Programs & Examples On #Rtti

RTTI stands for Run-Time Type Information, it is also known as reflection; it allows access to compile-time data at run-time.

is vs typeof

Does it matter which is faster, if they don't do the same thing? Comparing the performance of statements with different meaning seems like a bad idea.

is tells you if the object implements ClassA anywhere in its type heirarchy. GetType() tells you about the most-derived type.

Not the same thing.

How to set 'X-Frame-Options' on iframe?

(I'm resurrecting this answer because I would like to share the workaround I created to solve this issue)

If you don't have access to the website hosting the web page you want to serve within the <iframe> element, you can circumvent the X-Frame-Options SAMEORIGIN restrictions by using a CORS-enabled reverse proxy that could request the web page(s) from the web server (upstream) and serve them to the end-user.

Here's a visual diagram of the concept:

enter image description here

Since I was unhappy with the CORS proxies I found, I ended up creating one myself, which I called CORSflare: it has been designed to run in a Cloudflare Worker (serverless computing), therefore it's a 100% free workaround - as long as you don't need it to accept more than 100.000 request per day.

You can find the proxy source code on GitHub; the full documentation, including the installation instruction, can be found in this post of my blog.

jQuery - get all divs inside a div with class ".container"

To get all divs under 'container', use the following:

$(".container>div")  //or
$(".container").children("div");

You can stipulate a specific #id instead of div to get a particular one.

You say you want a div with an 'undefined' id. if I understand you right, the following would achieve this:

$(".container>div[id=]")

How do I return clean JSON from a WCF Service?

If you want nice json without hardcoding attributes into your service classes,

use <webHttp defaultOutgoingResponseFormat="Json"/> in your behavior config

Uncaught SyntaxError: Unexpected token :

If nothing makes sense, this error can also be caused by PHP Error that is embedded inside html/javascript, such as the one below

<br />
<b>Deprecated</b>:  mysql_connect(): The mysql extension is deprecated and will be removed in the future: use mysqli or PDO instead in <b>C:\Projects\rwp\demo\en\super\ge.php</b> on line <b>54</b><br />
var zNodes =[{ id:1, pId:0, name:"ACE", url: "/ace1.php", target:"_self", open:true}

Not the <br /> etc in the code that are inserted into html by PHP is causing the error. To fix this kind of error (suppress warning), used this code in the start

error_reporting(E_ERROR | E_PARSE);

To view, right click on page, "view source" and then examine complete html to spot this error.

Install IPA with iTunes 11

I always use the iPhone configuration utility for this. Allows much more control and is faster - you don't have to sync the whole device.

How can I create a Java 8 LocalDate from a long Epoch time in Milliseconds?

You can start with Instant.ofEpochMilli(long):

LocalDate date =
  Instant.ofEpochMilli(startDateLong)
  .atZone(ZoneId.systemDefault())
  .toLocalDate();

Convert string to date then format the date

Use SimpleDateFormat#format(Date):

String start_dt = "2011-01-01";
DateFormat formatter = new SimpleDateFormat("yyyy-MM-DD"); 
Date date = (Date)formatter.parse(start_dt);
SimpleDateFormat newFormat = new SimpleDateFormat("MM-dd-yyyy");
String finalString = newFormat.format(date);

How do I set up CLion to compile and run?

I met some problems in Clion and finally, I solved them. Here is some experience.

  1. Download and install MinGW
  2. g++ and gcc package should be installed by default. Use the MinGW installation manager to install mingw32-libz and mingw32-make. You can open MinGW installation manager through C:\MinGW\libexec\mingw-get.exe This step is the most important step. If Clion cannot find make, C compiler and C++ compiler, recheck the MinGW installation manager to make every necessary package is installed.
  3. In Clion, open File->Settings->Build,Execution,Deployment->Toolchains. Set MinGW home as your local MinGW file.
  4. Start your "Hello World"!

How to set Google Chrome in WebDriver

Aditya,

As you said in your last comment that you are trying to access chrome of some other system so based on that you should keep your chrome driver in that system itself.

for example: if you are trying to access linux chrome from windows then you need to put your chrome driver in linux at some place and give permission as 777 and use below code at your windows system.

System.setProperty("webdriver.chrome.driver", "\\var\\www\\Jar\\chromedriver");
Capability= DesiredCapabilities.chrome();   Capability.setPlatform(org.openqa.selenium.Platform.ANY);
browser=new RemoteWebDriver(new URL(nodeURL),Capability);

This is working code of my system.

When to use static keyword before global variables?

You should not define global variables in header files. You should define them in .c source file.

  • If global variable is to be visible within only one .c file, you should declare it static.

  • If global variable is to be used across multiple .c files, you should not declare it static. Instead you should declare it extern in header file included by all .c files that need it.

Example:

  • example.h

    extern int global_foo;
    
  • foo.c

    #include "example.h"
    
    int global_foo = 0;
    static int local_foo = 0;
    
    int foo_function()
    {
       /* sees: global_foo and local_foo
          cannot see: local_bar  */
       return 0;
    }
    
  • bar.c

    #include "example.h"
    
    static int local_bar = 0;
    static int local_foo = 0;
    
    int bar_function()
    {
        /* sees: global_foo, local_bar */
        /* sees also local_foo, but it's not the same local_foo as in foo.c
           it's another variable which happen to have the same name.
           this function cannot access local_foo defined in foo.c
        */
        return 0;
    }
    

Swift presentViewController

You can use below code :

var vc = self.storyboard?.instantiateViewControllerWithIdentifier("YourViewController") as! YourViewController;
            vc.mode_Player = 1
            self.presentViewController(vc, animated: true, completion: nil)

Rails - controller action name to string

Rails 2.X: @controller.action_name

Rails 3.1.X: controller.action_name, action_name

Rails 4.X: action_name

What is the best way to update the entity in JPA

It depends on number of entities which are going to be updated, if you have large number of entities using JPA Query Update statement is better as you dont have to load all the entities from database, if you are going to update just one entity then using find and update is fine.

What is the fastest factorial function in JavaScript?

// if you don't want to update the Math object, use `var factorial = ...`
Math.factorial = (function() {
    var f = function(n) {
        if (n < 1) {return 1;}  // no real error checking, could add type-check
        return (f[n] > 0) ? f[n] : f[n] = n * f(n -1);
    }
    for (i = 0; i < 101; i++) {f(i);} // precalculate some values
    return f;
}());

factorial(6); // 720, initially cached
factorial[6]; // 720, same thing, slightly faster access, 
              // but fails above current cache limit of 100
factorial(100); // 9.33262154439441e+157, called, but pulled from cache
factorial(142); // 2.6953641378881614e+245, called
factorial[141]; // 1.89814375907617e+243, now cached

This does the caching of the first 100 values on the fly, and does not introduce an external variable into scope for the cache, storing the values as properties of the function object itself, which means that if you know factorial(n) has already been calculated, you can simply refer to it as factorial[n], which is slightly more efficient. Running these first 100 values will take sub-millisecond time in modern browsers.

How to define custom exception class in Java, the easiest way?

Exception class has two constructors

  • public Exception() -- This constructs an Exception without any additional information.Nature of the exception is typically inferred from the class name.
  • public Exception(String s) -- Constructs an exception with specified error message.A detail message is a String that describes the error condition for this particular exception.

Interactive shell using Docker Compose

You can do docker-compose exec SERVICE_NAME sh on the command line. The SERVICE_NAME is defined in your docker-compose.yml. For example,

services:
    zookeeper:
        image: wurstmeister/zookeeper
        ports:
          - "2181:2181"

The SERVICE_NAME would be "zookeeper".

Check file uploaded is in csv format

There are a lot of possible MIME types for CSV files, depending on the user's OS and browser version.

This is how I currently validate the MIME types of my CSV files:

$csv_mimetypes = array(
    'text/csv',
    'text/plain',
    'application/csv',
    'text/comma-separated-values',
    'application/excel',
    'application/vnd.ms-excel',
    'application/vnd.msexcel',
    'text/anytext',
    'application/octet-stream',
    'application/txt',
);

if (in_array($_FILES['upload']['type'], $csv_mimetypes)) {
    // possible CSV file
    // could also check for file content at this point
}

Python: Is there an equivalent of mid, right, and left from BASIC?

Thanks Andy W

I found that the mid() did not quite work as I expected and I modified as follows:

def mid(s, offset, amount):
    return s[offset-1:offset+amount-1]

I performed the following test:

print('[1]23', mid('123', 1, 1))
print('1[2]3', mid('123', 2, 1))
print('12[3]', mid('123', 3, 1))
print('[12]3', mid('123', 1, 2))
print('1[23]', mid('123', 2, 2))

Which resulted in:

[1]23 1
1[2]3 2
12[3] 3
[12]3 12
1[23] 23

Which was what I was expecting. The original mid() code produces this:

[1]23 2
1[2]3 3
12[3] 
[12]3 23
1[23] 3

But the left() and right() functions work fine. Thank you.

How can I convert an image into Base64 string using JavaScript?

If you have a file object, this simple function will work:

function getBase64 (file, callback) {

    const reader = new FileReader();

    reader.addEventListener('load', () => callback(reader.result));

    reader.readAsDataURL(file);
}

Usage example:

getBase64(fileObjectFromInput, function(base64Data){
    console.log("Base64 of file is", base64Data); // Here you can have your code which uses Base64 for its operation, // file to Base64 by oneshubh
});

How to use null in switch

You have to make a

if (i == null) {
   doSomething0();
} else {
   switch (i) {
   }
}

Is a GUID unique 100% of the time?

From http://www.guidgenerator.com/online-guid-generator.aspx

What is a GUID?

GUID (or UUID) is an acronym for 'Globally Unique Identifier' (or 'Universally Unique Identifier'). It is a 128-bit integer number used to identify resources. The term GUID is generally used by developers working with Microsoft technologies, while UUID is used everywhere else.

How unique is a GUID?

128-bits is big enough and the generation algorithm is unique enough that if 1,000,000,000 GUIDs per second were generated for 1 year the probability of a duplicate would be only 50%. Or if every human on Earth generated 600,000,000 GUIDs there would only be a 50% probability of a duplicate.

jQuery Clone table row

Try this code, I used the following code for cloning and removing the cloned element, i have also used new class (newClass) which can be added automatically with the newly cloned html

for cloning..

 $(".tr_clone_add").live('click', function() {
    var $tr    = $(this).closest('.tr_clone');
    var newClass='newClass';
    var $clone = $tr.clone().addClass(newClass);
    $clone.find(':text').val('');
    $tr.after($clone);
});

for removing the clone element.

$(".tr_clone_remove").live('click', function() { //Once remove button is clicked
    $(".newClass:last").remove(); //Remove field html
    x--; //Decrement field counter
});

html is as followinng

<tr class="tr_clone">
                       <!-- <td>1</td>-->
                        <td><input type="text" class="span12"></td>
                        <td><input type="text" class="span12"></td>
                        <td><input type="text" class="span12"></td>
                        <td><input type="text" class="span12"></td>
                        <td><input type="text" class="span10" readonly>
                        <span><a href="javascript:void(0);" class="tr_clone_add" title="Add field"><span><i class="icon-plus-sign"></i></span></a> <a href="javascript:void(0);" class="tr_clone_remove" title="Remove field"><span style="color: #D63939;"><i class="icon-remove-sign"></i></span></a> </span> </td> </tr>

Why do abstract classes in Java have constructors?

All the classes including the abstract classes can have constructors.Abstract class constructors will be called when its concrete subclass will be instantiated

How to validate a url in Python? (Malformed or not)

EDIT

As pointed out by @Kwame , the below code does validate the url even if the .com or .co etc are not present.

also pointed out by @Blaise, URLs like https://www.google is a valid URL and you need to do a DNS check for checking if it resolves or not, separately.

This is simple and works:

So min_attr contains the basic set of strings that needs to be present to define the validity of a URL, i.e http:// part and google.com part.

urlparse.scheme stores http:// and

urlparse.netloc store the domain name google.com

from urlparse import urlparse
def url_check(url):

    min_attr = ('scheme' , 'netloc')
    try:
        result = urlparse(url)
        if all([result.scheme, result.netloc]):
            return True
        else:
            return False
    except:
        return False

all() returns true if all the variables inside it return true. So if result.scheme and result.netloc is present i.e. has some value then the URL is valid and hence returns True.

How to document a method with parameter(s)?

Building upon the type-hints answer (https://stackoverflow.com/a/9195565/2418922), which provides a better structured way to document types of parameters, there exist also a structured manner to document both type and descriptions of parameters:

def copy_net(
    infile: (str, 'The name of the file to send'),
    host: (str, 'The host to send the file to'),
    port: (int, 'The port to connect to')):

    pass

example adopted from: https://pypi.org/project/autocommand/

JQuery style display value

Just call css with one argument

  $('#idDetails').css('display');

If I understand your question. Otherwise, you want cletus' answer.

Python subprocess.Popen "OSError: [Errno 12] Cannot allocate memory"

Maybe you can simply

$ sudo bash -c "echo vm.overcommit_memory=1 >> /etc/sysctl.conf"
$ sudo sysctl -p

It works for my case.

Reference: https://github.com/openai/gym/issues/110#issuecomment-220672405

How do I enable saving of filled-in fields on a PDF form?

In Acrobat, click on the "Advanced" tab, then click on "Enable Features in Adobe Reader." This should do the trick.

Clone Object without reference javascript

You could define a clone function.

I use this one :

function goclone(source) {
    if (Object.prototype.toString.call(source) === '[object Array]') {
        var clone = [];
        for (var i=0; i<source.length; i++) {
            clone[i] = goclone(source[i]);
        }
        return clone;
    } else if (typeof(source)=="object") {
        var clone = {};
        for (var prop in source) {
            if (source.hasOwnProperty(prop)) {
                clone[prop] = goclone(source[prop]);
            }
        }
        return clone;
    } else {
        return source;
    }
}

var B = goclone(A);

It doesn't copy the prototype, functions, and so on. But you should adapt it (and maybe simplify it) for you own need.

How do I combine 2 javascript variables into a string

if you want to concatenate the string representation of the values of two variables, use the + sign :

var var1 = 1;
var var2 = "bob";
var var3 = var2 + var1;//=bob1

But if you want to keep the two in only one variable, but still be able to access them later, you could make an object container:

function Container(){
   this.variables = [];
}
Container.prototype.addVar = function(var){
   this.variables.push(var);
}
Container.prototype.toString = function(){
   var result = '';
   for(var i in this.variables)
       result += this.variables[i];
   return result;
}

var var1 = 1;
var var2 = "bob";
var container = new Container();
container.addVar(var2);
container.addVar(var1);
container.toString();// = bob1

the advantage is that you can get the string representation of the two variables, bit you can modify them later :

container.variables[0] = 3;
container.variables[1] = "tom";
container.toString();// = tom3

illegal use of break statement; javascript

I have a function next() which will maybe inspire you.

function queue(target) {
        var array = Array.prototype;

        var queueing = [];

        target.queue = queue;
        target.queued = queued;

        return target;

        function queued(action) {
            return function () {
                var self = this;
                var args = arguments;

                queue(function (next) {
                    action.apply(self, array.concat.apply(next, args));
                });
            };
        }

        function queue(action) {
            if (!action) {
                return;
            }

            queueing.push(action);

            if (queueing.length === 1) {
                next();
            }
        }

        function next() {
            queueing[0](function (err) {
                if (err) {
                    throw err;
                }

                queueing = queueing.slice(1);

                if (queueing.length) {
                    next();
                }
            });
        }
    }

Count occurrences of a char in a string using Bash

I Would suggest the following:

var="any given string"
N=${#var}
G=${var//g/}
G=${#G}
(( G = N - G ))
echo "$G"

No call to any other program

How to clear text area with a button in html using javascript?

Change in your html with adding the function on the button click

 <input type="button" value="Clear" onclick="javascript:eraseText();"> 
    <textarea id='output' rows=20 cols=90></textarea>

Try this in your js file:

function eraseText() {
    document.getElementById("output").value = "";
}

Where should I put the CSS and Javascript code in an HTML webpage?

Put Stylesheets at the Top Links to discussion

While researching performance at Yahoo!, we discovered that moving stylesheets to the document HEAD makes pages appear to be loading faster. This is because putting stylesheets in the HEAD allows the page to render progressively.

Front-end engineers that care about performance want a page to load progressively; that is, we want the browser to display whatever content it has as soon as possible. This is especially important for pages with a lot of content and for users on slower Internet connections. The importance of giving users visual feedback, such as progress indicators, has been well researched and documented. In our case the HTML page is the progress indicator! When the browser loads the page progressively the header, the navigation bar, the logo at the top, etc. all serve as visual feedback for the user who is waiting for the page. This improves the overall user experience.

The problem with putting stylesheets near the bottom of the document is that it prohibits progressive rendering in many browsers, including Internet Explorer. These browsers block rendering to avoid having to redraw elements of the page if their styles change. The user is stuck viewing a blank white page.

The HTML specification clearly states that stylesheets are to be included in the HEAD of the page: "Unlike A, [LINK] may only appear in the HEAD section of a document, although it may appear any number of times." Neither of the alternatives, the blank white screen or flash of unstyled content, are worth the risk. The optimal solution is to follow the HTML specification and load your stylesheets in the document HEAD.

Put Scripts at the Bottom

The problem caused by scripts is that they block parallel downloads. The HTTP/1.1 specification suggests that browsers download no more than two components in parallel per hostname. If you serve your images from multiple hostnames, you can get more than two downloads to occur in parallel. While a script is downloading, however, the browser won't start any other downloads, even on different hostnames.

In some situations it's not easy to move scripts to the bottom. If, for example, the script uses document.write to insert part of the page's content, it can't be moved lower in the page. There might also be scoping issues. In many cases, there are ways to workaround these situations.

An alternative suggestion that often comes up is to use deferred scripts. The DEFER attribute indicates that the script does not contain document.write, and is a clue to browsers that they can continue rendering. Unfortunately, Firefox doesn't support the DEFER attribute. In Internet Explorer, the script may be deferred, but not as much as desired. If a script can be deferred, it can also be moved to the bottom of the page. That will make your web pages load faster.

Java - Using Accessor and Mutator methods

Let's go over the basics: "Accessor" and "Mutator" are just fancy names fot a getter and a setter. A getter, "Accessor", returns a class's variable or its value. A setter, "Mutator", sets a class variable pointer or its value.

So first you need to set up a class with some variables to get/set:

public class IDCard
{
    private String mName;
    private String mFileName;
    private int mID;

}

But oh no! If you instantiate this class the default values for these variables will be meaningless. B.T.W. "instantiate" is a fancy word for doing:

IDCard test = new IDCard();

So - let's set up a default constructor, this is the method being called when you "instantiate" a class.

public IDCard()
{
    mName = "";
    mFileName = "";
    mID = -1;
}

But what if we do know the values we wanna give our variables? So let's make another constructor, one that takes parameters:

public IDCard(String name, int ID, String filename)
{
    mName = name;
    mID = ID;
    mFileName = filename;
}

Wow - this is nice. But stupid. Because we have no way of accessing (=reading) the values of our variables. So let's add a getter, and while we're at it, add a setter as well:

public String getName()
{
    return mName;
}

public void setName( String name )
{
    mName = name;
}

Nice. Now we can access mName. Add the rest of the accessors and mutators and you're now a certified Java newbie. Good luck.

the getSource() and getActionCommand()

Assuming you are talking about the ActionEvent class, then there is a big difference between the two methods.

getActionCommand() gives you a String representing the action command. The value is component specific; for a JButton you have the option to set the value with setActionCommand(String command) but for a JTextField if you don't set this, it will automatically give you the value of the text field. According to the javadoc this is for compatability with java.awt.TextField.

getSource() is specified by the EventObject class that ActionEvent is a child of (via java.awt.AWTEvent). This gives you a reference to the object that the event came from.

Edit:

Here is a example. There are two fields, one has an action command explicitly set, the other doesn't. Type some text into each then press enter.

public class Events implements ActionListener {

  private static JFrame frame; 

  public static void main(String[] args) {

    frame = new JFrame("JTextField events");
    frame.getContentPane().setLayout(new FlowLayout());

    JTextField field1 = new JTextField(10);
    field1.addActionListener(new Events());
    frame.getContentPane().add(new JLabel("Field with no action command set"));
    frame.getContentPane().add(field1);

    JTextField field2 = new JTextField(10);
    field2.addActionListener(new Events());
    field2.setActionCommand("my action command");
    frame.getContentPane().add(new JLabel("Field with an action command set"));
    frame.getContentPane().add(field2);


    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(220, 150);
    frame.setResizable(false);
    frame.setVisible(true);
  }

  @Override
  public void actionPerformed(ActionEvent evt) {
    String cmd = evt.getActionCommand();
    JOptionPane.showMessageDialog(frame, "Command: " + cmd);
  }

}

XPath to select multiple tags

You can avoid the repetition with an attribute test instead:

a/b/*[local-name()='c' or local-name()='d' or local-name()='e']

Contrary to Dimitre's antagonistic opinion, the above is not incorrect in a vacuum where the OP has not specified the interaction with namespaces. The self:: axis is namespace restrictive, local-name() is not. If the OP's intention is to capture c|d|e regardless of namespace (which I'd suggest is even a likely scenario given the OR nature of the problem) then it is "another answer that still has some positive votes" which is incorrect.

You can't be definitive without definition, though I'm quite happy to delete my answer as genuinely incorrect if the OP clarifies his question such that I am incorrect.

Omitting all xsi and xsd namespaces when serializing an object in .NET?

This is the first of my two answers to the question.

If you want fine control over the namespaces - for example if you want to omit some of them but not others, or if you want to replace one namespace with another, you can do this using XmlAttributeOverrides.

Suppose you have this type definition:

// explicitly specify a namespace for this type,
// to be used during XML serialization.
[XmlRoot(Namespace="urn:Abracadabra")]
public class MyTypeWithNamespaces
{
    // private fields backing the properties
    private int _Epoch;
    private string _Label;

    // explicitly define a distinct namespace for this element
    [XmlElement(Namespace="urn:Whoohoo")]
    public string Label
    {
        set {  _Label= value; } 
        get { return _Label; } 
    }

    // this property will be implicitly serialized to XML using the
    // member name for the element name, and inheriting the namespace from
    // the type.
    public int Epoch
    {
        set {  _Epoch= value; } 
        get { return _Epoch; } 
    }
}

And this serialization pseudo-code:

        var o2= new MyTypeWithNamespaces() { ..initializers...};
        ns.Add( "", "urn:Abracadabra" );
        XmlSerializer s2 = new XmlSerializer(typeof(MyTypeWithNamespaces));
        s2.Serialize(System.Console.Out, o2, ns);

You would get something like this XML:

<MyTypeWithNamespaces xmlns="urn:Abracadabra">
  <Label xmlns="urn:Whoohoo">Cimsswybclaeqjh</Label>
  <Epoch>97</Epoch>
</MyTypeWithNamespaces>

Notice that there is a default namespace on the root element, and there is also a distinct namespace on the "Label" element. These namespaces were dictated by the attributes decorating the type, in the code above.

The Xml Serialization framework in .NET includes the possibility to explicitly override the attributes that decorate the actual code. You do this with the XmlAttributesOverrides class and friends. Suppose I have the same type, and I serialize it this way:

        // instantiate the container for all attribute overrides
        XmlAttributeOverrides xOver = new XmlAttributeOverrides();

        // define a set of XML attributes to apply to the root element
        XmlAttributes xAttrs1 = new XmlAttributes();

        // define an XmlRoot element (as if [XmlRoot] had decorated the type)
        // The namespace in the attribute override is the empty string. 
        XmlRootAttribute xRoot = new XmlRootAttribute() { Namespace = ""};

        // add that XmlRoot element to the container of attributes
        xAttrs1.XmlRoot= xRoot;

        // add that bunch of attributes to the container holding all overrides
        xOver.Add(typeof(MyTypeWithNamespaces), xAttrs1);

        // create another set of XML Attributes
        XmlAttributes xAttrs2 = new XmlAttributes();

        // define an XmlElement attribute, for a type of "String", with no namespace
        var xElt = new XmlElementAttribute(typeof(String)) { Namespace = ""};

        // add that XmlElement attribute to the 2nd bunch of attributes
        xAttrs2.XmlElements.Add(xElt);

        // add that bunch of attributes to the container for the type, and
        // specifically apply that bunch to the "Label" property on the type.
        xOver.Add(typeof(MyTypeWithNamespaces), "Label", xAttrs2);

        // instantiate a serializer with the overrides 
        XmlSerializer s3 = new XmlSerializer(typeof(MyTypeWithNamespaces), xOver);

        // serialize
        s3.Serialize(System.Console.Out, o2, ns2);

The result looks like this;

<MyTypeWithNamespaces>
  <Label>Cimsswybclaeqjh</Label>
  <Epoch>97</Epoch>
</MyTypeWithNamespaces>

You have stripped the namespaces.

A logical question is, can you strip all namespaces from arbitrary types during serialization, without going through the explicit overrides? The answer is YES, and how to do it is in my next response.

Page redirect after certain time PHP

You can use javascript to redirect after some time

setTimeout(function () {
   window.location.href= 'http://www.google.com'; // the redirect goes here

},5000); // 5 seconds

MySQL > Table doesn't exist. But it does (or it should)

Same exact problem after TimeMachine backup import. My solution was to stop the MySQL server and fix read-write permissions on the ib* files.

How can I count text lines inside an DOM element? Can I?

I found a way to calc the line number when I develop a html editor. The primary method is that:

  1. In IE you can call getBoundingClientRects, it returns each line as a rectangle

  2. In webkit or new standard html engine, it returns each element or node's client rectangles, in this case you can compare each rectangles, I mean each there must be a rectangle is the largest, so you can ignore those rectangles that height is smaller(if there is a rectangle's top smaller than it and bottom larger than it, the condition is true.)

so let's see the test result:

enter image description here

The green rectangle is the largest rectangle in each row

The red rectangle is the selection boundary

The blue rectangle is the boundary from start to selection after expanding, we see it may larger than red rectangle, so we have to check each rectangle's bottom to limit it must smaller than red rectangle's bottom.

        var lineCount = "?";
        var rects;
        if (window.getSelection) {
            //Get all client rectangles from body start to selection, count those rectangles that has the max bottom and min top
            var bounding = {};
            var range = window.getSelection().getRangeAt(0);//As this is the demo code, I dont check the range count
            bounding = range.getBoundingClientRect();//!!!GET BOUNDING BEFORE SET START!!!

            //Get bounding and fix it , when the cursor is in the last character of lineCount, it may expand to the next lineCount.
            var boundingTop = bounding.top;
            var boundingBottom = bounding.bottom;
            var node = range.startContainer;
            if (node.nodeType !== 1) {
                node = node.parentNode;
            }
            var style = window.getComputedStyle(node);
            var lineHeight = parseInt(style.lineHeight);
            if (!isNaN(lineHeight)) {
                boundingBottom = boundingTop + lineHeight;
            }
            else {
                var fontSize = parseInt(style.fontSize);
                if (!isNaN(fontSize)) {
                    boundingBottom = boundingTop + fontSize;
                }
            }
            range = range.cloneRange();

            //Now we have enougn datas to compare

            range.setStart(body, 0);
            rects = range.getClientRects();
            lineCount = 0;
            var flags = {};//Mark a flags to avoid of check some repeat lines again
            for (var i = 0; i < rects.length; i++) {
                var rect = rects[i];
                if (rect.width === 0 && rect.height === 0) {//Ignore zero rectangles
                    continue;
                }
                if (rect.bottom > boundingBottom) {//Check if current rectangle out of the real bounding of selection
                    break;
                }
                var top = rect.top;
                var bottom = rect.bottom;
                if (flags[top]) {
                    continue;
                }
                flags[top] = 1;

                //Check if there is no rectangle contains this rectangle in vertical direction.
                var succ = true;
                for (var j = 0; j < rects.length; j++) {
                    var rect2 = rects[j];
                    if (j !== i && rect2.top < top && rect2.bottom > bottom) {
                        succ = false;
                        break;
                    }
                }
                //If succ, add lineCount 1
                if (succ) {
                    lineCount++;
                }
            }
        }
        else if (editor.document.selection) {//IN IE8 getClientRects returns each single lineCount as a rectangle
            var range = body.createTextRange();
            range.setEndPoint("EndToEnd", range);
            rects = range.getClientRects();
            lineCount = rects.length;
        }
        //Now we get lineCount here

How to convert HTML to PDF using iTextSharp

Here's the link I used as a guide. Hope this helps!

Converting HTML to PDF using ITextSharp

protected void Page_Load(object sender, EventArgs e)
    {
        try
        {
            string strHtml = string.Empty;
            //HTML File path -http://aspnettutorialonline.blogspot.com/
            string htmlFileName = Server.MapPath("~") + "\\files\\" + "ConvertHTMLToPDF.htm";
            //pdf file path. -http://aspnettutorialonline.blogspot.com/
            string pdfFileName = Request.PhysicalApplicationPath + "\\files\\" + "ConvertHTMLToPDF.pdf";

            //reading html code from html file
            FileStream fsHTMLDocument = new FileStream(htmlFileName, FileMode.Open, FileAccess.Read);
            StreamReader srHTMLDocument = new StreamReader(fsHTMLDocument);
            strHtml = srHTMLDocument.ReadToEnd();
            srHTMLDocument.Close();

            strHtml = strHtml.Replace("\r\n", "");
            strHtml = strHtml.Replace("\0", "");

            CreatePDFFromHTMLFile(strHtml, pdfFileName);

            Response.Write("pdf creation successfully with password -http://aspnettutorialonline.blogspot.com/");
        }
        catch (Exception ex)
        {
            Response.Write(ex.Message);
        }
    }
    public void CreatePDFFromHTMLFile(string HtmlStream, string FileName)
    {
        try
        {
            object TargetFile = FileName;
            string ModifiedFileName = string.Empty;
            string FinalFileName = string.Empty;

            /* To add a Password to PDF -http://aspnettutorialonline.blogspot.com/ */
            TestPDF.HtmlToPdfBuilder builder = new TestPDF.HtmlToPdfBuilder(iTextSharp.text.PageSize.A4);
            TestPDF.HtmlPdfPage first = builder.AddPage();
            first.AppendHtml(HtmlStream);
            byte[] file = builder.RenderPdf();
            File.WriteAllBytes(TargetFile.ToString(), file);

            iTextSharp.text.pdf.PdfReader reader = new iTextSharp.text.pdf.PdfReader(TargetFile.ToString());
            ModifiedFileName = TargetFile.ToString();
            ModifiedFileName = ModifiedFileName.Insert(ModifiedFileName.Length - 4, "1");

            string password = "password";
            iTextSharp.text.pdf.PdfEncryptor.Encrypt(reader, new FileStream(ModifiedFileName, FileMode.Append), iTextSharp.text.pdf.PdfWriter.STRENGTH128BITS, password, "", iTextSharp.text.pdf.PdfWriter.AllowPrinting);
            //http://aspnettutorialonline.blogspot.com/
            reader.Close();
            if (File.Exists(TargetFile.ToString()))
                File.Delete(TargetFile.ToString());
            FinalFileName = ModifiedFileName.Remove(ModifiedFileName.Length - 5, 1);
            File.Copy(ModifiedFileName, FinalFileName);
            if (File.Exists(ModifiedFileName))
                File.Delete(ModifiedFileName);

        }
        catch (Exception ex)
        {
            throw ex;
        }
    }

You can download the sample file. Just place the html you want to convert in the files folder and run. It will automatically generate the pdf file and place it in the same folder. But in your case, you can specify your html path in the htmlFileName variable.

Retrofit 2: Get JSON from Response body

You can use it like this.

 public void onResponse(Call<JsonObject> call, Response<JsonObject> response) {
            if (response.isSuccessful()) {
                try {
                    JSONObject jsonObject = new JSONObject(new Gson().toJson(response.body()));
                    msg = jsonObject.getString("msg");
                    status = jsonObject.getBoolean("status");

                    msg = jsonObject.getString("msg");
                    status = jsonObject.getBoolean("status");
                } catch (JSONException e) {
                    e.printStackTrace();
                }

                Toast.makeText(MainActivity.this, msg, Toast.LENGTH_SHORT).show();
                Log.e("cvbnop",response.body().toString());
            } else {
                Toast.makeText(MainActivity.this, "Some error occurred...", Toast.LENGTH_LONG).show();
            }
        }

Update statement with inner join on Oracle

Do not use some of the answers above.

Some suggest the use of nested SELECT, don't do that, it is excruciatingly slow. If you have lots of records to update, use join, so something like:

update (select bonus 
        from employee_bonus b 
        inner join employees e on b.employee_id = e.employee_id 
        where e.bonus_eligible = 'N') t
set t.bonus = 0;

See this link for more details. http://geekswithblogs.net/WillSmith/archive/2008/06/18/oracle-update-with-join-again.aspx.

Also, ensure that there are primary keys on all the tables you are joining.

Heroku 'Permission denied (publickey) fatal: Could not read from remote repository' woes

I had the exact same error (on windows 7) and the cause was different. I solved it in a different way so I thought I'd add the cause and solution here for others.

Even though the error seemed to point to heroku really the error was saying "Heroku can't get to the git repository". I swore I had the same keys on all the servers because I created it and uploaded it to one after the other at the same time.

After spending almost a day on this I realized that because git was only showing me the fingerprint and not the actual key. I couldn't verify that it's key matched the one on my HD or heroku. I looked in the known hosts file and guess what... it shows the keys for each server and I was able to clearly see that the git and heroku public keys did not match.

1) I deleted all the files in my key folder, the key from github using their website, and the key from heroku using git bash and the command heroku keys:clear

2) Followed github's instructions here to generate a new key pair and upload the public key to git

3) using git bash- heroku keys:add to upload the same key to heroku.

Now git push heroku master works.

what a nightmare, hope this helped somebody.

Bryan

What is the difference between display: inline and display: inline-block?

display: inline; is a display mode to use in a sentence. For instance, if you have a paragraph and want to highlight a single word you do:

<p>
    Pellentesque habitant morbi <em>tristique</em> senectus
    et netus et malesuada fames ac turpis egestas.
</p>

The <em> element has a display: inline; by default, because this tag is always used in a sentence. The <p> element has a display: block; by default, because it's neither a sentence nor in a sentence, it's a block of sentences.

An element with display: inline; cannot have a height or a width or a vertical margin. An element with display: block; can have a width, height and margin.
If you want to add a height to the <em> element, you need to set this element to display: inline-block;. Now you can add a height to the element and every other block style (the block part of inline-block), but it is placed in a sentence (the inline part of inline-block).

AngularJS : Custom filters and ng-repeat

One of the easiest ways to fix this is to use the $ which is the search all.

Here is a plunker that shows it working. I have changed the checkboxes to radio ( because I thought they should be complementary )..

http://plnkr.co/edit/dHzvm6hR5P8G4wPuTxoi?p=preview

If you want a very specific way of doing this ( instead of doing a generic search ) you need work with functions in the search.

The documentation is here

http://docs.angularjs.org/api/ng.filter:filter

How do you easily create empty matrices javascript?

If you really like one-liners and there is a use for underscore.js in your project (which is a great library) you can do write-only things like:

_.range(9).map(function(n) {
      return _.range(9).map(function(n) {
            return null;
      });
});

But I would go with standard for-cycle version mentioned above.

Sort array of objects by object fields

If you are using this inside Codeigniter, you can use the methods:

usort($jobs, array($this->job_model, "sortJobs"));  // function inside Model
usort($jobs, array($this, "sortJobs")); // Written inside Controller.

@rmooney thank you for the suggestion. It really helps me.

How can I make a ComboBox non-editable in .NET?

To make the text portion of a ComboBox non-editable, set the DropDownStyle property to "DropDownList". The ComboBox is now essentially select-only for the user. You can do this in the Visual Studio designer, or in C# like this:

stateComboBox.DropDownStyle = ComboBoxStyle.DropDownList;

Link to the documentation for the ComboBox DropDownStyle property on MSDN.

aspx page to redirect to a new page

Even if you don't control the server, you can still see the error messages by adding the following line to the Web.config file in your project (bewlow <system.web>):

<customErrors mode="off" />

MySQL date format DD/MM/YYYY select query?

for my case this worked

str_to_date(date, '%e/%m/%Y' )

How do I give PHP write access to a directory?

Simple 3-Step Solution

Abstract: You need to set the owner of the directory to the user that PHP uses (web server user).


Step 1: Determine PHP User

Create a PHP file containing the following:

<?php echo `whoami`; ?>

Upload it to your web server. The output should be similar to the following:

www-data

Therefore, the PHP user is www-data.


Step 2: Determine Owner of Directory

Next, check the details of the web directory via the command line:

ls -dl /var/www/example.com/public_html/example-folder

The result should be similar to the following:

drwxrwxr-x 2 exampleuser1 exampleuser2 4096 Mar 29 16:34 example-folder

Therefore, the owner of the directory is exampleuser1.


Step 3: Change Directory Owner to PHP User

Afterwards, change the owner of the web directory to the PHP user:

sudo chown -R www-data /var/www/example.com/public_html/example-folder

Verify that the owner of the web directory has been changed:

ls -dl /var/www/example.com/public_html/example-folder

The result should be similar to the following:

drwxrwxr-x 2 www-data exampleuser2 4096 Mar 29 16:34 example-folder

Therefore, the owner of example-folder has successfully been changed to the PHP user: www-data.


Done! PHP should now be able to write to the directory.

How do I change the background color of the ActionBar of an ActionBarActivity using XML?

Its very simple for those who are using API 21 or greater Use this code below

for Dark ActionBar

<resources>
<style name="AppTheme" parent="Theme.AppCompat.NoActionBar">
    <!-- Customize your theme here. -->
    <item name="android:background">@color/colorDarkGrey</item>
</style>

for_LightActionBar

<resources>
<style name="AppTheme" parent="Theme.AppCompat.Light.ActionBar">
    <item name="android:background">@color/colorDarkGrey</item>
</style>

sendKeys() in Selenium web driver

I doubt for Keys.TAB in sendKeys method... if you want to use TAB you need to do something like below:

Actions builder = new Actions(driver);
builder.keyDown(Keys.TAB).perform()

How do I escape ampersands in XML so they are rendered as entities in HTML?

The & character is itself an escape character in XML so the solution is to concatenate it and a Unicode decimal equivalent for & thus ensuring that there are no XML parsing errors. That is, replace the character & with &#038;.

git push: permission denied (public key)

This worked for me. Simplest solution by far.

If you are using GitHub for Windows and getting this error, the problem might be that you are trying to run the command in the wrong shell or mode. If you are trying to do git push origin master in the regular command prompt or PowerShell, this is the problem.

You need to do it in a git shell. Simply open Github for Windows, right click, and select "Open Shell Here". It looks like a regular PowerShell window, but it's not, which makes it really confusing for newbies to git, like myself.

I hope others find this useful.

Bootstrap table without stripe / borders

The border styling is set on the td elements.

html:

<table class='table borderless'>

css:

.borderless td, .borderless th {
    border: none;
}

Update: Since Bootstrap 4.1 you can use .table-borderless to remove the border.

https://getbootstrap.com/docs/4.1/content/tables/#borderless-table

In C#, can a class inherit from another class and an interface?

Unrelated to the question (Mehrdad's answer should get you going), and I hope this isn't taken as nitpicky: classes don't inherit interfaces, they implement them.

.NET does not support multiple-inheritance, so keeping the terms straight can help in communication. A class can inherit from one superclass and can implement as many interfaces as it wishes.


In response to Eric's comment... I had a discussion with another developer about whether or not interfaces "inherit", "implement", "require", or "bring along" interfaces with a declaration like:

public interface ITwo : IOne

The technical answer is that ITwo does inherit IOne for a few reasons:

  • Interfaces never have an implementation, so arguing that ITwo implements IOne is flat wrong
  • ITwo inherits IOne methods, if MethodOne() exists on IOne then it is also accesible from ITwo. i.e: ((ITwo)someObject).MethodOne()) is valid, even though ITwo does not explicitly contain a definition for MethodOne()
  • ...because the runtime says so! typeof(IOne).IsAssignableFrom(typeof(ITwo)) returns true

We finally agreed that interfaces support true/full inheritance. The missing inheritance features (such as overrides, abstract/virtual accessors, etc) are missing from interfaces, not from interface inheritance. It still doesn't make the concept simple or clear, but it helps understand what's really going on under the hood in Eric's world :-)

How to get the file path from URI?

Here is the answer to the question here

Actually we have to get it from the sharable ContentProvider of Camera Application.

EDIT . Copying answer that worked for me

private String getRealPathFromURI(Uri contentUri) {
String[] proj = { MediaStore.Images.Media.DATA };
CursorLoader loader = new CursorLoader(mContext, contentUri, proj, null, null, null);
Cursor cursor = loader.loadInBackground();
int column_index = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
cursor.moveToFirst();
String result = cursor.getString(column_index);
cursor.close();
return result;

}

How do you delete an ActiveRecord object?

It's destroy and destroy_all methods, like

user.destroy
User.find(15).destroy
User.destroy(15)
User.where(age: 20).destroy_all
User.destroy_all(age: 20)

Alternatively you can use delete and delete_all which won't enforce :before_destroy and :after_destroy callbacks or any dependent association options.

User.delete_all(condition: 'value') will allow you to delete records without a primary key

Note: from @hammady's comment, user.destroy won't work if User model has no primary key.

Note 2: From @pavel-chuchuva's comment, destroy_all with conditions and delete_all with conditions has been deprecated in Rails 5.1 - see guides.rubyonrails.org/5_1_release_notes.html

jQuery, checkboxes and .is(":checked")

$("#personal").click(function() {
      if ($(this).is(":checked")) {
            alert('Personal');
        /* var validator = $("#register_france").validate(); 
        validator.resetForm(); */
      }
            }
            );

JSFIDDLE

Why is this error, 'Sequence contains no elements', happening?

If this is the offending line:

db.Responses.Where(y => y.ResponseId.Equals(item.ResponseId)).First();

Then it's because there is no object in Responses for which the ResponseId == item.ResponseId, and you can't get the First() record if there are no matches.

Try this instead:

var response
  = db.Responses.Where(y => y.ResponseId.Equals(item.ResponseId)).FirstOrDefault();

if (response != null)
{
    // take some alternative action
}
else
    temp.Response = response;

The FirstOrDefault() extension returns an objects default value if no match is found. For most objects (other than primitive types), this is null.

How to use execvp()

In cpp, you need to pay special attention to string types when using execvp:

#include <iostream>
#include <string>
#include <cstring>
#include <stdio.h>
#include <unistd.h>
using namespace std;

const size_t MAX_ARGC = 15; // 1 command + # of arguments
char* argv[MAX_ARGC + 1]; // Needs +1 because of the null terminator at the end
// c_str() converts string to const char*, strdup converts const char* to char*
argv[0] = strdup(command.c_str());

// start filling up the arguments after the first command
size_t arg_i = 1;
while (cin && arg_i < MAX_ARGC) {
    string arg;
    cin >> arg;
    if (arg.empty()) {
        argv[arg_i] = nullptr;
        break;
    } else {
        argv[arg_i] = strdup(arg.c_str());
    }
    ++arg_i;
}

// Run the command with arguments
if (execvp(command.c_str(), argv) == -1) {
    // Print error if command not found
    cerr << "command '" << command << "' not found\n";
}

Reference: execlp?execvp?????

Python - How do you run a .py file?

Your command should include the url parameter as stated in the script usage comments. The main function has 2 parameters, url and out (which is set to a default value) C:\python23\python "C:\PathToYourScript\SCRIPT.py" http://yoururl.com "C:\OptionalOutput\"

In Bootstrap open Enlarge image in modal

css:

img.modal-img {
  cursor: pointer;
  transition: 0.3s;
}
img.modal-img:hover {
  opacity: 0.7;
}
.img-modal {
  display: none;
  position: fixed;
  z-index: 99999;
  padding-top: 100px;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
  overflow: auto;
  background-color: rgba(0,0,0,0.9);
}
.img-modal img {
  margin: auto;
  display: block;
  width: 80%;
  max-width: 700%;
}
.img-modal div {
  margin: auto;
  display: block;
  width: 80%;
  max-width: 700px;
  text-align: center;
  color: #ccc;
  padding: 10px 0;
  height: 150px;
}
.img-modal img, .img-modal div {
  animation: zoom 0.6s;
}
.img-modal span {
  position: absolute;
  top: 15px;
  right: 35px;
  color: #f1f1f1;
  font-size: 40px;
  font-weight: bold;
  transition: 0.3s;
  cursor: pointer;
}
@media only screen and (max-width: 700px) {
  .img-modal img {
    width: 100%;
  }
}
@keyframes zoom {
  0% {
    transform: scale(0);
  }
  100% {
    transform: scale(1);
  }
}

Javascript:

_x000D_
_x000D_
$('img.modal-img').each(function() {_x000D_
    var modal = $('<div class="img-modal"><span>&times;</span><img /><div></div></div>');_x000D_
    modal.find('img').attr('src', $(this).attr('src'));_x000D_
    if($(this).attr('alt'))_x000D_
      modal.find('div').text($(this).attr('alt'));_x000D_
    $(this).after(modal);_x000D_
    modal = $(this).next();_x000D_
    $(this).click(function(event) {_x000D_
      modal.show(300);_x000D_
      modal.find('span').show(0.3);_x000D_
    });_x000D_
    modal.find('span').click(function(event) {_x000D_
      modal.hide(300);_x000D_
    });_x000D_
  });_x000D_
  $(document).keyup(function(event) {_x000D_
    if(event.which==27)_x000D_
      $('.img-modal>span').click();_x000D_
  });
_x000D_
img.modal-img {_x000D_
  cursor: pointer;_x000D_
  transition: 0.3s;_x000D_
}_x000D_
img.modal-img:hover {_x000D_
  opacity: 0.7;_x000D_
}_x000D_
.img-modal {_x000D_
  display: none;_x000D_
  position: fixed;_x000D_
  z-index: 99999;_x000D_
  padding-top: 100px;_x000D_
  left: 0;_x000D_
  top: 0;_x000D_
  width: 100%;_x000D_
  height: 100%;_x000D_
  overflow: auto;_x000D_
  background-color: rgba(0,0,0,0.9);_x000D_
}_x000D_
.img-modal img {_x000D_
  margin: auto;_x000D_
  display: block;_x000D_
  width: 80%;_x000D_
  max-width: 700%;_x000D_
}_x000D_
.img-modal div {_x000D_
  margin: auto;_x000D_
  display: block;_x000D_
  width: 80%;_x000D_
  max-width: 700px;_x000D_
  text-align: center;_x000D_
  color: #ccc;_x000D_
  padding: 10px 0;_x000D_
  height: 150px;_x000D_
}_x000D_
.img-modal img, .img-modal div {_x000D_
  animation: zoom 0.6s;_x000D_
}_x000D_
.img-modal span {_x000D_
  position: absolute;_x000D_
  top: 15px;_x000D_
  right: 35px;_x000D_
  color: #f1f1f1;_x000D_
  font-size: 40px;_x000D_
  font-weight: bold;_x000D_
  transition: 0.3s;_x000D_
  cursor: pointer;_x000D_
}_x000D_
@media only screen and (max-width: 700px) {_x000D_
  .img-modal img {_x000D_
    width: 100%;_x000D_
  }_x000D_
}_x000D_
@keyframes zoom {_x000D_
  0% {_x000D_
    transform: scale(0);_x000D_
  }_x000D_
  100% {_x000D_
    transform: scale(1);_x000D_
  }_x000D_
}_x000D_
Javascript:_x000D_
_x000D_
$('img.modal-img').each(function() {_x000D_
    var modal = $('<div class="img-modal"><span>&times;</span><img /><div></div></div>');_x000D_
    modal.find('img').attr('src', $(this).attr('src'));_x000D_
    if($(this).attr('alt'))_x000D_
      modal.find('div').text($(this).attr('alt'));_x000D_
    $(this).after(modal);_x000D_
    modal = $(this).next();_x000D_
    $(this).click(function(event) {_x000D_
      modal.show(300);_x000D_
      modal.find('span').show(0.3);_x000D_
    });_x000D_
    modal.find('span').click(function(event) {_x000D_
      modal.hide(300);_x000D_
    });_x000D_
  });_x000D_
  $(document).keyup(function(event) {_x000D_
    if(event.which==27)_x000D_
      $('.img-modal>span').click();_x000D_
  });_x000D_
_x000D_
HTML:
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>_x000D_
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>_x000D_
<link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet"/>_x000D_
<img src="http://www.google.com/favicon.ico" class="modal-img">
_x000D_
_x000D_
_x000D_

How does += (plus equal) work?

x += 1 is just shorthand for x = x + 1 It can also be used for strings:

var string = "foo"
string += "bar"

Git fetch remote branch

If you already know your remote branch like so...

git remote
=> One
=> Two

and you know the branch name you wish to checkout, for example, br1.2.3.4, then do

git fetch One
=> returns all meta data of remote, that is, the branch name in question.

All that is left is to checkout the branch

git checkout br.1.2.3.4

Then make any new branches off of it.

Is it possible to have SSL certificate for IP address, not domain name?

The answer is yes. In short, it is a subject alternative name (SAN) certificate that contains IPs where you would typically see DNS entries. The certificate type is not limited to Public IPs - that restriction is only imposed by a signing authority rather than the technology. I just wanted to clarify that point. I suspect you really just want to get rid of that pesky insecure prompt on your internal websites and devices without the cost and hassle of giving them DNS names then paying for a CA to issue a cert every year or two. You should NOT be trying to convince the world that your IP address is a reputable website and folks should feel comfortable providing their payment information. Now that we have established why no reputable organization wants to issue this type of certificate, lets just do it ourselves with a self signed SAN certificate. Internally I have a trusted certificate that is deployed to all of our hosts, then I sign this type of certificate with it and all devices become trusted. Doing that here is beyond the scope of the question but I think it relevant to the discussion as the question and solution go hand in hand. To be concise, here is how to generate an individual self signed SAN certificate with IP addresses. Expand the IP list to include your entire subnet and use one cert for everything.

#!/bin/bash
#using: OpenSSL 1.1.1c FIPS  28 May 2019 / CentOS Linux release 8.2.2004

C=US ; ST=Confusion ; L=Anywhere ; O=Private\ Subnet ; [email protected]
BITS=2048
CN=RFC1918
DOM=company.com
SUBJ="/C=$C/ST=$ST/L=$L/O=$O/CN=$CN.$DOM"

openssl genrsa -out ip.key $BITS

SAN='\n[SAN]\nsubjectAltName=IP:192.168.1.0,IP:192.168.1.1,IP:192.168.1.2,IP:192.168.1.3,IP:192.168.1.4,IP:192.168.1.5,IP:192.168.1.6,IP:192.168.1.7,IP:192.168.1.8,IP:192.168.1.9,IP:192.168.1.10'

cp /etc/pki/tls/openssl.cnf /tmp/openssl.cnf
echo -e "$SAN" >> /tmp/openssl.cnf

openssl req -subj "$SUBJ" -new -x509 -days 10950 \
    -key ip.key -out ip.crt -batch \
    -set_serial 168933982 \
    -config /tmp/openssl.cnf \
    -extensions SAN

openssl x509 -in ip.crt -noout -text

target="_blank" vs. target="_new"

Using target="_blank" will instruct the browser to create a new browser tab or window when the user clicks on the link.

Using target="_new" is technically invalid according to the specifications, but as far as I know every browser will behave the same way:

  • it will search for a tab or window with the context name "_new"
  • if a "_new" tab/window is found, then the URL is loaded into it
  • if it's not found, a new tab/window is created with the context name "_new", and the URL loaded into it

Note target="_new" will behave exactly the same as target="new", and the latter is valid HTML while the former is invalid HTML.

Adding some confusion to this, in HTML4 the target attribute was deprecated. In HTML5 this decision was reversed, and it is an official part of the spec once again. All browsers support target no matter what version of HTML you are using, but some validators will flag the use as deprecated if your doctype is HTML4.

Determining if Swift dictionary contains key and obtaining any of its values

My solution for a cache implementation that stores optional NSAttributedString:

public static var attributedMessageTextCache    = [String: NSAttributedString?]()

    if attributedMessageTextCache.index(forKey: "key") != nil
    {
        if let attributedMessageText = TextChatCache.attributedMessageTextCache["key"]
        {
            return attributedMessageText
        }
        return nil
    }

    TextChatCache.attributedMessageTextCache["key"] = .some(.none)
    return nil

How to approach a "Got minus one from a read call" error when connecting to an Amazon RDS Oracle instance

The immediate cause of the problem is that the JDBC driver has attempted to read from a network Socket that has been closed by "the other end".

This could be due to a few things:

  • If the remote server has been configured (e.g. in the "SQLNET.ora" file) to not accept connections from your IP.

  • If the JDBC url is incorrect, you could be attempting to connect to something that isn't a database.

  • If there are too many open connections to the database service, it could refuse new connections.

Given the symptoms, I think the "too many connections" scenario is the most likely. That suggests that your application is leaking connections; i.e. creating connections and then failing to (always) close them.

Set The Window Position of an application via command line

Thanks To FuzzyWuzzy , set the following code ( Quick & Dirty Example for 1920x1080 screen resolution - without automatic width and height calculation or function use etc ) in AutoHotKey to achive the following : enter image description here

v_cmd = c:\temp\1st_Monitor.ps1
Run, Powershell.exe -executionpolicy remotesigned -File %v_cmd%
SetTitleMatchMode 2
SetTitleMatchMode Fast
WinWait, PowerShell
Sleep, 1000
    ;A = Active window - [x,y,width,height]
WinMove A,, 0, 0,1920,500

v_cmd = c:\temp\2nd_Monitor.ps1
Run, Powershell.exe -executionpolicy remotesigned -File %v_cmd%
WinWait, PowerShell
Sleep, 1000
    ;A = Active window - [x,y,width,height]
WinMove A,, 0, 500,960,400

v_cmd = c:\temp\3rd_Monitor.ps1
Run, Powershell.exe -executionpolicy remotesigned -File %v_cmd%
WinWait, PowerShell
Sleep, 1000
    ;A = Active window - [x,y,width,height]
WinMove A,, 960, 500,960,400

SMALL EDIT same code with Auto X / Y screen size calculation [ 4 monitors ], yet, can be used for 3 / 2 monitors as well.

Screen_X = %A_ScreenWidth%
Screen_Y = %A_ScreenHeight%

v_cmd = c:\temp\1st_Monitor.ps1
Run, Powershell.exe -executionpolicy remotesigned -File %v_cmd%
SetTitleMatchMode 2
SetTitleMatchMode Fast
WinWait, PowerShell
Sleep, 1000
    ;A = Active window - [x,y,width,height]
WinMove A,, 0, 0,Screen_X/2,Screen_Y/2

v_cmd = c:\temp\2nd_Monitor.ps1
Run, Powershell.exe -executionpolicy remotesigned -File %v_cmd%
WinWait, PowerShell
Sleep, 1000
    ;A = Active window - [x,y,width,height]
WinMove A,, Screen_X/2, 0,Screen_X/2,Screen_Y/2

v_cmd = c:\temp\3rd_Monitor.ps1
Run, Powershell.exe -executionpolicy remotesigned -File %v_cmd%
WinWait, PowerShell
Sleep, 1000
    ;A = Active window - [x,y,width,height]
WinMove A,, 0, Screen_Y/2,Screen_X/2,Screen_Y/2

v_cmd = c:\temp\4th_Monitor.ps1
Run, Powershell.exe -executionpolicy remotesigned -File %v_cmd%
WinWait, PowerShell
Sleep, 1000
    ;A = Active window - [x,y,width,height]
WinMove A,, Screen_X/2, Screen_Y/2,Screen_X/2,Screen_Y/2

Error message "Unable to install or run the application. The application requires stdole Version 7.0.3300.0 in the GAC"

So it turns out that the .NET files were copied to C:\Program Files\Microsoft.NET\Primary Interop Assemblies\. However, they were never registered in the GAC.

I ended up manually dragging the files in C:\Program Files\Microsoft.NET\Primary Interop Assemblies to C:\windows\assembly and the application worked on that problem machine. You could also do this programmatically with Gacutil.

So it seems that something happened to .NET during the install, but this seems to correct the problem. I hope that helps someone else out!

React Hooks useState() with Object

Thanks Philip this helped me - my use case was I had a form with lot of input fields so I maintained initial state as object and I was not able to update the object state.The above post helped me :)

const [projectGroupDetails, setProjectGroupDetails] = useState({
    "projectGroupId": "",
    "projectGroup": "DDD",
    "project-id": "",
    "appd-ui": "",
    "appd-node": ""    
});

const inputGroupChangeHandler = (event) => {
    setProjectGroupDetails((prevState) => ({
       ...prevState,
       [event.target.id]: event.target.value
    }));
}

<Input 
    id="projectGroupId" 
    labelText="Project Group Id" 
    value={projectGroupDetails.projectGroupId} 
    onChange={inputGroupChangeHandler} 
/>


parseInt with jQuery

Two issues:

  1. You're passing the jQuery wrapper of the element into parseInt, which isn't what you want, as parseInt will call toString on it and get back "[object Object]". You need to use val or text or something (depending on what the element is) to get the string you want.

  2. You're not telling parseInt what radix (number base) it should use, which puts you at risk of odd input giving you odd results when parseInt guesses which radix to use.

Fix if the element is a form field:

//                               vvvvv-- use val to get the value
var test = parseInt($("#testid").val(), 10);
//                                    ^^^^-- tell parseInt to use decimal (base 10)

Fix if the element is something else and you want to use the text within it:

//                               vvvvvv-- use text to get the text
var test = parseInt($("#testid").text(), 10);
//                                     ^^^^-- tell parseInt to use decimal (base 10)

Switch case with conditions

function date_conversion(start_date){
    var formattedDate = new Date(start_date);
    var d = formattedDate.getDate();
    var m =  formattedDate.getMonth();
    var month;
    m += 1;  // JavaScript months are 0-11
    switch (m) {
        case 1: {
            month="Jan";
            break;
        }
        case 2: {
            month="Feb";
            break;
        }
        case 3: {
            month="Mar";
            break;
        }
        case 4: {
            month="Apr";
            break;
        }
        case 5: {
            month="May";
            break;
        }
        case 6: {
            month="Jun";
            break;
        }
        case 7: {
            month="Jul";
            break;
        }
        case 8: {
            month="Aug";
            break;
        }
        case 9: {
            month="Sep";
            break;
        }
        case 10: {
            month="Oct";
            break;
        }
        case 11: {
            month="Nov";
            break;
        }
        case 12: {
            month="Dec";
            break;
        }
    }
    var y = formattedDate.getFullYear();
    var now_date=d + "-" + month + "-" + y;
    return now_date;
}

HTML: Select multiple as dropdown

A similar question was asked here

If you're able to add an external library to your project, you can try Chosen

Here's a sample:

_x000D_
_x000D_
$(".chosen-select").chosen({_x000D_
  no_results_text: "Oops, nothing found!"_x000D_
})
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
<script src="https://cdn.rawgit.com/harvesthq/chosen/gh-pages/chosen.jquery.min.js"></script>_x000D_
<link href="https://cdn.rawgit.com/harvesthq/chosen/gh-pages/chosen.min.css" rel="stylesheet"/>_x000D_
_x000D_
<form action="http://httpbin.org/post" method="post">_x000D_
  <select data-placeholder="Begin typing a name to filter..." multiple class="chosen-select" name="test">_x000D_
    <option value=""></option>_x000D_
    <option>American Black Bear</option>_x000D_
    <option>Asiatic Black Bear</option>_x000D_
    <option>Brown Bear</option>_x000D_
    <option>Giant Panda</option>_x000D_
    <option>Sloth Bear</option>_x000D_
    <option>Sun Bear</option>_x000D_
    <option>Polar Bear</option>_x000D_
    <option>Spectacled Bear</option>_x000D_
  </select>_x000D_
  <input type="submit">_x000D_
</form>
_x000D_
_x000D_
_x000D_

One thing I've run into, you have to include JQuery BEFORE you include Chosen or you'll get errors.

Redirecting to a relative URL in JavaScript

You can do a relative redirect:

window.location.href = '../'; //one level up

or

window.location.href = '/path'; //relative to domain

Aligning two divs side-by-side

If you wrapped your divs, like this:

<div id="main">
  <div id="sidebar"></div>
  <div id="page-wrap"></div>
</div>

You could use this styling:

#main { 
    width: 800px;
    margin: 0 auto;
}
#sidebar    {
    width: 200px;
    height: 400px;
    background: red;
    float: left;
}

#page-wrap  {
    width: 600px;
    background: #ffffff;
    height: 400px;
    margin-left: 200px;
}

This is a slightly different look though, so I'm not sure it's what you're after. This would center all 800px as a unit, not the 600px centered with the 200px on the left side. The basic approach is your sidebar floats left, but inside the main div, and the #page-wrap has the width of your sidebar as it's left margin to move that far over.

Update based on comments: For this off-centered look, you can do this:

<div id="page-wrap">
  <div id="sidebar"></div>
</div>

With this styling:

#sidebar    {
    position: absolute;
    left: -200px;
    width: 200px;
    height: 400px;
    background: red;    
}

#page-wrap  {
    position: relative;
    width: 600px;
    background: #ffffff;
    height: 400px;
    margin: 0 auto;
}

What is the difference between mocking and spying when using Mockito?

If there is an object with 8 methods and you have a test where you want to call 7 real methods and stub one method you have two options:

  1. Using a mock you would have to set it up by invoking 7 callRealMethod and stub one method
  2. Using a spy you have to set it up by stubbing one method

The official documentation on doCallRealMethod recommends using a spy for partial mocks.

See also javadoc spy(Object) to find out more about partial mocks. Mockito.spy() is a recommended way of creating partial mocks. The reason is it guarantees real methods are called against correctly constructed object because you're responsible for constructing the object passed to spy() method.

require is not defined? Node.js

To supplement what everyone else has said above, your js file is being read on the client side when you have a path to it in your HTML file. At least that was the problem for me. I had it as a script in my tag in my index.html Hope this helps!

A JRE or JDK must be available in order to run Eclipse. No JVM was found after searching the following locations

I found a solution wherein the Eclipse.ini the location was the old version of Java, and after updating the new version of java the location of -vm

C:\Program Files\Java\jre1.8.0_201\bin

was same so I had to change the directory to my new version of Java.

So solution is to just open the most updated Java version and copying its directory path and replacing it in the Eclipse.ini file.

Performance of FOR vs FOREACH in PHP

It's 2020 and stuffs had greatly evolved with php 7.4 and opcache.

Here is the OP^ benchmark, ran as unix CLI, without the echo and html parts.

Test ran locally on a regular computer.

php -v

PHP 7.4.6 (cli) (built: May 14 2020 10:02:44) ( NTS )

Modified benchmark script:

<?php 
 ## preperations; just a simple environment state

  $test_iterations = 100;
  $test_arr_size = 1000;

  // a shared function that makes use of the loop; this should
  // ensure no funny business is happening to fool the test
  function test($input)
  {
    //echo '<!-- '.trim($input).' -->';
  }

  // for each test we create a array this should avoid any of the
  // arrays internal representation or optimizations from getting
  // in the way.

  // normal array
  $test_arr1 = array();
  $test_arr2 = array();
  $test_arr3 = array();
  // hash tables
  $test_arr4 = array();
  $test_arr5 = array();

  for ($i = 0; $i < $test_arr_size; ++$i)
  {
    mt_srand();
    $hash = md5(mt_rand());
    $key = substr($hash, 0, 5).$i;

    $test_arr1[$i] = $test_arr2[$i] = $test_arr3[$i] = $test_arr4[$key] = $test_arr5[$key]
      = $hash;
  }

  ## foreach

  $start = microtime(true);
  for ($j = 0; $j < $test_iterations; ++$j)
  {
    foreach ($test_arr1 as $k => $v)
    {
      test($v);
    }
  }
  echo 'foreach '.(microtime(true) - $start)."\n";  

  ## foreach (using reference)

  $start = microtime(true);
  for ($j = 0; $j < $test_iterations; ++$j)
  {
    foreach ($test_arr2 as &$value)
    {
      test($value);
    }
  }
  echo 'foreach (using reference) '.(microtime(true) - $start)."\n";

  ## for

  $start = microtime(true);
  for ($j = 0; $j < $test_iterations; ++$j)
  {
    $size = count($test_arr3);
    for ($i = 0; $i < $size; ++$i)
    {
      test($test_arr3[$i]);
    }
  }
  echo 'for '.(microtime(true) - $start)."\n";  

  ## foreach (hash table)

  $start = microtime(true);
  for ($j = 0; $j < $test_iterations; ++$j)
  {
    foreach ($test_arr4 as $k => $v)
    {
      test($v);
    }
  }
  echo 'foreach (hash table) '.(microtime(true) - $start)."\n";

  ## for (hash table)

  $start = microtime(true);
  for ($j = 0; $j < $test_iterations; ++$j)
  {
    $keys = array_keys($test_arr5);
    $size = sizeOf($test_arr5);
    for ($i = 0; $i < $size; ++$i)
    {
      test($test_arr5[$keys[$i]]);
    }
  }
  echo 'for (hash table) '.(microtime(true) - $start)."\n";

Output:

foreach 0.0032877922058105
foreach (using reference) 0.0029420852661133
for 0.0025191307067871
foreach (hash table) 0.0035080909729004
for (hash table) 0.0061779022216797

As you can see the evolution is insane, about 560 time faster than reported in 2012.

On my machines and servers, following my numerous experiments, basics for loops are the fastest. This is even clearer using nested loops ($i $j $k..)

It is also the most flexible in usage, and has a better readability from my view.

Getting Http Status code number (200, 301, 404, etc.) from HttpWebRequest and HttpWebResponse

Just coerce the StatusCode to int.

var statusNumber;
try {
   response = (HttpWebResponse)request.GetResponse();
   // This will have statii from 200 to 30x
   statusNumber = (int)response.StatusCode;
}
catch (WebException we) {
    // Statii 400 to 50x will be here
    statusNumber = (int)we.Response.StatusCode;
}

What exactly does the .join() method do?

To expand a bit more on what others are saying, if you wanted to use join to simply concatenate your two strings, you would do this:

strid = repr(595)
print ''.join([array.array('c', random.sample(string.ascii_letters, 20 - len(strid)))
    .tostring(), strid])

How to construct a set out of list items in python?

Here is another solution:

>>>list1=["C:\\","D:\\","E:\\","C:\\"]
>>>set1=set(list1)
>>>set1
set(['E:\\', 'D:\\', 'C:\\'])

In this code I have used the set method in order to turn it into a set and then it removed all duplicate values from the list

Best way to parseDouble with comma as decimal separator?

You of course need to use the correct locale. This question will help.

Casting string to enum

As an extra, you can take the Enum.Parse answers already provided and put them in an easy-to-use static method in a helper class.

public static T ParseEnum<T>(string value)
{
    return (T)Enum.Parse(typeof(T), value, ignoreCase: true);
}

And use it like so:

{
   Content = ParseEnum<ContentEnum>(fileContentMessage);
};

Especially helpful if you have lots of (different) Enums to parse.

What does the symbol \0 mean in a string-literal?

char str[]= "Hello\0";

That would be 7 bytes.

In memory it'd be:

48 65 6C 6C 6F 00 00
H  e  l  l  o  \0 \0

Edit:

  • What does the \0 symbol mean in a C string?
    It's the "end" of a string. A null character. In memory, it's actually a Zero. Usually functions that handle char arrays look for this character, as this is the end of the message. I'll put an example at the end.

  • What is the length of str array? (Answered before the edit part)
    7

  • and with how much 0s it is ending?
    You array has two "spaces" with zero; str[5]=str[6]='\0'=0

Extra example:
Let's assume you have a function that prints the content of that text array. You could define it as:

char str[40];

Now, you could change the content of that array (I won't get into details on how to), so that it contains the message: "This is just a printing test" In memory, you should have something like:

54 68 69 73 20 69 73 20 6a 75 73 74 20 61 20 70 72 69 6e 74
69 6e 67 20 74 65 73 74 00 00 00 00 00 00 00 00 00 00 00 00

So you print that char array. And then you want a new message. Let's say just "Hello"

48 65 6c 6c 6f 00 73 20 6a 75 73 74 20 61 20 70 72 69 6e 74
69 6e 67 20 74 65 73 74 00 00 00 00 00 00 00 00 00 00 00 00

Notice the 00 on str[5]. That's how the print function will know how much it actually needs to send, despite the actual longitude of the vector and the whole content.

Remove innerHTML from div

divToUpdate.innerHTML =     "";   

How do you keep parents of floated elements from collapsing?

Although the code isn't perfectly semantic, I think it's more straightforward to have what I call a "clearing div" at the bottom of every container with floats in it. In fact, I've included the following style rule in my reset block for every project:

.clear 
{
   clear: both;
}

If you're styling for IE6 (god help you), you might want to give this rule a 0px line-height and height as well.

OWIN Security - How to Implement OAuth2 Refresh Tokens

Freddy's answer helped me a lot to get this working. For the sake of completeness here's how you could implement hashing of the token:

private string ComputeHash(Guid input)
{
    byte[] source = input.ToByteArray();

    var encoder = new SHA256Managed();
    byte[] encoded = encoder.ComputeHash(source);

    return Convert.ToBase64String(encoded);
}

In CreateAsync:

var guid = Guid.NewGuid();
...
_refreshTokens.TryAdd(ComputeHash(guid), refreshTokenTicket);
context.SetToken(guid.ToString());

ReceiveAsync:

public async Task ReceiveAsync(AuthenticationTokenReceiveContext context)
{
    Guid token;

    if (Guid.TryParse(context.Token, out token))
    {
        AuthenticationTicket ticket;

        if (_refreshTokens.TryRemove(ComputeHash(token), out ticket))
        {
            context.SetTicket(ticket);
        }
    }
}

Can't bind to 'formControl' since it isn't a known property of 'input' - Angular2 Material Autocomplete issue

Another reason this can happen:

The component you are using formControl in is not declared in a module that imports the ReactiveFormsModule.

So check the module that declares the component that throws this error.

jQuery.active function

This is a variable jQuery uses internally, but had no reason to hide, so it's there to use. Just a heads up, it becomes jquery.ajax.active next release. There's no documentation because it's exposed but not in the official API, lots of things are like this actually, like jQuery.cache (where all of jQuery.data() goes).

I'm guessing here by actual usage in the library, it seems to be there exclusively to support $.ajaxStart() and $.ajaxStop() (which I'll explain further), but they only care if it's 0 or not when a request starts or stops. But, since there's no reason to hide it, it's exposed to you can see the actual number of simultaneous AJAX requests currently going on.


When jQuery starts an AJAX request, this happens:

if ( s.global && ! jQuery.active++ ) {
  jQuery.event.trigger( "ajaxStart" );
}

This is what causes the $.ajaxStart() event to fire, the number of connections just went from 0 to 1 (jQuery.active++ isn't 0 after this one, and !0 == true), this means the first of the current simultaneous requests started. The same thing happens at the other end. When an AJAX request stops (because of a beforeSend abort via return false or an ajax call complete function runs):

if ( s.global && ! --jQuery.active ) {
  jQuery.event.trigger( "ajaxStop" );
}

This is what causes the $.ajaxStop() event to fire, the number of requests went down to 0, meaning the last simultaneous AJAX call finished. The other global AJAX handlers fire in there along the way as well.

Can't execute jar- file: "no main manifest attribute"

You might have the same problem as I do. After creating your .jar file, write jar xf app.jar META-INF/MANIFEST.MF. This will create a copy of the file to your current directory so you can read it. If it only says something like:

Manifest-Version: 1.0

Created-By: 1.8.0_51 (Oracle Corporation)

and does not contain the "Main-Class" declaration, then I think you found your problem.

I do not know how to solve it, though. I checked other people with same/similar problems on StackOverflow and couldn't find an answer. However with this information you can perhaps get some better help (given the fact that you have the same problem as I).

Edit: I had tried with a manifest-file but didn't get it to work, but my mistake was to only name one of the classes when creating the jar-file. I wrote *.class instead and it works now.

Although I don't know why there is a need to create a manifest-file. But I guess it's fine as long as it works.

Convert python datetime to epoch with strftime

I had serious issues with Timezones and such. The way Python handles all that happen to be pretty confusing (to me). Things seem to be working fine using the calendar module (see links 1, 2, 3 and 4).

>>> import datetime
>>> import calendar
>>> aprilFirst=datetime.datetime(2012, 04, 01, 0, 0)
>>> calendar.timegm(aprilFirst.timetuple())
1333238400

-didSelectRowAtIndexPath: not being called

you must check this selection must be single selection and editing must be no seleciton during edition and you change setting in uttableviewcell properties also you edit in table view cell style must be custom and identifier must be Rid and section is none

How to list all dates between two dates

You can use a numbers table:

DECLARE @Date1 DATE, @Date2 DATE
SET @Date1 = '20150528'
SET @Date2 = '20150531'

SELECT DATEADD(DAY,number+1,@Date1) [Date]
FROM master..spt_values
WHERE type = 'P'
AND DATEADD(DAY,number+1,@Date1) < @Date2

Results:

+------------+
¦    Date    ¦
¦------------¦
¦ 2015-05-29 ¦
¦ 2015-05-30 ¦
+------------+

How to do a GitHub pull request

I've started a project to help people making their first GitHub pull request. You can do the hands-on tutorial to make your first PR here

The workflow is simple as

  • Fork the repo in github
  • Get clone url by clicking on clone repo button
  • Go to terminal and run git clone <clone url you copied earlier>
  • Make a branch for changes you're makeing git checkout -b branch-name
  • Make necessary changes
  • Commit your changes git commit
  • Push your changes to your fork on GitHub git push origin branch-name
  • Go to your fork on GitHub to see a Compare and pull request button
  • Click on it and give necessary details

Oracle - How to create a materialized view with FAST REFRESH and JOINS

You will get the error on REFRESH_FAST, if you do not create materialized view logs for the master table(s) the query is referring to. If anyone is not familiar with materialized views or using it for the first time, the better way is to use oracle sqldeveloper and graphically put in the options, and the errors also provide much better sense.

ORA-30926: unable to get a stable set of rows in the source tables

Had the error today on a 12c and none of the existing answers fit (no duplicates, no non-deterministic expressions in the WHERE clause). My case was related to that other possible cause of the error, according to Oracle's message text (emphasis below):

ORA-30926: unable to get a stable set of rows in the source tables
Cause: A stable set of rows could not be got because of large dml activity or a non-deterministic where clause.

The merge was part of a larger batch, and was executed on a live database with many concurrent users. There was no need to change the statement. I just committed the transaction before the merge, then ran the merge separately, and committed again. So the solution was found in the suggested action of the message:

Action: Remove any non-deterministic where clauses and reissue the dml.

In-memory size of a Python structure

One can also make use of the tracemalloc module from the Python standard library. It seems to work well for objects whose class is implemented in C (unlike Pympler, for instance).

How can I show a message box with two buttons?

I did

msgbox "TEXT HERE",3,"TITLE HERE"
If Yes=true then
(result)

else
msgbox "Closing..."

how get yesterday and tomorrow datetime in c#

Use DateTime.AddDays() (MSDN Documentation DateTime.AddDays Method).

DateTime tomorrow = DateTime.Now.AddDays(1);
DateTime yesterday = DateTime.Now.AddDays(-1);

how to create inline style with :before and :after

I resolved a similar problem by border-color: inherit

, see:

<li style="border-color: <?php echo $hex ?>;">...</li>

li {
    border-width: 0;
}

li:before {
    content: '';
    display: inline-block;
    float: none;
    margin-right: 10px;
    border-width: 4px;
    border-style: solid;
    border-color: inherit;
}

How can I style the border and title bar of a window in WPF?

You need to set

WindowStyle="None", AllowsTransparency="True" and optionally ResizeMode="NoResize"
and then set the Style property of the window to your custom window style, where you design the appearance of the window (title bar, buttons, border) to anything you want and display the window contents in a ContentPresenter.

This seems to be a good article on how you can achieve this, but there are many other articles on the internet.

How to use JavaScript to change div backgroundColor

To do this without jQuery or any other library, you'll need to attach onMouseOver and onMouseOut events to each div and change the style in the event handlers.

For example:

var category = document.getElementById("catestory");
for (var child = category.firstChild; child != null; child = child.nextSibling) {
    if (child.nodeType == 1 && child.className == "content") {
        child.onmouseover = function() {
            this.style.backgroundColor = "#FF0000";
        }

        child.onmouseout = function() {
            // Set to transparent to let the original background show through.
            this.style.backgroundColor = "transparent"; 
        }
    }
}

If your h2 has not set its own background, the div background will show through and color it too.

How to List All Redis Databases?

There is no command to do it (like you would do it with MySQL for instance). The number of Redis databases is fixed, and set in the configuration file. By default, you have 16 databases. Each database is identified by a number (not a name).

You can use the following command to know the number of databases:

CONFIG GET databases
1) "databases"
2) "16"

You can use the following command to list the databases for which some keys are defined:

INFO keyspace
# Keyspace
db0:keys=10,expires=0
db1:keys=1,expires=0
db3:keys=1,expires=0

Please note that you are supposed to use the "redis-cli" client to run these commands, not telnet. If you want to use telnet, then you need to run these commands formatted using the Redis protocol.

For instance:

*2
$4
INFO
$8
keyspace

$79
# Keyspace
db0:keys=10,expires=0
db1:keys=1,expires=0
db3:keys=1,expires=0

You can find the description of the Redis protocol here: http://redis.io/topics/protocol

How to implement class constructor in Visual Basic?

Suppose your class is called MyStudent. Here's how you define your class constructor:

Public Class MyStudent
    Public StudentId As Integer

    'Here's the class constructor:
    Public Sub New(newStudentId As Integer)
        StudentId = newStudentId
    End Sub
End Class

Here's how you call it:

Dim student As New MyStudent(studentId)

Of course, your class constructor can contain as many or as few arguments as you need--even none, in which case you leave the parentheses empty. You can also have several constructors for the same class, all with different combinations of arguments. These are known as different "signatures" for your class constructor.

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

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

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

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

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

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

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

Convert JSON String To C# Object

add this ddl to reference to your project: System.Web.Extensions.dll

use this namespace: using System.Web.Script.Serialization;

public class IdName
{
    public int Id { get; set; }
    public string Name { get; set; }
}


   string jsonStringSingle = "{'Id': 1, 'Name':'Thulasi Ram.S'}".Replace("'", "\"");
   var entity = new JavaScriptSerializer().Deserialize<IdName>(jsonStringSingle);

   string jsonStringCollection = "[{'Id': 2, 'Name':'Thulasi Ram.S'},{'Id': 2, 'Name':'Raja Ram.S'},{'Id': 3, 'Name':'Ram.S'}]".Replace("'", "\"");
   var collection = new JavaScriptSerializer().Deserialize<IEnumerable<IdName>>(jsonStringCollection);

How can I remove or replace SVG content?

You should use append("svg:svg"), not append("svg") so that D3 makes the element with the correct 'namespace' if you're using xhtml.

How can I pass request headers with jQuery's getJSON() method?

I agree with sunetos that you'll have to use the $.ajax function in order to pass request headers. In order to do that, you'll have to write a function for the beforeSend event handler, which is one of the $.ajax() options. Here's a quick sample on how to do that:

<html>
  <head>
    <script src="http://code.jquery.com/jquery-1.4.2.min.js"></script>
    <script type="text/javascript">
      $(document).ready(function() {
        $.ajax({
          url: 'service.svc/Request',
          type: 'GET',
          dataType: 'json',
          success: function() { alert('hello!'); },
          error: function() { alert('boo!'); },
          beforeSend: setHeader
        });
      });

      function setHeader(xhr) {
        xhr.setRequestHeader('securityCode', 'Foo');
        xhr.setRequestHeader('passkey', 'Bar');
      }
    </script>
  </head>
  <body>
    <h1>Some Text</h1>
  </body>
</html>

If you run the code above and watch the traffic in a tool like Fiddler, you'll see two requests headers passed in:

  • securityCode with a value of Foo
  • passkey with a value of Bar

The setHeader function could also be inline in the $.ajax options, but I wanted to call it out.

Hope this helps!

How do I convert a long to a string in C++?

Well if you are fan of copy-paste, here it is:

#include <sstream>

template <class T>
inline std::string to_string (const T& t)
{
    std::stringstream ss;
    ss << t;
    return ss.str();
}

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)

git ahead/behind info between master and branch?

Here's a trick I found to compare two branches and show how many commits each branch is ahead of the other (a more general answer on your question 1):

For local branches: git rev-list --left-right --count master...test-branch

For remote branches: git rev-list --left-right --count origin/master...origin/test-branch

This gives output like the following:

1 7

This output means: "Compared to master, test-branch is 7 commits ahead and 1 commit behind."

You can also compare local branches with remote branches, e.g. origin/master...master to find out how many commits the local master branch is ahead/behind its remote counterpart.

Can we use join for two different database tables?

SQL Server allows you to join tables from different databases as long as those databases are on the same server. The join syntax is the same; the only difference is that you must fully specify table names.

Let's suppose you have two databases on the same server - Db1 and Db2. Db1 has a table called Clients with a column ClientId and Db2 has a table called Messages with a column ClientId (let's leave asside why those tables are in different databases).

Now, to perform a join on the above-mentioned tables you will be using this query:

select *
from Db1.dbo.Clients c
join Db2.dbo.Messages m on c.ClientId = m.ClientId

Auto line-wrapping in SVG text

Building on @Mike Gledhill's code, I've taken it a step further and added more parameters. If you have a SVG RECT and want text to wrap inside it, this may be handy:

function wraptorect(textnode, boxObject, padding, linePadding) {

    var x_pos = parseInt(boxObject.getAttribute('x')),
    y_pos = parseInt(boxObject.getAttribute('y')),
    boxwidth = parseInt(boxObject.getAttribute('width')),
    fz = parseInt(window.getComputedStyle(textnode)['font-size']);  // We use this to calculate dy for each TSPAN.

    var line_height = fz + linePadding;

// Clone the original text node to store and display the final wrapping text.

   var wrapping = textnode.cloneNode(false);        // False means any TSPANs in the textnode will be discarded
   wrapping.setAttributeNS(null, 'x', x_pos + padding);
   wrapping.setAttributeNS(null, 'y', y_pos + padding);

// Make a copy of this node and hide it to progressively draw, measure and calculate line breaks.

   var testing = wrapping.cloneNode(false);
   testing.setAttributeNS(null, 'visibility', 'hidden');  // Comment this out to debug

   var testingTSPAN = document.createElementNS(null, 'tspan');
   var testingTEXTNODE = document.createTextNode(textnode.textContent);
   testingTSPAN.appendChild(testingTEXTNODE);

   testing.appendChild(testingTSPAN);
   var tester = document.getElementsByTagName('svg')[0].appendChild(testing);

   var words = textnode.textContent.split(" ");
   var line = line2 = "";
   var linecounter = 0;
   var testwidth;

   for (var n = 0; n < words.length; n++) {

      line2 = line + words[n] + " ";
      testing.textContent = line2;
      testwidth = testing.getBBox().width;

      if ((testwidth + 2*padding) > boxwidth) {

        testingTSPAN = document.createElementNS('http://www.w3.org/2000/svg', 'tspan');
        testingTSPAN.setAttributeNS(null, 'x', x_pos + padding);
        testingTSPAN.setAttributeNS(null, 'dy', line_height);

        testingTEXTNODE = document.createTextNode(line);
        testingTSPAN.appendChild(testingTEXTNODE);
        wrapping.appendChild(testingTSPAN);

        line = words[n] + " ";
        linecounter++;
      }
      else {
        line = line2;
      }
    }

    var testingTSPAN = document.createElementNS('http://www.w3.org/2000/svg', 'tspan');
    testingTSPAN.setAttributeNS(null, 'x', x_pos + padding);
    testingTSPAN.setAttributeNS(null, 'dy', line_height);

    var testingTEXTNODE = document.createTextNode(line);
    testingTSPAN.appendChild(testingTEXTNODE);

    wrapping.appendChild(testingTSPAN);

    testing.parentNode.removeChild(testing);
    textnode.parentNode.replaceChild(wrapping,textnode);

    return linecounter;
}

document.getElementById('original').onmouseover = function () {

    var container = document.getElementById('destination');
    var numberoflines = wraptorect(this,container,20,1);
    console.log(numberoflines);  // In case you need it

};

Jquery Date picker Default Date

While the defaultDate does not set the widget. What is needed is something like:

$(".datepicker").datepicker({
    showButtonPanel: true,
    numberOfMonths: 2

});

$(".datepicker[value='']").datepicker("setDate", "-0d"); 

TimePicker Dialog from clicking EditText

I dont know if this will work for you, it works for me just fine.

Create a method for the Date/Time picker dialog.

private DatePickerDialog.OnDateSetListener datePickerListener = new DatePickerDialog.OnDateSetListener() {

    // when dialog box is called, below method will be called.
    // The arguments will be working to get the Day of Week to show it in a special TextView for it.

    public void onDateSet(DatePicker view, int selectedYear,
                          int selectedMonth, int selectedDay) {
        String year1 = String.valueOf(selectedYear);
        String month1 = String.valueOf(selectedMonth + 1);
        String day1 = String.valueOf(selectedDay);
        delivDate.setText(month1 + "/" + day1 + "/" + year1);
        delivDay.setText(DateFormat.format("EEEE", new Date(selectedYear, selectedMonth, selectedDay - 1)).toString());
    }
};

and then, wherever you want you can do it just like this

public void setDateOnClick (View view) {
    Calendar cal = Calendar.getInstance();

    DatePickerDialog datePicker = new DatePickerDialog(this, datePickerListener,
            cal.get(Calendar.YEAR),
            cal.get(Calendar.MONTH),
            cal.get(Calendar.DAY_OF_MONTH));
    //Create a cancel button and set the title of the dialog.
    datePicker.setCancelable(false);
    datePicker.setTitle("Select the date");
    datePicker.show();
}

hope you find this as your solution.

What issues should be considered when overriding equals and hashCode in Java?

One gotcha I have found is where two objects contain references to each other (one example being a parent/child relationship with a convenience method on the parent to get all children).
These sorts of things are fairly common when doing Hibernate mappings for example.

If you include both ends of the relationship in your hashCode or equals tests it's possible to get into a recursive loop which ends in a StackOverflowException.
The simplest solution is to not include the getChildren collection in the methods.

How to get the EXIF data from a file using C#

Getting EXIF data from a JPEG image involves:

  1. Seeking to the JPEG markers which mentions the beginning of the EXIF data,. e.g. normally oxFFE1 is the marker inserted while encoding EXIF data, which is a APPlication segment, where EXIF data goes.
  2. Parse all the data from say 0xFFE1 to 0xFFE2 . This data would be stream of bytes, in the JPEG encoded file.
  3. ASCII equivalent of these bytes would contain various information related to Image Date, Camera Model Name, Exposure etc...

CSS smooth bounce animation

Here is code not using the percentage in the keyframes. Because you used percentages the animation does nothing a long time.

  • 0% translate 0px
  • 20% translate 0px
  • etc.

How does this example work:

  1. We set an animation. This is a short hand for animation properties.
  2. We immediately start the animation since we use from and to in the keyframes. from is = 0% and to is = 100%
  3. We can now control how fast it will bounce by setting the animation time: animation: bounce 1s infinite alternate; the 1s is how long the animation will last.

_x000D_
_x000D_
.ball {_x000D_
  margin-top: 50px;_x000D_
  border-radius: 50%;_x000D_
  width: 50px;_x000D_
  height: 50px;_x000D_
  background-color: cornflowerblue;_x000D_
  border: 2px solid #999;_x000D_
  animation: bounce 1s infinite alternate;_x000D_
  -webkit-animation: bounce 1s infinite alternate;_x000D_
}_x000D_
@keyframes bounce {_x000D_
  from {_x000D_
    transform: translateY(0px);_x000D_
  }_x000D_
  to {_x000D_
    transform: translateY(-15px);_x000D_
  }_x000D_
}_x000D_
@-webkit-keyframes bounce {_x000D_
  from {_x000D_
    transform: translateY(0px);_x000D_
  }_x000D_
  to {_x000D_
    transform: translateY(-15px);_x000D_
  }_x000D_
}
_x000D_
<div class="ball"></div>
_x000D_
_x000D_
_x000D_

Detect Safari browser

Read many answers and posts and determined the most accurate solution. Tested in Safari, Chrome, Firefox (desktop and iOS versions). First we need to detect Apple vendor and then exclude Chrome and Firefox (for iOS).

let isSafari = navigator.vendor.match(/apple/i) &&
             !navigator.userAgent.match(/crios/i) &&
             !navigator.userAgent.match(/fxios/i);

if (isSafari) {
  //
} else {
  //
}

Changing the JFrame title

these methods can help setTitle("your new title"); or super("your new title");

SPAN vs DIV (inline-block)

I know this Q is old, but why not use all DIVs instead of the SPANs? Then everything plays all happy together.

Example:

<div> 
   <div> content1(divs,p, spans, etc) </div> 
   <div> content2(divs,p, spans, etc) </div> 
   <div> content3(divs,p, spans, etc) </div> 
</div> 
<div> 
   <div> content4(divs,p, spans, etc) </div> 
   <div> content5(divs,p, spans, etc) </div> 
   <div> content6(divs,p, spans, etc) </div> 
</div>

Where is the Docker daemon log?

In my environment(docker for mac 17.07), there is no log file at ~/Library/Containers/com.docker.docker/Data/com.docker.driver.amd64-linux/log/d??ocker.log

Instead I can find log file as below.

  1. Enter into VM.

    $ screen ~/Library/Containers/com.docker.docker/Data/com.docker.driver.amd64-linux/tty
    or
    $ screen ~/Library/Containers/com.docker.docker/Data/vms/0/tty

  2. Check log file

    / # tail -f /var/log/docker.log

How to get Activity's content view?

You can also override onContentChanged() which is among others fired when setContentView() has been called.

jQuery window scroll event does not fire up

$('#div').scroll(function () {
   if ($(this).scrollTop() + $(this).innerHeight() >= $(this)[0].scrollHeight-1) {

     //fire your event


    }
}

Difference between no-cache and must-revalidate

Agreed with part of @Jeffrey Fox's answer:

max-age=0, must-revalidate and no-cache aren't exactly identical.

Not agreed with this part:

With no-cache, it would just show the cached content, which would be probably preferred by the user (better to have something stale than nothing at all).

What should implementations do when cache-control: no-cache revalidation failed is just not specified in the RFC document. It's all up to implementations. They may throw a 504 error like cache-control: must-revalidate or just serve a stale copy from cache.

How to change color of Toolbar back button in Android?

To style the Toolbar on Android 21+ it's a bit different.

<style name="DarkTheme.v21" parent="DarkTheme.v19">
        <!-- toolbar background color -->
        <item name="android:navigationBarColor">@color/color_primary_blue_dark</item>
        <!-- toolbar back button color -->
        <item name="toolbarNavigationButtonStyle">@style/Toolbar.Button.Navigation.Tinted</item>
    </style>

    <style name="Toolbar.Button.Navigation.Tinted" parent="Widget.AppCompat.Toolbar.Button.Navigation">
        <item name="tint">@color/color_white</item>
    </style>

Jenkins restrict view of jobs per user

Only one plugin help me: Role-Based Strategy :

wiki.jenkins-ci.org/display/JENKINS/Role+Strategy+Plugin

But official documentation (wiki.jenkins-ci.org/display/JENKINS/Role+Strategy+Plugin) is deficient.

The following configurations worked for me:

configure-role-strategy-plugin-in-jenkins

Basically you just need to create roles and match them with job names using regex.

How To Show And Hide Input Fields Based On Radio Button Selection

You'll need to also set the height of the element to 0 when it's hidden. I ran into this problem while using jQuery, my solution was to set the height and opacity to 0 when it's hidden, then change height to auto and opacity to 1 when it's un-hidden.

I'd recommend looking at jQuery. It's pretty easy to pick up and will allow you to do things like this a lot more easily.

$('#yesCheck').click(function() {
    $('#ifYes').slideDown();
});
$('#noCheck').click(function() {
    $('#ifYes').slideUp();
});

It's slightly better for performance to change the CSS with jQuery and use CSS3 animations to do the dropdown, but that's also more complex. The example above should work, but I haven't tested it.

How to export DataTable to Excel

Solution based on tuncalik (thanks for idea) article, but in case of big tables is working much more faster (and is a little less clear).

public static class My_DataTable_Extensions
{
    /// <summary>
    /// Export DataTable to Excel file
    /// </summary>
    /// <param name="DataTable">Source DataTable</param>
    /// <param name="ExcelFilePath">Path to result file name</param>
    public static void ExportToExcel(this System.Data.DataTable DataTable, string ExcelFilePath = null)
    {
        try
        {
            int ColumnsCount;

            if (DataTable == null || (ColumnsCount = DataTable.Columns.Count) == 0)
                throw new Exception("ExportToExcel: Null or empty input table!\n");

            // load excel, and create a new workbook
            Microsoft.Office.Interop.Excel.Application Excel = new Microsoft.Office.Interop.Excel.Application();
            Excel.Workbooks.Add();

            // single worksheet
            Microsoft.Office.Interop.Excel._Worksheet Worksheet = Excel.ActiveSheet;

            object[] Header = new object[ColumnsCount];

            // column headings               
            for (int i = 0; i < ColumnsCount; i++)
                Header[i] = DataTable.Columns[i].ColumnName;

            Microsoft.Office.Interop.Excel.Range HeaderRange = Worksheet.get_Range((Microsoft.Office.Interop.Excel.Range)(Worksheet.Cells[1, 1]), (Microsoft.Office.Interop.Excel.Range)(Worksheet.Cells[1, ColumnsCount]));
            HeaderRange.Value = Header;
            HeaderRange.Interior.Color = System.Drawing.ColorTranslator.ToOle(System.Drawing.Color.LightGray);
            HeaderRange.Font.Bold = true;

            // DataCells
            int RowsCount = DataTable.Rows.Count;
            object[,] Cells = new object[RowsCount, ColumnsCount];

            for (int j = 0; j < RowsCount; j++)
                for (int i = 0; i < ColumnsCount; i++)
                    Cells[j, i] = DataTable.Rows[j][i];

            Worksheet.get_Range((Microsoft.Office.Interop.Excel.Range)(Worksheet.Cells[2, 1]), (Microsoft.Office.Interop.Excel.Range)(Worksheet.Cells[RowsCount + 1, ColumnsCount])).Value = Cells;

            // check fielpath
            if (ExcelFilePath != null && ExcelFilePath != "")
            {
                try
                {
                    Worksheet.SaveAs(ExcelFilePath);
                    Excel.Quit();
                    System.Windows.MessageBox.Show("Excel file saved!");
                }
                catch (Exception ex)
                {
                    throw new Exception("ExportToExcel: Excel file could not be saved! Check filepath.\n"
                        + ex.Message);
                }
            }
            else    // no filepath is given
            {
                Excel.Visible = true;
            }
        }
        catch (Exception ex)
        {
            throw new Exception("ExportToExcel: \n" + ex.Message);
        }
    }
}

Action Image MVC3 Razor

slide modification changed Helper

     public static IHtmlString ActionImageLink(this HtmlHelper html, string action, object routeValues, string styleClass, string alt)
    {
        var url = new UrlHelper(html.ViewContext.RequestContext);
        var anchorBuilder = new TagBuilder("a");
        anchorBuilder.MergeAttribute("href", url.Action(action, routeValues));
        anchorBuilder.AddCssClass(styleClass);
        string anchorHtml = anchorBuilder.ToString(TagRenderMode.Normal);

        return new HtmlString(anchorHtml);
    }

CSS Class

.Edit {
       background: url('../images/edit.png') no-repeat right;
       display: inline-block;
       height: 16px;
       width: 16px;
      }

Create the link just pass the class name

     @Html.ActionImageLink("Edit", new { id = item.ID }, "Edit" , "Edit") 

database attached is read only

Answer from Varun Rathore is OK but you must consider that starting from Windows Server 2008 R2 and higher the SQLServer service will run under a local virtual account and not anymore under the old well known "NETWORK SERVICE". Due to this, to switch a newly attached DB to "not read only mode", you must setup permissions on the ldf and mdf files for local machine user line "NT SERVICE\MSSQLSERVER" where MSSQLSERVER would be the service name in a pretty standard installation.

Checkout this https://docs.microsoft.com/en-us/sql/database-engine/configure-windows/configure-windows-service-accounts-and-permissions#VA_Desc for details configuring service permissions

jQuery: Get selected element tag name

nodeName will give you the tag name in uppercase, while localName will give you the lower case.

$("yourelement")[0].localName 

will give you : yourelement instead of YOURELEMENT

Example of waitpid() in use?

#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/wait.h>

int main (){
    int pid;
    int status;

    printf("Parent: %d\n", getpid());

    pid = fork();
    if (pid == 0){
        printf("Child %d\n", getpid());
        sleep(2);
        exit(EXIT_SUCCESS);
    }

//Comment from here to...
    //Parent waits process pid (child)
    waitpid(pid, &status, 0);
    //Option is 0 since I check it later

    if (WIFSIGNALED(status)){
        printf("Error\n");
    }
    else if (WEXITSTATUS(status)){
        printf("Exited Normally\n");
    }
//To Here and see the difference
    printf("Parent: %d\n", getpid());

    return 0;
}

How to use regex in file find

Use -regex:

From the man page:

-regex pattern
       File name matches regular expression pattern.  This is a match on the whole path, not a search.  For example, to match a file named './fubar3',  you  can  use  the
       regular expression '.*bar.' or '.*b.*3', but not 'b.*r3'.

Also, I don't believe find supports regex extensions such as \d. You need to use [0-9].

find . -regex '.*test\.log\.[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9]\.zip'

Why does "return list.sort()" return None, not the list?

Python habitually returns None from functions and methods that mutate the data, such as list.sort, list.append, and random.shuffle, with the idea being that it hints to the fact that it was mutating.

If you want to take an iterable and return a new, sorted list of its items, use the sorted builtin function.

jquery ajax function not working

I think you have putted e.preventDefault(); before ajax call that's why its prevent calling of that function and your Ajax call will not call.

So try to remove that e.prevent Default() before Ajax call and add it to the after Ajax call.

How to change the remote repository for a git submodule?

git config --file=.gitmodules -e opens the default editor in which you can update the path

Create Map in Java

Map <Integer, Point2D.Double> hm = new HashMap<Integer, Point2D>();
hm.put(1, new Point2D.Double(50, 50));

Using PropertyInfo.GetValue()

In your example propertyInfo.GetValue(this, null) should work. Consider altering GetNamesAndTypesAndValues() as follows:

public void GetNamesAndTypesAndValues()
{
  foreach (PropertyInfo propertyInfo in allClassProperties)
  {
    Console.WriteLine("{0} [type = {1}] [value = {2}]",
      propertyInfo.Name,
      propertyInfo.PropertyType,
      propertyInfo.GetValue(this, null));
  }
}

Changing datagridview cell color based on condition

make it simple

private void dataGridView1_cellformatting(object sender,DataGridViewCellFormattingEventArgs e)
{
     var amount = (int)e.Value;

     // return if rowCount = 0
     if (this.dataGridView1.Rows.Count == 0)
         return;

     if (amount > 0)
         e.CellStyle.BackColor = Color.Green; 
     else
         e.CellStyle.BackColor = Color.Red;

}

take a look cell formatting

Android Studio - UNEXPECTED TOP-LEVEL EXCEPTION:

I know that the problem was answered, but this could happen again and my solution was a little different from the ones that I found. In my case the solution wasn't related to include two different libraries in my project. See code below:

compileOptions {
    sourceCompatibility JavaVersion.VERSION_1_8
    targetCompatibility JavaVersion.VERSION_1_8
}

This code was giving that error "Unexpected Top-Level Exception". I fix the code making the following changes:

compileOptions {
    sourceCompatibility JavaVersion.VERSION_1_7
    targetCompatibility JavaVersion.VERSION_1_7
}

Java heap terminology: young, old and permanent generations?

What is the young generation?

The Young Generation is where all new objects are allocated and aged. When the young generation fills up, this causes a minor garbage collection. A young generation full of dead objects is collected very quickly. Some survived objects are aged and eventually move to the old generation.

What is the old generation?

The Old Generation is used to store long surviving objects. Typically, a threshold is set for young generation object and when that age is met, the object gets moved to the old generation. Eventually the old generation needs to be collected. This event is called a major garbage collection

What is the permanent generation?

The Permanent generation contains metadata required by the JVM to describe the classes and methods used in the application. The permanent generation is populated by the JVM at runtime based on classes in use by the application.

PermGen has been replaced with Metaspace since Java 8 release.

PermSize & MaxPermSize parameters will be ignored now

How does the three generations interact/relate to each other?

enter image description here

Image source & oracle technetwork tutorial article: http://www.oracle.com/webfolder/technetwork/tutorials/obe/java/gc01/index.html

"The General Garbage Collection Process" in above article explains the interactions between them with many diagrams.

Have a look at summary diagram:

enter image description here

How to do INSERT into a table records extracted from another table

inserting data form one table to another table in different DATABASE

insert into DocTypeGroup 
    Select DocGrp_Id,DocGrp_SubId,DocGrp_GroupName,DocGrp_PM,DocGrp_DocType 
    from Opendatasource( 'SQLOLEDB','Data Source=10.132.20.19;UserID=sa;Password=gchaturthi').dbIPFMCI.dbo.DocTypeGroup

How to make HTML table cell editable?

HTML5 supports contenteditable,

<table border="3">
<thead>
<tr>Heading 1</tr>
<tr>Heading 2</tr>
</thead>
<tbody>
<tr>
<td contenteditable='true'></td>
<td contenteditable='true'></td>
</tr>
<tr>
<td contenteditable='true'></td>
<td contenteditable='true'></td>
</tr>
</tbody>
</table>

3rd party edit

To quote the mdn entry on contenteditable

The attribute must take one of the following values:

  • true or the empty string, which indicates that the element must be editable;

  • false, which indicates that the element must not be editable.

If this attribute is not set, its default value is inherited from its parent element.

This attribute is an enumerated one and not a Boolean one. This means that the explicit usage of one of the values true, false or the empty string is mandatory and that a shorthand ... is not allowed.

// wrong not allowed
<label contenteditable>Example Label</label> 

// correct usage
<label contenteditable="true">Example Label</label>.

How to force HTTPS using a web.config file

For those using ASP.NET MVC. You can use the RequireHttpsAttribute to force all responses to be HTTPS:

GlobalFilters.Filters.Add(new RequireHttpsAttribute());

Other things you may also want to do to help secure your site:

  1. Force Anti-Forgery tokens to use SSL/TLS:

    AntiForgeryConfig.RequireSsl = true;
    
  2. Require Cookies to require HTTPS by default by changing the Web.config file:

    <system.web>
        <httpCookies httpOnlyCookies="true" requireSSL="true" />
    </system.web>
    
  3. Use the NWebSec.Owin NuGet package and add the following line of code to enable Strict Transport Security (HSTS) across the site. Don't forget to add the Preload directive below and submit your site to the HSTS Preload site. More information here and here. Note that if you are not using OWIN, there is a Web.config method you can read up on on the NWebSec site.

    // app is your OWIN IAppBuilder app in Startup.cs
    app.UseHsts(options => options.MaxAge(days: 720).Preload());
    
  4. Use the NWebSec.Owin NuGet package and add the following line of code to enable Public Key Pinning (HPKP) across the site. More information here and here.

    // app is your OWIN IAppBuilder app in Startup.cs
    app.UseHpkp(options => options
        .Sha256Pins(
            "Base64 encoded SHA-256 hash of your first certificate e.g. cUPcTAZWKaASuYWhhneDttWpY3oBAkE3h2+soZS7sWs=",
            "Base64 encoded SHA-256 hash of your second backup certificate e.g. M8HztCzM3elUxkcjR2S5P4hhyBNf6lHkmjAHKhpGPWE=")
        .MaxAge(days: 30));
    
  5. Include the https scheme in any URL's used. Content Security Policy (CSP) HTTP header and Subresource Integrity (SRI) do not play nice when you imit the scheme in some browsers. It is better to be explicit about HTTPS. e.g.

    <script src="https://ajax.aspnetcdn.com/ajax/bootstrap/3.3.4/bootstrap.min.js">
    </script>
    
  6. Use the ASP.NET MVC Boilerplate Visual Studio project template to generate a project with all of this and much more built in. You can also view the code on GitHub.

Renaming columns in Pandas

One line or Pipeline solutions

I'll focus on two things:

  1. OP clearly states

    I have the edited column names stored it in a list, but I don't know how to replace the column names.

    I do not want to solve the problem of how to replace '$' or strip the first character off of each column header. OP has already done this step. Instead I want to focus on replacing the existing columns object with a new one given a list of replacement column names.

  2. df.columns = new where new is the list of new columns names is as simple as it gets. The drawback of this approach is that it requires editing the existing dataframe's columns attribute and it isn't done inline. I'll show a few ways to perform this via pipelining without editing the existing dataframe.


Setup 1
To focus on the need to rename of replace column names with a pre-existing list, I'll create a new sample dataframe df with initial column names and unrelated new column names.

df = pd.DataFrame({'Jack': [1, 2], 'Mahesh': [3, 4], 'Xin': [5, 6]})
new = ['x098', 'y765', 'z432']

df

   Jack  Mahesh  Xin
0     1       3    5
1     2       4    6

Solution 1
pd.DataFrame.rename

It has been said already that if you had a dictionary mapping the old column names to new column names, you could use pd.DataFrame.rename.

d = {'Jack': 'x098', 'Mahesh': 'y765', 'Xin': 'z432'}
df.rename(columns=d)

   x098  y765  z432
0     1     3     5
1     2     4     6

However, you can easily create that dictionary and include it in the call to rename. The following takes advantage of the fact that when iterating over df, we iterate over each column name.

# Given just a list of new column names
df.rename(columns=dict(zip(df, new)))

   x098  y765  z432
0     1     3     5
1     2     4     6

This works great if your original column names are unique. But if they are not, then this breaks down.


Setup 2
Non-unique columns

df = pd.DataFrame(
    [[1, 3, 5], [2, 4, 6]],
    columns=['Mahesh', 'Mahesh', 'Xin']
)
new = ['x098', 'y765', 'z432']

df

   Mahesh  Mahesh  Xin
0       1       3    5
1       2       4    6

Solution 2
pd.concat using the keys argument

First, notice what happens when we attempt to use solution 1:

df.rename(columns=dict(zip(df, new)))

   y765  y765  z432
0     1     3     5
1     2     4     6

We didn't map the new list as the column names. We ended up repeating y765. Instead, we can use the keys argument of the pd.concat function while iterating through the columns of df.

pd.concat([c for _, c in df.items()], axis=1, keys=new) 

   x098  y765  z432
0     1     3     5
1     2     4     6

Solution 3
Reconstruct. This should only be used if you have a single dtype for all columns. Otherwise, you'll end up with dtype object for all columns and converting them back requires more dictionary work.

Single dtype

pd.DataFrame(df.values, df.index, new)

   x098  y765  z432
0     1     3     5
1     2     4     6

Mixed dtype

pd.DataFrame(df.values, df.index, new).astype(dict(zip(new, df.dtypes)))

   x098  y765  z432
0     1     3     5
1     2     4     6

Solution 4
This is a gimmicky trick with transpose and set_index. pd.DataFrame.set_index allows us to set an index inline, but there is no corresponding set_columns. So we can transpose, then set_index, and transpose back. However, the same single dtype versus mixed dtype caveat from solution 3 applies here.

Single dtype

df.T.set_index(np.asarray(new)).T

   x098  y765  z432
0     1     3     5
1     2     4     6

Mixed dtype

df.T.set_index(np.asarray(new)).T.astype(dict(zip(new, df.dtypes)))

   x098  y765  z432
0     1     3     5
1     2     4     6

Solution 5
Use a lambda in pd.DataFrame.rename that cycles through each element of new.
In this solution, we pass a lambda that takes x but then ignores it. It also takes a y but doesn't expect it. Instead, an iterator is given as a default value and I can then use that to cycle through one at a time without regard to what the value of x is.

df.rename(columns=lambda x, y=iter(new): next(y))

   x098  y765  z432
0     1     3     5
1     2     4     6

And as pointed out to me by the folks in sopython chat, if I add a * in between x and y, I can protect my y variable. Though, in this context I don't believe it needs protecting. It is still worth mentioning.

df.rename(columns=lambda x, *, y=iter(new): next(y))

   x098  y765  z432
0     1     3     5
1     2     4     6

Invariant Violation: Could not find "store" in either the context or props of "Connect(SportsDatabase)"

For me it was import issue, hope it helps. default import by WebStorm was wrong.

replace

import connect from "react-redux/lib/connect/connect";

with

import {connect} from "react-redux";

Remove by _id in MongoDB console

I've just bumped into this myself and this variation worked for me:

db.foo.remove({**_id**: new ObjectId("4f872685a64eed5a980ca536")})

When should we use mutex and when should we use semaphore

Here is how I remember when to use what -

Semaphore: Use a semaphore when you (thread) want to sleep till some other thread tells you to wake up. Semaphore 'down' happens in one thread (producer) and semaphore 'up' (for same semaphore) happens in another thread (consumer) e.g.: In producer-consumer problem, producer wants to sleep till at least one buffer slot is empty - only the consumer thread can tell when a buffer slot is empty.

Mutex: Use a mutex when you (thread) want to execute code that should not be executed by any other thread at the same time. Mutex 'down' happens in one thread and mutex 'up' must happen in the same thread later on. e.g.: If you are deleting a node from a global linked list, you do not want another thread to muck around with pointers while you are deleting the node. When you acquire a mutex and are busy deleting a node, if another thread tries to acquire the same mutex, it will be put to sleep till you release the mutex.

Spinlock: Use a spinlock when you really want to use a mutex but your thread is not allowed to sleep. e.g.: An interrupt handler within OS kernel must never sleep. If it does the system will freeze / crash. If you need to insert a node to globally shared linked list from the interrupt handler, acquire a spinlock - insert node - release spinlock.

JQuery Bootstrap Multiselect plugin - Set a value as selected in the multiselect dropdown

work fine for me ,change ids according to you requirement.

$("#FormId select#status_id_new").val('');
 $("#FormId select#status_id_new").multiselect("refresh");

Test if string is a number in Ruby on Rails

Here's a benchmark for common ways to address this problem. Note which one you should use probably depends on the ratio of false cases expected.

  1. If they are relatively uncommon casting is definitely fastest.
  2. If false cases are common and you are just checking for ints, comparison vs a transformed state is a good option.
  3. If false cases are common and you are checking floats, regexp is probably the way to go

If performance doesn't matter use what you like. :-)

Integer checking details:

# 1.9.3-p448
#
# Calculating -------------------------------------
#                 cast     57485 i/100ms
#            cast fail      5549 i/100ms
#                 to_s     47509 i/100ms
#            to_s fail     50573 i/100ms
#               regexp     45187 i/100ms
#          regexp fail     42566 i/100ms
# -------------------------------------------------
#                 cast  2353703.4 (±4.9%) i/s -   11726940 in   4.998270s
#            cast fail    65590.2 (±4.6%) i/s -     327391 in   5.003511s
#                 to_s  1420892.0 (±6.8%) i/s -    7078841 in   5.011462s
#            to_s fail  1717948.8 (±6.0%) i/s -    8546837 in   4.998672s
#               regexp  1525729.9 (±7.0%) i/s -    7591416 in   5.007105s
#          regexp fail  1154461.1 (±5.5%) i/s -    5788976 in   5.035311s

require 'benchmark/ips'

int = '220000'
bad_int = '22.to.2'

Benchmark.ips do |x|
  x.report('cast') do
    Integer(int) rescue false
  end

  x.report('cast fail') do
    Integer(bad_int) rescue false
  end

  x.report('to_s') do
    int.to_i.to_s == int
  end

  x.report('to_s fail') do
    bad_int.to_i.to_s == bad_int
  end

  x.report('regexp') do
    int =~ /^\d+$/
  end

  x.report('regexp fail') do
    bad_int =~ /^\d+$/
  end
end

Float checking details:

# 1.9.3-p448
#
# Calculating -------------------------------------
#                 cast     47430 i/100ms
#            cast fail      5023 i/100ms
#                 to_s     27435 i/100ms
#            to_s fail     29609 i/100ms
#               regexp     37620 i/100ms
#          regexp fail     32557 i/100ms
# -------------------------------------------------
#                 cast  2283762.5 (±6.8%) i/s -   11383200 in   5.012934s
#            cast fail    63108.8 (±6.7%) i/s -     316449 in   5.038518s
#                 to_s   593069.3 (±8.8%) i/s -    2962980 in   5.042459s
#            to_s fail   857217.1 (±10.0%) i/s -    4263696 in   5.033024s
#               regexp  1383194.8 (±6.7%) i/s -    6884460 in   5.008275s
#          regexp fail   723390.2 (±5.8%) i/s -    3613827 in   5.016494s

require 'benchmark/ips'

float = '12.2312'
bad_float = '22.to.2'

Benchmark.ips do |x|
  x.report('cast') do
    Float(float) rescue false
  end

  x.report('cast fail') do
    Float(bad_float) rescue false
  end

  x.report('to_s') do
    float.to_f.to_s == float
  end

  x.report('to_s fail') do
    bad_float.to_f.to_s == bad_float
  end

  x.report('regexp') do
    float =~ /^[-+]?[0-9]*\.?[0-9]+$/
  end

  x.report('regexp fail') do
    bad_float =~ /^[-+]?[0-9]*\.?[0-9]+$/
  end
end

How do I set 'semi-bold' font via CSS? Font-weight of 600 doesn't make it look like the semi-bold I see in my Photoshop file

font-family: 'Open Sans'; font-weight: 600; important to change to a different font-family

SQL alias for SELECT statement

Not sure exactly what you try to denote with that syntax, but in almost all RDBMS-es you can use a subquery in the FROM clause (sometimes called an "inline-view"):

SELECT..
FROM (
     SELECT ...
     FROM ...
     ) my_select
WHERE ...

In advanced "enterprise" RDBMS-es (like oracle, SQL Server, postgresql) you can use common table expressions which allows you to refer to a query by name and reuse it even multiple times:

-- Define the CTE expression name and column list.
WITH Sales_CTE (SalesPersonID, SalesOrderID, SalesYear)
AS
-- Define the CTE query.
(
    SELECT SalesPersonID, SalesOrderID, YEAR(OrderDate) AS SalesYear
    FROM Sales.SalesOrderHeader
    WHERE SalesPersonID IS NOT NULL
)
-- Define the outer query referencing the CTE name.
SELECT SalesPersonID, COUNT(SalesOrderID) AS TotalSales, SalesYear
FROM Sales_CTE
GROUP BY SalesYear, SalesPersonID
ORDER BY SalesPersonID, SalesYear;

(example from http://msdn.microsoft.com/en-us/library/ms190766(v=sql.105).aspx)

How can I set the 'backend' in matplotlib in Python?

This can also be set in the configuration file matplotlibrc (as explained in the error message), for instance:

# The default backend; one of GTK GTKAgg GTKCairo GTK3Agg GTK3Cairo
# CocoaAgg MacOSX Qt4Agg Qt5Agg TkAgg WX WXAgg Agg Cairo GDK PS PDF SVG
backend : Agg

That way, the backend does not need to be hardcoded if the code is shared with other people. For more information, check the documentation.

Check if image exists on server using JavaScript?

You can just check if the image loads or not by using the built in events that is provided for all images.

The onload and onerror events will tell you if the image loaded successfully or if an error occured :

var image = new Image();

image.onload = function() {
    // image exists and is loaded
    document.body.appendChild(image);
}
image.onerror = function() {
    // image did not load

    var err = new Image();
    err.src = '/error.png';

    document.body.appendChild(err);
}

image.src = "../imgs/6.jpg";

XSD - how to allow elements in any order any number of times?

This is what finally worked for me:

<xsd:element name="bar">
  <xsd:complexType>
    <xsd:sequence>
      <!--  Permit any of these tags in any order in any number     -->
      <xsd:choice minOccurs="0" maxOccurs="unbounded">
        <xsd:element name="child1" type="xsd:string" />
        <xsd:element name="child2" type="xsd:string" />
        <xsd:element name="child3" type="xsd:string" />
      </xsd:choice>
    </xsd:sequence>
  </xsd:complexType>
</xsd:element>

Create a custom View by inflating a layout?

In practice, I have found that you need to be a bit careful, especially if you are using a bit of xml repeatedly. Suppose, for example, that you have a table that you wish to create a table row for each entry in a list. You've set up some xml:

In my_table_row.xml:

<?xml version="1.0" encoding="utf-8"?>
<TableRow xmlns:android="http://schemas.android.com/apk/res/android" 
  android:orientation="vertical"
  android:layout_width="match_parent"
  android:layout_height="match_parent" android:id="@+id/myTableRow">
    <ImageButton android:src="@android:drawable/ic_menu_delete" android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/rowButton"/>
    <TextView android:layout_height="wrap_content" android:layout_width="wrap_content" android:textAppearance="?android:attr/textAppearanceMedium" android:text="TextView" android:id="@+id/rowText"></TextView>
</TableRow>

Then you want to create it once per row with some code. It assume that you have defined a parent TableLayout myTable to attach the Rows to.

for (int i=0; i<numRows; i++) {
    /*
     * 1. Make the row and attach it to myTable. For some reason this doesn't seem
     * to return the TableRow as you might expect from the xml, so you need to
     * receive the View it returns and then find the TableRow and other items, as
     * per step 2.
     */
    LayoutInflater inflater = (LayoutInflater)getBaseContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    View v =  inflater.inflate(R.layout.my_table_row, myTable, true);

    // 2. Get all the things that we need to refer to to alter in any way.
    TableRow    tr        = (TableRow)    v.findViewById(R.id.profileTableRow);
    ImageButton rowButton = (ImageButton) v.findViewById(R.id.rowButton);
    TextView    rowText   = (TextView)    v.findViewById(R.id.rowText);

    // 3. Configure them out as you need to
    rowText.setText("Text for this row");
    rowButton.setId(i); // So that when it is clicked we know which one has been clicked!
    rowButton.setOnClickListener(this); // See note below ...           

    /*
     * To ensure that when finding views by id on the next time round this
     * loop (or later) gie lots of spurious, unique, ids.
     */
    rowText.setId(1000+i);
    tr.setId(3000+i);
}

For a clear simple example on handling rowButton.setOnClickListener(this), see Onclicklistener for a programatically created button.

How to crop an image using PIL?

There is a crop() method:

w, h = yourImage.size
yourImage.crop((0, 30, w, h-30)).save(...)

How can I cast int to enum?

From an int:

YourEnum foo = (YourEnum)yourInt;

From a string:

YourEnum foo = (YourEnum) Enum.Parse(typeof(YourEnum), yourString);

// The foo.ToString().Contains(",") check is necessary for enumerations marked with an [Flags] attribute
if (!Enum.IsDefined(typeof(YourEnum), foo) && !foo.ToString().Contains(","))
{
    throw new InvalidOperationException($"{yourString} is not an underlying value of the YourEnum enumeration.")
}

Update:

From number you can also

YourEnum foo = (YourEnum)Enum.ToObject(typeof(YourEnum) , yourInt);

Setting and getting localStorage with jQuery

You said you are attempting to get the text from a div and store it on local storage.

Please Note: Text and Html are different. In the question you mentioned text. html() will return Html content like <a>example</a>. if you want to get Text content then you have to use text() instead of html() then the result will be example instead of <a>example<a>. Anyway, I am using your terminology let it be Text.

Step 1: get the text from div.

what you did is not get the text from div but set the text to a div.

$('#test').html("Test"); 

is actually setting text to div and the output will be a jQuery object. That is why it sets it as [object Object].

To get the text you have to write like this
$('#test').html();

This will return a string not an object so the result will be Test in your case.

Step 2: set it to local storage.

Your approach is correct and you can write it as

localStorage.key=value

But the preferred approach is

localStorage.setItem(key,value); to set

localStorage.getItem(key); to get.

key and value must be strings.

so in your context code will become

$('#test').html("Test");
localStorage.content = $('#test').html();
$('#test').html(localStorage.content);

But I don't find any meaning in your code. Because you want to get the text from div and store it on local storage. And again you are reading the same from local storage and set to div. just like a=10; b=a; a=b;

If you are facing any other problems please update your question accordingly.

How do I change the android actionbar title and icon

If you want to change the Action bar title just give the following 1 line code in the onCreate() of your Activity

getActionBar().setTitle("Test");

Changing background colour of tr element on mouseover

You can give the tr an id and do it.

tr#element{
    background-color: green;
    cursor: pointer;
    height: 30px;

}

tr#element:hover{
    background-color: blue;
    cursor: pointer;

}

<table width="400px">
<tr id="element">
<td></td>
</tr>
</table>

jQuery count child elements

$("#selected > ul > li").size()

or:

$("#selected > ul > li").length

Delaying a jquery script until everything else has loaded

Have you tried loading all the initialization functions using the $().ready, running the jQuery function you wanted last?

Perhaps you can use setTimeout() on the $().ready function you wanted to run, calling the functionality you wanted to load.

Or, use setInterval() and have the interval check to see if all the other load functions have completed (store the status in a boolean variable). When conditions are met, you could cancel the interval and run the load function.

Best way to do a PHP switch with multiple values per case?

Version 1 is certainly easier on the eyes, clearer as to your intentions, and easier to add case-conditions to.

I've never tried the second version. In many languages, this wouldn't even compile because each case labels has to evaluate to a constant-expression.

Error: cannot open display: localhost:0.0 - trying to open Firefox from CentOS 6.2 64bit and display on Win7

In my case the issue was caused due to mismatch in .Xauthority file. Which initially showed up with "Invalid MIT-MAGIC-COOKIE-1" error and then "Error: cannot open display: :0.0" afterwards

Regenerating the .Xauthorityfile from the user under which I am running the vncserver and resetting the password with a restart of the vnc service and dbus service fixed the issue for me.

Ruby on Rails: Where to define global constants?

A common place to put application-wide global constants is inside config/application.

module MyApp
  FOO ||= ENV.fetch('FOO', nil)
  BAR ||= %w(one two three)

  class Application < Rails::Application
    config.foo_bar = :baz
  end
end

Collapsing Sidebar with Bootstrap

Bootstrap 3

Yes, it's possible. This "off-canvas" example should help to get you started.

https://codeply.com/p/esYgHWB2zJ

Basically you need to wrap the layout in an outer div, and use media queries to toggle the layout on smaller screens.

/* collapsed sidebar styles */
@media screen and (max-width: 767px) {
  .row-offcanvas {
    position: relative;
    -webkit-transition: all 0.25s ease-out;
    -moz-transition: all 0.25s ease-out;
    transition: all 0.25s ease-out;
  }
  .row-offcanvas-right
  .sidebar-offcanvas {
    right: -41.6%;
  }

  .row-offcanvas-left
  .sidebar-offcanvas {
    left: -41.6%;
  }
  .row-offcanvas-right.active {
    right: 41.6%;
  }
  .row-offcanvas-left.active {
    left: 41.6%;
  }
  .sidebar-offcanvas {
    position: absolute;
    top: 0;
    width: 41.6%;
  }
  #sidebar {
    padding-top:0;
  }
}

Also, there are several more Bootstrap sidebar examples here


Bootstrap 4

Create a responsive navbar sidebar "drawer" in Bootstrap 4?

How do I split a string in Rust?

There are three simple ways:

  1. By separator:

     s.split("separator")  |  s.split('/')  |  s.split(char::is_numeric)
    
  2. By whitespace:

     s.split_whitespace()
    
  3. By newlines:

     s.lines()
    
  4. By regex: (using regex crate)

     Regex::new(r"\s").unwrap().split("one two three")
    

The result of each kind is an iterator:

let text = "foo\r\nbar\n\nbaz\n";
let mut lines = text.lines();

assert_eq!(Some("foo"), lines.next());
assert_eq!(Some("bar"), lines.next());
assert_eq!(Some(""), lines.next());
assert_eq!(Some("baz"), lines.next());

assert_eq!(None, lines.next());

What is the HTML tabindex attribute?

Controlling the order of tabbing (pressing the tab key to move focus) within the page.

Reference: http://www.w3.org/TR/html401/interact/forms.html#h-17.11.1

gulp command not found - error after installing gulp

The NodeJS installer appears to add the user/AppData/Roaming/npm path to the user environment path, which is appropriate.

Normally, the PATH environment variable at the command line is the combination of the user environment path and the system environment path.

However, if the user environment path + the system environment path is larger than about 1920 characters, Windows does not not combine the user and system paths - only the system environment path is used.

See: https://stackoverflow.com/a/21270921/301152

So, when you open the Advanced System Settings in Windows to edit your environment variables, take a look to see if the user/AppData/Roaming/npm path is already in your user environment PATH. If it is, then the problem is that your user + system paths are too long, causing Windows to ignore your user path. Trim your user and/or system path strings and gulp should work as installed.

If you can't find anything to trim away from your user and system paths, then add the user/AppData/Roaming/npm path to the system environment path and call it a hack.

Update with two tables?

For Microsoft Access

UPDATE TableA A
    INNER JOIN TableB B
    ON A.ID = B.ID
SET A.Name = B.Name

Skip first entry in for loop in python?

Based on @SvenMarnach 's Answer, but bit simpler and without using deque

>>> def skip(iterable, at_start=0, at_end=0):
    it = iter(iterable)
    it = itertools.islice(it, at_start, None)
    it, it1 = itertools.tee(it)
    it1 = itertools.islice(it1, at_end, None)
    return (next(it) for _ in it1)

>>> list(skip(range(10), at_start=2, at_end=2))
[2, 3, 4, 5, 6, 7]
>>> list(skip(range(10), at_start=2, at_end=5))
[2, 3, 4]

Also Note, based on my timeit result, this is marginally faster than the deque solution

>>> iterable=xrange(1000)
>>> stmt1="""
def skip(iterable, at_start=0, at_end=0):
    it = iter(iterable)
    it = itertools.islice(it, at_start, None)
    it, it1 = itertools.tee(it)
    it1 = itertools.islice(it1, at_end, None)
    return (next(it) for _ in it1)
list(skip(iterable,2,2))
    """
>>> stmt2="""
def skip(iterable, at_start=0, at_end=0):
    it = iter(iterable)
    for x in itertools.islice(it, at_start):
        pass
    queue = collections.deque(itertools.islice(it, at_end))
    for x in it:
        queue.append(x)
        yield queue.popleft()
list(skip(iterable,2,2))
        """
>>> timeit.timeit(stmt = stmt1, setup='from __main__ import iterable, skip, itertools', number = 10000)
2.0313770640908047
>>> timeit.timeit(stmt = stmt2, setup='from __main__ import iterable, skip, itertools, collections', number = 10000)
2.9903135454296716

How to remove specific session in asp.net?

A single way to remove sessions is setting it to null;

Session["your_session"] = null;

PermGen elimination in JDK 8

Reasons of ignoring these argument is permanent generation has been removed in HotSpot for JDK8 because of following drawbacks

  • Fixed size at startup – difficult to tune.
  • Internal Hotspot types were Java objects : Could move with full GC, opaque, not strongly typed and hard to debug, needed meta-metadata.
  • Simplify full collections : Special iterators for metadata for each collector
  • Want to deallocate class data concurrently and not during GC pause
  • Enable future improvements that were limited by PermGen.

The Permanent Generation (PermGen) space has completely been removed and is kind of replaced by a new space called Metaspace. The consequences of the PermGen removal is that obviously the PermSize and MaxPermSize JVM arguments are ignored and you will never get a java.lang.OutOfMemoryError: PermGen error.

Advantages of MetaSpace

  • Take advantage of Java Language Specification property : Classes and associated metadata lifetimes match class loader’s
  • Per loader storage area – Metaspace
  • Linear allocation only
  • No individual reclamation (except for RedefineClasses and class loading failure)
  • No GC scan or compaction
  • No relocation for metaspace objects

Metaspace Tuning

The maximum metaspace size can be set using the -XX:MaxMetaspaceSize flag, and the default is unlimited, which means that only your system memory is the limit. The -XX:MetaspaceSize tuning flag defines the initial size of metaspace If you don’t specify this flag, the Metaspace will dynamically re-size depending of the application demand at runtime.

Change enables other optimizations and features in the future

  • Application class data sharing
  • Young collection optimizations, G1 class unloading
  • Metadata size reductions and internal JVM footprint projects

There is improved GC performace also.

How to get unique values in an array

Short and sweet solution using second array;

var axes2=[1,4,5,2,3,1,2,3,4,5,1,3,4];

    var distinct_axes2=[];

    for(var i=0;i<axes2.length;i++)
        {
        var str=axes2[i];
        if(distinct_axes2.indexOf(str)==-1)
            {
            distinct_axes2.push(str);
            }
        }
    console.log("distinct_axes2 : "+distinct_axes2); // distinct_axes2 : 1,4,5,2,3

Why is there no xrange function in Python3?

comp:~$ python Python 2.7.6 (default, Jun 22 2015, 17:58:13) [GCC 4.8.2] on linux2

>>> import timeit
>>> timeit.timeit("[x for x in xrange(1000000) if x%4]",number=100)

5.656799077987671

>>> timeit.timeit("[x for x in xrange(1000000) if x%4]",number=100)

5.579368829727173

>>> timeit.timeit("[x for x in range(1000000) if x%4]",number=100)

21.54827117919922

>>> timeit.timeit("[x for x in range(1000000) if x%4]",number=100)

22.014557123184204

With timeit number=1 param:

>>> timeit.timeit("[x for x in range(1000000) if x%4]",number=1)

0.2245171070098877

>>> timeit.timeit("[x for x in xrange(1000000) if x%4]",number=1)

0.10750913619995117

comp:~$ python3 Python 3.4.3 (default, Oct 14 2015, 20:28:29) [GCC 4.8.4] on linux

>>> timeit.timeit("[x for x in range(1000000) if x%4]",number=100)

9.113872020003328

>>> timeit.timeit("[x for x in range(1000000) if x%4]",number=100)

9.07014398300089

With timeit number=1,2,3,4 param works quick and in linear way:

>>> timeit.timeit("[x for x in range(1000000) if x%4]",number=1)

0.09329321900440846

>>> timeit.timeit("[x for x in range(1000000) if x%4]",number=2)

0.18501482300052885

>>> timeit.timeit("[x for x in range(1000000) if x%4]",number=3)

0.2703447980020428

>>> timeit.timeit("[x for x in range(1000000) if x%4]",number=4)

0.36209142999723554

So it seems if we measure 1 running loop cycle like timeit.timeit("[x for x in range(1000000) if x%4]",number=1) (as we actually use in real code) python3 works quick enough, but in repeated loops python 2 xrange() wins in speed against range() from python 3.

What is the naming convention in Python for variable and function names?

The coding style is usually part of an organization's internal policy/convention standards, but I think in general, the all_lower_case_underscore_separator style (also called snake_case) is most common in python.

Get month and year from a datetime in SQL Server 2005

Funny, I was just playing around writing this same query out in SQL Server and then LINQ.

SELECT 
    DATENAME(mm, article.Created) AS Month, 
    DATENAME(yyyy, article.Created) AS Year, 
    COUNT(*) AS Total 
FROM Articles AS article 
GROUP BY 
    DATENAME(mm, article.Created), 
    DATENAME(yyyy, article.Created) 
ORDER BY Month, Year DESC

It produces the following ouput (example).

Month | Year | Total

January | 2009 | 2

How to both read and write a file in C#

Don't forget the easy route:

    static void Main(string[] args)
    {
        var text = File.ReadAllText(@"C:\words.txt");
        File.WriteAllText(@"C:\words.txt", text + "DERP");
    }

Twitter bootstrap hide element on small devices

<div class="small hidden-xs">
    Some Content Here
</div>

This also works for elements not necessarily used in a grid /small column. When it is rendered on larger screens the font-size will be smaller than your default text font-size.

This answer satisfies the question in the OP title (which is how I found this Q/A).

Shell script to delete directories older than n days

OR

rm -rf `find /path/to/base/dir/* -type d -mtime +10`

Updated, faster version of it:

find /path/to/base/dir/* -mtime +10 -print0 | xargs -0 rm -f

how to force maven to update local repo

If you are installing into local repository, there is no special index/cache update needed.

Make sure that:

  1. You have installed the first artifact in your local repository properly. Simply copying the file to .m2 may not work as expected. Make sure you install it by mvn install

  2. The dependency in 2nd project is setup correctly. Check on any typo in groupId/artifactId/version, or unmatched artifact type/classifier.

How to pass variable as a parameter in Execute SQL Task SSIS?

The EXCEL and OLED DB connection managers use the parameter names 0 and 1.

I was using a oledb connection and wasted couple of hours trying to figure out the reason why the query was not working or taking the parameters. the above explanation helped a lot Thanks a lot.

What is stability in sorting algorithms and why is it important?

Stable sort will always return same solution (permutation) on same input.

For instance [2,1,2] will be sorted using stable sort as permutation [2,1,3] (first is index 2, then index 1 then index 3 in sorted output) That mean that output is always shuffled same way. Other non stable, but still correct permutation is [2,3,1].

Quick sort is not stable sort and permutation differences among same elements depends on algorithm for picking pivot. Some implementations pick up at random and that can make quick sort yielding different permutations on same input using same algorithm.

Stable sort algorithm is necessary deterministic.

CreateProcess error=206, The filename or extension is too long when running main() method

I faced this problem today and I was able to solve it using this Gradle plugin

It's github url is this

IF you, like me, have no idea what Gradle is but need to run a backend to do your front end work, what you need to do is find the build.gradle file that is being called to start your BE server and add this to the top:

plugins {
  id "ua.eshepelyuk.ManifestClasspath" version "1.0.0"
}

Error 5 : Access Denied when starting windows service

One of the causes for this error is insufficient permissions (Authenticated Users) in your local folder. To give permission for 'Authenticated Users' Open the security tab in properties of your folder, Edit and Add 'Authenticated Users' group and Apply changes.

Once this was done I was able to run services even through network service account (before this I was only able to run with Local system account).

Javascript Equivalent to PHP Explode()

If you want to defined your own function, try this:

function explode (delimiter, string, limit) {
  if (arguments.length < 2 ||
    typeof delimiter === 'undefined' ||
    typeof string === 'undefined') {
    return null
  }
  if (delimiter === '' ||
    delimiter === false ||
    delimiter === null) {
    return false
  }
  if (typeof delimiter === 'function' ||
    typeof delimiter === 'object' ||
    typeof string === 'function' ||
    typeof string === 'object') {
    return {
      0: ''
    }
  }
  if (delimiter === true) {
    delimiter = '1'
  }

  // Here we go...
  delimiter += ''
  string += ''

  var s = string.split(delimiter)

  if (typeof limit === 'undefined') return s

  // Support for limit
  if (limit === 0) limit = 1

  // Positive limit
  if (limit > 0) {
    if (limit >= s.length) {
      return s
    }
    return s
      .slice(0, limit - 1)
      .concat([s.slice(limit - 1)
        .join(delimiter)
      ])
  }

  // Negative limit
  if (-limit >= s.length) {
    return []
  }

  s.splice(s.length + limit)
  return s
}

Taken from: http://locutus.io/php/strings/explode/

How do I use sudo to redirect output to a location I don't have permission to write to?

How about writing a script?

Filename: myscript

#!/bin/sh

/bin/ls -lah /root > /root/test.out

# end script

Then use sudo to run the script:

sudo ./myscript

Printing 2D array in matrix format

Your can do it like this in short hands.

        int[,] values=new int[2,3]{{2,4,5},{4,5,2}};

        for (int i = 0; i < values.GetLength(0); i++)
        {
            for (int k = 0; k < values.GetLength(1); k++) {
                Console.Write(values[i,k]);
            }

            Console.WriteLine();
        }

How to change Oracle default data pump directory to import dumpfile?

I want change default directory dumpfile.

You could create a new directory and give it required privileges, for example:

SQL> CREATE DIRECTORY dmpdir AS '/opt/oracle';
Directory created.

SQL> GRANT read, write ON DIRECTORY dmpdir TO scott;
Grant succeeded.

To use the newly created directory, you could just add it as a parameter:

DIRECTORY=dmpdir

Oracle introduced a default directory from 10g R2, called DATA_PUMP_DIR, that can be used. To check the location, you could look into dba_directories:

SQL> select DIRECTORY_NAME, DIRECTORY_PATH from dba_directories where DIRECTORY_NAME = 'DATA_PUMP_DIR';

DIRECTORY_NAME       DIRECTORY_PATH
-------------------- --------------------------------------------------
DATA_PUMP_DIR        C:\app\Lalit/admin/orcl/dpdump/

SQL>