faster.

  • Instructions are only emitted on the 64-bit compile (that is, prefetch). This makes 64-bit faster.

The three factors together match with the observed seemingly conflicting results.

How to convert string into float in JavaScript?

You can use this function. It will replace the commas with ' ' and then it will parseFlaot the value and after that it will again adjust the commas in value. 

function convertToFloat(val) {
        if (val != '') {
            if (val.indexOf(',') !== -1)
                val.replace(',', '');
            val = parseFloat(val);
            while (/(\d+)(\d{3})/.test(val.toString())) {
                val = val.toString().replace(/(\d+)(\d{3})/, '$1' + ',' + '$2');
            }
        }
        return val;
    }

Adding an HTTP Header to the request in a servlet filter

as https://stackoverflow.com/users/89391/miku pointed out this would be a complete ServletFilter example that uses the code that also works for Jersey to add the remote_addr header. 

package com.bitplan.smartCRM.web;

import java.io.IOException;
import java.util.Collections;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;

/**
 * 
 * @author wf
 * 
 */
public class RemoteAddrFilter implements Filter {

    @Override
    public void destroy() {

    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response,
            FilterChain chain) throws IOException, ServletException {
        HttpServletRequest req = (HttpServletRequest) request;
        HeaderMapRequestWrapper requestWrapper = new HeaderMapRequestWrapper(req);
        String remote_addr = request.getRemoteAddr();
        requestWrapper.addHeader("remote_addr", remote_addr);
        chain.doFilter(requestWrapper, response); // Goes to default servlet.
    }

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    // https://stackoverflow.com/questions/2811769/adding-an-http-header-to-the-request-in-a-servlet-filter
    // http://sandeepmore.com/blog/2010/06/12/modifying-http-headers-using-java/
    // http://bijubnair.blogspot.de/2008/12/adding-header-information-to-existing.html
    /**
     * allow adding additional header entries to a request
     * 
     * @author wf
     * 
     */
    public class HeaderMapRequestWrapper extends HttpServletRequestWrapper {
        /**
         * construct a wrapper for this request
         * 
         * @param request
         */
        public HeaderMapRequestWrapper(HttpServletRequest request) {
            super(request);
        }

        private Map<String, String> headerMap = new HashMap<String, String>();

        /**
         * add a header with given name and value
         * 
         * @param name
         * @param value
         */
        public void addHeader(String name, String value) {
            headerMap.put(name, value);
        }

        @Override
        public String getHeader(String name) {
            String headerValue = super.getHeader(name);
            if (headerMap.containsKey(name)) {
                headerValue = headerMap.get(name);
            }
            return headerValue;
        }

        /**
         * get the Header names
         */
        @Override
        public Enumeration<String> getHeaderNames() {
            List<String> names = Collections.list(super.getHeaderNames());
            for (String name : headerMap.keySet()) {
                names.add(name);
            }
            return Collections.enumeration(names);
        }

        @Override
        public Enumeration<String> getHeaders(String name) {
            List<String> values = Collections.list(super.getHeaders(name));
            if (headerMap.containsKey(name)) {
                values.add(headerMap.get(name));
            }
            return Collections.enumeration(values);
        }

    }

}

web.xml snippet:

<!--  first filter adds remote addr header -->
<filter>
    <filter-name>remoteAddrfilter</filter-name>
    <filter-class>com.bitplan.smartCRM.web.RemoteAddrFilter</filter-class>
</filter>
<filter-mapping>
    <filter-name>remoteAddrfilter</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

How can I pass command-line arguments to a Perl program?

 
my $output_file;

if((scalar (@ARGV) == 2) && ($ARGV[0] eq "-i"))

{

$output_file= chomp($ARGV[1]) ;


}

javax.xml.bind.UnmarshalException: unexpected element. Expected elements are (none)

Alternatively if you want to persist in using the DocumentType class. Then you could just add the following annotation on top of your DocumentType class.

    @XmlRootElement(name="document")

Note: the String value "document" refers to the name of the root tag of the xml message.

How do I write a backslash (\) in a string?

The previous answer is correct but in this specific case I would recommend using the System.IO.Path.Combine method.

You can find more details here: http://msdn.microsoft.com/en-us/library/fyy7a5kt.aspx

Save image from url with curl PHP

This is easiest implement.

function downloadFile($url, $path)
{
    $newfname = $path;
    $file = fopen($url, 'rb');
    if ($file) {
        $newf = fopen($newfname, 'wb');
        if ($newf) {
            while (!feof($file)) {
                fwrite($newf, fread($file, 1024 * 8), 1024 * 8);
            }
        }
    }
    if ($file) {
        fclose($file);
    }
    if ($newf) {
        fclose($newf);
    }
}

How to replace master branch in Git, entirely, from another branch?

You can rename/remove master on remote, but this will be an issue if lots of people have based their work on the remote master branch and have pulled that branch in their local repo.
That might not be the case here since everyone seems to be working on branch 'seotweaks'.

In that case you can:
git remote --show may not work. (Make a git remote show to check how your remote is declared within your local repo. I will assume 'origin')
(Regarding GitHub, house9 comments: "I had to do one additional step, click the 'Admin' button on GitHub and set the 'Default Branch' to something other than 'master', then put it back afterwards")

git branch -m master master-old  # rename master on local
git push origin :master          # delete master on remote
git push origin master-old       # create master-old on remote
git checkout -b master seotweaks # create a new local master on top of seotweaks
git push origin master           # create master on remote

But again:

  • if other users try to pull while master is deleted on remote, their pulls will fail ("no such ref on remote")
  • when master is recreated on remote, a pull will attempt to merge that new master on their local (now old) master: lots of conflicts. They actually need to reset --hard their local master to the remote/master branch they will fetch, and forget about their current master.

ES6 exporting/importing in index file

Also, bear in mind that if you need to export multiple functions at once, like actions you can use

export * from './XThingActions';

python .replace() regex

In order to replace text using regular expression use the re.sub function:

sub(pattern, repl, string[, count, flags])

It will replace non-everlaping instances of pattern by the text passed as string. If you need to analyze the match to extract information about specific group captures, for instance, you can pass a function to the string argument. more info here.

Examples

>>> import re
>>> re.sub(r'a', 'b', 'banana')
'bbnbnb'

>>> re.sub(r'/\d+', '/{id}', '/andre/23/abobora/43435')
'/andre/{id}/abobora/{id}'

MySQL said: Documentation #1045 - Access denied for user 'root'@'localhost' (using password: NO)

Check your MySQL Port number 3306.

Is there any other MySQL Install in your system on same port ?

If any installation found the change the port number to any number between 3301-3309 (except 3306)

user name : root
password : ' ' (Empty)

Increase max_execution_time in PHP?

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

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

Capture key press (or keydown) event on DIV element

(1) Set the tabindex attribute:

<div id="mydiv" tabindex="0" />

(2) Bind to keydown:

 $('#mydiv').on('keydown', function(event) {
    //console.log(event.keyCode);
    switch(event.keyCode){
       //....your actions for the keys .....
    }
 });

To set the focus on start:

$(function() {
   $('#mydiv').focus();
});

To remove - if you don't like it - the div focus border, set outline: none in the CSS.

See the table of keycodes for more keyCode possibilities.

All of the code assuming you use jQuery.

#

How do I determine whether an array contains a particular value in Java?

Create a boolean initially set to false. Run a loop to check every value in the array and compare to the value you are checking against. If you ever get a match, set boolean to true and stop the looping. Then assert that the boolean is true.

How to show shadow around the linearlayout in Android?

Try this.. layout_shadow.xml

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
    <item>
        <shape android:shape="rectangle">
            <solid android:color="#CABBBBBB"/>
            <corners android:radius="2dp" />
        </shape>
    </item>

    <item
        android:left="0dp"
        android:right="0dp"
        android:top="0dp"
        android:bottom="2dp">
        <shape android:shape="rectangle">
            <solid android:color="@android:color/white"/>
            <corners android:radius="2dp" />
        </shape>
    </item>
</layer-list>

Apply to your layout like this

 android:background="@drawable/layout_shadow"

How to add a vertical Separator?

This should do exactly what the author wanted:

<StackPanel Orientation="Horizontal">
    <Separator Style="{StaticResource {x:Static ToolBar.SeparatorStyleKey}}" />            
</StackPanel>

if you want a horizontal separator, change the Orientation of the StackPanel to Vertical.

Change Placeholder Text using jQuery

$(this).val() is a string. Use parseInt($(this).val(), 10) or check for '1'. The ten is to denote base 10.

$(function () {
    $('input[placeholder], textarea[placeholder]').blur();
    $('#serMemdd').change(function () {
        var k = $(this).val();
        if (k == '1') {
            $("#serMemtb").attr("placeholder", "Type a name (Lastname, Firstname)").blur();
        }
        else if (k == '2') {
            $("#serMemtb").attr("placeholder", "Type an ID").blur();
        }
        else if (k == '3') {
            $("#serMemtb").attr("placeholder", "Type a Location").blur();
        }
    });
});

Or

$(function () {
    $('input[placeholder], textarea[placeholder]').placeholder();
    $('#serMemdd').change(function () {
        var k = parseInt($(this).val(), 10);
        if (k == 1) {
            $("#serMemtb").attr("placeholder", "Type a name (Lastname, Firstname)").blur();
        }
        else if (k == 2) {
            $("#serMemtb").attr("placeholder", "Type an ID").blur();
        }
        else if (k == 3) {
            $("#serMemtb").attr("placeholder", "Type a Location").blur();
        }
    });
});

Other Plugins

ori has brought to my attention that the plugin you are using does not overcome IEs HTML failure.

Try something like this: http://archive.plugins.jquery.com/project/input-placeholder

Call int() function on every list element?

Another way,

for i, v in enumerate(numbers): numbers[i] = int(v)

check if "it's a number" function in Oracle

How is the column defined? If its a varchar field, then its not a number (or stored as one). Oracle may be able to do the conversion for you (eg, select * from someTable where charField = 0), but it will only return rows where the conversion holds true and is possible. This is also far from ideal situation performance wise.

So, if you want to do number comparisons and treat this column as a number, perhaps it should be defined as a number?

That said, here's what you might do:

create or replace function myToNumber(i_val in varchar2) return number is
 v_num number;
begin
 begin
   select to_number(i_val) into v_num from dual;
 exception
   when invalid_number then
   return null;
 end;
 return v_num;
end;

You might also include the other parameters that the regular to_number has. Use as so:

select * from someTable where myToNumber(someCharField) > 0;

It won't return any rows that Oracle sees as an invalid number.

Cheers.

tr:hover not working

You need to use <!DOCTYPE html> for :hover to work with anything other than the <a> tag. Try adding that to the top of your HTML.

How do I find which process is leaking memory?

In addition to top, you can use System Monitor (System - Administration - System Monitor, then select Processes tab). Select View - All Processes, go to Edit - Preferences and enable Virtual Memory column. Sort either by this column, or by Memory column

How do I find if a string starts with another string in Ruby?

The method mentioned by steenslag is terse, and given the scope of the question it should be considered the correct answer. However it is also worth knowing that this can be achieved with a regular expression, which if you aren't already familiar with in Ruby, is an important skill to learn.

Have a play with Rubular: http://rubular.com/

But in this case, the following ruby statement will return true if the string on the left starts with 'abc'. The \A in the regex literal on the right means 'the beginning of the string'. Have a play with rubular - it will become clear how things work.

'abcdefg' =~  /\Aabc/

size of uint8, uint16 and uint32?

uint8, uint16, uint32, and uint64 are probably Microsoft-specific types.

As of the 1999 standard, C supports standard typedefs with similar meanings, defined in <stdint.h>: uint8_t, uint16_t, uint32_t, and uint64_t. I'll assume that the Microsoft-specific types are defined similarly. Microsoft does support <stdint.h>, at least as of Visual Studio 2010, but older code may use uint8 et al.

The predefined types char, short, int et al have sizes that vary from one C implementation to another. The C standard has certain minimum requirements (char is at least 8 bits, short and int are at least 16, long is at least 32, and each type in that list is at least as wide as the previous type), but permits some flexibility. For example, I've seen systems where int is 16, 32, or 64 bits.

char is almost always exactly 8 bits, but it's permitted to be wider. And plain char may be either signed or unsigned.

uint8_t is required to be an unsigned integer type that's exactly 8 bits wide. It's likely to be a typedef for unsigned char, though it might be a typedef for plain char if plain char happens to be unsigned. If there is no predefined 8-bit unsigned type, then uint8_t will not be defined at all.

Similarly, each uintN_t type is an unsigned type that's exactly N bits wide.

In addition, <stdint.h> defines corresponding signed intN_t types, as well as int_fastN_t and int_leastN_t types that are at least the specified width.

The [u]intN_t types are guaranteed to have no padding bits, so the size of each is exactly N bits. The signed intN_t types are required to use a 2's-complement representation.

Although uint32_t might be the same as unsigned int, for example, you shouldn't assume that. Use unsigned int when you need an unsigned integer type that's at least 16 bits wide, and that's the "natural" size for the current system. Use uint32_t when you need an unsigned integer type that's exactly 32 bits wide.

(And no, uint64 or uint64_t is not the same as double; double is a floating-point type.)

Webpack how to build production code and how to use it

This will help you.

plugins: [
    new webpack.DefinePlugin({
      'process.env': {
        // This has effect on the react lib size
        'NODE_ENV': JSON.stringify('production'),
      }
    }),
    new ExtractTextPlugin("bundle.css", {allChunks: false}),
    new webpack.optimize.AggressiveMergingPlugin(),
    new webpack.optimize.OccurrenceOrderPlugin(),
    new webpack.optimize.DedupePlugin(),
    new webpack.optimize.UglifyJsPlugin({
      mangle: true,
      compress: {
        warnings: false, // Suppress uglification warnings
        pure_getters: true,
        unsafe: true,
        unsafe_comps: true,
        screw_ie8: true
      },
      output: {
        comments: false,
      },
      exclude: [/\.min\.js$/gi] // skip pre-minified libs
    }),
    new webpack.IgnorePlugin(/^\.\/locale$/, [/moment$/]), //https://stackoverflow.com/questions/25384360/how-to-prevent-moment-js-from-loading-locales-with-webpack
    new CompressionPlugin({
      asset: "[path].gz[query]",
      algorithm: "gzip",
      test: /\.js$|\.css$|\.html$/,
      threshold: 10240,
      minRatio: 0
    })
  ],

Rotate a div using javascript

Can be pretty easily done assuming you're using jQuery and css3:

http://jsfiddle.net/S7JDU/8/

HTML:

<div id="clicker">Click Here</div>
<div id="rotating"></div>

CSS:

#clicker { 
    width: 100px; 
    height: 100px; 
    background-color: Green; 
}

#rotating { 
    width: 100px; 
    height: 100px; 
    background-color: Red; 
    margin-top: 50px; 
    -webkit-transition: all 0.3s ease-in-out;
    -moz-transition: all 0.3s ease-in-out;
    -o-transition: all 0.3s ease-in-out;
    transition: all 0.3s ease-in-out;
}

.rotated { 
    transform:rotate(25deg); 
    -webkit-transform:rotate(25deg); 
    -moz-transform:rotate(25deg); 
    -o-transform:rotate(25deg); 
}

JS:

$(document).ready(function() {
    $('#clicker').click(function() {
        $('#rotating').toggleClass('rotated');
    });
});

What is __main__.py?

Some of the answers here imply that given a "package" directory (with or without an explicit __init__.py file), containing a __main__.py file, there is no difference between running that directory with the -m switch or without.

The big difference is that without the -m switch, the "package" directory is first added to the path (i.e. sys.path), and then the files are run normally, without package semantics.

Whereas with the -m switch, package semantics (including relative imports) are honoured, and the package directory itself is never added to the system path.

This is a very important distinction, both in terms of whether relative imports will work or not, but more importantly in terms of dictating what will be imported in the case of unintended shadowing of system modules.

Example:

Consider a directory called PkgTest with the following structure

:~/PkgTest$ tree
.
+-- pkgname
¦   +-- __main__.py
¦   +-- secondtest.py
¦   +-- testmodule.py
+-- testmodule.py

where the __main__.py file has the following contents:

:~/PkgTest$ cat pkgname/__main__.py
import os
print( "Hello from pkgname.__main__.py. I am the file", os.path.abspath( __file__ ) )
print( "I am being accessed from", os.path.abspath( os.curdir ) )
from  testmodule import main as firstmain;     firstmain()
from .secondtest import main as secondmain;    secondmain()

(with the other files defined similarly with similar printouts).

If you run this without the -m switch, this is what you'll get. Note that the relative import fails, but more importantly note that the wrong testmodule has been chosen (i.e. relative to the working directory):

:~/PkgTest$ python3 pkgname
Hello from pkgname.__main__.py. I am the file ~/PkgTest/pkgname/__main__.py
I am being accessed from ~/PkgTest
Hello from testmodule.py. I am the file ~/PkgTest/pkgname/testmodule.py
I am being accessed from ~/PkgTest
Traceback (most recent call last):
  File "/usr/lib/python3.6/runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "/usr/lib/python3.6/runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "pkgname/__main__.py", line 10, in <module>
    from .secondtest import main as secondmain
ImportError: attempted relative import with no known parent package

Whereas with the -m switch, you get what you (hopefully) expected:

:~/PkgTest$ python3 -m pkgname
Hello from pkgname.__main__.py. I am the file ~/PkgTest/pkgname/__main__.py
I am being accessed from ~/PkgTest
Hello from testmodule.py. I am the file ~/PkgTest/testmodule.py
I am being accessed from ~/PkgTest
Hello from secondtest.py. I am the file ~/PkgTest/pkgname/secondtest.py
I am being accessed from ~/PkgTest

Note: In my honest opinion, running without -m should be avoided. In fact I would go further and say that I would create any executable packages in such a way that they would fail unless run via the -m switch.

In other words, I would only import from 'in-package' modules explicitly via 'relative imports', assuming that all other imports represent system modules. If someone attempts to run your package without the -m switch, the relative import statements will throw an error, instead of silently running the wrong module.

C#: HttpClient with POST parameters

A cleaner alternative would be to use a Dictionary to handle parameters. They are key-value pairs after all.

private static readonly HttpClient httpclient;

static MyClassName()
{
    // HttpClient is intended to be instantiated once and re-used throughout the life of an application. 
    // Instantiating an HttpClient class for every request will exhaust the number of sockets available under heavy loads. 
    // This will result in SocketException errors.
    // https://docs.microsoft.com/en-us/dotnet/api/system.net.http.httpclient?view=netframework-4.7.1
    httpclient = new HttpClient();    
} 

var url = "http://myserver/method";
var parameters = new Dictionary<string, string> { { "param1", "1" }, { "param2", "2" } };
var encodedContent = new FormUrlEncodedContent (parameters);

var response = await httpclient.PostAsync (url, encodedContent).ConfigureAwait (false);
if (response.StatusCode == HttpStatusCode.OK) {
    // Do something with response. Example get content:
    // var responseContent = await response.Content.ReadAsStringAsync ().ConfigureAwait (false);
}

Also dont forget to Dispose() httpclient, if you dont use the keyword using

As stated in the Remarks section of the HttpClient class in the Microsoft docs, HttpClient should be instantiated once and re-used.

Edit:

You may want to look into response.EnsureSuccessStatusCode(); instead of if (response.StatusCode == HttpStatusCode.OK).

You may want to keep your httpclient and dont Dispose() it. See: Do HttpClient and HttpClientHandler have to be disposed?

Edit:

Do not worry about using .ConfigureAwait(false) in .NET Core. For more details look at https://blog.stephencleary.com/2017/03/aspnetcore-synchronization-context.html

Subdomain on different host

sub domain is part of the domain, it's like subletting a room of an apartment. A records has to be setup on the dns for the domain e.g

mydomain.com has IP 123.456.789.999 and hosted with Godaddy. Now to get the sub domain

anothersite.mydomain.com

of which the site is actually on another server then

login to Godaddy and add an A record dnsimple anothersite.mydomain.com and point the IP to the other server 98.22.11.11

And that's it.

Node.js: Gzip compression?

If you're using Express, then you can use its compress method as part of the configuration:

var express = require('express');
var app = express.createServer();
app.use(express.compress());

And you can find more on compress here: http://expressjs.com/api.html#compress

And if you're not using Express... Why not, man?! :)

NOTE: (thanks to @ankitjaininfo) This middleware should be one of the first you "use" to ensure all responses are compressed. Ensure that this is above your routes and static handler (eg. how I have it above).

NOTE: (thanks to @ciro-costa) Since express 4.0, the express.compress middleware is deprecated. It was inherited from connect 3.0 and express no longer includes connect 3.0. Check Express Compression for getting the middleware.

Why use the params keyword?

It allows you to add as many base type parameters in your call as you like.

addTwoEach(10, 2, 4, 6)

whereas with the second form you have to use an array as parameter

addTwoEach(new int[] {10,2,4,6})

Change bullets color of an HTML list without using span

Building off @Marc's solution -- since the bullet character is rendered differently with different fonts and browsers, I used the following css3 technique with border-radius to make a bullet that I have more control over:

li:before {
    content: '';
    background-color: #898989;
    display: inline-block;
    position: relative;
    height: 12px;
    width: 12px;
    border-radius: 6px;
    -webkit-border-radius: 6px;
    -moz-border-radius: 6px;
    -moz-background-clip: padding;
    -webkit-background-clip: padding-box;
    background-clip: padding-box;
    margin-right: 4px;
    top: 2px;
}

Comments in Markdown

If you are using Jekyll or octopress following will also work.

{% comment %} 
    These commments will not include inside the source.
{% endcomment %}

The Liquid tags {% comment %} are parsed first and removed before the MarkDown processor even gets to it. Visitors will not see when they try to view source from their browser.

Why maven settings.xml file is not there?

As per the maven's documentation, there are two possible settings.xml locations

One is the global maven's repo (Your initial download and subsequent unzipped files from apache maven) $M2_HOME/conf/settings.xml

And the second is the user created one (Your local copy) ${user.home}/.m2/settings.xml

The local copy takes precedence over the global copy in terms of settings information. But it is said that they both get merged during "runtime". If you need to have your local copy of the settings.xml, simply copy from the global copy and paste in your .m2 folder and adjust the details as needed

Floating point exception

It's caused by n % x where x = 0 in the first loop iteration. You can't calculate a modulus with respect to 0.

Content-Disposition:What are the differences between "inline" and "attachment"?

It might also be worth mentioning that inline will try to open Office Documents (xls, doc etc) directly from the server, which might lead to a User Credentials Prompt.

see this link:

http://forums.asp.net/t/1885657.aspx/1?Access+the+SSRS+Report+in+excel+format+on+server

somebody tried to deliver an Excel Report from SSRS via ASP.Net -> the user always got prompted to enter the credentials. After clicking cancel on the prompt it would be opened anyway...

If the Content Disposition is marked as Attachment it will automatically be saved to the temp folder after clicking open and then opened in Excel from the local copy.

SQL How to replace values of select return?

Replace the value in select statement itself...

(CASE WHEN Mobile LIKE '966%' THEN (select REPLACE(CAST(Mobile AS nvarchar(MAX)),'966','0')) ELSE Mobile END)

What is the non-jQuery equivalent of '$(document).ready()'?

This does not answer the question nor does it show any non-jQuery code. See @ sospedra's answer below.

The nice thing about $(document).ready() is that it fires before window.onload. The load function waits until everything is loaded, including external assets and images. $(document).ready, however, fires when the DOM tree is complete and can be manipulated. If you want to acheive DOM ready, without jQuery, you might check into this library. Someone extracted just the ready part from jQuery. Its nice and small and you might find it useful:

domready at Google Code

Catching "Maximum request length exceeded"

You can solve this by increasing the maximum request length in your web.config:

<?xml version="1.0" encoding="utf-8"?>
<configuration>
    <system.web>
        <httpRuntime maxRequestLength="102400" />
    </system.web>
</configuration>

The example above is for a 100Mb limit.

What's the best three-way merge tool?

The summary is that I found ECMerge to be a great, though commercial product. http://www.elliecomputing.com/products/merge_overview.asp

enter image description here

I also agree with MrTelly that Ultracompare is very good. One nice feature is that it will compare RTF and Word docs, which is handy when you end up programming in word with the sales guys and they don't manage their docs correctly.

Bootstrap 4 align navbar items to the right

In my case, I wanted just one set of navigation buttons / options and found that this will work:

<div class="collapse navbar-collapse justify-content-end" id="navbarCollapse">
  <ul class="navbar-nav">
    <li class="nav-item">
      <a class="nav-link" href="#">Sign Out</a>
    </li>
  </ul>
</div>

So, you will add justify-content-end to the div and omit mr-auto on the list.

Here is a working example.

In mocha testing while calling asynchronous function how to avoid the timeout Error: timeout of 2000ms exceeded

You can either set the timeout when running your test:

mocha --timeout 15000

Or you can set the timeout for each suite or each test programmatically:

describe('...', function(){
  this.timeout(15000);

  it('...', function(done){
    this.timeout(15000);
    setTimeout(done, 15000);
  });
});

For more info see the docs.

Add padding on view programmatically

You can set padding to your view by pro grammatically throughout below code - 

view.setPadding(0,1,20,3);

And, also there are different type of padding available -

Padding

PaddingBottom

PaddingLeft

PaddingRight

PaddingTop

These, links will refer Android Developers site. Hope this helps you lot.

Incrementing a date in JavaScript

This a simpler method , and it will return the date in simple yyyy-mm-dd format , Here it is

function incDay(date, n) {
    var fudate = new Date(new Date(date).setDate(new Date(date).getDate() + n));
    fudate = fudate.getFullYear() + '-' + (fudate.getMonth() + 1) + '-' + fudate.toDateString().substring(8, 10);
    return fudate;
}

example :

var tomorrow = incDay(new Date(), 1); // the next day of today , aka tomorrow :) .
var spicaldate = incDay("2020-11-12", 1); // return "2020-11-13" .
var somedate = incDay("2020-10-28", 5); // return "2020-11-02" .

Note

incDay(new Date("2020-11-12"), 1); 
incDay("2020-11-12", 1);

will return the same result .

How to get N rows starting from row M from sorted table in T-SQL

This thread is quite old, but currently you can do this: much cleaner imho

SELECT *
FROM Sales.SalesOrderDetail
ORDER BY SalesOrderDetailID
OFFSET 20 ROWS
FETCH NEXT 10 ROWS ONLY;
GO

source: http://blog.sqlauthority.com/2013/12/30/sql-server-mysql-limit-and-offset-skip-and-return-only-next-few-rows-paging-solution/

How to get rid of "Unnamed: 0" column in a pandas DataFrame?

It's the index column, pass pd.to_csv(..., index=False) to not write out an unnamed index column in the first place, see the to_csv() docs.

Example:

In [37]:
df = pd.DataFrame(np.random.randn(5,3), columns=list('abc'))
pd.read_csv(io.StringIO(df.to_csv()))

Out[37]:
   Unnamed: 0         a         b         c
0           0  0.109066 -1.112704 -0.545209
1           1  0.447114  1.525341  0.317252
2           2  0.507495  0.137863  0.886283
3           3  1.452867  1.888363  1.168101
4           4  0.901371 -0.704805  0.088335

compare with:

In [38]:
pd.read_csv(io.StringIO(df.to_csv(index=False)))

Out[38]:
          a         b         c
0  0.109066 -1.112704 -0.545209
1  0.447114  1.525341  0.317252
2  0.507495  0.137863  0.886283
3  1.452867  1.888363  1.168101
4  0.901371 -0.704805  0.088335

You could also optionally tell read_csv that the first column is the index column by passing index_col=0:

In [40]:
pd.read_csv(io.StringIO(df.to_csv()), index_col=0)

Out[40]:
          a         b         c
0  0.109066 -1.112704 -0.545209
1  0.447114  1.525341  0.317252
2  0.507495  0.137863  0.886283
3  1.452867  1.888363  1.168101
4  0.901371 -0.704805  0.088335

XDocument or XmlDocument

XDocument is from the LINQ to XML API, and XmlDocument is the standard DOM-style API for XML. If you know DOM well, and don't want to learn LINQ to XML, go with XmlDocument. If you're new to both, check out this page that compares the two, and pick which one you like the looks of better.

I've just started using LINQ to XML, and I love the way you create an XML document using functional construction. It's really nice. DOM is clunky in comparison.

Expand a random range from 1–5 to 1–7

First, I move ramdom5() on the 1 point 6 times, to get 7 random numbers. Second, I add 7 numbers to obtain common sum. Third, I get remainder of the division at 7. Last, I add 1 to get results from 1 till 7. This method gives an equal probability of getting numbers in the range from 1 to 7, with the exception of 1. 1 has a slightly higher probability.

public int random7(){
    Random random = new Random();
    //function (1 + random.nextInt(5)) is given
    int random1_5 = 1 + random.nextInt(5); // 1,2,3,4,5
    int random2_6 = 2 + random.nextInt(5); // 2,3,4,5,6
    int random3_7 = 3 + random.nextInt(5); // 3,4,5,6,7
    int random4_8 = 4 + random.nextInt(5); // 4,5,6,7,8
    int random5_9 = 5 + random.nextInt(5); // 5,6,7,8,9
    int random6_10 = 6 + random.nextInt(5); //6,7,8,9,10
    int random7_11 = 7 + random.nextInt(5); //7,8,9,10,11

    //sumOfRandoms is between 28 and 56
    int sumOfRandoms = random1_5 + random2_6 + random3_7 + 
                       random4_8 + random5_9 + random6_10 + random7_11;
    //result is number between 0 and 6, and
    //equals 0 if sumOfRandoms = 28 or 35 or 42 or 49 or 56 , 5 options
    //equals 1 if sumOfRandoms = 29 or 36 or 43 or 50, 4 options
    //equals 2 if sumOfRandoms = 30 or 37 or 44 or 51, 4 options
    //equals 3 if sumOfRandoms = 31 or 38 or 45 or 52, 4 options
    //equals 4 if sumOfRandoms = 32 or 39 or 46 or 53, 4 options
    //equals 5 if sumOfRandoms = 33 or 40 or 47 or 54, 4 options
    //equals 6 if sumOfRandoms = 34 or 41 or 48 or 55, 4 options
    //It means that the probabilities of getting numbers between 0 and 6 are almost equal.
    int result = sumOfRandoms % 7;
    //we should add 1 to move the interval [0,6] to the interval [1,7]
    return 1 + result;
}

jquery get height of iframe content when loaded

ok I finally found a good solution:

$('iframe').load(function() {
    this.style.height =
    this.contentWindow.document.body.offsetHeight + 'px';
});

Because some browsers (older Safari and Opera) report onload completed before CSS renders you need to set a micro Timeout and blank out and reassign the iframe's src. 

$('iframe').load(function() {
    setTimeout(iResize, 50);
    // Safari and Opera need a kick-start.
    var iSource = document.getElementById('your-iframe-id').src;
    document.getElementById('your-iframe-id').src = '';
    document.getElementById('your-iframe-id').src = iSource;
});
function iResize() {
    document.getElementById('your-iframe-id').style.height = 
    document.getElementById('your-iframe-id').contentWindow.document.body.offsetHeight + 'px';
}

Converting year and month ("yyyy-mm" format) to a date?

The most concise solution if you need the dates to be in Date format:

library(zoo)
month <- "2000-03"
as.Date(as.yearmon(month))
[1] "2000-03-01"

as.Date will fix the first day of each month to a yearmon object for you.

How should I import data from CSV into a Postgres table using pgAdmin 3?

You may have a table called 'test'

COPY test(gid, "name", the_geom)
FROM '/home/data/sample.csv'
WITH DELIMITER ','
CSV HEADER

Getting all types that implement an interface

I appreciate this is a very old question but I thought I would add another answer for future users as all the answers to date use some form of Assembly.GetTypes.

Whilst GetTypes() will indeed return all types, it does not necessarily mean you could activate them and could thus potentially throw a ReflectionTypeLoadException.

A classic example for not being able to activate a type would be when the type returned is derived from base but base is defined in a different assembly from that of derived, an assembly that the calling assembly does not reference.

So say we have:

Class A // in AssemblyA
Class B : Class A, IMyInterface // in AssemblyB
Class C // in AssemblyC which references AssemblyB but not AssemblyA

If in ClassC which is in AssemblyC we then do something as per accepted answer:

var type = typeof(IMyInterface);
var types = AppDomain.CurrentDomain.GetAssemblies()
    .SelectMany(s => s.GetTypes())
    .Where(p => type.IsAssignableFrom(p));

Then it will throw a ReflectionTypeLoadException.

This is because without a reference to AssemblyA in AssemblyC you would not be able to:

var bType = typeof(ClassB);
var bClass = (ClassB)Activator.CreateInstance(bType);

In other words ClassB is not loadable which is something that the call to GetTypes checks and throws on.

So to safely qualify the result set for loadable types then as per this Phil Haacked article Get All Types in an Assembly and Jon Skeet code you would instead do something like:

public static class TypeLoaderExtensions {
    public static IEnumerable<Type> GetLoadableTypes(this Assembly assembly) {
        if (assembly == null) throw new ArgumentNullException("assembly");
        try {
            return assembly.GetTypes();
        } catch (ReflectionTypeLoadException e) {
            return e.Types.Where(t => t != null);
        }
    }
}

And then:

private IEnumerable<Type> GetTypesWithInterface(Assembly asm) {
    var it = typeof (IMyInterface);
    return asm.GetLoadableTypes().Where(it.IsAssignableFrom).ToList();
}

How to add class active on specific li on user click with jQuery

//Write a javascript method to bind click event of each "li" item

    function BindClickEvent()
    {
    var selector = '.nav li';
    //Removes click event of each li
    $(selector ).unbind('click');
    //Add click event
    $(selector ).bind('click', function()
    {
        $(selector).removeClass('active');
        $(this).addClass('active');
    });

    }

//first call this method when first time when page load

    $( document ).ready(function() {
         BindClickEvent();
    });

//Call BindClickEvent method from server side 

    protected void Page_Load(object sender, EventArgs e)
    {
        ScriptManager.RegisterStartupScript(Page,GetType(), Guid.NewGuid().ToString(),"BindClickEvent();",true);
    }

Show special characters in Unix while using 'less' Command

For less use -u to display carriage returns (^M) and backspaces (^H), or -U to show the previous and tabs (^I) for example:

$ awk 'BEGIN{print "foo\bbar\tbaz\r\n"}' | less -U 
foo^Hbar^Ibaz^M

(END)

Without the -U switch the output would be:

fobar   baz

(END)

See man less for more exact description on the features.

How to do a SOAP wsdl web services call from the command line

 
curl --header "Content-Type: text/xml;charset=UTF-8" --header "SOAPAction:ACTION_YOU_WANT_TO_CALL" --data @FILE_NAME URL_OF_THE_SERVICE

Above command was helpful for me

Example

curl --header "Content-Type: text/xml;charset=UTF-8" --header "SOAPAction:urn:GetVehicleLimitedInfo" --data @request.xml http://11.22.33.231:9080/VehicleInfoQueryService.asmx

More info

Check if an element is present in a Bash array

 
array=("word" "two words") # let's look for "two words"

using grep and printf:

(printf '%s\n' "${array[@]}" | grep -x -q "two words") && <run_your_if_found_command_here>

using for:

(for e in "${array[@]}"; do [[ "$e" == "two words" ]] && exit 0; done; exit 1) && <run_your_if_found_command_here>

For not_found results add || <run_your_if_notfound_command_here>

How do I kill an Activity when the Back button is pressed?

add this to your activity

@Override
public boolean onKeyDown(int keyCode, KeyEvent event)
{
    if ((keyCode == KeyEvent.KEYCODE_BACK))
    {
        finish();
    }
    return super.onKeyDown(keyCode, event);
}

How can I transition height: 0; to height: auto; using CSS?

_x000D_
_x000D_ 
.menu {_x000D_
    margin: 0 auto;_x000D_
    padding: 0;_x000D_
    list-style: none;_x000D_
    text-align: center;_x000D_
    max-width: 300px;_x000D_
    width: 100%;_x000D_
}_x000D_
_x000D_
.menu li {_x000D_
    display: block;_x000D_
    margin-bottom: 5px;_x000D_
}_x000D_
.menu li a {_x000D_
    color: #333;_x000D_
    display: inline-block;_x000D_
    font-size: 20px;_x000D_
    line-height: 28px;_x000D_
    font-weight: 500;_x000D_
    font-family: "Poppins", sans-serif;_x000D_
    transition: all 0.5s;_x000D_
    margin: 0 0 10px;_x000D_
}_x000D_
_x000D_
.menu li.submenu .submenu_item {_x000D_
    margin: 0;_x000D_
    padding: 0;_x000D_
    width: 100%;_x000D_
    max-height: 0;_x000D_
    overflow: hidden;_x000D_
    display: flex;_x000D_
    flex-direction: row;_x000D_
    text-align: center;_x000D_
    flex-wrap: wrap;_x000D_
    justify-content: center;_x000D_
    align-items: center;_x000D_
    transition: max-height 1s ease-out !important;_x000D_
    transition-delay: 0s !important;_x000D_
}_x000D_
_x000D_
.menu li.submenu:hover .submenu_item {_x000D_
    max-height: 1000px;_x000D_
    transition: max-height 2s ease-in !important;_x000D_
}_x000D_
_x000D_
.menu li.submenu .submenu_item li {_x000D_
    margin-bottom: 0;_x000D_
    width: 100%;_x000D_
    display: block;_x000D_
    margin: 0;_x000D_
    padding: 0;_x000D_
    list-style: none;_x000D_
    position: relative;_x000D_
}
_x000D_ 
<p>First you should complete markup  like this</p>_x000D_
_x000D_
<ul class="menu">_x000D_
  <li class="submenu">_x000D_
    <a href="#">Home</a>_x000D_
    <ul class="submenu_item">_x000D_
        <li><a href="index.html">Default</a></li>_x000D_
        <li><a href="index-2.html">Particle</a></li>_x000D_
        <li><a href="index-3.html">Youtube Video</a></li>_x000D_
        <li><a href="index-4.html">Self Hosted Video</a></li>_x000D_
        <li><a href="index-5.html">Slideshow</a></li>_x000D_
    </ul>_x000D_
  </li>_x000D_
</ul>
_x000D_
_x000D_
_x000D_

How to implement static class member functions in *.cpp file?

Yes you can define static member functions in *.cpp file. If you define it in the header, compiler will by default treat it as inline. However, it does not mean separate copies of the static member function will exist in the executable. Please follow this post to learn more about this: Are static member functions in c++ copied in multiple translation units?

numpy matrix vector multiplication

Simplest solution

Use numpy.dot or a.dot(b). See the documentation here.

>>> a = np.array([[ 5, 1 ,3], 
                  [ 1, 1 ,1], 
                  [ 1, 2 ,1]])
>>> b = np.array([1, 2, 3])
>>> print a.dot(b)
array([16, 6, 8])

This occurs because numpy arrays are not matrices, and the standard operations *, +, -, / work element-wise on arrays. Instead, you could try using numpy.matrix, and * will be treated like matrix multiplication.

Other Solutions

Also know there are other options:

  • As noted below, if using python3.5+ the @ operator works as you'd expect:

    >>> print(a @ b)
array([16, 6, 8])

  • If you want overkill, you can use numpy.einsum. The documentation will give you a flavor for how it works, but honestly, I didn't fully understand how to use it until reading this answer and just playing around with it on my own.

    >>> np.einsum('ji,i->j', a, b)
array([16, 6, 8])

  • As of mid 2016 (numpy 1.10.1), you can try the experimental numpy.matmul, which works like numpy.dot with two major exceptions: no scalar multiplication but it works with stacks of matrices. 

    >>> np.matmul(a, b)
array([16, 6, 8])

  • numpy.inner functions the same way as numpy.dot for matrix-vector multiplication but behaves differently for matrix-matrix and tensor multiplication (see Wikipedia regarding the differences between the inner product and dot product in general or see this SO answer regarding numpy's implementations).

    >>> np.inner(a, b)
array([16, 6, 8])

# Beware using for matrix-matrix multiplication though!
>>> b = a.T
>>> np.dot(a, b)
array([[35,  9, 10],
       [ 9,  3,  4],
       [10,  4,  6]])
>>> np.inner(a, b) 
array([[29, 12, 19],
       [ 7,  4,  5],
       [ 8,  5,  6]])

Rarer options for edge cases

  • If you have tensors (arrays of dimension greater than or equal to one), you can use numpy.tensordot with the optional argument axes=1:

    >>> np.tensordot(a, b, axes=1)
array([16,  6,  8])

  • Don't use numpy.vdot if you have a matrix of complex numbers, as the matrix will be flattened to a 1D array, then it will try to find the complex conjugate dot product between your flattened matrix and vector (which will fail due to a size mismatch n*m vs n).

How to initialize all members of an array to the same value?

If you want to ensure that every member of the array is explicitly initialized, just omit the dimension from the declaration:

int myArray[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9 };

The compiler will deduce the dimension from the initializer list. Unfortunately, for multidimensional arrays only the outermost dimension may be omitted:

int myPoints[][3] = { { 1, 2, 3 }, { 4, 5, 6 }, { 7, 8, 9} };

is OK, but

int myPoints[][] = { { 1, 2, 3 }, { 4, 5, 6 }, { 7, 8, 9} };

is not.

How do I increase the RAM and set up host-only networking in Vagrant?

You can easily increase your VM's RAM by modifying the memory property of config.vm.provider section in your vagrant file.

config.vm.provider "virtualbox" do |vb|
 vb.memory = "4096"
end

This allocates about 4GB of RAM to your VM. You can change this according to your requirement. For example, following setting would allocate 2GB of RAM to your VM. 

config.vm.provider "virtualbox" do |vb|
 vb.memory = "2048"
end

Try removing the config.vm.customize ["modifyvm", :id, "--memory", 1024] in your file, and adding the above code.

For the network configuration, try modifying the config.vm.network :hostonly, "199.188.44.20" in your file toconfig.vm.network "private_network", ip: "199.188.44.20"

How to get DataGridView cell value in messagebox?

 
      try
        {

            for (int rows = 0; rows < dataGridView1.Rows.Count; rows++)
            {

                for (int col = 0; col < dataGridView1.Rows[rows].Cells.Count; col++)
                {
                    s1 = dataGridView1.Rows[0].Cells[0].Value.ToString();
                    label20.Text = s1;
                }
            }
        }
        catch (Exception ex)
        {
            MessageBox.Show("try again"+ex);
        }

Alter SQL table - allow NULL column value

The following MySQL statement should modify your column to accept NULLs.

ALTER TABLE `MyTable`
ALTER COLUMN `Col3` varchar(20) DEFAULT NULL

Force GUI update from UI Thread

I had the same problem with property Enabled and I discovered a first chance exception raised because of it is not thread-safe. I found solution about "How to update the GUI from another thread in C#?" here https://stackoverflow.com/a/661706/1529139 And it works !

Create folder with batch but only if it doesn't already exist

 
mkdir C:\VTS 2> NUL

create a folder called VTS and output A subdirectory or file TEST already exists to NUL.

or 

(C:&(mkdir "C:\VTS" 2> NUL))&

change the drive letter to C:, mkdir, output error to NUL and run the next command.

How do I find the mime-type of a file with php?

if you're only dealing with images you can use the [getimagesize()][1] function which contains all sorts of info about the image, including the type.

A more general approach would be to use the FileInfo extension from PECL. The PHP documentation for this extension can be found at: http://us.php.net/manual/en/ref.fileinfo.php

Some people have serious complaints about that extension... so if you run into serious issues or cannot install the extension for some reason you might want to check out the deprecated function mime_content_type()

C compiler for Windows?

I personally have been looking into using MinGW (what Bloodshed uses) with the Code Blocks IDE.

I am also considering using the Digital Mars C/C++ compiler.

Both seem to be well regarded.

Default property value in React component using TypeScript

You can use the spread operator to re-assign props with a standard functional component. The thing I like about this approach is that you can mix required props with optional ones that have a default value.

interface MyProps {
   text: string;
   optionalText?: string;
}

const defaultProps = {
   optionalText = "foo";
}

const MyComponent = (props: MyProps) => {
   props = { ...defaultProps, ...props }
}

Failed to resolve: com.android.support:appcompat-v7:26.0.0

enter image description hereI was facing the same issue but I switched 26.0.0-beta1 dependencies to 26.1.0 and it's working now.

Calculate RSA key fingerprint

If your SSH agent is running, it is

ssh-add -l

to list RSA fingerprints of all identities, or -L for listing public keys.

If your agent is not running, try:

ssh-agent sh -c 'ssh-add; ssh-add -l'

And for your public keys:

ssh-agent sh -c 'ssh-add; ssh-add -L'

If you get the message: 'The agent has no identities.', then you have to generate your RSA key by ssh-keygen first.

What's the pythonic way to use getters and setters?

Using @property and @attribute.setter helps you to not only use the "pythonic" way but also to check the validity of attributes both while creating the object and when altering it.

class Person(object):
    def __init__(self, p_name=None):
        self.name = p_name

    @property
    def name(self):
        return self._name

    @name.setter
    def name(self, new_name):
        if type(new_name) == str: #type checking for name property
            self._name = new_name
        else:
            raise Exception("Invalid value for name")

By this, you actually 'hide' _name attribute from client developers and also perform checks on name property type. Note that by following this approach even during the initiation the setter gets called. So:

p = Person(12)

Will lead to:

Exception: Invalid value for name

But:

>>>p = person('Mike')
>>>print(p.name)
Mike
>>>p.name = 'George'
>>>print(p.name)
George
>>>p.name = 2.3 # Causes an exception

How to set background image in Java?

The answer will vary slightly depending on whether the application or applet is using AWT or Swing.

(Basically, classes that start with J such as JApplet and JFrame are Swing, and Applet and Frame are AWT.)

In either case, the basic steps would be:

  1. Draw or load an image into a Image object.
  2. Draw the background image in the painting event of the Component you want to draw the background in.

Step 1. Loading the image can be either by using the Toolkit class or by the ImageIO class.

The Toolkit.createImage method can be used to load an Image from a location specified in a String:

Image img = Toolkit.getDefaultToolkit().createImage("background.jpg");

Similarly, ImageIO can be used:

Image img = ImageIO.read(new File("background.jpg");

Step 2. The painting method for the Component that should get the background will need to be overridden and paint the Image onto the component.

For AWT, the method to override is the paint method, and use the drawImage method of the Graphics object that is handed into the paint method:

public void paint(Graphics g)
{
    // Draw the previously loaded image to Component.
    g.drawImage(img, 0, 0, null);

    // Draw sprites, and other things.
    // ....
}

For Swing, the method to override is the paintComponent method of the JComponent, and draw the Image as with what was done in AWT.

public void paintComponent(Graphics g)
{
    // Draw the previously loaded image to Component.
    g.drawImage(img, 0, 0, null);

    // Draw sprites, and other things.
    // ....
}

Simple Component Example

Here's a Panel which loads an image file when instantiated, and draws that image on itself:

class BackgroundPanel extends Panel
{
    // The Image to store the background image in.
    Image img;
    public BackgroundPanel()
    {
        // Loads the background image and stores in img object.
        img = Toolkit.getDefaultToolkit().createImage("background.jpg");
    }

    public void paint(Graphics g)
    {
        // Draws the img to the BackgroundPanel.
        g.drawImage(img, 0, 0, null);
    }
}

For more information on painting:

How to check if PHP array is associative or sequential?

Yet another way to do this.

function array_isassociative($array)
{
    // Create new Array,  Make it the same size as the input array
    $compareArray = array_pad(array(), count($array), 0);

    // Compare the two array_keys
    return (count(array_diff_key($array, $compareArray))) ? true : false;

}

Force browser to clear cache

Look into the cache-control and the expires META Tag.

<META HTTP-EQUIV="CACHE-CONTROL" CONTENT="NO-CACHE">
<META HTTP-EQUIV="EXPIRES" CONTENT="Mon, 22 Jul 2002 11:12:01 GMT">

Another common practices is to append constantly-changing strings to the end of the requested files. For instance:

<script type="text/javascript" src="main.js?v=12392823"></script>