Programs & Examples On #Oscommerce

Open source e-commerce application based on PHP & MySQL. The project was started in 2000 by Harald Ponce de Leon and is one of the most popular e-commerce applications.

What exactly does the .join() method do?

To append a string, just concatenate it with the + sign.

E.g.

>>> a = "Hello, "
>>> b = "world"
>>> str = a + b
>>> print str
Hello, world

join connects strings together with a separator. The separator is what you place right before the join. E.g.

>>> "-".join([a,b])
'Hello, -world'

Join takes a list of strings as a parameter.

Alternative Windows shells, besides CMD.EXE?

Try Clink. It's awesome, especially if you are used to bash keybindings and features.

(As already pointed out - there is a similar question: Is there a better Windows Console Window?)

Consider defining a bean of type 'package' in your configuration [Spring-Boot]

I think you can make it simplified by annotated your repository with @Repository, then it will be enabled automatically by Spring Framework.

Converting newline formatting from Mac to Windows

On Yosemite OSX, use this command:

sed -e 's/^M$//' -i '' filename

where the ^M sequence is achieved by pressing Ctrl+V then Enter.

How to make --no-ri --no-rdoc the default for gem install?

Step by steps:

To create/edit the .gemrc file from the terminal:

vi  ~/.gemrc

You will open a editor called vi. paste in:

gem: --no-ri --no-rdoc

click 'esc'-button.

type in:

:exit

You can check if everything is correct with this command:

sudo /Applications/TextEdit.app/Contents/MacOS/TextEdit ~/.gemrc

How do I style radio buttons with images - laughing smiley for good, sad smiley for bad?

Images can be placed in place of radio buttons by using label and span elements.

   <div class="customize-radio">
        <label>Favourite Smiley</label>
        <br>
        <label for="hahaha">
          <input type="radio" name="smiley" id="hahaha">
          <span class="haha-img"></span>
          HAHAHA
        </label>
        <label for="kiss">
          <input type="radio" name="smiley" id="kiss">
          <span class="kiss-img"></span>
          Kiss
        </label>
        <label for="tongueOut">
          <input type="radio" name="smiley" id="tongueOut">
          <span class="tongueout-img"></span>
          TongueOut
        </label>
    </div>

Radio button should be hidden,

.customize-radio label > input[type = 'radio'] {
    visibility: hidden;
    position: absolute;
}

Image can be given in the span tag,

.customize-radio label > input[type = 'radio'] ~ span{
    cursor: pointer;
    width: 27px;
    height: 24px;
    display: inline-block;
    background-size: 27px 24px;
    background-repeat: no-repeat;
}
.haha-img {
    background-image: url('hahabefore.png');
}

.kiss-img{
    background-image: url('kissbefore.png');
}
.tongueout-img{
    background-image: url('tongueoutbefore.png');
}

To change the image on click of radio button, add checked state to the input tag,

.customize-radio label > input[type = 'radio']:checked ~ span.haha-img{
     background-image: url('haha.png');
}
.customize-radio label > input[type = 'radio']:checked ~ span.kiss-img{
    background-image: url('kiss.png');
}
.customize-radio label > input[type = 'radio']:checked ~ span.tongueout-img{
        background-image: url('tongueout.png');
}

If you have any queries, Refer to the following link, As I have taken solution from the below blog, http://frontendsupport.blogspot.com/2018/06/cool-radio-buttons-with-images.html

break/exit script

Perhaps you just want to stop executing a long script at some point. ie. like you want to hard code an exit() in C or Python.

print("this is the last message")
stop()
print("you should not see this")

Can Selenium WebDriver open browser windows silently in the background?

I suggest using PhantomJS. For more information, you may visit the Phantom Official Website.

As far as I know PhantomJS works only with Firefox...

After downloading PhantomJs.exe you need to import it to your project as you can see in the picture below PhantomJS.

I have placed mine inside: common ? Library ? phantomjs.exe

Enter image description here

Now all you have to do inside your Selenium code is to change the line

browser = webdriver.Firefox()

To something like

import os
path2phantom = os.getcwd() + "\common\Library\phantomjs.exe"
browser = webdriver.PhantomJS(path2phantom)

The path to PhantomJS may be different... change as you like :)

This hack worked for me, and I'm pretty sure it will work for u too ;)

How to stop creating .DS_Store on Mac?

If you want the .DS_Store files to become invisible (they still exist but can't be seen) then run the following command in the "Terminal" window:

defaults write com.apple.finder AppleShowAllFiles FALSE; killall Finder

This will set the system default to stop showing these files on your Desktop and elsewhere. It will also restart the Finder in order to make this change visible (especially on your Desktop).

Prompt for user input in PowerShell

Place this at the top of your script. It will cause the script to prompt the user for a password. The resulting password can then be used elsewhere in your script via $pw.

   Param(
     [Parameter(Mandatory=$true, Position=0, HelpMessage="Password?")]
     [SecureString]$password
   )

   $pw = [Runtime.InteropServices.Marshal]::PtrToStringAuto([Runtime.InteropServices.Marshal]::SecureStringToBSTR($password))

If you want to debug and see the value of the password you just read, use:

   write-host $pw

Is Constructor Overriding Possible?

I found this as a good example for this question:

    class Publication {

    private String title;

    public Publication(String title) {
        this.title = title;
    }

    public String getDetails() {
        return "title=\"" + title + "\"";
    }

}

class Newspaper extends Publication {

    private String source;

    public Newspaper(String title, String source) {
        super(title);
        this.source = source;
    }

    @Override
    public String getDetails() {
        return super.getDetails() + ", source=\"" + source + "\"";
    }
}

class Article extends Publication {

    private String author;

    public Article(String title, String author) {
        super(title);
        this.author = author;
    }

    @Override
    public String getDetails() {
        return super.getDetails() + ", author=\"" + author + "\"";
    }

}

class Announcement extends Publication {

    private int daysToExpire;

    public Announcement(String title, int daysToExpire) {
        super(title);
        this.daysToExpire = daysToExpire;
    }

    @Override
    public String getDetails() {
        return super.getDetails() + ", daysToExpire=" + daysToExpire;
    }

}

Why XML-Serializable class need a parameterless constructor

This is a limitation of XmlSerializer. Note that BinaryFormatter and DataContractSerializer do not require this - they can create an uninitialized object out of the ether and initialize it during deserialization.

Since you are using xml, you might consider using DataContractSerializer and marking your class with [DataContract]/[DataMember], but note that this changes the schema (for example, there is no equivalent of [XmlAttribute] - everything becomes elements).

Update: if you really want to know, BinaryFormatter et al use FormatterServices.GetUninitializedObject() to create the object without invoking the constructor. Probably dangerous; I don't recommend using it too often ;-p See also the remarks on MSDN:

Because the new instance of the object is initialized to zero and no constructors are run, the object might not represent a state that is regarded as valid by that object. The current method should only be used for deserialization when the user intends to immediately populate all fields. It does not create an uninitialized string, since creating an empty instance of an immutable type serves no purpose.

I have my own serialization engine, but I don't intend making it use FormatterServices; I quite like knowing that a constructor (any constructor) has actually executed.

What is Robocopy's "restartable" option?

Restartable mode (/Z) has to do with a partially-copied file. With this option, should the copy be interrupted while any particular file is partially copied, the next execution of robocopy can pick up where it left off rather than re-copying the entire file.

That option could be useful when copying very large files over a potentially unstable connection.

Backup mode (/B) has to do with how robocopy reads files from the source system. It allows the copying of files on which you might otherwise get an access denied error on either the file itself or while trying to copy the file's attributes/permissions. You do need to be running in an Administrator context or otherwise have backup rights to use this flag.

Android Webview gives net::ERR_CACHE_MISS message

Also make sure your code doesn't have true for setBlockNetworkLoads

webView.getSettings().setBlockNetworkLoads (false);

How to type a new line character in SQL Server Management Studio

If you are trying to enter data directly into the table in grid view (presumably Right Click TableName and Select Open Table), then you can enter your unicode text string and wherever you want a carriage return just type 13 with the alt key pressed in the numeric keypad.

That would be Alt+13. This works only from the numeric keypad and does not work with the number keys on the top of the keyboard. The carriage return will be stored as a square

Returning anonymous type in C#

In C# 7 we can use tuples to accomplish this:

public List<(int SomeVariable, string AnotherVariable)> TheMethod(SomeParameter)
{
  using (MyDC TheDC = new MyDC())
  {
     var TheQueryFromDB = (....
                       select new { SomeVariable = ....,
                                    AnotherVariable = ....}
                       ).ToList();

      return TheQueryFromDB
                .Select(s => (
                     SomeVariable = s.SomeVariable, 
                     AnotherVariable = s.AnotherVariable))
                 .ToList();
  }
}

You might need to install System.ValueTuple nuget package though.

Naming Classes - How to avoid calling everything a "<WhatEver>Manager"?

I asked a similar question, but where possible I try to copy the names already in the .NET framework, and I look for ideas in the Java and Android frameworks.

It seems Helper, Manager, and Util are the unavoidable nouns you attach for coordinating classes that contain no state and are generally procedural and static. An alternative is Coordinator.

You could get particularly purple prosey with the names and go for things like Minder, Overseer, Supervisor, Administrator, and Master, but as I said I prefer keeping it like the framework names you're used to.


Some other common suffixes (if that is the correct term) you also find in the .NET framework are:

  • Builder
  • Writer
  • Reader
  • Handler
  • Container

What's the difference between HEAD, working tree and index, in Git?

Working tree

Your working tree are the files that you are currently working on.

Git index

  • The git "index" is where you place files you want commit to the git repository.

  • The index is also known as cache, directory cache, current directory cache, staging area, staged files.

  • Before you "commit" (checkin) files to the git repository, you need to first place the files in the git "index".

  • The index is not the working directory: you can type a command such as git status, and git will tell you what files in your working directory have been added to the git index (for example, by using the git add filename command).

  • The index is not the git repository: files in the git index are files that git would commit to the git repository if you used the git commit command.

SSIS Connection Manager Not Storing SQL Password

I use a variable to store the entire connection string and pass it into the ConnectionString expression. This overwrites all settings for the connection and allows you store the password.

Import pfx file into particular certificate store from command line

Anchoring my findings here for future readers.

Import certificate to Trusted Root Certification Authorities on Local Machine:

CERTUTIL -addstore -enterprise -f -v root "somCertificat.cer"

Import pfx to Personal on local machine

CERTUTIL -f -p somePassword -importpfx "somePfx.pfx"

Import pfx to Trusted People on local machine - Link to importpfx.exe

importpfx.exe -f "somePfx.pfx" -p "somePassword" -t MACHINE -s "TRUSTEDPEOPLE"

Import certificate to Trusted People on local machine

Certutil -addstore -f "TRUSTEDPEOPLE" "someCertificate.cer"

Find an element by class name, from a known parent element

You were close. You can do:

var element = $("#parentDiv").find(".myClassNameOfInterest");

Alternatively, you can do:

var element = $(".myClassNameOfInterest", "#parentDiv");

...which sets the context of the jQuery object to the #parentDiv.

EDIT:

Additionally, it may be faster in some browsers if you do div.myClassNameOfInterest instead of just .myClassNameOfInterest.

How can I get an object's absolute position on the page in Javascript?

I would definitely suggest using element.getBoundingClientRect().

https://developer.mozilla.org/en-US/docs/Web/API/element.getBoundingClientRect

Summary

Returns a text rectangle object that encloses a group of text rectangles.

Syntax

var rectObject = object.getBoundingClientRect();

Returns

The returned value is a TextRectangle object which is the union of the rectangles returned by getClientRects() for the element, i.e., the CSS border-boxes associated with the element.

The returned value is a TextRectangle object, which contains read-only left, top, right and bottom properties describing the border-box, in pixels, with the top-left relative to the top-left of the viewport.

Here's a browser compatibility table taken from the linked MDN site:

+---------------+--------+-----------------+-------------------+-------+--------+
|    Feature    | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari |
+---------------+--------+-----------------+-------------------+-------+--------+
| Basic support | 1.0    | 3.0 (1.9)       | 4.0               | (Yes) | 4.0    |
+---------------+--------+-----------------+-------------------+-------+--------+

It's widely supported, and is really easy to use, not to mention that it's really fast. Here's a related article from John Resig: http://ejohn.org/blog/getboundingclientrect-is-awesome/

You can use it like this:

var logo = document.getElementById('hlogo');
var logoTextRectangle = logo.getBoundingClientRect();

console.log("logo's left pos.:", logoTextRectangle.left);
console.log("logo's right pos.:", logoTextRectangle.right);

Here's a really simple example: http://jsbin.com/awisom/2 (you can view and edit the code by clicking "Edit in JS Bin" in the upper right corner).

Or here's another one using Chrome's console: Using element.getBoundingClientRect() in Chrome

Note:

I have to mention that the width and height attributes of the getBoundingClientRect() method's return value are undefined in Internet Explorer 8. It works in Chrome 26.x, Firefox 20.x and Opera 12.x though. Workaround in IE8: for width, you could subtract the return value's right and left attributes, and for height, you could subtract bottom and top attributes (like this).

Which method performs better: .Any() vs .Count() > 0?

It depends, how big is the data set and what are your performance requirements?

If it's nothing gigantic use the most readable form, which for myself is any, because it's shorter and readable rather than an equation.

OSX El Capitan: sudo pip install OSError: [Errno: 1] Operation not permitted

I fully agree with Mikko, but if you still want to do it, here is the way:

  • Restart in recovery mode (Hold cmd + R)
  • Open terminal from utilities
  • Use the command csrutil disable

Remove decimal values using SQL query

Your data type is DECIMAL with decimal places, say DECIMAL(10,2). The values in your database are 12, 15, 18, and 20.

12 is the same as 12.0 and 12.00 and 12.000 . It is up to the tool you are using to select the data with, how to display the numbers. Yours either defaults to two digits for decimals or it takes the places from your data definition.

If you only want integers in your column, then change its data type to INT. It makes no sense to use DECIMAL then.

If you want integers and decimals in that column then stay with the DECIMAL type. If you don't like the way you are shown the values, then format them in your application. It's up to that client program to decide for instance if to display point or comma for the decimal separator. (The database can be used from different locations.)

Also don't rely on any database or session settings like a decimal separator being a point and not a comma and then use REPLACE on it. That can work for one person and not for the other.

How to pass multiple parameters in thread in VB

Dim evaluator As New Thread(Sub() Me.testthread(goodList, 1))
With evaluator
.IsBackground = True ' not necessary...
.Start()
End With

How do I see which checkbox is checked?

Try this

index.html

<form action="form.php" method="post">
    Do you like stackoverflow?
    <input type="checkbox" name="like" value="Yes" />  
    <input type="submit" name="formSubmit" value="Submit" /> 
</form>

form.php

<html>
<head>
</head>
<body>

<?php
    if(isset($_POST['like']))
    {
        echo "<h1>You like Stackoverflow.<h1>";
    }
    else
    {
        echo "<h1>You don't like Stackoverflow.</h1>";
    }   
?>

</body>
</html>

Or this

<?php
    if(isset($_POST['like'])) && 
    $_POST['like'] == 'Yes') 
    {
        echo "You like Stackoverflow.";
    }
    else
    {
        echo "You don't like Stackoverflow.";
    }   
?>

How to debug Ruby scripts

Well, ruby standard lib has an easy to use gdb-like console debugger: http://ruby-doc.org/stdlib-2.1.0/libdoc/debug/rdoc/DEBUGGER__.html No need to install any extra gems. Rails scripts can be debugged that way too.

e.g.

def say(word)
  require 'debug'
  puts word
end

Select something that has more/less than x character

Today I was trying same in db2 and used below, in my case I had spaces at the end of varchar column data

SELECT EmployeeName FROM EmployeeTable WHERE LENGTH(TRIM(EmployeeName))> 4;

Bootstrap dropdown menu not working (not dropping down when clicked)

i faced the same problem , the solution worked for me , hope it will work for you too.

<script src="content/js/jquery.min.js"></script>
<script src="content/js/bootstrap.min.js"></script>
<script>
    $(document).ready(function () {
        $('.dropdown-toggle').dropdown();
    });
</script>

Please include the "jquery.min.js" file before "bootstrap.min.js" file, if you shuffle the order it will not work.

How to split (chunk) a Ruby array into parts of X elements?

If you're using rails you can also use in_groups_of:

foo.in_groups_of(3)

Dynamically Add C# Properties at Runtime

you could deserialize your json string into a dictionary and then add new properties then serialize it.

 var jsonString = @"{}";

        var jsonDoc = JsonSerializer.Deserialize<Dictionary<string, object>>(jsonString);

        jsonDoc.Add("Name", "Khurshid Ali");

        Console.WriteLine(JsonSerializer.Serialize(jsonDoc));

How to convert UTF8 string to byte array?

The TextEncoder and TextDecoder Encoding API will let you both encode and decode UTF-8 easily (using typed arrays):

const encoded = new TextEncoder().encode("Ge?a s?? ??sµe");
const decoded = new TextDecoder().decode(encoded);

console.log(encoded, decoded);

Browser support isn't too bad, and there's a polyfill that should work in IE11 and older versions of Edge.


Older versions of TextEncoder supported other different encodings as a string constructor parameter argument, but since Firefox 48 and Chrome 53 this is no-longer supported and TextEncoder and TextDecoder support only UTF-8.

So this will no-longer work in modern web-browsers used since 2016:

new TextDecoder("shift-jis").decode(new Uint8Array(textbuffer))

What is the difference between an abstract function and a virtual function?

Here I am writing some sample code hoping this may be a rather tangible example to see the behaviors of the interfaces, abstract classes and ordinary classes on a very basic level. You can also find this code in github as a project if you want to use it as a demo: https://github.com/usavas/JavaAbstractAndInterfaceDemo

public interface ExampleInterface {

//    public void MethodBodyInInterfaceNotPossible(){
//    }
    void MethodInInterface();

}

public abstract class AbstractClass {
    public abstract void AbstractMethod();

    //    public abstract void AbstractMethodWithBodyNotPossible(){
    //
    //    };

    //Standard Method CAN be declared in AbstractClass
    public void StandardMethod(){
        System.out.println("Standard Method in AbstractClass (super) runs");
    }
}

public class ConcreteClass
    extends AbstractClass
    implements ExampleInterface{

    //Abstract Method HAS TO be IMPLEMENTED in child class. Implemented by ConcreteClass
    @Override
    public void AbstractMethod() {
        System.out.println("AbstractMethod overridden runs");
    }

    //Standard Method CAN be OVERRIDDEN.
    @Override
    public void StandardMethod() {
        super.StandardMethod();
        System.out.println("StandardMethod overridden in ConcreteClass runs");
    }

    public void ConcreteMethod(){
        System.out.println("Concrete method runs");
    }

    //A method in interface HAS TO be IMPLEMENTED in implementer class.
    @Override
    public void MethodInInterface() {
        System.out.println("MethodInInterface Implemented by ConcreteClass runs");

    //    Cannot declare abstract method in a concrete class
    //    public abstract void AbstractMethodDeclarationInConcreteClassNotPossible(){
    //
    //    }
    }
}

Should I use window.navigate or document.location in JavaScript?

support for document.location is also good though its a deprecated method. I've been using this method for a while with no problems. you can refer here for more details:

https://developer.mozilla.org/en-US/docs/Web/API/document.location

How to send parameters with jquery $.get()

Try this:

$.ajax({
    type: 'get',
    url: 'manageproducts.do',
    data: 'option=1',
    success: function(data) {

        availableProductNames = data.split(",");

        alert(availableProductNames);

    }
});

Also You have a few errors in your sample code, not sure if that was causing the error or it was just a typo upon entering the question.

How to convert int to float in python?

You can literally convert it into float using:


float_value = float(integer_value)

Likewise, you can convert an integer back to float datatype with:


integer_value = int(float_value)

Hope it helped. I advice you to read "Build-In Functions of Python" at this link: https://docs.python.org/2/library/functions.html

Read input numbers separated by spaces

int main() {
int sum = 0;
cout << "enter number" << endl;
int i = 0;
while (true) {
    cin >> i;
    sum += i;
    //cout << i << endl;
    if (cin.peek() == '\n') {
        break;
    }
    
}

cout << "result: " << sum << endl;
return 0;
}

I think this code works, you may enter any int numbers and spaces, it will calculate the sum of input ints

How to shrink/purge ibdata1 file in MySQL

That ibdata1 isn't shrinking is a particularly annoying feature of MySQL. The ibdata1 file can't actually be shrunk unless you delete all databases, remove the files and reload a dump.

But you can configure MySQL so that each table, including its indexes, is stored as a separate file. In that way ibdata1 will not grow as large. According to Bill Karwin's comment this is enabled by default as of version 5.6.6 of MySQL.

It was a while ago I did this. However, to setup your server to use separate files for each table you need to change my.cnf in order to enable this:

[mysqld]
innodb_file_per_table=1

https://dev.mysql.com/doc/refman/5.6/en/innodb-file-per-table-tablespaces.html

As you want to reclaim the space from ibdata1 you actually have to delete the file:

  1. Do a mysqldump of all databases, procedures, triggers etc except the mysql and performance_schema databases
  2. Drop all databases except the above 2 databases
  3. Stop mysql
  4. Delete ibdata1 and ib_log files
  5. Start mysql
  6. Restore from dump

When you start MySQL in step 5 the ibdata1 and ib_log files will be recreated.

Now you're fit to go. When you create a new database for analysis, the tables will be located in separate ibd* files, not in ibdata1. As you usually drop the database soon after, the ibd* files will be deleted.

http://dev.mysql.com/doc/refman/5.1/en/drop-database.html

You have probably seen this:
http://bugs.mysql.com/bug.php?id=1341

By using the command ALTER TABLE <tablename> ENGINE=innodb or OPTIMIZE TABLE <tablename> one can extract data and index pages from ibdata1 to separate files. However, ibdata1 will not shrink unless you do the steps above.

Regarding the information_schema, that is not necessary nor possible to drop. It is in fact just a bunch of read-only views, not tables. And there are no files associated with the them, not even a database directory. The informations_schema is using the memory db-engine and is dropped and regenerated upon stop/restart of mysqld. See https://dev.mysql.com/doc/refman/5.7/en/information-schema.html.

Maven build failed: "Unable to locate the Javac Compiler in: jre or jdk issue"

File eclipse.ini needs the vm argument to point to your JDK location.

Edit the eclipse.ini file to point to your JDK home, something as follows -

-vm
C:\Program Files\Java\jdk1.6.0_06

This ensures that Eclipse would be running off the JDK and not any default JRE on your machine.

Getting parts of a URL (Regex)

I like the regex that was published in "Javascript: The Good Parts". Its not too short and not too complex. This page on github also has the JavaScript code that uses it. But it an be adapted for any language. https://gist.github.com/voodooGQ/4057330

How to get all privileges back to the root user in MySQL?

If you facing grant permission access denied problem, you can try mysql to fix the problem:

grant all privileges on . to root@'localhost' identified by 'Your password';

grant all privileges on . to root@'IP ADDRESS' identified by 'Your password?';

your can try this on any mysql user, its working.

Use below command to login mysql with iP address.

mysql -h 10.0.0.23 -u root -p

Maven and Spring Boot - non resolvable parent pom - repo.spring.io (Unknown host)

The issue is with your project which is not able to complete maven build. Steps to follow :

  1. Right Click Application and RunAs maven install.
  2. If you get any error while reaching the repos online try giving the proxies in settings.xml under your .m2 directory.Check this link for setting proxies for maven build.
  3. Once done , try doing a Update Project by Right Click Project , Maven->Update Maven Project and select codebase and do check the Force Update of Snapshot/Release check box.

This will update your maven build and will surely remove your errors with pom.xml

Oracle pl-sql escape character (for a " ' ")

Your question implies that you're building the INSERT statement up by concatenating strings together. I suggest that this is a poor choice as it leaves you open to SQL injection attacks if the strings are derived from user input. A better choice is to use parameter markers and to bind the values to the markers. If you search for Oracle parameter markers you'll probably find some information for your specific implementation technology (e.g. C# and ADO, Java and JDBC, Ruby and RubyDBI, etc).

Share and enjoy.

MySQL Update Column +1?

update post set count = count + 1 where id = 101

How can I modify the size of column in a MySQL table?

Have you tried this?

ALTER TABLE <table_name> MODIFY <col_name> VARCHAR(65353);

This will change the col_name's type to VARCHAR(65353)

Disabled UIButton not faded or grey

This question has a lot of answers but all they looks not very useful in case if you really want to use backgroundColor to style your buttons. UIButton has nice option to set different images for different control states but there is not same feature for background colors. So one of solutions is to add extension which will generate images from color and apply them to button.

extension UIButton {
  private func image(withColor color: UIColor) -> UIImage? {
    let rect = CGRect(x: 0.0, y: 0.0, width: 1.0, height: 1.0)
    UIGraphicsBeginImageContext(rect.size)
    let context = UIGraphicsGetCurrentContext()

    context?.setFillColor(color.cgColor)
    context?.fill(rect)

    let image = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()

    return image
  }

  func setBackgroundColor(_ color: UIColor, for state: UIControlState) {
    self.setBackgroundImage(image(withColor: color), for: state)
  }
}

Only one issue with this solution -- this change won't be applied to buttons created in storyboard. As for me it's not an issue because I prefer to style UI from code. If you want to use storyboards then some additional magic with @IBInspectable needed.

Second option is subclassing but I prefer to avoid this.

Hibernate table not mapped error in HQL query

In addition to the accepted answer, one other check is to make sure that you have the right reference to your entity package in sessionFactory.setPackagesToScan(...) while setting up your session factory.

Distribution certificate / private key not installed

revoke all distribution certificate for developer.apple.com and the validate your app in Xcode there will be the option to create a new distribution certificate after you can export key for further use.

This work for me.

How to apply multiple transforms in CSS?

Some time in the future, we can write it like this:

li:nth-child(2) {
    rotate: 15deg;
    translate:-20px 0px;        
}

This will become especially useful when applying individual classes on an element:

<div class="teaser important"></div>

.teaser{rotate:10deg;}
.important{scale:1.5 1.5;}

This syntax is defined in the in-progress CSS Transforms Level 2 specification, but can't find anything about current browser support other then chrome canary. Hope some day i'll come back and update browser support here ;)

Found the info in this article which you might want to check out regarding workarounds for current browsers.

Is there any way to delete local commits in Mercurial?

Enable the "strip" extension and type the following:

hg strip #changeset# --keep

Where #changeset# is the hash for the changeset you want to remove. This will remove the said changeset including changesets that descend from it and will leave your working directory untouched. If you wish to also revert your committed code changes remove the --keep option.

For more information, check the Strip Extension.

If you get "unkown command 'strip'" you may need to enable it. To do so find the .hgrc or Mercurial.ini file and add the following to it:

[extensions]
strip =

Note that (as Juozas mentioned in his comment) having multiple heads is normal workflow in Mercurial. You should not use the strip command to battle that. Instead, you should merge your head with the incoming head, resolve any conflicts, test, and then push.

The strip command is useful when you really want to get rid of changesets that pollute the branch. In fact, if you're in this question's situation and you want to completely remove all "draft" change sets permanently, check out the top answer, which basically suggests doing:

hg strip 'roots(outgoing())'

How to calculate an angle from three points?

there IS a simple answer for this using high school math..

Let say that you have 3 points

To get angle from point A to B

angle = atan2(A.x - B.x, B.y - A.y)

To get angle from point B to C

angle2 = atan2(B.x - C.x, C.y - B.y)

Answer = 180 + angle2 - angle
If (answer < 0){
    return answer + 360
}else{
    return answer
}

I just used this code in the recent project that I made, change the B to P1.. you might as well remove the "180 +" if you want

How does one create an InputStream from a String?

Instead of CharSet.forName, using com.google.common.base.Charsets from Google's Guava (http://code.google.com/p/guava-libraries/wiki/StringsExplained#Charsets) is is slightly nicer:

InputStream is = new ByteArrayInputStream( myString.getBytes(Charsets.UTF_8) );

Which CharSet you use depends entirely on what you're going to do with the InputStream, of course.

How to delete items from a dictionary while iterating over it?

You could also do it in two steps:

remove = [k for k in mydict if k == val]
for k in remove: del mydict[k]

My favorite approach is usually to just make a new dict:

# Python 2.7 and 3.x
mydict = { k:v for k,v in mydict.items() if k!=val }
# before Python 2.7
mydict = dict((k,v) for k,v in mydict.iteritems() if k!=val)

Only allow specific characters in textbox

As mentioned in a comment (and another answer as I typed) you need to register an event handler to catch the keydown or keypress event on a text box. This is because TextChanged is only fired when the TextBox loses focus

The below regex lets you match those characters you want to allow

Regex regex = new Regex(@"[0-9+\-\/\*\(\)]");
MatchCollection matches = regex.Matches(textValue);

and this does the opposite and catches characters that aren't allowed

Regex regex = new Regex(@"[^0-9^+^\-^\/^\*^\(^\)]");
MatchCollection matches = regex.Matches(textValue);

I'm not assuming there'll be a single match as someone could paste text into the textbox. in which case catch textchanged

textBox1.TextChanged += new TextChangedEventHandler(textBox1_TextChanged);
private void textBox1_TextChanged(object sender, EventArgs e)
{
    Regex regex = new Regex(@"[^0-9^+^\-^\/^\*^\(^\)]");
    MatchCollection matches = regex.Matches(textBox1.Text);
    if (matches.Count > 0) {
       //tell the user
    }
}

and to validate single key presses

textBox1.KeyPress += new KeyPressEventHandler(textBox1_KeyPress);
private void textBox1_KeyPress(object sender, System.Windows.Forms.KeyPressEventArgs e)
{
    // Check for a naughty character in the KeyDown event.
    if (System.Text.RegularExpressions.Regex.IsMatch(e.KeyChar.ToString(), @"[^0-9^+^\-^\/^\*^\(^\)]"))
    {
        // Stop the character from being entered into the control since it is illegal.
        e.Handled = true;
    }
}

Codeigniter's `where` and `or_where`

You may group your library.available_until wheres area by grouping method of Codeigniter for without disable escaping where clauses.

$this->db
    ->select('*')
    ->from('library')
    ->where('library.rating >=', $form['slider'])
    ->where('library.votes >=', '1000')
    ->where('library.language !=', 'German')
    ->group_start() //this will start grouping
    ->where('library.available_until >=', date("Y-m-d H:i:s"))
    ->or_where('library.available_until =', "00-00-00 00:00:00")
    ->group_end() //this will end grouping
    ->where('library.release_year >=', $year_start)
    ->where('library.release_year <=', $year_end)
    ->join('rating_repo', 'library.id = rating_repo.id')

Reference: https://www.codeigniter.com/userguide3/database/query_builder.html#query-grouping

how to re-format datetime string in php?

https://en.functions-online.com/date.html?command={"format":"l jS \\of F Y h:i:s A"}

Found 'OR 1=1/* sql injection in my newsletter database

The specific value in your database isn't what you should be focusing on. This is likely the result of an attacker fuzzing your system to see if it is vulnerable to a set of standard attacks, instead of a targeted attack exploiting a known vulnerability.

You should instead focus on ensuring that your application is secure against these types of attacks; OWASP is a good resource for this.

If you're using parameterized queries to access the database, then you're secure against Sql injection, unless you're using dynamic Sql in the backend as well.

If you're not doing this, you're vulnerable and you should resolve this immediately.

Also, you should consider performing some sort of validation of e-mail addresses.

How to configure socket connect timeout

it might be too late but there is neat solution based on Task.WaitAny (c# 5 +) :

 public static bool ConnectWithTimeout(this Socket socket, string host, int port, int timeout)
        {
            bool connected = false;
            Task result = socket.ConnectAsync(host, port);               
            int index = Task.WaitAny(new[] { result }, timeout);
            connected = socket.Connected;
            if (!connected) {
              socket.Close();
            }

            return connected;
        }

Android SQLite: Update Statement

I use this class to handle database.I hope it will help some one in future.

Happy coding.

public class Database {

private static class DBHelper extends SQLiteOpenHelper {

    /**
     * Database name
     */
    private static final String DB_NAME = "db_name";

    /**
     * Table Names
     */
    public static final String TABLE_CART = "DB_CART";


    /**
     *  Cart Table Columns
     */
    public static final String CART_ID_PK = "_id";// Primary key

    public static final String CART_DISH_NAME = "dish_name";
    public static final String CART_DISH_ID = "menu_item_id";
    public static final String CART_DISH_QTY = "dish_qty";
    public static final String CART_DISH_PRICE = "dish_price";

    /**
     * String to create reservation tabs table
     */
    private final String CREATE_TABLE_CART = "CREATE TABLE IF NOT EXISTS "
            + TABLE_CART + " ( "
            + CART_ID_PK + " INTEGER PRIMARY KEY, "
            + CART_DISH_NAME + " TEXT , "
            + CART_DISH_ID + " TEXT , "
            + CART_DISH_QTY + " TEXT , "
            + CART_DISH_PRICE + " TEXT);";


    public DBHelper(Context context) {
        super(context, DB_NAME, null, 2);

    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL(CREATE_TABLE_CART);


    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int arg1, int arg2) {
        db.execSQL("DROP TABLE IF EXISTS " + CREATE_TABLE_CART);
        onCreate(db);
    }

}


     /**
      * CART handler
      */
      public static class Cart {


    /**
     * Check if Cart is available or not
     *
     * @param context
     * @return
     */
    public static boolean isCartAvailable(Context context) {

        DBHelper dbHelper = new DBHelper(context);
        SQLiteDatabase db = dbHelper.getReadableDatabase();
        boolean exists = false;

        try {
            String query = "SELECT * FROM " + DBHelper.TABLE_CART;
            Cursor cursor = db.rawQuery(query, null);
            exists = (cursor.getCount() > 0);
            cursor.close();
            db.close();
        } catch (SQLiteException e) {
            db.close();
        }

        return exists;
    }


    /**
     * Insert values in cart table
     *
     * @param context
     * @param dishName
     * @param dishPrice
     * @param dishQty
     * @return
     */
    public static boolean insertItem(Context context, String itemId, String dishName, String dishPrice, String dishQty) {

        DBHelper dbHelper = new DBHelper(context);
        SQLiteDatabase db = dbHelper.getWritableDatabase();
        ContentValues values = new ContentValues();
        values.put(DBHelper.CART_DISH_ID, "" + itemId);
        values.put(DBHelper.CART_DISH_NAME, "" + dishName);
        values.put(DBHelper.CART_DISH_PRICE, "" + dishPrice);
        values.put(DBHelper.CART_DISH_QTY, "" + dishQty);

        try {
            db.insert(DBHelper.TABLE_CART, null, values);
            db.close();
            return true;
        } catch (SQLiteException e) {
            db.close();
            return false;
        }
    }

    /**
     * Check for specific record by name
     *
     * @param context
     * @param dishName
     * @return
     */
    public static boolean isItemAvailable(Context context, String dishName) {

        DBHelper dbHelper = new DBHelper(context);
        SQLiteDatabase db = dbHelper.getReadableDatabase();
        boolean exists = false;

        String query = "SELECT * FROM " + DBHelper.TABLE_CART + " WHERE "
                + DBHelper.CART_DISH_NAME + " = '" + String.valueOf(dishName) + "'";


        try {
            Cursor cursor = db.rawQuery(query, null);

            exists = (cursor.getCount() > 0);
            cursor.close();

        } catch (SQLiteException e) {

            e.printStackTrace();
            db.close();

        }

        return exists;
    }

    /**
     * Update cart item by item name
     *
     * @param context
     * @param dishName
     * @param dishPrice
     * @param dishQty
     * @return
     */
    public static boolean updateItem(Context context, String itemId, String dishName, String dishPrice, String dishQty) {

        DBHelper dbHelper = new DBHelper(context);
        SQLiteDatabase db = dbHelper.getWritableDatabase();
        ContentValues values = new ContentValues();
        values.put(DBHelper.CART_DISH_ID, itemId);
        values.put(DBHelper.CART_DISH_NAME, dishName);
        values.put(DBHelper.CART_DISH_PRICE, dishPrice);
        values.put(DBHelper.CART_DISH_QTY, dishQty);

        try {

            String[] args = new String[]{dishName};
            db.update(DBHelper.TABLE_CART, values, DBHelper.CART_DISH_NAME + "=?", args);

            db.close();


            return true;
        } catch (SQLiteException e) {
            db.close();

            return false;
        }
    }

    /**
     * Get cart list
     *
     * @param context
     * @return
     */
    public static ArrayList<CartModel> getCartList(Context context) {

        DBHelper dbHelper = new DBHelper(context);
        SQLiteDatabase db = dbHelper.getReadableDatabase();

        ArrayList<CartModel> cartList = new ArrayList<>();

        try {
            String query = "SELECT * FROM " + DBHelper.TABLE_CART + ";";

            Cursor cursor = db.rawQuery(query, null);


            for (cursor.moveToFirst(); !cursor.isAfterLast(); cursor.moveToNext()) {

                cartList.add(new CartModel(
                        cursor.getString(cursor.getColumnIndex(DBHelper.CART_DISH_ID)),
                        cursor.getString(cursor.getColumnIndex(DBHelper.CART_DISH_NAME)),
                        cursor.getString(cursor.getColumnIndex(DBHelper.CART_DISH_QTY)),
                        Integer.parseInt(cursor.getString(cursor.getColumnIndex(DBHelper.CART_DISH_PRICE)))
                ));
            }

            db.close();

        } catch (SQLiteException e) {
            db.close();
        }
        return cartList;
    }

   /**
     * Get total amount of cart items
     *
     * @param context
     * @return
     */
    public static String getTotalAmount(Context context) {

        DBHelper dbHelper = new DBHelper(context);
        SQLiteDatabase db = dbHelper.getReadableDatabase();

        double totalAmount = 0.0;

        try {
            String query = "SELECT * FROM " + DBHelper.TABLE_CART + ";";

            Cursor cursor = db.rawQuery(query, null);


            for (cursor.moveToFirst(); !cursor.isAfterLast(); cursor.moveToNext()) {

                totalAmount = totalAmount + Double.parseDouble(cursor.getString(cursor.getColumnIndex(DBHelper.CART_DISH_PRICE))) *
                        Double.parseDouble(cursor.getString(cursor.getColumnIndex(DBHelper.CART_DISH_QTY)));
            }

            db.close();


        } catch (SQLiteException e) {
            db.close();
        }


        if (totalAmount == 0.0)
            return "";
        else
            return "" + totalAmount;
    }


    /**
     * Get item quantity
     *
     * @param context
     * @param dishName
     * @return
     */
    public static String getItemQty(Context context, String dishName) {

        DBHelper dbHelper = new DBHelper(context);
        SQLiteDatabase db = dbHelper.getReadableDatabase();

        Cursor cursor = null;
        String query = "SELECT * FROM " + DBHelper.TABLE_CART + " WHERE " + DBHelper.CART_DISH_NAME + " = '" + dishName + "';";
        String quantity = "0";

        try {
            cursor = db.rawQuery(query, null);

            if (cursor.getCount() > 0) {

                cursor.moveToFirst();
                quantity = cursor.getString(cursor
                        .getColumnIndex(DBHelper.CART_DISH_QTY));

                return quantity;
            }


        } catch (SQLiteException e) {
            e.printStackTrace();
        }

        return quantity;
    }


    /**
     * Delete cart item by name
     *
     * @param context
     * @param dishName
     */
    public static void deleteCartItem(Context context, String dishName) {
        DBHelper dbHelper = new DBHelper(context);
        SQLiteDatabase db = dbHelper.getReadableDatabase();

        try {

            String[] args = new String[]{dishName};
            db.delete(DBHelper.TABLE_CART, DBHelper.CART_DISH_NAME + "=?", args);

            db.close();
        } catch (SQLiteException e) {
            db.close();
            e.printStackTrace();
        }

    }


}//End of cart class

/**
 * Delete database table
 *
 * @param context
 */
public static void deleteCart(Context context) {
    DBHelper dbHelper = new DBHelper(context);
    SQLiteDatabase db = dbHelper.getReadableDatabase();

    try {

        db.execSQL("DELETE FROM " + DBHelper.TABLE_CART);

    } catch (SQLiteException e) {
        e.printStackTrace();
    }

}

}

Usage:

  if(Database.Cart.isCartAvailable(context)){

       Database.deleteCart(context);

   }

How to update/modify an XML file in python?

Using ElementTree:

import xml.etree.ElementTree

# Open original file
et = xml.etree.ElementTree.parse('file.xml')

# Append new tag: <a x='1' y='abc'>body text</a>
new_tag = xml.etree.ElementTree.SubElement(et.getroot(), 'a')
new_tag.text = 'body text'
new_tag.attrib['x'] = '1' # must be str; cannot be an int
new_tag.attrib['y'] = 'abc'

# Write back to file
#et.write('file.xml')
et.write('file_new.xml')

note: output written to file_new.xml for you to experiment, writing back to file.xml will replace the old content.

IMPORTANT: the ElementTree library stores attributes in a dict, as such, the order in which these attributes are listed in the xml text will NOT be preserved. Instead, they will be output in alphabetical order. (also, comments are removed. I'm finding this rather annoying)

ie: the xml input text <b y='xxx' x='2'>some body</b> will be output as <b x='2' y='xxx'>some body</b>(after alphabetising the order parameters are defined)

This means when committing the original, and changed files to a revision control system (such as SVN, CSV, ClearCase, etc), a diff between the 2 files may not look pretty.

Create a .csv file with values from a Python list

Here is a secure version of Alex Martelli's:

import csv

with open('filename', 'wb') as myfile:
    wr = csv.writer(myfile, quoting=csv.QUOTE_ALL)
    wr.writerow(mylist)

Setting session variable using javascript

It is very important to understand both sessionStorage and localStorage as they both have different uses:

From MDN:

All of your web storage data is contained within two object-like structures inside the browser: sessionStorage and localStorage. The first one persists data for as long as the browser is open (the data is lost when the browser is closed) and the second one persists data even after the browser is closed and then opened again.

sessionStorage - Saves data until the browser is closed, the data is deleted when the tab/browser is closed.

localStorage - Saves data "forever" even after the browser is closed BUT you shouldn't count on the data you store to be there later, the data might get deleted by the browser at any time because of pretty much anything, or deleted by the user, best practice would be to validate that the data is there first, and continue the rest if it is there. (or set it up again if its not there)

To understand more, read here: localStorage | sessionStorage

I want to align the text in a <td> to the top

Add a vertical-align property to the TD, like this:

<td style="width: 259px; vertical-align: top;">
main page
</td>

What is the meaning of "operator bool() const"

operator bool() const 
{
    return col != 0;
}

Defines how the class is convertable to a boolean value, the const after the () is used to indicate this method does not mutate (change the members of this class).

You would usually use such operators as follows:

airplaysdk sdkInstance;
if (sdkInstance) {
    std::cout << "Instance is active" << std::endl;
} else {
    std::cout << "Instance is in-active error!" << std::endl;
}

Environment variable to control java.io.tmpdir?

Use

$ java -XshowSettings
Property settings:
    java.home = /home/nisar/javadev/javasuncom/jdk1.7.0_17/jre
    java.io.tmpdir = /tmp

You don't have write permissions for the /var/lib/gems/2.3.0 directory

Reinstalling Compass worked for me.. It's a magic!

sudo gem install -n /usr/local/bin compass

Subscript out of range error in this Excel VBA script

Set sh1 = Worksheets(filenum(lngPosition)).Activate

You are getting Subscript out of range error error becuase it cannot find that Worksheet.

Also please... please... please do not use .Select/.Activate/Selection/ActiveCell You might want to see How to Avoid using Select in Excel VBA Macros.

Chart creating dynamically. in .net, c#

You need to attach the Form1_Load handler to the Load event:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Windows.Forms.DataVisualization.Charting;
using System.Diagnostics;

namespace WindowsFormsApplication6
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            Load += Form1_Load;
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            Random rnd = new Random();
            Chart mych = new Chart();
            mych.Height = 100;
            mych.Width = 100;
            mych.BackColor = SystemColors.Highlight;
            mych.Series.Add("duck");

            mych.Series["duck"].SetDefault(true);
            mych.Series["duck"].Enabled = true;
            mych.Visible = true;

            for (int q = 0; q < 10; q++)
            {
                int first = rnd.Next(0, 10);
                int second = rnd.Next(0, 10);
                mych.Series["duck"].Points.AddXY(first, second);
                Debug.WriteLine(first + "  " + second);
            }

            Controls.Add(mych);
        }
    }
}

When to use window.opener / window.parent / window.top

  • window.opener refers to the window that called window.open( ... ) to open the window from which it's called
  • window.parent refers to the parent of a window in a <frame> or <iframe>
  • window.top refers to the top-most window from a window nested in one or more layers of <iframe> sub-windows

Those will be null (or maybe undefined) when they're not relevant to the referring window's situation. ("Referring window" means the window in whose context the JavaScript code is run.)

How to keep a git branch in sync with master

The accepted answer via git merge will get the job done but leaves a messy commit hisotry, correct way should be 'rebase' via the following steps(assuming you want to keep your feature branch in sycn with develop before you do the final push before PR).

1 git fetch from your feature branch (make sure the feature branch you are working on is update to date)

2 git rebase origin/develop

3 if any conflict shall arise, resolve them one by one

4 use git rebase --continue once all conflicts are dealt with

5 git push --force

Write bytes to file

The simplest way would be to convert your hexadecimal string to a byte array and use the File.WriteAllBytes method.

Using the StringToByteArray() method from this question, you'd do something like this:

string hexString = "0CFE9E69271557822FE715A8B3E564BE";

File.WriteAllBytes("output.dat", StringToByteArray(hexString));

The StringToByteArray method is included below:

public static byte[] StringToByteArray(string hex) {
    return Enumerable.Range(0, hex.Length)
                     .Where(x => x % 2 == 0)
                     .Select(x => Convert.ToByte(hex.Substring(x, 2), 16))
                     .ToArray();
}

Reading and displaying data from a .txt file

public class PassdataintoFile {

    public static void main(String[] args) throws IOException  {
        try {
            PrintWriter pw = new PrintWriter("C:/new/hello.txt", "UTF-8");
            PrintWriter pw1 = new PrintWriter("C:/new/hello.txt");
             pw1.println("Hi chinni");
             pw1.print("your succesfully entered text into file");
             pw1.close();
        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (UnsupportedEncodingException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        BufferedReader br = new BufferedReader(new FileReader("C:/new/hello.txt"));
           String line;
           while((line = br.readLine())!= null)
           {
               System.out.println(line);
           }
           br.close();
    }

}

How to remove unwanted space between rows and columns in table?

Have you tried removing the TRs that have a colspan and see if it changes anything?

I have experienced colspans and rowspans to be pretty nasty when it comes down to accurate table-designs. If your images look alright without the colspan-TRs, I'd start from there and build a nested tableset.

Also your style.css doesn't seem to be complete, maybe there's something wrong there? I'd at least add padding: 0; margin: 0; to the table (or to the class "mytable"). Make sure, your images don't have spaces and/or borders, too (e.g. by adding img { border: 0; } to your stylesheet).

What is a bus error?

A segfault is accessing memory that you're not allowed to access. It's read-only, you don't have permission, etc...

A bus error is trying to access memory that can't possibly be there. You've used an address that's meaningless to the system, or the wrong kind of address for that operation.

<strong> vs. font-weight:bold & <em> vs. font-style:italic

HTML represents meaning; CSS represents appearance. How you mark up text in a document is not determined by how that text appears on screen, but simply what it means. As another example, some other HTML elements, like headings, are styled font-weight: bold by default, but they are marked up using <h1><h6>, not <strong> or <b>.

In HTML5, you use <strong> to indicate important parts of a sentence, for example:

<p><strong>Do not touch.</strong> Contains <strong>hazardous</strong> materials.

And you use <em> to indicate linguistic stress, for example:

<p>A Gentleman: I suppose he does. But there's no point in asking.
<p>A Lady: Why not?
<p>A Gentleman: Because he doesn't row.
<p>A Lady: He doesn't <em>row</em>?
<p>A Gentleman: No. He <em>doesn't</em> row.
<p>A Lady: Ah. I see what you mean.

These elements are semantic elements that just happen to have bold and italic representations by default, but you can style them however you like. For example, in the <em> sample above, you could represent stress emphasis in uppercase instead of italics, but the functional purpose of the <em> element remains the same — to change the context of a sentence by emphasizing specific words or phrases over others:

em {
    font-style: normal;
    text-transform: uppercase;
}

Note that the original answer (below) applied to HTML standards prior to HTML5, in which <strong> and <em> had somewhat different meanings, <b> and <i> were purely presentational and had no semantic meaning whatsoever. Like <strong> and <em> respectively, they have similar presentational defaults but may be styled differently.


You use <strong> and <em> to indicate intense emphasis and normal emphasis respectively.

Or think of it this way: font-weight: bold is closer to <b> than <strong>, and font-style: italic is closer to <i> than <em>. These visual styles are purely visual: tools like screen readers aren't going to understand what bold and italic mean, but some screen readers are able to read <strong> and <em> text in a more emphasized tone.

Is there a way to create multiline comments in Python?

Well, you can try this (when running the quoted, the input to the first question should quoted with '):

"""
print("What's your name? ")
myName = input()
print("It's nice to meet you " + myName)
print("Number of characters is ")
print(len(myName))
age = input("What's your age? ")
print("You will be " + str(int(age)+1) + " next year.")

"""
a = input()
print(a)
print(a*5)

Whatever enclosed between """ will be commented.

If you are looking for single-line comments then it's #.

SQL Server: Get data for only the past year

GETDATE() returns current date and time.

If last year starts in midnight of current day last year (like in original example) you should use something like:

DECLARE @start datetime
SET @start = dbo.getdatewithouttime(DATEADD(year, -1, GETDATE())) -- cut time (hours, minutes, ect.) --  getdatewithouttime() function doesn't exist in MS SQL -- you have to write one
SELECT column1, column2, ..., columnN FROM table WHERE date >= @start

A function to convert null to string

Its possible to make this even shorter with C# 6:

public string NullToString(string Value)
{
    return value?.ToString() ?? "";
}

Check for file exists or not in sql server?

You can achieve this using a cursor but the performance is much slower than whileloop.. Here's the code:

set nocount on
declare cur cursor local fast_forward for
    (select filepath from Directory)
open cur;
declare @fullpath varchar(250);
declare @isExists int;

fetch from cur into @fullpath
while @@FETCH_STATUS = 0
    begin
        exec xp_fileexist @fullpath, @isExists out
        if @isExists = 1            
            print @fullpath + char(9) + char(9) + 'file exists'
        else            
            print @fullpath + char(9) + char(9) + 'file does not exists'
        fetch from cur into @fullpath
    end
close cur
deallocate cur

or you can put it in a tempTable if you want to integrate it in your frontend..

create proc GetFileStatus as
begin
    set nocount on
    create table #tempFileStatus(FilePath varchar(300),FileStatus varchar(30))
    declare cur cursor local fast_forward for
        (select filepath from Directory)
    open cur;
    declare @fullpath varchar(250);
    declare @isExists int;

    fetch from cur into @fullpath
    while @@FETCH_STATUS = 0
        begin
            exec xp_fileexist @fullpath, @isExists out
            if @isExists = 1                
                insert into #tempFileStatus values(@fullpath,'File exist')
            else
                insert into #tempFileStatus values(@fullpath,'File does not exists')
            fetch from cur into @fullpath
        end
    close cur
    deallocate cur
    select * from #tempFileStatus
    drop table #tempFileStatus
end

then call it using:

exec GetFileStatus

How do you install an APK file in the Android emulator?

Goto Shell/Terminal/, reach at android-sdk/tools directory then

adb install fileName.apk // (u can run this command on windows)
or 
./adb install fileName.apk  //( u can run this command on linux)

How to know which version of Symfony I have?

For Symfony 3.4

Check the constant in this file vendor/symfony/http-kernel/Kernel.php

const VERSION = '3.4.3';

OR

composer show | grep symfony/http-kernel

Thymeleaf using path variables to th:href

A cleaner and easier way to do this

<a href="somepage.html" th:href="@{|/my/url/${variable}|}">A Link</a>

I found this solution in Thymeleaf Documentation on "4.8 Literal substitutions".

Get only filename from url in php without any variable values which exist in the url

Use this function:

function getScriptName()
{
    $filename = baseName($_SERVER['REQUEST_URI']);
    $ipos = strpos($filename, "?");
    if ( !($ipos === false) )   $filename = substr($filename, 0, $ipos);
    return $filename;
}

Subtract minute from DateTime in SQL Server 2005

Have you tried

SELECT DATEADD(mi, -15,'2000-01-01 08:30:00')

DATEDIFF is the difference between 2 dates.

What is the best way to add options to a select from a JavaScript object with jQuery?

Most of the other answers use the each function to iterate over the selectValues. This requires that append be called into for each element and a reflow gets triggered when each is added individually.

Updating this answer to a more idiomatic functional method (using modern JS) can be formed to call append only once, with an array of option elements created using map and an Option element constructor.

Using an Option DOM element should reduce function call overhead as the option element doesn't need to be updated after creation and jQuery's parsing logic need not run.

$('mySelect').append($.map(selectValues, (k, v) => new Option(k, v)))

This can be simplified further if you make a factory utility function that will new up an option object:

const newoption = (...args) => new Option(...args)

Then this can be provided directly to map:

$('mySelect').append($.map(selectValues, newoption))

Previous Formulation

Because append also allows passing values as a variable number of arguments, we can precreate the list of option elements map and append them as arguments in a single call by using apply.

$.fn.append.apply($('mySelect'), $.map(selectValues, (k, v) => $("<option/>").val(k).text(v)));

It looks like that in later versions of jQuery, append also accepts an array argument and this can be simplified somewhat:

$('mySelect').append($.map(selectValues, (k, v) => $("<option/>").val(k).text(v)))

Validating email addresses using jQuery and regex

This is my solution:

function isValidEmailAddress(emailAddress) {
    var pattern = new RegExp(/^[+a-zA-Z0-9._-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,4}$/i);
    // alert( pattern.test(emailAddress) );
    return pattern.test(emailAddress);
};

Found that RegExp over here: http://mdskinner.com/code/email-regex-and-validation-jquery

Python/Django: log to console under runserver, log to file under Apache

I use this:

logging.conf:

[loggers]
keys=root,applog
[handlers]
keys=rotateFileHandler,rotateConsoleHandler

[formatters]
keys=applog_format,console_format

[formatter_applog_format]
format=%(asctime)s-[%(levelname)-8s]:%(message)s

[formatter_console_format]
format=%(asctime)s-%(filename)s%(lineno)d[%(levelname)s]:%(message)s

[logger_root]
level=DEBUG
handlers=rotateFileHandler,rotateConsoleHandler

[logger_applog]
level=DEBUG
handlers=rotateFileHandler
qualname=simple_example

[handler_rotateFileHandler]
class=handlers.RotatingFileHandler
level=DEBUG
formatter=applog_format
args=('applog.log', 'a', 10000, 9)

[handler_rotateConsoleHandler]
class=StreamHandler
level=DEBUG
formatter=console_format
args=(sys.stdout,)

testapp.py:

import logging
import logging.config

def main():
    logging.config.fileConfig('logging.conf')
    logger = logging.getLogger('applog')

    logger.debug('debug message')
    logger.info('info message')
    logger.warn('warn message')
    logger.error('error message')
    logger.critical('critical message')
    #logging.shutdown()

if __name__ == '__main__':
    main()

Parcelable encountered IOException writing serializable object getactivity()

I faced Same issue, the issues was there are some inner classes with the static keyword.After removing the static keyword it started working and also the inner class should implements to Serializable

Issue scenario

class A implements Serializable{ 
  class static B{
  } 
}

Resolved By

class A implements Serializable{ 
      class B implements Serializable{
      } 
    }

How can I put a ListView into a ScrollView without it collapsing?

You should not put a ListView in a ScrollView because a ListView already is a ScrollView. So that would be like putting a ScrollView in a ScrollView.

What are you trying to accomplish?

How to detect simple geometric shapes using OpenCV

If you have only these regular shapes, there is a simple procedure as follows :

  1. Find Contours in the image ( image should be binary as given in your question)
  2. Approximate each contour using approxPolyDP function.
  3. First, check number of elements in the approximated contours of all the shapes. It is to recognize the shape. For eg, square will have 4, pentagon will have 5. Circles will have more, i don't know, so we find it. ( I got 16 for circle and 9 for half-circle.)
  4. Now assign the color, run the code for your test image, check its number, fill it with corresponding colors.

Below is my example in Python:

import numpy as np
import cv2

img = cv2.imread('shapes.png')
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)

ret,thresh = cv2.threshold(gray,127,255,1)

contours,h = cv2.findContours(thresh,1,2)

for cnt in contours:
    approx = cv2.approxPolyDP(cnt,0.01*cv2.arcLength(cnt,True),True)
    print len(approx)
    if len(approx)==5:
        print "pentagon"
        cv2.drawContours(img,[cnt],0,255,-1)
    elif len(approx)==3:
        print "triangle"
        cv2.drawContours(img,[cnt],0,(0,255,0),-1)
    elif len(approx)==4:
        print "square"
        cv2.drawContours(img,[cnt],0,(0,0,255),-1)
    elif len(approx) == 9:
        print "half-circle"
        cv2.drawContours(img,[cnt],0,(255,255,0),-1)
    elif len(approx) > 15:
        print "circle"
        cv2.drawContours(img,[cnt],0,(0,255,255),-1)

cv2.imshow('img',img)
cv2.waitKey(0)
cv2.destroyAllWindows()

Below is the output:

enter image description here

Remember, it works only for regular shapes.

Alternatively to find circles, you can use houghcircles. You can find a tutorial here.

Regarding iOS, OpenCV devs are developing some iOS samples this summer, So visit their site : www.code.opencv.org and contact them.

You can find slides of their tutorial here : http://code.opencv.org/svn/gsoc2012/ios/trunk/doc/CVPR2012_OpenCV4IOS_Tutorial.pdf

RegEx: Grabbing values between quotation marks

echo 'junk "Foo Bar" not empty one "" this "but this" and this neither' | sed 's/[^\"]*\"\([^\"]*\)\"[^\"]*/>\1</g'

This will result in: >Foo Bar<><>but this<

Here I showed the result string between ><'s for clarity, also using the non-greedy version with this sed command we first throw out the junk before and after that ""'s and then replace this with the part between the ""'s and surround this by ><'s.

How to run JUnit tests with Gradle?

How do I add a junit 4 dependency correctly?

Assuming you're resolving against a standard Maven (or equivalent) repo:

dependencies {
    ...
    testCompile "junit:junit:4.11"  // Or whatever version
}

Run those tests in the folders of tests/model?

You define your test source set the same way:

sourceSets {
    ...

    test {
        java {
            srcDirs = ["test/model"]  // Note @Peter's comment below
        }
    }
}

Then invoke the tests as:

./gradlew test

EDIT: If you are using JUnit 5 instead, there are more steps to complete, you should follow this tutorial.

What does "Use of unassigned local variable" mean?

Use "default"!!!

    string myString = default;
    double myDouble = defaul;

    if(!String.IsNullOrEmpty(myString))
       myDouble = 1.5;

    return myDouble;

Android Studio marks R in red with error message "cannot resolve symbol R", but build succeeds

The solution is simple:

Go to File > Project Structure > app and choose the Flavours tab, select API 21: Android 5.0 (Lollipop) in the drop down list for Min Sdk Version.

Resize to fit image in div, and center horizontally and vertically

Only tested in Chrome 44.

Example: http://codepen.io/hugovk/pen/OVqBoq

HTML:

<div>
<img src="http://lorempixel.com/1600/900/">
</div>

CSS:

<style type="text/css">
img {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translateX(-50%) translateY(-50%);
    max-width: 100%;
    max-height: 100%;
}
</style>

Freemarker iterating over hashmap keys

If using a BeansWrapper with an exposure level of Expose.SAFE or Expose.ALL, then the standard Java approach of iterating the entry set can be employed:

For example, the following will work in Freemarker (since at least version 2.3.19):

<#list map.entrySet() as entry>  
  <input type="hidden" name="${entry.key}" value="${entry.value}" />
</#list>

In Struts2, for instance, an extension of the BeanWrapper is used with the exposure level defaulted to allow this manner of iteration.

How to set JAVA_HOME for multiple Tomcat instances?

I had the same problem my OS is windows 8 and I am using Tomcat 8, I just edited the setclasspath.bat file in bin folder and set JAVA_HOME and JRE_HOME like this...

@echo off
...
...
set "JRE_HOME=%ProgramFiles%\Java\jre8"
set "JAVA_HOME=%ProgramFiles%\Java\jdk1.7.0_03"
...
...

and it works fine for me now......

Compare every item to every other item in ArrayList

for (int i = 0; i < list.size(); i++) {
  for (int j = i+1; j < list.size(); j++) {
    // compare list.get(i) and list.get(j)
  }
}

Angular2 change detection: ngOnChanges not firing for nested object

Here's a hack that just got me out of trouble with this one.

So a similar scenario to the OP - I've got a nested Angular component that needs data passed down to it, but the input points to an array, and as mentioned above, Angular doesn't see a change as it does not examine the contents of the array.

So to fix it I convert the array to a string for Angular to detect a change, and then in the nested component I split(',') the string back to an array and its happy days again.

Running code in main thread from another thread

A condensed code block is as follows:

   new Handler(Looper.getMainLooper()).post(new Runnable() {
       @Override
       public void run() {
           // things to do on the main thread
       }
   });

This does not involve passing down the Activity reference or the Application reference.

Kotlin Equivalent:

    Handler(Looper.getMainLooper()).post(Runnable {
        // things to do on the main thread
    })

Python "extend" for a dictionary

As others have mentioned, a.update(b) for some dicts a and b will achieve the result you've asked for in your question. However, I want to point out that many times I have seen the extend method of mapping/set objects desire that in the syntax a.extend(b), a's values should NOT be overwritten by b's values. a.update(b) overwrites a's values, and so isn't a good choice for extend.

Note that some languages call this method defaults or inject, as it can be thought of as a way of injecting b's values (which might be a set of default values) in to a dictionary without overwriting values that might already exist.

Of course, you could simple note that a.extend(b) is nearly the same as b.update(a); a=b. To remove the assignment, you could do it thus:

def extend(a,b):
    """Create a new dictionary with a's properties extended by b,
    without overwriting.

    >>> extend({'a':1,'b':2},{'b':3,'c':4})
    {'a': 1, 'c': 4, 'b': 2}
    """
    return dict(b,**a)

Thanks to Tom Leys for that smart idea using a side-effect-less dict constructor for extend.

How to pip install a package with min and max version range?

you can also use:

pip install package==0.5.*

which is more consistent and easy to read.

How to access local files of the filesystem in the Android emulator?

Update! You can access the Android filesystem via Android Device Monitor. In Android Studio go to Tools >> Android >> Android Device Monitor.

Note that you can run your app in the simulator while using the Android Device Monitor. But you cannot debug you app while using the Android Device Monitor.

How to handle a single quote in Oracle SQL

Use two single-quotes

SQL> SELECT 'D''COSTA' name FROM DUAL;

NAME
-------
D'COSTA

Alternatively, use the new (10g+) quoting method:

SQL> SELECT q'$D'COSTA$' NAME FROM DUAL;

NAME
-------
D'COSTA

Printing list elements on separated lines in Python

Another good option for handling this kind of option is the pprint module, which (among other things) pretty prints long lists with one element per line:

>>> import sys
>>> import pprint
>>> pprint.pprint(sys.path)
['',
 '/usr/lib/python27.zip',
 '/usr/lib/python2.7',
 '/usr/lib/python2.7/plat-linux2',
 '/usr/lib/python2.7/lib-tk',
 '/usr/lib/python2.7/lib-old',
 '/usr/lib/python2.7/lib-dynload',
 '/usr/lib/python2.7/site-packages',
 '/usr/lib/python2.7/site-packages/PIL',
 '/usr/lib/python2.7/site-packages/gst-0.10',
 '/usr/lib/python2.7/site-packages/gtk-2.0',
 '/usr/lib/python2.7/site-packages/setuptools-0.6c11-py2.7.egg-info',
 '/usr/lib/python2.7/site-packages/webkit-1.0']
>>> 

data.table vs dplyr: can one do something well the other can't or does poorly?

Here's my attempt at a comprehensive answer from the dplyr perspective, following the broad outline of Arun's answer (but somewhat rearranged based on differing priorities).

Syntax

There is some subjectivity to syntax, but I stand by my statement that the concision of data.table makes it harder to learn and harder to read. This is partly because dplyr is solving a much easier problem!

One really important thing that dplyr does for you is that it constrains your options. I claim that most single table problems can be solved with just five key verbs filter, select, mutate, arrange and summarise, along with a "by group" adverb. That constraint is a big help when you're learning data manipulation, because it helps order your thinking about the problem. In dplyr, each of these verbs is mapped to a single function. Each function does one job, and is easy to understand in isolation.

You create complexity by piping these simple operations together with %>%. Here's an example from one of the posts Arun linked to:

diamonds %>%
  filter(cut != "Fair") %>%
  group_by(cut) %>%
  summarize(
    AvgPrice = mean(price),
    MedianPrice = as.numeric(median(price)),
    Count = n()
  ) %>%
  arrange(desc(Count))

Even if you've never seen dplyr before (or even R!), you can still get the gist of what's happening because the functions are all English verbs. The disadvantage of English verbs is that they require more typing than [, but I think that can be largely mitigated by better autocomplete.

Here's the equivalent data.table code:

diamondsDT <- data.table(diamonds)
diamondsDT[
  cut != "Fair", 
  .(AvgPrice = mean(price),
    MedianPrice = as.numeric(median(price)),
    Count = .N
  ), 
  by = cut
][ 
  order(-Count) 
]

It's harder to follow this code unless you're already familiar with data.table. (I also couldn't figure out how to indent the repeated [ in a way that looks good to my eye). Personally, when I look at code I wrote 6 months ago, it's like looking at a code written by a stranger, so I've come to prefer straightforward, if verbose, code.

Two other minor factors that I think slightly decrease readability:

  • Since almost every data table operation uses [ you need additional context to figure out what's happening. For example, is x[y] joining two data tables or extracting columns from a data frame? This is only a small issue, because in well-written code the variable names should suggest what's happening.

  • I like that group_by() is a separate operation in dplyr. It fundamentally changes the computation so I think should be obvious when skimming the code, and it's easier to spot group_by() than the by argument to [.data.table.

I also like that the the pipe isn't just limited to just one package. You can start by tidying your data with tidyr, and finish up with a plot in ggvis. And you're not limited to the packages that I write - anyone can write a function that forms a seamless part of a data manipulation pipe. In fact, I rather prefer the previous data.table code rewritten with %>%:

diamonds %>% 
  data.table() %>% 
  .[cut != "Fair", 
    .(AvgPrice = mean(price),
      MedianPrice = as.numeric(median(price)),
      Count = .N
    ), 
    by = cut
  ] %>% 
  .[order(-Count)]

And the idea of piping with %>% is not limited to just data frames and is easily generalised to other contexts: interactive web graphics, web scraping, gists, run-time contracts, ...)

Memory and performance

I've lumped these together, because, to me, they're not that important. Most R users work with well under 1 million rows of data, and dplyr is sufficiently fast enough for that size of data that you're not aware of processing time. We optimise dplyr for expressiveness on medium data; feel free to use data.table for raw speed on bigger data.

The flexibility of dplyr also means that you can easily tweak performance characteristics using the same syntax. If the performance of dplyr with the data frame backend is not good enough for you, you can use the data.table backend (albeit with a somewhat restricted set of functionality). If the data you're working with doesn't fit in memory, then you can use a database backend.

All that said, dplyr performance will get better in the long-term. We'll definitely implement some of the great ideas of data.table like radix ordering and using the same index for joins & filters. We're also working on parallelisation so we can take advantage of multiple cores.

Features

A few things that we're planning to work on in 2015:

  • the readr package, to make it easy to get files off disk and in to memory, analogous to fread().

  • More flexible joins, including support for non-equi-joins.

  • More flexible grouping like bootstrap samples, rollups and more

I'm also investing time into improving R's database connectors, the ability to talk to web apis, and making it easier to scrape html pages.

SQL Server Convert Varchar to Datetime

As has been said, datetime has no format/string representational format.

You can change the string output with some formatting.

To convert your string to a datetime:

declare @date nvarchar(25) 
set @date = '2011-09-28 18:01:00' 

-- To datetime datatype
SELECT CONVERT(datetime, @date)

Gives:

-----------------------
2011-09-28 18:01:00.000

(1 row(s) affected)

To convert that to the string you want:

-- To VARCHAR of your desired format
SELECT CONVERT(VARCHAR(10), CONVERT(datetime, @date), 105) +' '+ CONVERT(VARCHAR(8), CONVERT(datetime, @date), 108)

Gives:

-------------------
28-09-2011 18:01:00

(1 row(s) affected)

What is a typedef enum in Objective-C?

A typedef allows the programmer to define one Objective-C type as another. For example,

typedef int Counter; defines the type Counter to be equivalent to the int type. This drastically improves code readability.

invalid types 'int[int]' for array subscript

int myArray[10][10][10];

should be

int myArray[10][10][10][10];

How to convert an Object {} to an Array [] of key-value pairs in JavaScript

Use Object.keys and Array#map methods.

_x000D_
_x000D_
var obj = {_x000D_
  "1": 5,_x000D_
  "2": 7,_x000D_
  "3": 0,_x000D_
  "4": 0,_x000D_
  "5": 0,_x000D_
  "6": 0,_x000D_
  "7": 0,_x000D_
  "8": 0,_x000D_
  "9": 0,_x000D_
  "10": 0,_x000D_
  "11": 0,_x000D_
  "12": 0_x000D_
};_x000D_
// get all object property names_x000D_
var res = Object.keys(obj)_x000D_
  // iterate over them and generate the array_x000D_
  .map(function(k) {_x000D_
    // generate the array element _x000D_
    return [+k, obj[k]];_x000D_
  });_x000D_
_x000D_
console.log(res);
_x000D_
_x000D_
_x000D_

Node.js Web Application examples/tutorials

The closest thing is likely Dav Glass's experimental work using node.js, express and YUI3. Basically, he explains how YUI3 is used to render markup on the server side, then sent to the client where binding to event and data occurs. The beauty is YUI3 is used as-is on both the client and the server. Makes a lot of sense. The one big issue is there is not yet a production ready server-side DOM library.

screencast

How to set a class attribute to a Symfony2 form input

Like this:

{{ form_widget(form.description, { 'attr': {'class': 'form-control', 'rows': '5', 'style': 'resize:none;'} }) }}

How to code a BAT file to always run as admin mode?

Use the complete physical drive\path to your Target batch file in the shortcut Properties.

This does not work in Windows 10 if you use subst drives like I tried to do at first...

How to update data in one table from corresponding data in another table in SQL Server 2005

 UPDATE Employee SET Empid=emp3.empid 
 FROM EMP_Employee AS emp3
 WHERE Employee.Empid=emp3.empid

Find current directory and file's directory

To get the full path to the directory a Python file is contained in, write this in that file:

import os 
dir_path = os.path.dirname(os.path.realpath(__file__))

(Note that the incantation above won't work if you've already used os.chdir() to change your current working directory, since the value of the __file__ constant is relative to the current working directory and is not changed by an os.chdir() call.)


To get the current working directory use

import os
cwd = os.getcwd()

Documentation references for the modules, constants and functions used above:

What exactly is the meaning of an API?

It is a set of software components that interact with one another. It provides a set of functions, variables, and object classes for the creation of an application, operating system or any other thing.

Angular 5 Service to read local .json file

import data  from './data.json';
export class AppComponent  {
    json:any = data;
}

See this article for more details.

Reading file using fscanf() in C

scanf() and friends return the number of input items successfully matched. For your code, that would be two or less (in case of less matches than specified). In short, be a little more careful with the manual pages:

#include <stdio.h>
#include <errno.h>
#include <stdbool.h>

int main(void)
{
    char item[9], status;

    FILE *fp;

    if((fp = fopen("D:\\Sample\\database.txt", "r+")) == NULL) {
        printf("No such file\n");
        exit(1);
    }

    while (true) {
        int ret = fscanf(fp, "%s %c", item, &status);
        if(ret == 2)
            printf("\n%s \t %c", item, status);
        else if(errno != 0) {
            perror("scanf:");
            break;
        } else if(ret == EOF) {
            break;
        } else {
            printf("No match.\n");
        }
    }
    printf("\n");
    if(feof(fp)) {
        puts("EOF");
    }
    return 0;
}

JS - window.history - Delete a state

You may have moved on by now, but... as far as I know there's no way to delete a history entry (or state).

One option I've been looking into is to handle the history yourself in JavaScript and use the window.history object as a carrier of sorts.

Basically, when the page first loads you create your custom history object (we'll go with an array here, but use whatever makes sense for your situation), then do your initial pushState. I would pass your custom history object as the state object, as it may come in handy if you also need to handle users navigating away from your app and coming back later.

var myHistory = [];

function pageLoad() {
    window.history.pushState(myHistory, "<name>", "<url>");

    //Load page data.
}

Now when you navigate, you add to your own history object (or don't - the history is now in your hands!) and use replaceState to keep the browser out of the loop.

function nav_to_details() {
    myHistory.push("page_im_on_now");
    window.history.replaceState(myHistory, "<name>", "<url>");

    //Load page data.
}

When the user navigates backwards, they'll be hitting your "base" state (your state object will be null) and you can handle the navigation according to your custom history object. Afterward, you do another pushState.

function on_popState() {
    // Note that some browsers fire popState on initial load,
    // so you should check your state object and handle things accordingly.
    // (I did not do that in these examples!)

    if (myHistory.length > 0) {
        var pg = myHistory.pop();
        window.history.pushState(myHistory, "<name>", "<url>");

        //Load page data for "pg".
    } else {
        //No "history" - let them exit or keep them in the app.
    }
}

The user will never be able to navigate forward using their browser buttons because they are always on the newest page.

From the browser's perspective, every time they go "back", they've immediately pushed forward again.

From the user's perspective, they're able to navigate backwards through the pages but not forward (basically simulating the smartphone "page stack" model).

From the developer's perspective, you now have a high level of control over how the user navigates through your application, while still allowing them to use the familiar navigation buttons on their browser. You can add/remove items from anywhere in the history chain as you please. If you use objects in your history array, you can track extra information about the pages as well (like field contents and whatnot).

If you need to handle user-initiated navigation (like the user changing the URL in a hash-based navigation scheme), then you might use a slightly different approach like...

var myHistory = [];

function pageLoad() {
    // When the user first hits your page...
    // Check the state to see what's going on.

    if (window.history.state === null) {
        // If the state is null, this is a NEW navigation,
        //    the user has navigated to your page directly (not using back/forward).

        // First we establish a "back" page to catch backward navigation.
        window.history.replaceState(
            { isBackPage: true },
            "<back>",
            "<back>"
        );

        // Then push an "app" page on top of that - this is where the user will sit.
        // (As browsers vary, it might be safer to put this in a short setTimeout).
        window.history.pushState(
            { isBackPage: false },
            "<name>",
            "<url>"
        );

        // We also need to start our history tracking.
        myHistory.push("<whatever>");

        return;
    }

    // If the state is NOT null, then the user is returning to our app via history navigation.

    // (Load up the page based on the last entry of myHistory here)

    if (window.history.state.isBackPage) {
        // If the user came into our app via the back page,
        //     you can either push them forward one more step or just use pushState as above.

        window.history.go(1);
        // or window.history.pushState({ isBackPage: false }, "<name>", "<url>");
    }

    setTimeout(function() {
        // Add our popstate event listener - doing it here should remove
        //     the issue of dealing with the browser firing it on initial page load.
        window.addEventListener("popstate", on_popstate);
    }, 100);
}

function on_popstate(e) {
    if (e.state === null) {
        // If there's no state at all, then the user must have navigated to a new hash.

        // <Look at what they've done, maybe by reading the hash from the URL>
        // <Change/load the new page and push it onto the myHistory stack>
        // <Alternatively, ignore their navigation attempt by NOT loading anything new or adding to myHistory>

        // Undo what they've done (as far as navigation) by kicking them backwards to the "app" page
        window.history.go(-1);

        // Optionally, you can throw another replaceState in here, e.g. if you want to change the visible URL.
        // This would also prevent them from using the "forward" button to return to the new hash.
        window.history.replaceState(
            { isBackPage: false },
            "<new name>",
            "<new url>"
        );
    } else {
        if (e.state.isBackPage) {
            // If there is state and it's the 'back' page...

            if (myHistory.length > 0) {
                // Pull/load the page from our custom history...
                var pg = myHistory.pop();
                // <load/render/whatever>

                // And push them to our "app" page again
                window.history.pushState(
                    { isBackPage: false },
                    "<name>",
                    "<url>"
                );
            } else {
                // No more history - let them exit or keep them in the app.
            }
        }

        // Implied 'else' here - if there is state and it's NOT the 'back' page
        //     then we can ignore it since we're already on the page we want.
        //     (This is the case when we push the user back with window.history.go(-1) above)
    }
}

Yarn install command error No such file or directory: 'install'

Just copy and paste this code one after on your terminal It worked perfectly well for me.

sudo apt remove cmdtest
sudo apt remove yarn
curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | sudo apt-key add -
echo "deb https://dl.yarnpkg.com/debian/ stable main" | sudo tee /etc/apt/sources.list.d/yarn.list
sudo apt-get update
sudo apt-get install yarn -y

How to set the color of "placeholder" text?

Nobody likes the "refer to this answer" answers, but in this case it may help: Change an HTML5 input's placeholder color with CSS

Since it's only supported by a couple of browsers, you can try the jQuery placeholder plugin (assuming you can\are using jQuery). It allows you to style the placeholder text via CSS since it's really only a swap trick it does with focus events.

The plugin does not activate on browsers that support it, though, so you can have CSS that targets chrome\firefox and the jQuery plugin's CSS to catch the rest.

The plugin can be found here: https://github.com/mathiasbynens/jquery-placeholder

Cross-Origin Read Blocking (CORB)

Try to install "Moesif CORS" extension if you are facing issue in google chrome. As it is cross origin request, so chrome is not accepting a response even when the response status code is 200

Call a REST API in PHP

You can go with POSTMAN, an application who makes APIs easy. Fill request fields and then it will generate code for you in different languages. Just click code on the right side and select your prefered language.

"PKIX path building failed" and "unable to find valid certification path to requested target"

If you are seeing this issue in a linux container when java application is trying to communicate with another application/site, it is because the certificate have been imported incorrectly into the load balancer. There is sequence of steps to be followed for importing certificates and that if not done correctly, you will see issues like

Caused by: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid 
certification path to requested target

Once the certs are imported correctly, it should be done. No need to tinker with any JDK certs.

Boolean vs boolean in Java

You can use the Boolean constants - Boolean.TRUE and Boolean.FALSE instead of 0 and 1. You can create your variable as of type boolean if primitive is what you are after. This way you won't have to create new Boolean objects.

push() a two-dimensional array

You have some errors in your code:

  1. Use myArray[i].push( 0 ); to add a new column. Your code (myArray[i][j].push(0);) would work in a 3-dimensional array as it tries to add another element to an array at position [i][j].
  2. You only expand (col-d)-many columns in all rows, even in those, which haven't been initialized yet and thus have no entries so far.

One correct, although kind of verbose version, would be the following:

var r = 3; //start from rows 3

var rows = 8;
var cols = 7;

// expand to have the correct amount or rows
for( var i=r; i<rows; i++ ) {
  myArray.push( [] );
}

// expand all rows to have the correct amount of cols
for (var i = 0; i < rows; i++)
{
    for (var j =  myArray[i].length; j < cols; j++)
    {
        myArray[i].push(0);
    }
}

VBScript How can I Format Date?

Suggest calling 'Now' only once in the function to guard against the minute, or even the day, changing during the execution of the function.

Thus:

Function timeStamp()
    Dim t 
    t = Now
    timeStamp = Year(t) & "-" & _
    Right("0" & Month(t),2)  & "-" & _
    Right("0" & Day(t),2)  & "_" & _  
    Right("0" & Hour(t),2) & _
    Right("0" & Minute(t),2) '    '& _    Right("0" & Second(t),2) 
End Function

R: numeric 'envir' arg not of length one in predict()

There are several problems here:

  1. The newdata argument of predict() needs a predictor variable. You should thus pass it values for Coupon, instead of Total, which is the response variable in your model.

  2. The predictor variable needs to be passed in as a named column in a data frame, so that predict() knows what the numbers its been handed represent. (The need for this becomes clear when you consider more complicated models, having more than one predictor variable).

  3. For this to work, your original call should pass df in through the data argument, rather than using it directly in your formula. (This way, the name of the column in newdata will be able to match the name on the RHS of the formula).

With those changes incorporated, this will work:

model <- lm(Total ~ Coupon, data=df)
new <- data.frame(Coupon = df$Coupon)
predict(model, newdata = new, interval="confidence")

Define preprocessor macro through CMake?

The other solution proposed on this page are useful some versions of Cmake < 3.3.2. Here the solution for the version I am using (i.e., 3.3.2). Check the version of your Cmake by using $ cmake --version and pick the solution that fits with your needs. The cmake documentation can be found on the official page.

With CMake version 3.3.2, in order to create

#define foo

I needed to use:

add_definitions(-Dfoo)   # <--------HERE THE NEW CMAKE LINE inside CMakeLists.txt
add_executable( ....)
target_link_libraries(....)

and, in order to have a preprocessor macro definition like this other one:

#define foo=5

the line is so modified:

add_definitions(-Dfoo=5)   # <--------HERE THE NEW CMAKE LINE inside CMakeLists.txt
add_executable( ....)
target_link_libraries(....)

How to pass a value from Vue data to href?

If you want to display links coming from your state or store in Vue 2.0, you can do like this:

<a v-bind:href="''"> {{ url_link }} </a>

How do you split and unsplit a window/view in Eclipse IDE?

This is possible with the menu items Window>Editor>Toggle Split Editor.

Current shortcut for splitting is:

Azerty keyboard:

  • Ctrl + _ for split horizontally, and
  • Ctrl + { for split vertically.

Qwerty US keyboard:

  • Ctrl + Shift + - (accessing _) for split horizontally, and
  • Ctrl + Shift + [ (accessing {) for split vertically.

MacOS - Qwerty US keyboard:

  • + Shift + - (accessing _) for split horizontally, and
  • + Shift + [ (accessing {) for split vertically.

On any other keyboard if a required key is unavailable (like { on a german Qwertz keyboard), the following generic approach may work:

  • Alt + ASCII code + Ctrl then release Alt

Example: ASCII for '{' = 123, so press 'Alt', '1', '2', '3', 'Ctrl' and release 'Alt', effectively typing '{' while 'Ctrl' is pressed, to split vertically.

Example of vertical split:

https://bugs.eclipse.org/bugs/attachment.cgi?id=238285

PS:

  • The menu items Window>Editor>Toggle Split Editor were added with Eclipse Luna 4.4 M4, as mentioned by Lars Vogel in "Split editor implemented in Eclipse M4 Luna"
  • The split editor is one of the oldest and most upvoted Eclipse bug! Bug 8009
  • The split editor functionality has been developed in Bug 378298, and will be available as of Eclipse Luna M4. The Note & Newsworthy of Eclipse Luna M4 will contain the announcement.

Printing a 2D array in C

Is this any help?

#include <stdio.h>

#define MAX 10

int main()
{
    char grid[MAX][MAX];
    int i,j,row,col;

    printf("Please enter your grid size: ");
    scanf("%d %d", &row, &col);


    for (i = 0; i < row; i++) {
        for (j = 0; j < col; j++) {
            grid[i][j] = '.';
            printf("%c ", grid[i][j]);
        }
        printf("\n");
    }

    return 0;
}

Cannot overwrite model once compiled Mongoose

This happened to me when I write like this:

import User from '../myuser/User.js';

However, the true path is '../myUser/User.js'

CSS Background Opacity

.transbg{/* Fallback for web browsers that don't support RGBa */
background-color: rgb(0, 0, 0);
/* RGBa with 0.6 opacity */
background-color: rgba(0, 0, 0, 0.6);
/* For IE 5.5 - 7*/
filter:progid:DXImageTransform.Microsoft.gradient(startColorstr=#99000000, endColorstr=#99000000);
/* For IE 8*/
-ms-filter: "progid:DXImageTransform.Microsoft.gradient(startColorstr=#99000000, endColorstr=#99000000)";}

Can I force pip to reinstall the current version?

You might want to have all three options: --upgrade and --force-reinstall ensures reinstallation, while --no-deps avoids reinstalling dependencies.

$ sudo pip install --upgrade --no-deps --force-reinstall <packagename>

Otherwise you might run into the problem that pip starts to recompile Numpy or other large packages.

How are ssl certificates verified?

Here is a very simplified explanation:

  1. Your web browser downloads the web server's certificate, which contains the public key of the web server. This certificate is signed with the private key of a trusted certificate authority.

  2. Your web browser comes installed with the public keys of all of the major certificate authorities. It uses this public key to verify that the web server's certificate was indeed signed by the trusted certificate authority.

  3. The certificate contains the domain name and/or ip address of the web server. Your web browser confirms with the certificate authority that the address listed in the certificate is the one to which it has an open connection.

  4. Your web browser generates a shared symmetric key which will be used to encrypt the HTTP traffic on this connection; this is much more efficient than using public/private key encryption for everything. Your browser encrypts the symmetric key with the public key of the web server then sends it back, thus ensuring that only the web server can decrypt it, since only the web server has its private key.

Note that the certificate authority (CA) is essential to preventing man-in-the-middle attacks. However, even an unsigned certificate will prevent someone from passively listening in on your encrypted traffic, since they have no way to gain access to your shared symmetric key.

PHP: How do I display the contents of a textfile on my page?

I have to display files of computer code. If special characters are inside the file like less than or greater than, a simple "include" will not display them. Try:

$file = 'code.ino';
$orig = file_get_contents($file);
$a = htmlentities($orig);

echo '<code>';
echo '<pre>';

echo $a;

echo '</pre>';
echo '</code>';

Entity Framework Migrations renaming tables and columns

I just tried the same in EF6 (code first entity rename). I simply renamed the class and added a migration using the package manager console and voila, a migration using RenameTable(...) was automatically generated for me. I have to admit that I made sure the only change to the entity was renaming it so no new columns or renamed columns so I cannot be certain if this is an EF6 thing or just that EF was (always) able to detect such simple migrations.

How to add style from code behind?

try this

 lblMsg.Text = @"Your search result for <b style=""color:green;"">" + txtCode.Text.Trim() + "</b> ";

Adding items to an object through the .push() method

This is really easy: Example

//my object
var sendData = {field1:value1, field2:value2};

//add element
sendData['field3'] = value3;

Need to navigate to a folder in command prompt

Just use the change directory (cd) command.

cd d:\windows\movie

How to assign a NULL value to a pointer in python?

left = None

left is None #evaluates to True

Input placeholders for Internet Explorer

I suggest you a simple function :

function bindInOut(element,value)
{
    element.focus(function()
    {
        if(element.val() == value) element.val('');         
    }).
    blur(function()
    {
        if(element.val() == '') element.val(value);
    });

    element.blur();
}

And to use it, call it in this way :

bindInOut($('#input'),'Here your value :)');

PHP absolute path to root

use dirname(__FILE__) in a global configuration file.

Get type name without full namespace

typeof(T).Name // class name, no namespace
typeof(T).FullName // namespace and class name
typeof(T).Namespace // namespace, no class name

How to tell if a JavaScript function is defined

if (callback && typeof(callback) == "function")

Note that callback (by itself) evaluates to false if it is undefined, null, 0, or false. Comparing to null is overly specific.

Converting java.sql.Date to java.util.Date

If you really want the runtime type to be util.Date then just do this:

java.util.Date utilDate = new java.util.Date(sqlDate.getTime());

Brian.

The tilde operator in Python

~ is the bitwise complement operator in python which essentially calculates -x - 1

So a table would look like

i  ~i  
0  -1
1  -2
2  -3
3  -4 
4  -5 
5  -6

So for i = 0 it would compare s[0] with s[len(s) - 1], for i = 1, s[1] with s[len(s) - 2].

As for your other question, this can be useful for a range of bitwise hacks.

The operation cannot be completed because the DbContext has been disposed error

The reason why it is throwing the error is the object is disposed and after that we are trying to access the table values through the object, but object is disposed.Better to convert that into ToList() so that we can have values

Maybe it isn't actually getting the data until you use it (it is lazy loading), so dataContext doesn't exist when you are trying to do the work. I bet if you did the ToList() in scope it would be ok.

try
{
    IQueryable<User> users;
    var ret = null;

    using (var dataContext = new dataContext())
    {
        users = dataContext.Users.Where(x => x.AccountID == accountId && x.IsAdmin == false);

        if(users.Any())
        {
            ret = users.Select(x => x.ToInfo()).ToList(); 
        }

     }

   Return ret;
}
catch (Exception ex)
{
    ...
}

What is the difference between 'java', 'javaw', and 'javaws'?

java: Java application executor which is associated with a console to display output/errors

javaw: (Java windowed) application executor not associated with console. So no display of output/errors. It can be used to silently push the output/errors to text files. It is mostly used to launch GUI-based applications.

javaws: (Java web start) to download and run the distributed web applications. Again, no console is associated.

All are part of JRE and use the same JVM.

How do I decode a base64 encoded string?

Simple:

byte[] data = Convert.FromBase64String(encodedString);
string decodedString = Encoding.UTF8.GetString(data);

How to convert a list into data table

private DataTable CreateDataTable(IList<T> item)
{
    Type type = typeof(T);
    var properties = type.GetProperties();

    DataTable dataTable = new DataTable();
    foreach (PropertyInfo info in properties)
    {
        dataTable.Columns.Add(new DataColumn(info.Name, Nullable.GetUnderlyingType(info.PropertyType) ?? info.PropertyType));
    }

    foreach (T entity in item)
    {
        object[] values = new object[properties.Length];
        for (int i = 0; i < properties.Length; i++)
        {
            values[i] = properties[i].GetValue(entity);
        }

        dataTable.Rows.Add(values);
    }
    return dataTable;
}

How to force cp to overwrite without confirmation

Another way to call the command without the alias is to use the command builtin in bash.

command cp -rf /zzz/zzz/*

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

Suppose a 9800GT GPU:

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

https://www.tutorialspoint.com/cuda/cuda_threads.htm

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

func1();
__syncthreads();
func2();
__syncthreads();

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

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

Note:

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


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

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

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

How to set MimeBodyPart ContentType to "text/html"?

Call MimeMessage.saveChanges() on the enclosing message, which will update the headers by cascading down the MIME structure into a call to MimeBodyPart.updateHeaders() on your body part. It's this updateHeaders call that transfers the content type from the DataHandler to the part's MIME Content-Type header.

When you set the content of a MimeBodyPart, JavaMail internally (and not obviously) creates a DataHandler object wrapping the object you passed in. The part's Content-Type header is not updated immediately.

There's no straightforward way to do it in your test program, since you don't have a containing MimeMessage and MimeBodyPart.updateHeaders() isn't public.


Here's a working example that illuminates expected and unexpected outputs:

public class MailTest {

  public static void main( String[] args ) throws Exception {
    Session mailSession = Session.getInstance( new Properties() );
    Transport transport = mailSession.getTransport();

    String text = "Hello, World";
    String html = "<h1>" + text + "</h1>";

    MimeMessage message = new MimeMessage( mailSession );
    Multipart multipart = new MimeMultipart( "alternative" );

    MimeBodyPart textPart = new MimeBodyPart();
    textPart.setText( text, "utf-8" );

    MimeBodyPart htmlPart = new MimeBodyPart();
    htmlPart.setContent( html, "text/html; charset=utf-8" );

    multipart.addBodyPart( textPart );
    multipart.addBodyPart( htmlPart );
    message.setContent( multipart );

    // Unexpected output.
    System.out.println( "HTML = text/html : " + htmlPart.isMimeType( "text/html" ) );
    System.out.println( "HTML Content Type: " + htmlPart.getContentType() );

    // Required magic (violates principle of least astonishment).
    message.saveChanges();

    // Output now correct.    
    System.out.println( "TEXT = text/plain: " + textPart.isMimeType( "text/plain" ) );
    System.out.println( "HTML = text/html : " + htmlPart.isMimeType( "text/html" ) );
    System.out.println( "HTML Content Type: " + htmlPart.getContentType() );
    System.out.println( "HTML Data Handler: " + htmlPart.getDataHandler().getContentType() );
  }
}

Can I create view with parameter in MySQL?

Actually if you create func:

create function p1() returns INTEGER DETERMINISTIC NO SQL return @p1;

and view:

create view h_parm as
select * from sw_hardware_big where unit_id = p1() ;

Then you can call a view with a parameter:

select s.* from (select @p1:=12 p) parm , h_parm s;

I hope it helps.

Positioning background image, adding padding

To add space before background image, one could define the 'width' of element which is using 'background-image' object. And then to define a pixel value in 'background-position' property to create space from left side.

For example, I'd a scenario where I got a navigation menu which had a bullet before link item and the bullet graphic were changeable if corrosponding link turns into an active state. Further, the active link also had a background-color to show, and this background-color had approximate 15px padding both on left and right side of link item (so on left, it includes bullet icon of link too).

While padding-right fulfill the purpose to have background-color stretched upto 15px more on right of link text. The padding-left only added to space between link text and bullet.

So I took the width of background-color object from PSD design (for ex. 82px) and added that to li element (in a class created to show active state) and then I set background-position value to 20px. Which resulted in bullet icon shifted inside from the left edge. And its provided me desired output of having left padding before bullet icon used as background image.

Please note, you may need to adjust your padding / margin values accordingly, which may used either for space between link items or for spacing between bullet icon and link text.

Troubleshooting "Illegal mix of collations" error in mysql

This code needs to be put inside Run SQL query/queries on database

SQL QUERY WINDOW

ALTER TABLE `table_name` CHANGE `column_name` `column_name`   VARCHAR(128) CHARACTER SET utf8 COLLATE utf8_unicode_ci NULL DEFAULT NULL;

Please replace table_name and column_name with appropriate name.

Two models in one view in ASP MVC 3

Another option which doesn't have the need to create a custom Model is to use a Tuple<>.

@model Tuple<Person,Order>

It's not as clean as creating a new class which contains both, as per Andi's answer, but it is viable.

git repo says it's up-to-date after pull but files are not updated

Try this:

 git fetch --all
 git reset --hard origin/master

Explanation:

git fetch downloads the latest from remote without trying to merge or rebase anything.

Please let me know if you have any questions!

How to find Google's IP address?

Here is a bash script that returns the IP (v4 and v6) ranges using @WorkWise's answer:

domainsToDig=$(dig @8.8.8.8 _spf.google.com TXT +short | \
    sed \
        -e 's/"v=spf1//' \
        -e 's/ ~all"//' \
        -e 's/ include:/\n/g' | \
    tail -n+2)
for domain in $domainsToDig ; do
    dig @8.8.8.8 $domain TXT +short | \
        sed \
            -e 's/"v=spf1//' \
            -e 's/ ~all"//' \
            -e 's/ ip.:/\n/g' | \
        tail -n+2
done

Set order of columns in pandas dataframe

Add the 'columns' parameter:

frame = pd.DataFrame({
        'one thing':[1,2,3,4],
        'second thing':[0.1,0.2,1,2],
        'other thing':['a','e','i','o']},
        columns=['one thing', 'second thing', 'other thing']
)

Serializing/deserializing with memory stream

BinaryFormatter may produce invalid output in some specific cases. For example it will omit unpaired surrogate characters. It may also have problems with values of interface types. Read this documentation page including community content.

If you find your error to be persistent you may want to consider using XML serializer like DataContractSerializer or XmlSerializer.

How do you use subprocess.check_output() in Python?

Adding on to the one mentioned by @abarnert

a better one is to catch the exception

import subprocess
try:
    py2output = subprocess.check_output(['python', 'py2.py', '-i', 'test.txt'],stderr= subprocess.STDOUT)  
    #print('py2 said:', py2output)
    print "here"
except subprocess.CalledProcessError as e:
    print "Calledprocerr"

this stderr= subprocess.STDOUT is for making sure you dont get the filenotfound error in stderr- which cant be usually caught in filenotfoundexception, else you would end up getting

python: can't open file 'py2.py': [Errno 2] No such file or directory

Infact a better solution to this might be to check, whether the file/scripts exist and then to run the file/script

How do I abort/cancel TPL Tasks?

Task are being executed on the ThreadPool (at least, if you are using the default factory), so aborting the thread cannot affect the tasks. For aborting tasks, see Task Cancellation on msdn.

Proper Linq where clauses

Looking under the hood, the two statements will be transformed into different query representations. Depending on the QueryProvider of Collection, this might be optimized away or not.

When this is a linq-to-object call, multiple where clauses will lead to a chain of IEnumerables that read from each other. Using the single-clause form will help performance here.

When the underlying provider translates it into a SQL statement, the chances are good that both variants will create the same statement.

How to put a link on a button with bootstrap?

Another trick to get the link color working correctly inside the <button> markup

<button type="button" class="btn btn-outline-success and-all-other-classes"> 
  <a href="#" style="color:inherit"> Button text with correct colors </a>
</button>

Please keep in mind that in bs4 beta e.g. btn-primary-outline changed to btn-outline-primary

JavaScript replace \n with <br />

Use a regular expression for .replace().:

messagetoSend = messagetoSend.replace(/\n/g, "<br />");

If those linebreaks were made by windows-encoding, you will also have to replace the carriage return.

messagetoSend = messagetoSend.replace(/\r\n/g, "<br />");

Using Transactions or SaveChanges(false) and AcceptAllChanges()?

With the Entity Framework most of the time SaveChanges() is sufficient. This creates a transaction, or enlists in any ambient transaction, and does all the necessary work in that transaction.

Sometimes though the SaveChanges(false) + AcceptAllChanges() pairing is useful.

The most useful place for this is in situations where you want to do a distributed transaction across two different Contexts.

I.e. something like this (bad):

using (TransactionScope scope = new TransactionScope())
{
    //Do something with context1
    //Do something with context2

    //Save and discard changes
    context1.SaveChanges();

    //Save and discard changes
    context2.SaveChanges();

    //if we get here things are looking good.
    scope.Complete();
}

If context1.SaveChanges() succeeds but context2.SaveChanges() fails the whole distributed transaction is aborted. But unfortunately the Entity Framework has already discarded the changes on context1, so you can't replay or effectively log the failure.

But if you change your code to look like this:

using (TransactionScope scope = new TransactionScope())
{
    //Do something with context1
    //Do something with context2

    //Save Changes but don't discard yet
    context1.SaveChanges(false);

    //Save Changes but don't discard yet
    context2.SaveChanges(false);

    //if we get here things are looking good.
    scope.Complete();
    context1.AcceptAllChanges();
    context2.AcceptAllChanges();

}

While the call to SaveChanges(false) sends the necessary commands to the database, the context itself is not changed, so you can do it again if necessary, or you can interrogate the ObjectStateManager if you want.

This means if the transaction actually throws an exception you can compensate, by either re-trying or logging state of each contexts ObjectStateManager somewhere.

See my blog post for more.

Node.js on multi-core machines

One method would be to run multiple instances of node.js on the server and then put a load balancer (preferably a non-blocking one like nginx) in front of them.

Vue.js getting an element within a component

In Vue2 be aware that you can access this.$refs.uniqueName only after mounting the component.

Where will log4net create this log file?

I was developing for .NET core 2.1 using log4net 2.0.8 and found NealWalters code moans about 0 arguments for XmlConfigurator.Configure(). I found a solution by Matt Watson here

        log4net.GlobalContext.Properties["LogFileName"] = @"E:\\file1"; //log file path
        var logRepository = LogManager.GetRepository(Assembly.GetEntryAssembly());
        XmlConfigurator.Configure(logRepository, new FileInfo("log4net.config"));

Removing trailing newline character from fgets() input

 for(int i = 0; i < strlen(Name); i++ )
{
    if(Name[i] == '\n') Name[i] = '\0';
}

You should give it a try. This code basically loop through the string until it finds the '\n'. When it's found the '\n' will be replaced by the null character terminator '\0'

Note that you are comparing characters and not strings in this line, then there's no need to use strcmp():

if(Name[i] == '\n') Name[i] = '\0';

since you will be using single quotes and not double quotes. Here's a link about single vs double quotes if you want to know more

Excel vba - convert string to number

If, for example, x = 5 and is stored as string, you can also just:

x = x + 0

and the new x would be stored as a numeric value.

Why Choose Struct Over Class?

  • Structure and class are user defied data types

  • By default, structure is a public whereas class is private

  • Class implements the principal of encapsulation

  • Objects of a class are created on the heap memory

  • Class is used for re usability whereas structure is used for grouping the data in the same structure

  • Structure data members cannot be initialized directly but they can be assigned by the outside the structure

  • Class data members can be initialized directly by the parameter less constructor and assigned by the parameterized constructor

Difference between JE/JNE and JZ/JNZ

JE and JZ are just different names for exactly the same thing: a conditional jump when ZF (the "zero" flag) is equal to 1.

(Similarly, JNE and JNZ are just different names for a conditional jump when ZF is equal to 0.)

You could use them interchangeably, but you should use them depending on what you are doing:

  • JZ/JNZ are more appropriate when you are explicitly testing for something being equal to zero:

    dec  ecx
    jz   counter_is_now_zero
    
  • JE and JNE are more appropriate after a CMP instruction:

    cmp  edx, 42
    je   the_answer_is_42
    

    (A CMP instruction performs a subtraction, and throws the value of the result away, while keeping the flags; which is why you get ZF=1 when the operands are equal and ZF=0 when they're not.)

How can I get the Google cache age of any URL or web page?

You'll need to scrape the resulting page, but you can view the most recent cache page using this URL:

http://webcache.googleusercontent.com/search?q=cache:www.something.com/path

Google information is put in the first div in the body tag.

Replace Multiple String Elements in C#

I'm doing something similar, but in my case I'm doing serialization/De-serialization so I need to be able to go both directions. I find using a string[][] works nearly identically to the dictionary, including initialization, but you can go the other direction too, returning the substitutes to their original values, something that the dictionary really isn't set up to do.

Edit: You can use Dictionary<Key,List<Values>> in order to obtain same result as string[][]

Convert an int to ASCII character

          A PROGRAM TO CONVERT INT INTO ASCII.




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

           char data[1000]= {' '};           /*thing in the bracket is optional*/
           char data1[1000]={' '};
           int val, a;
           char varray [9];

           void binary (int digit)
          {
              if(digit==0)
               val=48;
              if(digit==1)
               val=49;
              if(digit==2)
               val=50;
              if(digit==3)
               val=51;
              if(digit==4)
               val=52;
              if(digit==5)
               val=53;
              if(digit==6)
               val=54;
              if(digit==7)
               val=55;
              if(digit==8)
               val=56;
              if(digit==9)
                val=57;
                a=0;

           while(val!=0)
           {
              if(val%2==0)
               {
                varray[a]= '0';
               }

               else
               varray[a]='1';
               val=val/2;
               a++;
           }


           while(a!=7)
          {
            varray[a]='0';
            a++;
           }


          varray [8] = NULL;
          strrev (varray);
          strcpy (data1,varray);
          strcat (data1,data);
          strcpy (data,data1);

         }


          void main()
         {
           int num;
           clrscr();
           printf("enter number\n");
           scanf("%d",&num);
           if(num==0)
           binary(0);
           else
           while(num>0)
           {
           binary(num%10);
           num=num/10;
           }
           puts(data);
           getch();

           }

I check my coding and its working good.let me know if its helpful.thanks.

Fastest way to check if a value exists in a list

Code to check whether two elements exist in array whose product equals k:

n = len(arr1)
for i in arr1:
    if k%i==0:
        print(i)

Truncate Two decimal places without rounding

This is what i did:

        c1 = a1 - b1;
        d1 = Math.Ceiling(c1 * 100) / 100;

subtracting two inputted numbers without rounding up or down the decimals. because the other solutions does not work for me. don't know if it will work for others, i just want to share this :) Hope it works tho for those who's finding solution to a problem similar to mine. Thanks

PS: i'm a beginner so feel free to point out something on this. :D this is good if you're actually dealing with money, cause of the cents right? it only have 2 decimal places and rounding it is a no no.

How do I install a module globally using npm?

I had issues installing Express on Ubuntu:

If for some reason NPM command is missing, test npm command with npm help. If not there, follow these steps - http://arnolog.net/post/8424207595/installing-node-js-npm-express-mongoose-on-ubuntu

If just the Express command is not working, try:

sudo npm install -g express

This made everything work as I'm used to with Windows7 and OSX.

Hope this helps!

Link to "pin it" on pinterest without generating a button

The standard Pinterest button code (which you can generate here), is an <a> tag wrapping an <img> of the Pinterest button.

If you don't include the pinit.js script on your page, this <a> tag will work "as-is". You could improve the experience by registering your own click handler on these tags that opens a new window with appropriate dimensions, or at least adding target="_blank" to the tag to make it open clicks in a new window.

The tag syntax would look like:

<a href="http://pinterest.com/pin/create/button/?url={URI-encoded URL of the page to pin}&media={URI-encoded URL of the image to pin}&description={optional URI-encoded description}" class="pin-it-button" count-layout="horizontal">
    <img border="0" src="//assets.pinterest.com/images/PinExt.png" title="Pin It" />
</a>

If using the JavaScript versions of sharing buttons are ruining your page load times, you can improve your site by using asynchronous loading methods. For an example of doing this with the Pinterest button, check out my GitHub Pinterest button project with an improved HTML5 syntax.

Skip to next iteration in loop vba

The present solution produces the same flow as your OP. It does not use Labels, but this was not a requirement of the OP. You only asked for "a simple conditional loop that will go to the next iteration if a condition is true", and since this is cleaner to read, it is likely a better option than that using a Label.

What you want inside your for loop follows the pattern

If (your condition) Then
    'Do something
End If

In this case, your condition is Not(Return = 0 And Level = 0), so you would use

For i = 2 To 24
    Level = Cells(i, 4)
    Return = Cells(i, 5)

    If (Not(Return = 0 And Level = 0)) Then
        'Do something
    End If
Next i

PS: the condition is equivalent to (Return <> 0 Or Level <> 0)

Getting java.lang.ClassNotFoundException: org.apache.commons.logging.LogFactory exception

I generally assign the classpath to a variable and then verify it. I've written a small ruby script which I include in a my startup scripts which validates the classpath before launching java. Validating the classpath before the JVM starts has saved me lots of time troubleshooting these types of problems.

Incomplete type is not allowed: stringstream

An incomplete type error is when the compiler encounters the use of an identifier that it knows is a type, for instance because it has seen a forward-declaration of it (e.g. class stringstream;), but it hasn't seen a full definition for it (class stringstream { ... };).

This could happen for a type that you haven't used in your own code but is only present through included header files -- when you've included header files that use the type, but not the header file where the type is defined. It's unusual for a header to not itself include all the headers it needs, but not impossible.

For things from the standard library, such as the stringstream class, use the language standard or other reference documentation for the class or the individual functions (e.g. Unix man pages, MSDN library, etc.) to figure out what you need to #include to use it and what namespace to find it in if any. You may need to search for pages where the class name appears (e.g. man -k stringstream).

Correct way to convert size in bytes to KB, MB, GB in JavaScript

This is how a byte should be shown to a human:

function bytesToHuman(bytes, decimals = 2) {
  // https://en.wikipedia.org/wiki/Orders_of_magnitude_(data)
  const units = ["bytes", "KiB", "MiB", "GiB", "TiB", "PiB", "EiB"]; // etc

  let i = 0;
  let h = 0;

  let c = 1 / 1023; // change it to 1024 and see the diff

  for (; h < c && i < units.length; i++) {
    if ((h = Math.pow(1024, i) / bytes) >= c) {
      break;
    }
  }

  // remove toFixed and let `locale` controls formatting
  return (1 / h).toFixed(decimals).toLocaleString() + " " + units[i];
}

// test
for (let i = 0; i < 9; i++) {
  let val = i * Math.pow(10, i);
  console.log(val.toLocaleString() + " bytes is the same as " + bytesToHuman(val));

}

// let's fool around
console.log(bytesToHuman(1023));
console.log(bytesToHuman(1024));
console.log(bytesToHuman(1025));

How do I parse a string to a float or int?

for number and char together :

string_for_int = "498 results should get"
string_for_float = "498.45645765 results should get"

first import re:

 import re

 #for get integer part:
 print(int(re.search(r'\d+', string_for_int).group())) #498

 #for get float part:
 print(float(re.search(r'\d+\.\d+', string_for_float).group())) #498.45645765

for easy model :

value1 = "10"
value2 = "10.2"
print(int(value1)) #10
print(float(value2)) #10.2

Can't concatenate 2 arrays in PHP

It is indeed a key conflict. When concatenating arrays, duplicate keys are not overwritten.

Instead you must use array_merge()

$array = array_merge(array('Item 1'), array('Item 2'));

PHP's array_map including keys

Based on eis's answer, here's what I eventually did in order to avoid messing the original array:

$test_array = array("first_key" => "first_value",
                    "second_key" => "second_value");

$result_array = array();
array_walk($test_array, 
           function($a, $b) use (&$result_array) 
           { $result_array[] = "$b loves $a"; }, 
           $result_array);
var_dump($result_array);

Just get column names from hive table

If you simply want to see the column names this one line should provide it without changing any settings:

describe database.tablename;

However, if that doesn't work for your version of hive this code will provide it, but your default database will now be the database you are using:

use database;
describe tablename;

how to move elasticsearch data from one server to another

We can use elasticdump or multielasticdump to take the backup and restore it, We can move data from one server/cluster to another server/cluster.

Please find a detailed answer which I have provided here.

Vuejs: Event on route change

Watcher with the deep option didn't work for me.

Instead, I use updated() lifecycle hook which gets executed everytime the component's data changes. Just use it like you do with mounted().

mounted() {
   /* to be executed when mounted */
},
updated() {
   console.log(this.$route)
}

For your reference, visit the documentation.

javascript functions to show and hide divs

I usually do this with classes, that seems to force the browsers to reassess all the styling.

.hiddendiv {display:none;}
.visiblediv {display:block;}

then use;

<script>  
function show() {  
    document.getElementById('benefits').className='visiblediv';  
}  
function close() {  
    document.getElementById('benefits').className='hiddendiv';  
}    
</script>

Note the casing of "className" that trips me up a lot

Check folder size in Bash

To check the size of all of the directories within a directory, you can use:

du -h --max-depth=1

Auto-redirect to another HTML page

You can use <meta> tag refresh, and <meta> tag in <head> section

<META http-equiv="refresh" content="5;URL=your_url">