Programs & Examples On #Canonical link

is a keyword for the HTML attribute `rel` which allows specification of the preferred URL for web pages with duplicate content.

git: How to ignore all present untracked files?

IMHO better than the accepted answer is to use the following:

git config --local status.showUntrackedFiles no

The accepted answer does not work for when new files are added that are not in .gitignore

Get URL query string parameters

The PHP way to do it is using the function parse_url, which parses a URL and return its components. Including the query string.

Example:

$url = 'www.mysite.com/category/subcategory?myqueryhash';
echo parse_url($url, PHP_URL_QUERY); # output "myqueryhash"

Full documentation here

How can I use a JavaScript variable as a PHP variable?

You can do what you want, but not like that. What you need to do is make an AJAX request from JavaScript back to the server where a separate PHP script can do the database operation.

Call external javascript functions from java code

try {
        ScriptEngineManager manager = new ScriptEngineManager();
        ScriptEngine engine = manager.getEngineByName("JavaScript");
        System.out.println("okay1");
        FileInputStream fileInputStream = new FileInputStream("C:/Users/Kushan/eclipse-workspace/sureson.lk/src/main/webapp/js/back_end_response.js");
        System.out.println("okay2");
        if (fileInputStream != null){
         BufferedReader reader = new BufferedReader(new InputStreamReader(fileInputStream));
         engine.eval(reader);
         System.out.println("okay3");
        // Invocable javascriptEngine = null;
         System.out.println("okay4");
        Invocable invocableEngine = (Invocable)engine;
         System.out.println("okay5");
         int x=0;
         System.out.println("invocableEngine is : "+invocableEngine);
         Object object = invocableEngine.invokeFunction("backend_message",x);

         System.out.println("okay6");
        }
        }catch(Exception e) {
            System.out.println("erroe when calling js function"+ e);
        }

Send data from activity to fragment in Android

just stumbled across this question, while most of the methods above will work. I just want to add that you can use the Event Bus Library, especially in scenarios where the component (Activity or Fragment) has not been created, its good for all sizes of android projects and many use cases. I have personally used it in several projects i have on playstore.

In Bootstrap open Enlarge image in modal

    <div class="row" style="display:inline-block">

    <div class="col-lg-12">
        <h1 class="page-header">Thumbnail Gallery</h1>

            <div class="col-lg-3 col-md-4 col-xs-6 thumb">
            <a class="thumbnail" href="#" data-image-id="" data-toggle="modal" data-title="This is my title" data-caption="Some lovely red flowers" data-image="http://onelive.us/wp-content/uploads/2014/08/flower-delivery-online.jpg" data-target="#image-gallery">
                <img class="img-responsive" src="http://onelive.us/wp-content/uploads/2014/08/flower-delivery-online.jpg" alt="Short alt text">
            </a>
        </div>
            <div class="col-lg-3 col-md-4 col-xs-6 thumb">
            <a class="thumbnail" href="#" data-image-id="" data-toggle="modal" data-title="The car i dream about" data-caption="If you sponsor me, I can drive this car" data-image="http://www.picturesnew.com/media/images/car-image.jpg" data-target="#image-gallery">
                <img class="img-responsive" src="http://www.picturesnew.com/media/images/car-image.jpg" alt="A alt text">
            </a>
        </div>
            <div class="col-lg-3 col-md-4 col-xs-6 thumb">
            <a class="thumbnail" href="#" data-image-id="" data-toggle="modal" data-title="Im so nice" data-caption="And if there is money left, my girlfriend will receive this car" data-image="http://upload.wikimedia.org/wikipedia/commons/7/78/1997_Fiat_Panda.JPG" data-target="#image-gallery">
                <img class="img-responsive" src="http://upload.wikimedia.org/wikipedia/commons/7/78/1997_Fiat_Panda.JPG" alt="Another alt text">
            </a>
        </div>
</div>


<div class="modal fade" id="image-gallery" tabindex="-1" role="dialog" aria-labelledby="myModalLabel" aria-hidden="true">
    <div class="modal-dialog">
        <div class="modal-content">
            <div class="modal-header">
                <button type="button" class="close" data-dismiss="modal"><span aria-hidden="true">×</span><span class="sr-only">Close</span></button>
                <h4 class="modal-title" id="image-gallery-title"></h4>
            </div>
            <div class="modal-body">
                <img id="image-gallery-image" class="img-responsive" src="">
            </div>
            <div class="modal-footer">

                <div class="col-md-2">
                    <button type="button" class="btn btn-primary" id="show-previous-image">Previous</button>
                </div>

                <div class="col-md-8 text-justify" id="image-gallery-caption">
                    This text will be overwritten by jQuery
                </div>

                <div class="col-md-2">
                    <button type="button" id="show-next-image" class="btn btn-default">Next</button>
                </div>
            </div>
        </div>
    </div>
</div>



<script>
$(document).ready(function(){

    loadGallery(true, 'a.thumbnail');

    //This function disables buttons when needed
    function disableButtons(counter_max, counter_current){
        $('#show-previous-image, #show-next-image').show();
        if(counter_max == counter_current){
            $('#show-next-image').hide();
        } else if (counter_current == 1){
            $('#show-previous-image').hide();
        }
    }

    /**
     *
     * @param setIDs        Sets IDs when DOM is loaded. If using a PHP counter, set to false.
     * @param setClickAttr  Sets the attribute for the click handler.
     */

    function loadGallery(setIDs, setClickAttr){
        var current_image,
            selector,
            counter = 0;

        $('#show-next-image, #show-previous-image').click(function(){
            if($(this).attr('id') == 'show-previous-image'){
                current_image--;
            } else {
                current_image++;
            }

            selector = $('[data-image-id="' + current_image + '"]');
            updateGallery(selector);
        });

        function updateGallery(selector) {
            var $sel = selector;
            current_image = $sel.data('image-id');
            $('#image-gallery-caption').text($sel.data('caption'));
            $('#image-gallery-title').text($sel.data('title'));
            $('#image-gallery-image').attr('src', $sel.data('image'));
            disableButtons(counter, $sel.data('image-id'));
        }

        if(setIDs == true){
            $('[data-image-id]').each(function(){
                counter++;
                $(this).attr('data-image-id',counter);
            });
        }
        $(setClickAttr).on('click',function(){
            updateGallery($(this));
        });
    }
});
</script>

How do you do a deep copy of an object in .NET?

The MSDN documentation seems to hint that Clone should perform a deep copy, but it is never explicitly stated:

The ICloneable interface contains one member, Clone, which is intended to support cloning beyond that supplied by MemberWiseClone… The MemberwiseClone method creates a shallow copy…

You can find my post helpful.

http://pragmaticcoding.com/index.php/cloning-objects-in-c/

How can I close a browser window without receiving the "Do you want to close this window" prompt?

This will work :

<script type="text/javascript">
function closeWindowNoPrompt()
{
window.open('', '_parent', '');
window.close();
}
</script>

Changing route doesn't scroll to top in the new page

A little late to the party, but I've tried every possible method, and nothing worked correctly. Here is my elegant solution:

I use a controller that governs all my pages with ui-router. It allows me to redirect users who aren't authenticated or validated to an appropriate location. Most people put their middleware in their app's config, but I required some http requests, therefore a global controller works better for me.

My index.html looks like:

<main ng-controller="InitCtrl">
    <nav id="top-nav"></nav>
    <div ui-view></div>
</main>

My initCtrl.js looks like:

angular.module('MyApp').controller('InitCtrl', function($rootScope, $timeout, $anchorScroll) {
    $rootScope.$on('$locationChangeStart', function(event, next, current){
        // middleware
    });
    $rootScope.$on("$locationChangeSuccess", function(){
        $timeout(function() {
            $anchorScroll('top-nav');
       });
    });
});

I've tried every possible option, this method works the best.

How to install a specific version of a ruby gem?

For installing gem install gemname -v versionnumber

For uninstall gem uninstall gemname -v versionnumber

How to define a relative path in java

Firstly, see the different between absolute path and relative path here:

An absolute path always contains the root element and the complete directory list required to locate the file.

Alternatively, a relative path needs to be combined with another path in order to access a file.

In constructor File(String pathname), Javadoc's File class said that

A pathname, whether abstract or in string form, may be either absolute or relative.

If you want to get relative path, you must be define the path from the current working directory to file or directory.Try to use system properties to get this.As the pictures that you drew:

String localDir = System.getProperty("user.dir");
File file = new File(localDir + "\\config.properties");

Moreover, you should try to avoid using similar ".", "../", "/", and other similar relative to the file location relative path, because when files are moved, it is harder to handle.

In Java, how can I determine if a char array contains a particular character?

Here's a variation of Oscar's first version that doesn't use a for-each loop.

for (int i = 0; i < charArray.length; i++) {
    if (charArray[i] == 'q') {
        // do something
        break;
    }
}

You could have a boolean variable that gets set to false before the loop, then make "do something" set the variable to true, which you could test for after the loop. The loop could also be wrapped in a function call then just use 'return true' instead of the break, and add a 'return false' statement after the for loop.

angularjs directive call function specified in attribute and pass an argument to it

My solution:

  1. on polymer raise an event (eg. complete)
  2. define a directive linking the event to control function

Directive

/*global define */
define(['angular', './my-module'], function(angular, directives) {
    'use strict';
    directives.directive('polimerBinding', ['$compile', function($compile) {

            return {
                 restrict: 'A',
                scope: { 
                    method:'&polimerBinding'
                },
                link : function(scope, element, attrs) {
                    var el = element[0];
                    var expressionHandler = scope.method();
                    var siemEvent = attrs['polimerEvent'];
                    if (!siemEvent) {
                        siemEvent = 'complete';
                    }
                    el.addEventListener(siemEvent, function (e, options) {
                        expressionHandler(e.detail);
                    })
                }
            };
        }]);
});

Polymer component

<dom-module id="search">

<template>
<h3>Search</h3>
<div class="input-group">

    <textarea placeholder="search by expression (eg. temperature>100)"
        rows="10" cols="100" value="{{text::input}}"></textarea>
    <p>
        <button id="button" class="btn input-group__addon">Search</button>
    </p>
</div>
</template>

 <script>
  Polymer({
    is: 'search',
            properties: {
      text: {
        type: String,
        notify: true
      },

    },
    regularSearch: function(e) {
      console.log(this.range);
      this.fire('complete', {'text': this.text});
    },
    listeners: {
        'button.click': 'regularSearch',
    }
  });
</script>

</dom-module>

Page

 <search id="search" polimer-binding="searchData"
 siem-event="complete" range="{{range}}"></siem-search>

searchData is the control function

$scope.searchData = function(searchObject) {
                    alert('searchData '+ searchObject.text + ' ' + searchObject.range);

}

Efficient way to Handle ResultSet in Java

  1. Iterate over the ResultSet
  2. Create a new Object for each row, to store the fields you need
  3. Add this new object to ArrayList or Hashmap or whatever you fancy
  4. Close the ResultSet, Statement and the DB connection

Done

EDIT: now that you have posted code, I have made a few changes to it.

public List resultSetToArrayList(ResultSet rs) throws SQLException{
  ResultSetMetaData md = rs.getMetaData();
  int columns = md.getColumnCount();
  ArrayList list = new ArrayList(50);
  while (rs.next()){
     HashMap row = new HashMap(columns);
     for(int i=1; i<=columns; ++i){           
      row.put(md.getColumnName(i),rs.getObject(i));
     }
      list.add(row);
  }

 return list;
}

Gulp command not found after install

Not sure why the question was down-voted, but I had the same issue and following the blog post recommended solve the issue. One thing I should add is that in my case, once I ran:

npm config set prefix /usr/local

I confirmed the npm root -g was pointing to /usr/local/lib/node_modules/npm, but in order to install gulp in /usr/local/lib/node_modules, I had to use sudo:

sudo npm install gulp -g

com.google.android.gms:play-services-measurement-base is being requested by various other libraries

I have similar issue which resolved by :

  1. In app level gradle: Update all firebase dependencies to the latest version latest
  2. In project level gradle : update the dependency to the latest: gms.google-services, In my case it was: 'com.google.gms:google-services:4.2.0'

Property 'value' does not exist on type 'EventTarget'

Best way is to use templating => add id to your input and then use it value

<input type="text" #notaryLockup (keyup) = "searchNotary(notaryLockup.value)"placeholder="Entrez des information" >

searchNotary(value: string) {
 // your logic
}

this way you will never have Typescript error when strict verification is activated => See angular Docs

python error: no module named pylab

The error means pylab is not part of the standard Python libraries. You will need to down-load it and install it. I think it's available Here They have installation instructions here

hidden field in php

You absolutely can, I use this approach a lot w/ both JavaScript and PHP.

Field definition:

<input type="hidden" name="foo" value="<?php echo $var;?>" />

Access w/ PHP:

$_GET['foo'] or $_POST['foo']

Also: Don't forget to sanitize your inputs if they are going into a database. Feel free to use my routine: https://github.com/niczak/PHP-Sanitize-Post/blob/master/sanitize.php

Cheers!

JQuery html() vs. innerHTML

To answer your question:

.html() will just call .innerHTML after doing some checks for nodeTypes and stuff. It also uses a try/catch block where it tries to use innerHTML first and if that fails, it'll fallback gracefully to jQuery's .empty() + append()

Extracting jar to specified directory

This worked for me.

I created a folder then changed into the folder using CD option from command prompt.

Then executed the jar from there.

d:\LS\afterchange>jar xvf ..\mywar.war

Changing the width of Bootstrap popover

I also needed a wider popover for a search text field. I came up with this Javascript solution (here in Coffee):

$(".product-search-trigger")
  .click(-> false) # cancel click on <a> tag
  .popover
    container: "body"
    html: true
    placement: "left"
    title: "<strong>Product search</strong> enter number or name"
  .on("show.bs.popover", -> $(this).data("bs.popover").tip().css(maxWidth: "600px"))

The workaround is in the last line. Before the popover is being displayed the max-width option is set to a custom value. You could also add a custom class to the tip element.

Minimal web server using netcat

Try this:

while true ; do nc -l -p 1500 -c 'echo -e "HTTP/1.1 200 OK\n\n $(date)"'; done

The -cmakes netcat execute the given command in a shell, so you can use echo. If you don't need echo, use -e. For further information on this, try man nc. Note, that when using echo there is no way for your program (the date-replacement) to get the browser request. So you probably finally want to do something like this:

while true ; do nc -l -p 1500 -e /path/to/yourprogram ; done

Where yourprogram must do the protocol stuff like handling GET, sending HTTP 200 etc.

The localhost page isn’t working localhost is currently unable to handle this request. HTTP ERROR 500

Such kind of error normally happens when you try using functions like php_info() wrongly.

<?php 
     php_info(); // 500 error
     phpinfo(); // Works correctly
?>

A close look at your code will be better.

SQL comment header examples

I know this post is ancient, but well formatted code never goes out of style.

I use this template for all of my procedures. Some people don't like verbose code and comments, but as someone who frequently has to update stored procedures that haven't been touched since the mid 90s, I can tell you the value of writing well formatted and heavily commented code. Many were written to be as concise as possible, and it can sometimes take days to grasp the intent of a procedure. It's quite easy to see what a block of code is doing by simply reading it, but its far harder (and sometimes impossible) is understanding the intent of the code without proper commenting.

Explain it like you are walking a junior developer through it. Assume the person reading it knows little to nothing about functional area it's addressing and only has a limited understanding of SQL. Why? Many times people have to look at procedures to understand them even when they have no intention of or business modifying them.

/***************************************************************************************************
Procedure:          dbo.usp_DoSomeStuff
Create Date:        2018-01-25
Author:             Joe Expert
Description:        Verbose description of what the query does goes here. Be specific and don't be
                    afraid to say too much. More is better, than less, every single time. Think about
                    "what, when, where, how and why" when authoring a description.
Call by:            [schema.usp_ProcThatCallsThis]
                    [Application Name]
                    [Job]
                    [PLC/Interface]
Affected table(s):  [schema.TableModifiedByProc1]
                    [schema.TableModifiedByProc2]
Used By:            Functional Area this is use in, for example, Payroll, Accounting, Finance
Parameter(s):       @param1 - description and usage
                    @param2 - description and usage
Usage:              EXEC dbo.usp_DoSomeStuff
                        @param1 = 1,
                        @param2 = 3,
                        @param3 = 2
                    Additional notes or caveats about this object, like where is can and cannot be run, or
                    gotchas to watch for when using it.
****************************************************************************************************
SUMMARY OF CHANGES
Date(yyyy-mm-dd)    Author              Comments
------------------- ------------------- ------------------------------------------------------------
2012-04-27          John Usdaworkhur    Move Z <-> X was done in a single step. Warehouse does not
                                        allow this. Converted to two step process.
                                        Z <-> 7 <-> X
                                            1) move class Z to class 7
                                            2) move class 7 to class X

2018-03-22          Maan Widaplan       General formatting and added header information.
2018-03-22          Maan Widaplan       Added logic to automatically Move G <-> H after 12 months.
***************************************************************************************************/

In addition to this header, your code should be well commented and outlined from top to bottom. Add comment blocks to major functional sections like:

/***********************************
**  Process all new Inventory records
**  Verify quantities and mark as
**  available to ship.
************************************/

Add lots of inline comments explaining all criteria except the most basic, and ALWAYS format your code for readability. Long vertical pages of indented code are better than wide short ones and make it far easier to see where code blocks begin and end years later when someone else is supporting your code. Sometimes wide, non-indented code is more readable. If so, use that, but only when necessary.

UPDATE Pallets
SET class_code = 'X'
WHERE
    AND class_code != 'D'
    AND class_code = 'Z' 
    AND historical = 'N'
    AND quantity > 0
    AND GETDATE() > DATEADD(minute, 30, creation_date)
    AND pallet_id IN ( -- Only update pallets that we've created an Adjustment record for
        SELECT Adjust_ID
        FROM Adjustments
        WHERE
            AdjustmentStatus = 0
            AND RecID > @MaxAdjNumber

Edit

I've recently abandoned the banner style comment blocks because it's easy for the top and bottom comments to get separated as code the updated over time. You can end up with logically separate code within comment blocks that say they belong together which create more problems than it solves. I've begun instead surrounding multiple statement sections with BEGIN ... END blocks, and putting my flow comments next to the first line of each statement. This has the benefit of letting you collapse code block and be able to clearly read the high level flow comments, and when you branch one section open you'll be able to do the same with the individual statements within. This also lends itself very well to heavily nested levels of code. It's invaluable when your proc start to creep into the 200-400 line range and doesn't add any line bulk to an already long procedure.

Expanded

enter image description here

Collapsed

enter image description here

Setting and getting localStorage with jQuery

Use setItem and getItem if you want to write simple strings to localStorage. Also you should be using text() if it's the text you're after as you say, else you will get the full HTML as a string.

Sample using .text()

// get the text
var text = $('#test').text();

// set the item in localStorage
localStorage.setItem('test', text);

// alert the value to check if we got it
alert(localStorage.getItem('test'));

JSFiddle: https://jsfiddle.net/f3zLa3zc/


Storing the HTML itself

// get html
var html = $('#test')[0].outerHTML;

// set localstorage
localStorage.setItem('htmltest', html);

// test if it works
alert(localStorage.getItem('htmltest'));

JSFiddle:
https://jsfiddle.net/psfL82q3/1/


Update on user comment

A user want to update the localStorage when the div's content changes. Since it's unclear how the div contents changes (ajax, other method?) contenteditable and blur() is used to change the contents of the div and overwrite the old localStorage entry.

// get the text
var text = $('#test').text();

// set the item in localStorage
localStorage.setItem('test', text);

// bind text to 'blur' event for div
$('#test').on('blur', function() {

    // check the new text
    var newText = $(this).text();

    // overwrite the old text
    localStorage.setItem('test', newText);

    // test if it works
    alert(localStorage.getItem('test'));

});

If we were using ajax we would instead trigger the function it via the function responsible for updating the contents.

JSFiddle:
https://jsfiddle.net/g1b8m1fc/

How to loop through a collection that supports IEnumerable?

Along with the already suggested methods of using a foreach loop, I thought I'd also mention that any object that implements IEnumerable also provides an IEnumerator interface via the GetEnumerator method. Although this method is usually not necessary, this can be used for manually iterating over collections, and is particularly useful when writing your own extension methods for collections.

IEnumerable<T> mySequence;
using (var sequenceEnum = mySequence.GetEnumerator())
{
    while (sequenceEnum.MoveNext())
    {
        // Do something with sequenceEnum.Current.
    }
}

A prime example is when you want to iterate over two sequences concurrently, which is not possible with a foreach loop.

WAMP error: Forbidden You don't have permission to access /phpmyadmin/ on this server

I found that using localhost would not work properly to allow local access from the server. I had to use 127.0.0.1.

In phpmyadmin.conf this did not work:

Deny from all
Allow from localhost

this did work:

Deny from all
Allow from 127.0.0.1

I am using WampServer Version 2.2

Parse (split) a string in C++ using string delimiter (standard C++)

For string delimiter

Split string based on a string delimiter. Such as splitting string "adsf-+qwret-+nvfkbdsj-+orthdfjgh-+dfjrleih" based on string delimiter "-+", output will be {"adsf", "qwret", "nvfkbdsj", "orthdfjgh", "dfjrleih"}

#include <iostream>
#include <sstream>
#include <vector>

using namespace std;

// for string delimiter
vector<string> split (string s, string delimiter) {
    size_t pos_start = 0, pos_end, delim_len = delimiter.length();
    string token;
    vector<string> res;

    while ((pos_end = s.find (delimiter, pos_start)) != string::npos) {
        token = s.substr (pos_start, pos_end - pos_start);
        pos_start = pos_end + delim_len;
        res.push_back (token);
    }

    res.push_back (s.substr (pos_start));
    return res;
}

int main() {
    string str = "adsf-+qwret-+nvfkbdsj-+orthdfjgh-+dfjrleih";
    string delimiter = "-+";
    vector<string> v = split (str, delimiter);

    for (auto i : v) cout << i << endl;

    return 0;
}


Output

adsf
qwret
nvfkbdsj
orthdfjgh
dfjrleih




For single character delimiter

Split string based on a character delimiter. Such as splitting string "adsf+qwer+poui+fdgh" with delimiter "+" will output {"adsf", "qwer", "poui", "fdg"h}

#include <iostream>
#include <sstream>
#include <vector>

using namespace std;

vector<string> split (const string &s, char delim) {
    vector<string> result;
    stringstream ss (s);
    string item;

    while (getline (ss, item, delim)) {
        result.push_back (item);
    }

    return result;
}

int main() {
    string str = "adsf+qwer+poui+fdgh";
    vector<string> v = split (str, '+');

    for (auto i : v) cout << i << endl;

    return 0;
}


Output

adsf
qwer
poui
fdgh

Save PHP array to MySQL?

You can save your array as a json.
there is documentation for json data type: https://dev.mysql.com/doc/refman/5.7/en/json.html
I think this is the best solution, and will help you maintain your code more readable by avoiding crazy functions.
I expect this is helpful for you.

Assembly code vs Machine code vs Object code?

Source code, Assembly code, Machine code, Object code, Byte code, Executable file and Library file.

All these terms are often very confusing for most people for the fact that they think they are mutually exclusive. See the diagram to understand their relations. The description of each term is given below.


Types of code


Source code

Instructions in human readable (programming) language


High-level code

Instructions written in a high level (programming) language
e.g., C, C++ and Java programs


Assembly code

Instructions written in an assembly language (kind of low-level programming language). As the first step of the compilation process, high-level code is converted into this form. It is the assembly code which is then being converted into actual machine code. On most systems, these two steps are performed automatically as a part of the compilation process.
e.g., program.asm


Object code

The product of a compilation process. It may be in the form of machine code or byte code.
e.g., file.o


Machine code

Instructions in machine language.
e.g., a.out


Byte code

Instruction in an intermediate form which can be executed by an interpreter such as JVM.
e.g., Java class file


Executable file

The product of linking proccess. They are machine code which can be directly executed by the CPU.
e.g., an .exe file.

Note that in some contexts a file containing byte-code or scripting language instructions may also be considered executable.


Library file

Some code is compiled into this form for different reasons such as re-usability and later used by executable files.

Could not autowire field:RestTemplate in Spring boot application

Depending on what technologies you're using and what versions will influence how you define a RestTemplate in your @Configuration class.

Spring >= 4 without Spring Boot

Simply define an @Bean:

@Bean
public RestTemplate restTemplate() {
    return new RestTemplate();
}

Spring Boot <= 1.3

No need to define one, Spring Boot automatically defines one for you.

Spring Boot >= 1.4

Spring Boot no longer automatically defines a RestTemplate but instead defines a RestTemplateBuilder allowing you more control over the RestTemplate that gets created. You can inject the RestTemplateBuilder as an argument in your @Bean method to create a RestTemplate:

@Bean
public RestTemplate restTemplate(RestTemplateBuilder builder) {
   // Do any additional configuration here
   return builder.build();
}

Using it in your class

@Autowired
private RestTemplate restTemplate;

Reference

C++ Returning reference to local variable

This code snippet:

int& func1()
{
    int i;
    i = 1;
    return i;
}

will not work because you're returning an alias (a reference) to an object with a lifetime limited to the scope of the function call. That means once func1() returns, int i dies, making the reference returned from the function worthless because it now refers to an object that doesn't exist.

int main()
{
    int& p = func1();
    /* p is garbage */
}

The second version does work because the variable is allocated on the free store, which is not bound to the lifetime of the function call. However, you are responsible for deleteing the allocated int.

int* func2()
{
    int* p;
    p = new int;
    *p = 1;
    return p;
}

int main()
{
    int* p = func2();
    /* pointee still exists */
    delete p; // get rid of it
}

Typically you would wrap the pointer in some RAII class and/or a factory function so you don't have to delete it yourself.

In either case, you can just return the value itself (although I realize the example you provided was probably contrived):

int func3()
{
    return 1;
}

int main()
{
    int v = func3();
    // do whatever you want with the returned value
}

Note that it's perfectly fine to return big objects the same way func3() returns primitive values because just about every compiler nowadays implements some form of return value optimization:

class big_object 
{ 
public:
    big_object(/* constructor arguments */);
    ~big_object();
    big_object(const big_object& rhs);
    big_object& operator=(const big_object& rhs);
    /* public methods */
private:
    /* data members */
};

big_object func4()
{
    return big_object(/* constructor arguments */);
}

int main()
{
     // no copy is actually made, if your compiler supports RVO
    big_object o = func4();    
}

Interestingly, binding a temporary to a const reference is perfectly legal C++.

int main()
{
    // This works! The returned temporary will last as long as the reference exists
    const big_object& o = func4();    
    // This does *not* work! It's not legal C++ because reference is not const.
    // big_object& o = func4();  
}

Why do I get a "permission denied" error while installing a gem?

After setting the gems directory to the user directory that runs the gem install, using export GEM_HOME=/home/<user>/gems, the issue has been solved.

Purpose of a constructor in Java?

A constructor initializes an object when it is created . It has the same name as its class and is syntactically similar to a method , but constructor have no expicit return type.Typically , we use constructor to give initial value to the instance variables defined by the class , or to perform any other startup procedures required to make a fully formed object.

Here is an example of constructor:

class queen(){
   int beauty;

   queen(){ 
     beauty = 98;
   }
 }


class constructor demo{
    public static void main(String[] args){
       queen arth = new queen();
       queen y = new queen();

       System.out.println(arth.beauty+" "+y.beauty);

    }
} 

output is:

98 98

Here the construcor is :

queen(){
beauty =98;
}

Now the turn of parameterized constructor.

  class queen(){
   int beauty;

   queen(int x){ 
     beauty = x;
   }
 }


class constructor demo{
    public static void main(String[] args){
       queen arth = new queen(100);
       queen y = new queen(98);

       System.out.println(arth.beauty+" "+y.beauty);

    }
} 

output is:

100 98

Mailbox unavailable. The server response was: 5.7.1 Unable to relay for [email protected]

I was facing the identical problem and followed the (very clearly spelled out) steps in Vinod's reply, however this then created a different error:

Unable to read data from the transport connection: net_io_connectionclosed

I did a bit more digging and poking around and (while I'm not sure why this worked) I solved it by:
- Going back into IIS6.0 management console
- Open SMTP Virtual Server properties
- On General tab, changing the 'IP Address:' setting back to '(All Unassigned)'

Not sure why this works, but hopefully will help out someone facing the same problem in the future.

Best way to check for null values in Java?

Your last proposal is the best.

if (foo != null && foo.bar()) {
    etc...
}

Because:

  1. It is easier to read.
  2. It is safe : foo.bar() will never be executed if foo == null.
  3. It prevents from bad practice such as catching NullPointerExceptions (most of the time due to a bug in your code)
  4. It should execute as fast or even faster than other methods (even though I think it should be almost impossible to notice it).

How to set the action for a UIBarButtonItem in Swift

Swift 5 & iOS 13+ Programmatic Example

  1. You must mark your function with @objc, see below example!
  2. No parenthesis following after the function name! Just use #selector(name).
  3. private or public doesn't matter; you can use private.

Code Example

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
    
    let menuButtonImage = UIImage(systemName: "flame")
    let menuButton = UIBarButtonItem(image: menuButtonImage, style: .plain, target: self, action: #selector(didTapMenuButton))
    navigationItem.rightBarButtonItem = menuButton
}

@objc public func didTapMenuButton() {
    print("Hello World")
}

Cell spacing in UICollectionView

I have a horizontal UICollectionView and subclassed UICollectionViewFlowLayout. The collection view has large cells, and only shows one row of them at a time, and the collection view fits the width of the screen.

I tried iago849's answer and it worked, but then I found out I didn't even need his answer. For some reason, setting the minimumInterItemSpacing does nothing. The spacing between my items/cells can be entirely controlled by minimumLineSpacing.

Not sure why it works this way, but it works.

Suppress output of a function

Use the capture.output() function. It works very much like a one-off sink() and unlike invisible(), it can suppress more than just print messages. Set the file argument to /dev/null on UNIX or NUL on windows. For example, considering Dirk's note:

> invisible(cat("Hi\n"))
Hi

> capture.output( cat("Hi\n"), file='NUL')
> 

Does swift have a trim method on String?

Swift 3

let result = " abc ".trimmingCharacters(in: .whitespacesAndNewlines)

jQuery to serialize only elements within a div

$('#divId > input, #divId > select, #divId > textarea').serialize();

Apache Cordova - uninstall globally

Try sudo npm uninstall cordova -g to uninstall it globally and then just npm install cordova without the -g flag after cding to the local app directory

C++11 reverse range-based for-loop

Does this work for you:

#include <iostream>
#include <list>
#include <boost/range/begin.hpp>
#include <boost/range/end.hpp>
#include <boost/range/iterator_range.hpp>

int main(int argc, char* argv[]){

  typedef std::list<int> Nums;
  typedef Nums::iterator NumIt;
  typedef boost::range_reverse_iterator<Nums>::type RevNumIt;
  typedef boost::iterator_range<NumIt> irange_1;
  typedef boost::iterator_range<RevNumIt> irange_2;

  Nums n = {1, 2, 3, 4, 5, 6, 7, 8};
  irange_1 r1 = boost::make_iterator_range( boost::begin(n), boost::end(n) );
  irange_2 r2 = boost::make_iterator_range( boost::end(n), boost::begin(n) );


  // prints: 1 2 3 4 5 6 7 8 
  for(auto e : r1)
    std::cout << e << ' ';

  std::cout << std::endl;

  // prints: 8 7 6 5 4 3 2 1
  for(auto e : r2)
    std::cout << e << ' ';

  std::cout << std::endl;

  return 0;
}

How to count items in JSON object using command line?

The shortest expression is

curl 'http://…' | jq length

Pandas (python): How to add column to dataframe for index?

How about this:

from pandas import *

idx = Int64Index([171, 174, 173])
df = DataFrame(index = idx, data =([1,2,3]))
print df

It gives me:

     0
171  1
174  2
173  3

Is this what you are looking for?

How can I run a directive after the dom has finished rendering?

Here is how I do it:

app.directive('example', function() {

    return function(scope, element, attrs) {
        angular.element(document).ready(function() {
                //MANIPULATE THE DOM
        });
    };

});

Drawing a line/path on Google Maps

It is really easy with Google Maps Android API v2

Just copy the example from Developer documentation

(of course you have to init your map first)

GoogleMap map;
 // ... get a map.
 // Add a thin red line from London to New York.
 Polyline line = map.addPolyline(new PolylineOptions()
     .add(new LatLng(51.5, -0.1), new LatLng(40.7, -74.0))
     .width(5)
     .color(Color.RED));

Avoiding NullPointerException in Java

You can use an interceptor before the method call. That is what aspect-oriented programming focus on.

Suppose M1(Object test) is a method and M2 is a method where we apply an aspect before a method call, M2(Object test2). If test2 != null then call M1, otherwise do another thing. It works for all methods with whom you want to apply an aspect for. If you want to apply an aspect for an instance field and constructor you can use AspectJ. Spring can also be the best choice for a method aspect.

Swift programmatically navigate to another view controller/scene

You should push the new viewcontroller by using current navigation controller, not present.

self.navigationController.pushViewController(nextViewController, animated: true)

Why use @PostConstruct?

The main problem is that:

in a constructor, the injection of the dependencies has not yet occurred*

*obviously excluding Constructor Injection


Real-world example:

public class Foo {

    @Inject
    Logger LOG;

    @PostConstruct
    public void fooInit(){
        LOG.info("This will be printed; LOG has already been injected");
    }

    public Foo() {
        LOG.info("This will NOT be printed, LOG is still null");
        // NullPointerException will be thrown here
    }
}

IMPORTANT: @PostConstruct and @PreDestroy have been completely removed in Java 11.

To keep using them, you'll need to add the javax.annotation-api JAR to your dependencies.

Maven

<!-- https://mvnrepository.com/artifact/javax.annotation/javax.annotation-api -->
<dependency>
    <groupId>javax.annotation</groupId>
    <artifactId>javax.annotation-api</artifactId>
    <version>1.3.2</version>
</dependency>

Gradle

// https://mvnrepository.com/artifact/javax.annotation/javax.annotation-api
compile group: 'javax.annotation', name: 'javax.annotation-api', version: '1.3.2'

C# Lambda expressions: Why should I use them?

Anonymous functions and expressions are useful for one-off methods that don't benefit from the extra work required to create a full method.

Consider this example:

 List<string> people = new List<string> { "name1", "name2", "joe", "another name", "etc" };
 string person = people.Find(person => person.Contains("Joe"));

versus

 public string FindPerson(string nameContains, List<string> persons)
 {
     foreach (string person in persons)
         if (person.Contains(nameContains))
             return person;
     return null;
 }

These are functionally equivalent.

How to use support FileProvider for sharing content to other apps?

Fully working code sample how to share file from inner app folder. Tested on Android 7 and Android 5.

AndroidManifest.xml

</application>
   ....
    <provider
        android:name="androidx.core.content.FileProvider"
        android:authorities="android.getqardio.com.gmslocationtest"
        android:exported="false"
        android:grantUriPermissions="true">
        <meta-data
            android:name="android.support.FILE_PROVIDER_PATHS"
            android:resource="@xml/provider_paths"/>
    </provider>
</application>

xml/provider_paths

<?xml version="1.0" encoding="utf-8"?>
<paths>
    <files-path
        name="share"
        path="external_files"/>
</paths>

Code itself

    File imagePath = new File(getFilesDir(), "external_files");
    imagePath.mkdir();
    File imageFile = new File(imagePath.getPath(), "test.jpg");

    // Write data in your file

    Uri uri = FileProvider.getUriForFile(this, getPackageName(), imageFile);

    Intent intent = ShareCompat.IntentBuilder.from(this)
                .setStream(uri) // uri from FileProvider
                .setType("text/html")
                .getIntent()
                .setAction(Intent.ACTION_VIEW) //Change if needed
                .setDataAndType(uri, "image/*")
                .addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);

   startActivity(intent);

Authentication failed because remote party has closed the transport stream

If you want to use an older version of .net, create your own flag and cast it.

    //
    // Summary:
    //     Specifies the security protocols that are supported by the Schannel security
    //     package.
    [Flags]
    private enum MySecurityProtocolType
    {
        //
        // Summary:
        //     Specifies the Secure Socket Layer (SSL) 3.0 security protocol.
        Ssl3 = 48,
        //
        // Summary:
        //     Specifies the Transport Layer Security (TLS) 1.0 security protocol.
        Tls = 192,
        //
        // Summary:
        //     Specifies the Transport Layer Security (TLS) 1.1 security protocol.
        Tls11 = 768,
        //
        // Summary:
        //     Specifies the Transport Layer Security (TLS) 1.2 security protocol.
        Tls12 = 3072
    }
    public Session()
    {
        System.Net.ServicePointManager.SecurityProtocol = (SecurityProtocolType)(MySecurityProtocolType.Tls12 | MySecurityProtocolType.Tls11 | MySecurityProtocolType.Tls);
    }

How can I permanently enable line numbers in IntelliJ?

IntelliJ 14.X Onwards

From version 14.0 onwards, the path to the setting dialog is slightly different, a General submenu has been added between Editor and Appearance as shown below

enter image description here

IntelliJ 8.1.2 - 13.X

From IntelliJ 8.1.2 onwards, this option is in File | Settings1. Within the IDE Settings section of that dialog, you'll find it under Editor | Appearance.

  1. On a Mac, these are named IntelliJ IDEA | Preferences...

enter image description here

Round integers to the nearest 10

About the round(..) function returning a float

That float (double-precision in Python) is always a perfect representation of an integer, as long as it's in the range [-253..253]. (Pedants pay attention: it's not two's complement in doubles, so the range is symmetric about zero.)

See the discussion here for details.

How can I know if a process is running?

Despite of supported API from .Net frameworks regarding checking existing process by process ID, those functions are very slow. It costs a huge amount of CPU cycles to run Process.GetProcesses() or Process.GetProcessById/Name().

A much quicker method to check a running process by ID is to use native API OpenProcess(). If return handle is 0, the process doesn't exist. If handle is different than 0, the process is running. There's no guarantee this method would work 100% at all time due to permission.

using lodash .groupBy. how to add your own keys for grouped output?

Isn't it this simple?

var result = _(data)
            .groupBy(x => x.color)
            .map((value, key) => ({color: key, users: value}))
            .value();

Converting an integer to a string in PHP

$foo = 5;

$foo = $foo . "";

Now $foo is a string.

But, you may want to get used to casting. As casting is the proper way to accomplish something of that sort:

$foo = 5;
$foo = (string)$foo;

Another way is to encapsulate in quotes:

$foo = 5;
$foo = "$foo"

Override valueof() and toString() in Java enum

You can use a static Map in your enum that maps Strings to enum constants. Use it in a 'getEnum' static method. This skips the need to iterate through the enums each time you want to get one from its String value.

public enum RandomEnum {

    StartHere("Start Here"),
    StopHere("Stop Here");

    private final String strVal;
    private RandomEnum(String strVal) {
        this.strVal = strVal;
    }

    public static RandomEnum getEnum(String strVal) {
        if(!strValMap.containsKey(strVal)) {
            throw new IllegalArgumentException("Unknown String Value: " + strVal);
        }
        return strValMap.get(strVal);
    }

    private static final Map<String, RandomEnum> strValMap;
    static {
        final Map<String, RandomEnum> tmpMap = Maps.newHashMap();
        for(final RandomEnum en : RandomEnum.values()) {
            tmpMap.put(en.strVal, en);
        }
        strValMap = ImmutableMap.copyOf(tmpMap);
    }

    @Override
    public String toString() {
        return strVal;
    }
}

Just make sure the static initialization of the map occurs below the declaration of the enum constants.

BTW - that 'ImmutableMap' type is from the Google guava API, and I definitely recommend it in cases like this.


EDIT - Per the comments:

  1. This solution assumes that each assigned string value is unique and non-null. Given that the creator of the enum can control this, and that the string corresponds to the unique & non-null enum value, this seems like a safe restriction.
  2. I added the 'toSTring()' method as asked for in the question

Format numbers in django templates

Based on muhuk answer I did this simple tag encapsulating python string.format method.

  • Create a templatetags at your's application folder.
  • Create a format.py file on it.
  • Add this to it:

    from django import template
    
    register = template.Library()
    
    @register.filter(name='format')
    def format(value, fmt):
        return fmt.format(value)
    
  • Load it in your template {% load format %}
  • Use it. {{ some_value|format:"{:0.2f}" }}

Do I need to convert .CER to .CRT for Apache SSL certificates? If so, how?

The answer to the question how to convert a .cer file into a .crt file (they are encoded differently!) is:

openssl pkcs7 -print_certs -in certificate.cer -out certificate.crt

How can I create a two dimensional array in JavaScript?

This is mentioned in a few of the comments, but using Array.fill() will help construct a 2-d array:

function create2dArr(x,y) {
    var arr = [];
    for(var i = 0; i < y; i++) {
        arr.push(Array(x).fill(0));
    }
    return arr; 
}

this will result in an array of length x, y times in the returned array.

how to change onclick event with jquery?

You can easily change the onclick event of an element with jQuery without running the new function with:

$("#id").attr("onclick","new_function_name()");

By writing this line you actually change the onclick attribute of #id.

You can also use:

document.getElementById("id").attribute("onclick","new_function_name()");

Is "else if" faster than "switch() case"?

Far more important than the performance benefits of switch (which are relatively slight, but worth noting) are the readability issues.

I for one find a switch statement extremely clear in intent and pure whitespace, compared to chains of ifs.

Saving a select count(*) value to an integer (SQL Server)

[update] -- Well, my own foolishness provides the answer to this one. As it turns out, I was deleting the records from myTable before running the select COUNT statement.

How did I do that and not notice? Glad you asked. I've been testing a sql unit testing platform (tsqlunit, if you're interested) and as part of one of the tests I ran a truncate table statement, then the above. After the unit test is over everything is rolled back, and records are back in myTable. That's why I got a record count outside of my tests.

Sorry everyone...thanks for your help.

How to check if a Unix .tar.gz file is a valid file without uncompressing?

I have tried the following command and they work well.

bzip2 -t file.bz2
gunzip -t file.gz

However, we can found these two command are time-consuming. Maybe we need some more quick way to determine the intact of the compress files.

AltGr key not working, instead I have to use Ctrl+AltGr

I found a solution for my problem while writing my question !

Going into my remote session i tried two key combinations, and it solved the problem on my Desktop : Alt+Enter and Ctrl+Enter (i don't know which one solved the problem though)

I tried to reproduce the problem, but i couldn't... but i'm almost sure it's one of the key combinations described in the question above (since i experienced this problem several times)

So it seems the problem comes from the use of RDP (windows7 and 8)

Update 2017: Problem occurs on Windows 10 aswell.

How do I combine 2 select statements into one?

The Union command is what you need. If that doesn't work, you may need to refine what environment you are in.

Setting SMTP details for php mail () function

Check out your php.ini, you can set these values there.

Here's the description in the php manual: http://php.net/manual/en/mail.configuration.php

If you want to use several different SMTP servers in your application, I recommend using a "bigger" mailing framework, p.e. Swiftmailer

Cannot load properties file from resources directory

If it is simple application then getSystemResourceAsStream can also be used.

try (InputStream inputStream = ClassLoader.getSystemResourceAsStream("config.properties"))..

Matplotlib 2 Subplots, 1 Colorbar

As a beginner who stumbled across this thread, I'd like to add a python-for-dummies adaptation of abevieiramota's very neat answer (because I'm at the level that I had to look up 'ravel' to work out what their code was doing):

import numpy as np
import matplotlib.pyplot as plt

fig, ((ax1,ax2,ax3),(ax4,ax5,ax6)) = plt.subplots(2,3)

axlist = [ax1,ax2,ax3,ax4,ax5,ax6]

first = ax1.imshow(np.random.random((10,10)), vmin=0, vmax=1)
third = ax3.imshow(np.random.random((12,12)), vmin=0, vmax=1)

fig.colorbar(first, ax=axlist)

plt.show()

Much less pythonic, much easier for noobs like me to see what's actually happening here.

Context.startForegroundService() did not then call Service.startForeground()

So many answer but none worked in my case.

I have started service like this.

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
    startForegroundService(intent);
} else {
    startService(intent);
}

And in my service in onStartCommand

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
        Notification.Builder builder = new Notification.Builder(this, ANDROID_CHANNEL_ID)
                .setContentTitle(getString(R.string.app_name))
                .setContentText("SmartTracker Running")
                .setAutoCancel(true);
        Notification notification = builder.build();
        startForeground(NOTIFICATION_ID, notification);
    } else {
        NotificationCompat.Builder builder = new NotificationCompat.Builder(this)
                .setContentTitle(getString(R.string.app_name))
                .setContentText("SmartTracker is Running...")
                .setPriority(NotificationCompat.PRIORITY_DEFAULT)
                .setAutoCancel(true);
        Notification notification = builder.build();
        startForeground(NOTIFICATION_ID, notification);
    }

And don't forgot to set NOTIFICATION_ID non zero

private static final String ANDROID_CHANNEL_ID = "com.xxxx.Location.Channel";
private static final int NOTIFICATION_ID = 555;

SO everything was perfect but still crashing on 8.1 so cause was as below.

     if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            stopForeground(true);
        } else {
            stopForeground(true);
        }

I have called stop foreground with remove notificaton but once notification removed service become background and background service can not run in android O from background. started after push received.

So magical word is

   stopSelf();

So far so any reason your service is crashing follow all above steps and enjoy.

How do I create a comma-separated list using a SQL query?

Using COALESCE to Build Comma-Delimited String in SQL Server
http://www.sqlteam.com/article/using-coalesce-to-build-comma-delimited-string

Example:

DECLARE @EmployeeList varchar(100)

SELECT @EmployeeList = COALESCE(@EmployeeList + ', ', '') + 
   CAST(Emp_UniqueID AS varchar(5))
FROM SalesCallsEmployees
WHERE SalCal_UniqueID = 1

SELECT @EmployeeList

Android set bitmap to Imageview

this code works with me

 ImageView carView = (ImageView) v.findViewById(R.id.car_icon);

                            byte[] decodedString = Base64.decode(picture, Base64.NO_WRAP);
                            InputStream input=new ByteArrayInputStream(decodedString);
                            Bitmap ext_pic = BitmapFactory.decodeStream(input);
                            carView.setImageBitmap(ext_pic);

is it possible to add colors to python output?

being overwhelmed by being VERY NEW to python i missed some very simple and useful commands given here: Print in terminal with colors using Python? -

eventually decided to use CLINT as an answer that was given there by great and smart people

Android load from URL to Bitmap

Use Kotlin Coroutines to Handle Threading

The reason the code is crashing is because the Bitmap is attempting to be created on the Main Thread which is not allowed since it may cause Android Not Responding (ANR) errors.

Concepts Used

  • Kotlin Coroutines notes.
  • The Loading, Content, Error (LCE) pattern is used below. If interested you can learn more about it in this talk and video.
  • LiveData is used to return the data. I've compiled my favorite LiveData resource in these notes.
  • In the bonus code, toBitmap() is a Kotlin extension function requiring that library to be added to the app dependencies.

Implementation

Code

1. Create Bitmap in a different thread then the Main Thread.

In this sample using Kotlin Coroutines the function is being executed in the Dispatchers.IO thread which is meant for CPU based operations. The function is prefixed with suspend which is a Coroutine syntax.

Bonus - After the Bitmap is created it is also compressed into an ByteArray so it can be passed via an Intent later outlined in this full sample.

Repository.kt

suspend fun bitmapToByteArray(url: String) = withContext(Dispatchers.IO) {
    MutableLiveData<Lce<ContentResult.ContentBitmap>>().apply {
        postValue(Lce.Loading())
        postValue(Lce.Content(ContentResult.ContentBitmap(
            ByteArrayOutputStream().apply {
                try {                     
                    BitmapFactory.decodeStream(URL(url).openConnection().apply {
                        doInput = true
                        connect()
                    }.getInputStream())
                } catch (e: IOException) {
                   postValue(Lce.Error(ContentResult.ContentBitmap(ByteArray(0), "bitmapToByteArray error or null - ${e.localizedMessage}")))
                   null
                }?.compress(CompressFormat.JPEG, BITMAP_COMPRESSION_QUALITY, this)
           }.toByteArray(), "")))
        }
    }

ViewModel.kt

//Calls bitmapToByteArray from the Repository
private fun bitmapToByteArray(url: String) = liveData {
    emitSource(switchMap(repository.bitmapToByteArray(url)) { lce ->
        when (lce) {
            is Lce.Loading -> liveData {}
            is Lce.Content -> liveData {
                emit(Event(ContentResult.ContentBitmap(lce.packet.image, lce.packet.errorMessage)))
            }
            is Lce.Error -> liveData {
                Crashlytics.log(Log.WARN, LOG_TAG,
                        "bitmapToByteArray error or null - ${lce.packet.errorMessage}")
            }
        }
    })
}

Bonus - Convert ByteArray back to Bitmap.

Utils.kt

fun ByteArray.byteArrayToBitmap(context: Context) =
    run {
        BitmapFactory.decodeByteArray(this, BITMAP_OFFSET, size).run {
            if (this != null) this
            // In case the Bitmap loaded was empty or there is an error I have a default Bitmap to return.
            else AppCompatResources.getDrawable(context, ic_coinverse_48dp)?.toBitmap()
        }
    }

Equal height rows in a flex container

You can accomplish that now with display: grid:

_x000D_
_x000D_
.list {_x000D_
  display: grid;_x000D_
  overflow: hidden;_x000D_
  grid-template-columns: repeat(3, 1fr);_x000D_
  grid-auto-rows: 1fr;_x000D_
  grid-column-gap: 5px;_x000D_
  grid-row-gap: 5px;_x000D_
  max-width: 500px;_x000D_
}_x000D_
.list-item {_x000D_
  background-color: #ccc;_x000D_
  display: flex;_x000D_
  padding: 0.5em;_x000D_
  margin-bottom: 20px;_x000D_
}_x000D_
.list-content {_x000D_
  width: 100%;_x000D_
}
_x000D_
<ul class="list">_x000D_
  <li class="list-item">_x000D_
    <div class="list-content">_x000D_
      <h2>box 1</h2>_x000D_
      <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit.</p>_x000D_
    </div>_x000D_
  </li>_x000D_
  <li class="list-item">_x000D_
    <div class="list-content">_x000D_
      <h3>box 2</h3>_x000D_
      <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit.</p>_x000D_
    </div>_x000D_
  </li>_x000D_
_x000D_
  <li class="list-item">_x000D_
    <div class="list-content">_x000D_
      <h3>box 2</h3>_x000D_
      <p>Lorem ipsum dolor</p>_x000D_
    </div>_x000D_
  </li>_x000D_
_x000D_
  <li class="list-item">_x000D_
    <div class="list-content">_x000D_
      <h3>box 2</h3>_x000D_
      <p>Lorem ipsum dolor</p>_x000D_
    </div>_x000D_
  </li>_x000D_
  <li class="list-item">_x000D_
    <div class="list-content">_x000D_
      <h1>h1</h1>_x000D_
    </div>_x000D_
  </li>_x000D_
</ul>
_x000D_
_x000D_
_x000D_

Although the grid itself is not flexbox, it behaves very similar to a flexbox container, and the items inside the grid can be flex.

The grid layout is also very handy in the case you want responsive grids. That is, if you want the grid to have a different number of columns per row you can then just change grid-template-columns:

grid-template-columns: repeat(1, 1fr); // 1 column
grid-template-columns: repeat(2, 1fr); // 2 columns
grid-template-columns: repeat(3, 1fr); // 3 columns

and so on...

You can mix it with media queries and change according to the size of the page.

Sadly there is still no support for container queries / element queries in the browsers (out of the box) to make it work well with changing the number of columns according to the container size, not to the page size (this would be great to use with reusable webcomponents).

More information about the grid layout:

https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_Grid_Layout

Support of the Grid Layout accross browsers:

https://caniuse.com/#feat=css-grid

Color text in discord

Discord doesn't allow colored text. Though, currently, you have two options to "mimic" colored text.

Option #1 (Markdown code-blocks)

Discord supports Markdown and uses highlight.js to highlight code-blocks. Some programming languages have specific color outputs from highlight.js and can be used to mimic colored output.

To use code-blocks, send a normal message in this format (Which follows Markdown's standard format).

```language
message
```

Languages that currently reproduce nice colors: prolog (red/orange), css (yellow).

Option #2 (Embeds)

Discord now supports Embeds and Webhooks, which can be used to display colored blocks, they also support markdown. For documentation on how to use Embeds, please read your lib's documentation.

(Embed Cheat-sheet)
Embed Cheat-sheet

Updating records codeigniter

In your Controller

public function updtitle() 
{   
    $data = array(
        'table_name' => 'your_table_name_to_update', // pass the real table name
        'id' => $this->input->post('id'),
        'title' => $this->input->post('title')
    );

    $this->load->model('Updmodel'); // load the model first
    if($this->Updmodel->upddata($data)) // call the method from the model
    {
        // update successful
    }
    else
    {
        // update not successful
    }

}

In Your Model

public function upddata($data) {
    extract($data);
    $this->db->where('emp_no', $id);
    $this->db->update($table_name, array('title' => $title));
    return true;
}

The active record query is similar to

"update $table_name set title='$title' where emp_no=$id"

How can I match multiple occurrences with a regex in JavaScript similar to PHP's preg_match_all()?

To capture several parameters using the same name, I modified the while loop in Tomalak's method like this:

  while (match = re.exec(url)) {
    var pName = decode(match[1]);
    var pValue = decode(match[2]);
    params[pName] ? params[pName].push(pValue) : params[pName] = [pValue];
  }

input: ?firstname=george&lastname=bush&firstname=bill&lastname=clinton

returns: {firstname : ["george", "bill"], lastname : ["bush", "clinton"]}

How to replace case-insensitive literal substrings in Java

String target = "FOOBar";
target = target.replaceAll("(?i)foo", "");
System.out.println(target);

Output:

Bar

It's worth mentioning that replaceAll treats the first argument as a regex pattern, which can cause unexpected results. To solve this, also use Pattern.quote as suggested in the comments.

Make EditText ReadOnly

As android:editable="" is deprecated,

Setting

  • android:clickable="false"
  • android:focusable="false"
  • android:inputType="none"
  • android:cursorVisible="false"

will make it "read-only".

However, users will still be able to paste into the field or perform any other long click actions. To disable this, simply override onLongClickListener().
In Kotlin:

  • myEditText.setOnLongClickListener { true }

suffices.

Getting Gradle dependencies in IntelliJ IDEA using Gradle build

Andrey's above post is still valid for the latest version of Intellij as of 3rd Quarter of 2017. So use it. 'Cause, build project, and external command line gradle build, does NOT add it to the external dependencies in Intellij...crazy as that sounds it is true. Only difference now is that the UI looks different to the above, but still the same icon for updating is used. I am only putting an answer here, cause I cannot paste a snapshot of the new UI...I dont want any up votes per se. Andrey still gave the correct answer above: enter image description here

How to add jQuery in JS file

var jQueryScript = document.createElement('script');  
jQueryScript.setAttribute('src','https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js');
document.head.appendChild(jQueryScript);

Concatenate a list of pandas dataframes together

If the dataframes DO NOT all have the same columns try the following:

df = pd.DataFrame.from_dict(map(dict,df_list))

What is a classpath and how do I set it?

CLASSPATH is an environment variable (i.e., global variables of the operating system available to all the processes) needed for the Java compiler and runtime to locate the Java packages used in a Java program. (Why not call PACKAGEPATH?) This is similar to another environment variable PATH, which is used by the CMD shell to find the executable programs.

CLASSPATH can be set in one of the following ways:

CLASSPATH can be set permanently in the environment: In Windows, choose control panel ? System ? Advanced ? Environment Variables ? choose "System Variables" (for all the users) or "User Variables" (only the currently login user) ? choose "Edit" (if CLASSPATH already exists) or "New" ? Enter "CLASSPATH" as the variable name ? Enter the required directories and JAR files (separated by semicolons) as the value (e.g., ".;c:\javaproject\classes;d:\tomcat\lib\servlet-api.jar"). Take note that you need to include the current working directory (denoted by '.') in the CLASSPATH.

To check the current setting of the CLASSPATH, issue the following command:

> SET CLASSPATH

CLASSPATH can be set temporarily for that particular CMD shell session by issuing the following command:

> SET CLASSPATH=.;c:\javaproject\classes;d:\tomcat\lib\servlet-api.jar

Instead of using the CLASSPATH environment variable, you can also use the command-line option -classpath or -cp of the javac and java commands, for example,

> java –classpath c:\javaproject\classes com.abc.project1.subproject2.MyClass3

How can I convert a char to int in Java?

If you want to get the ASCII value of a character, or just convert it into an int, you need to cast from a char to an int.

What's casting? Casting is when we explicitly convert from one primitve data type, or a class, to another. Here's a brief example.

public class char_to_int
{
  public static void main(String args[])
  {
       char myChar = 'a';
       int  i = (int) myChar; // cast from a char to an int
       System.out.println ("ASCII value - " + i);
  }

In this example, we have a character ('a'), and we cast it to an integer. Printing this integer out will give us the ASCII value of 'a'.

SQL RANK() over PARTITION on joined tables

SELECT a.C_ID,a.QRY_ID,a.RES_ID,b.SCORE,ROW_NUMBER() OVER (ORDER BY SCORE DESC) AS [RANK]
FROM CONTACTS a JOIN RSLTS b ON a.QRY_ID=b.QRY_ID AND a.RES_ID=b.RES_ID
ORDER BY a.C_ID

How to run shell script on host from docker container?

The solution I use is to connect to the host over SSH and execute the command like this:

ssh -l ${USERNAME} ${HOSTNAME} "${SCRIPT}"

UPDATE

As this answer keeps getting up votes, I would like to remind (and highly recommend), that the account which is being used to invoke the script should be an account with no permissions at all, but only executing that script as sudo (that can be done from sudoers file).

Write in body request with HttpClient

If your xml is written by java.lang.String you can just using HttpClient in this way

    public void post() throws Exception{
        HttpClient client = new DefaultHttpClient();
        HttpPost post = new HttpPost("http://www.baidu.com");
        String xml = "<xml>xxxx</xml>";
        HttpEntity entity = new ByteArrayEntity(xml.getBytes("UTF-8"));
        post.setEntity(entity);
        HttpResponse response = client.execute(post);
        String result = EntityUtils.toString(response.getEntity());
    }

pay attention to the Exceptions.

BTW, the example is written by the httpclient version 4.x

Is it a bad practice to use break in a for loop?

No, break is the correct solution.

Adding a boolean variable makes the code harder to read and adds a potential source of errors.

Does Python have a package/module management system?

Recent progress

March 2014: Good news! Python 3.4 ships with Pip. Pip has long been Python's de-facto standard package manager. You can install a package like this:

pip install httpie

Wahey! This is the best feature of any Python release. It makes the community's wealth of libraries accessible to everyone. Newbies are no longer excluded from using community libraries by the prohibitive difficulty of setup.

However, there remains a number of outstanding frustrations with the Python packaging experience. Cumulatively, they make Python very unwelcoming for newbies. Also, the long history of neglect (ie. not shipping with a package manager for 14 years from Python 2.0 to Python 3.3) did damage to the community. I describe both below.

Outstanding frustrations

It's important to understand that while experienced users are able to work around these frustrations, they are significant barriers to people new to Python. In fact, the difficulty and general user-unfriendliness is likely to deter many of them.

PyPI website is counter-helpful

Every language with a package manager has an official (or quasi-official) repository for the community to download and publish packages. Python has the Python Package Index, PyPI. https://pypi.python.org/pypi

Let's compare its pages with those of RubyGems and Npm (the Node package manager).

  1. https://rubygems.org/gems/rails RubyGems page for the package rails
  2. https://www.npmjs.org/package/express Npm page for the package express
  3. https://pypi.python.org/pypi/simplejson/ PyPI page for the package simplejson

You'll see the RubyGems and Npm pages both begin with a one-line description of the package, then large friendly instructions how to install it.

Meanwhile, woe to any hapless Python user who naively browses to PyPI. On https://pypi.python.org/pypi/simplejson/ , they'll find no such helpful instructions. There is however, a large green 'Download' link. It's not unreasonable to follow it. Aha, they click! Their browser downloads a .tar.gz file. Many Windows users can't even open it, but if they persevere they may eventually extract it, then run setup.py and eventually with the help of Google setup.py install. Some will give up and reinvent the wheel..

Of course, all of this is wrong. The easiest way to install a package is with a Pip command. But PyPI didn't even mention Pip. Instead, it led them down an archaic and tedious path.

Error: Unable to find vcvarsall.bat

Numpy is one of Python's most popular libraries. Try to install it with Pip, you get this cryptic error message:

Error: Unable to find vcvarsall.bat

Trying to fix that is one of the most popular questions on Stack Overflow: "error: Unable to find vcvarsall.bat"

Few people succeed.

For comparison, in the same situation, Ruby prints this message, which explains what's going on and how to fix it:

Please update your PATH to include build tools or download the DevKit from http://rubyinstaller.org/downloads and follow the instructions at http://github.com/oneclick/rubyinstaller/wiki/Development-Kit

Publishing packages is hard

Ruby and Nodejs ship with full-featured package managers, Gem (since 2007) and Npm (since 2011), and have nurtured sharing communities centred around GitHub. Npm makes publishing packages as easy as installing them, it already has 64k packages. RubyGems lists 72k packages. The venerable Python package index lists only 41k.

History

Flying in the face of its "batteries included" motto, Python shipped without a package manager until 2014.

Until Pip, the de facto standard was a command easy_install. It was woefully inadequate. The was no command to uninstall packages.

Pip was a massive improvement. It had most the features of Ruby's Gem. Unfortunately, Pip was--until recently--ironically difficult to install. In fact, the problem remains a top Python question on Stack Overflow: "How do I install pip on Windows?"

Pressed <button> selector

You can do this if you use an <a> tag instead of a button. I know it's not exactly what you asked for, but it might give you some other options if you cannot find a solution to this:

Borrowing from a demo from another answer here I produced this:

_x000D_
_x000D_
a {_x000D_
  display: block;_x000D_
  font-size: 18px;_x000D_
  border: 2px solid gray;_x000D_
  border-radius: 100px;_x000D_
  width: 100px;_x000D_
  height: 100px;_x000D_
  text-align: center;_x000D_
  line-height: 100px;_x000D_
}_x000D_
_x000D_
a:active {_x000D_
  font-size: 18px;_x000D_
  border: 2px solid green;_x000D_
  border-radius: 100px;_x000D_
  width: 100px;_x000D_
  height: 100px;_x000D_
}_x000D_
_x000D_
a:target {_x000D_
  font-size: 18px;_x000D_
  border: 2px solid red;_x000D_
  border-radius: 100px;_x000D_
  width: 100px;_x000D_
  height: 100px;_x000D_
}
_x000D_
<a id="btn" href="#btn">Demo</a>
_x000D_
_x000D_
_x000D_

Notice the use of :target; this will be the style applied when the element is targeted via the hash. Which also means your HTML will need to be this: <a id="btn" href="#btn">Demo</a> a link targeting itself. and the demo http://jsfiddle.net/rlemon/Awdq5/4/

Thanks to @BenjaminGruenbaum here is a better demo: http://jsfiddle.net/agzVt/

Also, as a footnote: this should really be done with JavaScript and applying / removing CSS classes from the element. It would be much less convoluted.

Store a cmdlet's result value in a variable in Powershell

Just access the Priority property of the object returned from the pipeline:

$var = (Get-WSManInstance -enumerate wmicimv2/win32_process).Priority

(This won't work if Get-WSManInstance returns multiple objects.2)

For the second question: to get two properties there are several options, problably the simplest is to have have one variable* containing an object with two separate properties:

$var = (Get-WSManInstance -enumerate wmicimv2/win32_process | select -first 1 Priority, ProcessID)

and then use, assuming only one process:

$var.Priority

and

$var.ProcessID

If there are multiple processes $var will be an array which you can index, so to get the properties of the first process (using the array literal syntax @(...) so it is always a collection1):

$var = @(Get-WSManInstance -enumerate wmicimv2/win32_process | select -first 1 Priority, ProcessID)

and then use:

$var[0].Priority
$var[0].ProcessID

1 PowerShell helpfully for the command line, but not so helpfully in scripts has some extra logic when assigning the result of a pipeline to a variable: if no objects are returned then set $null, if one is returned then that object is assigned, otherwise an array is assigned. Forcing an array returns an array with zero, one or more (respectively) elements.

2 This changes in PowerShell V3 (at the time of writing in Release Candidate), using a member property on an array of objects will return an array of the value of those properties.

How to parse a month name (string) to an integer for comparison in C#?

I translate it into C# code in Spanish version, regards:

public string ObtenerNumeroMes(string NombreMes){

       string NumeroMes;   

       switch(NombreMes) {

        case ("ENERO") :
            NumeroMes = "01";
            return NumeroMes;

        case ("FEBRERO") :
            NumeroMes = "02";
            return NumeroMes;

        case ("MARZO") :
            NumeroMes = "03";
            return NumeroMes;

        case ("ABRIL") :
            NumeroMes = "04";
            return NumeroMes;

        case ("MAYO") :
            NumeroMes = "05";
            return NumeroMes;

        case ("JUNIO") :
            NumeroMes = "06";
            return NumeroMes;

        case ("JULIO") :
            NumeroMes = "07";
            return NumeroMes;

        case ("AGOSTO") :
            NumeroMes = "08";
            return NumeroMes;

        case ("SEPTIEMBRE") :
            NumeroMes = "09";
            return NumeroMes;

        case ("OCTUBRE") :
            NumeroMes = "10";
            return NumeroMes;

        case ("NOVIEMBRE") :
            NumeroMes = "11";
            return NumeroMes;

        case ("DICIEMBRE") :
            NumeroMes = "12";
            return NumeroMes;

            default:
            Console.WriteLine("Error");
            return "ERROR";

        }

   }

Deleting a pointer in C++

There is a rule in C++, for every new there is a delete.

  1. Why won't the first case work? Seems the most straightforward use to use and delete a pointer? The error says the memory wasn't allocated but 'cout' returned an address.

new is never called. So the address that cout prints is the address of the memory location of myVar, or the value assigned to myPointer in this case. By writing:

myPointer = &myVar;

you say:

myPointer = The address of where the data in myVar is stored

  1. On the second example the error is not being triggered but doing a cout of the value of myPointer still returns a memory address?

It returns an address that points to a memory location that has been deleted. Because first you create the pointer and assign its value to myPointer, second you delete it, third you print it. So unless you assign another value to myPointer, the deleted address will remain.

  1. Does #3 really work? Seems to work to me, the pointer is no longer storing an address, is this the proper way to delete a pointer?

NULL equals 0, you delete 0, so you delete nothing. And it's logic that it prints 0 because you did:

myPointer = NULL;

which equals:

myPointer = 0;

PHP Accessing Parent Class Variable

echo $this->bb;

The variable is inherited and is not private, so it is a part of the current object.


Here is additional information in response to your request for more information about using parent:::

Use parent:: when you want add extra functionality to a method from the parent class. For example, imagine an Airplane class:

class Airplane {
    private $pilot;

    public function __construct( $pilot ) {
        $this->pilot = $pilot;
    }
}

Now suppose we want to create a new type of Airplane that also has a navigator. You can extend the __construct() method to add the new functionality, but still make use of the functionality offered by the parent:

class Bomber extends Airplane {
    private $navigator;

    public function __construct( $pilot, $navigator ) {
        $this->navigator = $navigator;

        parent::__construct( $pilot ); // Assigns $pilot to $this->pilot
    }
}

In this way, you can follow the DRY principle of development but still provide all of the functionality you desire.

git with development, staging and production branches

Actually what made this so confusing is that the Beanstalk people stand behind their very non-standard use of Staging (it comes before development in their diagram, and it's not a mistake!

https://twitter.com/Beanstalkapp/status/306129447885631488

How to specify jdk path in eclipse.ini on windows 8 when path contains space

Sometimes spaces in path create a problem. You can add e.g. -vm C:\progra~1\Java\jre1.8.0_112\bin\javaw.exe

How to set default font family for entire Android app

Try this library, its lightweight and easy to implement

https://github.com/sunnag7/FontStyler

<com.sunnag.fontstyler.FontStylerView
              android:textStyle="bold"
              android:text="@string/about_us"
              android:layout_width="match_parent"
              android:layout_height="match_parent"
              android:paddingTop="8dp"
              app:fontName="Lato-Bold"
              android:textSize="18sp"
              android:id="@+id/textView64" />

Custom date format with jQuery validation plugin

Here is an example for a new validation method that will validate almost any date format, including:

  • dd/mm/yy or dd/mm/yyyy
  • dd.mm.yy or dd.mm.yyyy
  • dd,mm,yy or dd,mm,yyyy
  • dd mm yy or dd mm yyyy
  • dd-mm-yy or dd-mm-yyyy

Then, when you pass the value to the php you can convert it with strtotime

Here is how to add the method:

    $.validator.addMethod("anyDate",
    function(value, element) {
        return value.match(/^(0?[1-9]|[12][0-9]|3[0-1])[/., -](0?[1-9]|1[0-2])[/., -](19|20)?\d{2}$/);
    },
    "Please enter a date in the format!"
);

Then you add the new filter with:

$('#myForm')
.validate({
    rules : {
        field: {
            anyDate: true
        }
    }
})

;

Group by month and year in MySQL

Use

GROUP BY year, month DESC";

Instead of

GROUP BY MONTH(t.summaryDateTime) DESC";

Calculating Covariance with Python and Numpy

Thanks to unutbu for the explanation. By default numpy.cov calculates the sample covariance. To obtain the population covariance you can specify normalisation by the total N samples like this:

Covariance = numpy.cov(a, b, bias=True)[0][1]
print(Covariance)

or like this:

Covariance = numpy.cov(a, b, ddof=0)[0][1]
print(Covariance)

Can I use return value of INSERT...RETURNING in another INSERT?

DO $$
DECLARE tableId integer;
BEGIN
  INSERT INTO Table1 (name) VALUES ('a_title') RETURNING id INTO tableId;
  INSERT INTO Table2 (val) VALUES (tableId);
END $$;

Tested with psql (10.3, server 9.6.8)

Add text to textarea - Jquery

Just append() the text nodes:

$('#replyBox').append(quote); 

http://jsfiddle.net/nQErc/

Find closing HTML tag in Sublime Text

Under the "Goto" menu, Control + M is Jump to Matching Bracket. Works for parentheses as well.

Setting a width and height on an A tag

Below working for me

display: block;
width: 100%;

Javascript - Replace html using innerHTML

You are replacing the starting tag and then putting that back in innerHTML, so the code will be invalid. Make all the replacements before you put the code back in the element:

var html = strMessage1.innerHTML;
html = html.replace( /aaaaaa./g,'<a href=\"http://www.google.com/');
html = html.replace( /.bbbbbb/g,'/world\">Helloworld</a>');
strMessage1.innerHTML = html;

What permission do I need to access Internet from an Android application?

As per current versions, Android doesn't ask for permission to interact with the internet but you can add the below code which will help for users using older versions Just add these in AndroidManifest

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>

New line in JavaScript alert box

_x000D_
_x000D_
 alert("some text\nmore text in a new line");
_x000D_
_x000D_
_x000D_

_x000D_
_x000D_
alert("Line 1\nLine 2\nLine 3\nLine 4\nLine 5");
_x000D_
_x000D_
_x000D_

TypeError: a bytes-like object is required, not 'str'

Encoding and decoding can solve this in Python 3:

Client Side:

>>> host='127.0.0.1'
>>> port=1337
>>> import socket
>>> s=socket.socket(socket.AF_INET,socket.SOCK_STREAM)
>>> s.connect((host,port))
>>> st='connection done'
>>> byt=st.encode()
>>> s.send(byt)
15
>>>

Server Side:

>>> host=''
>>> port=1337
>>> import socket
>>> s=socket.socket(socket.AF_INET,socket.SOCK_STREAM)
>>> s.bind((host,port))
>>> s.listen(1)
>>> conn ,addr=s.accept()
>>> data=conn.recv(2000)
>>> data.decode()
'connection done'
>>>

Alter column in SQL Server

Try this one.

ALTER TABLE tb_TableName
ALTER COLUMN Record_Status VARCHAR(20) NOT NULL

ALTER TABLE tb_TableName
ADD CONSTRAINT DEF_Name DEFAULT '' FOR Record_Status

Permission denied (publickey,gssapi-keyex,gssapi-with-mic)

I was facing this issue for long time. Finally it was issue of ssh-add. Git ssh credentials were not taken into consideration.

Check following command might work for you:

ssh-add

Playing mp3 song on python

See also playsound

pip install playsound

import playsound
playsound.playsound('/path/to/filename.mp3', True)

How to cut a string after a specific character in unix

This will also do.

echo $var | cut -f2 -d":"

C: What is the difference between ++i and i++?

Please don't worry about the "efficiency" (speed, really) of which one is faster. We have compilers these days that take care of these things. Use whichever one makes sense to use, based on which more clearly shows your intent.

SMTP server response: 530 5.7.0 Must issue a STARTTLS command first

Problem Solved,

I edited the file /etc/postfix/master.cf

and commented

-o smtpd_relay_restrictions=permit_sasl_authenticated,reject

and changed the line from

-o smtpd_tls_security_level=encrypt 

to

-o smtpd_tls_security_level=may

And worked on fine

Adding Lombok plugin to IntelliJ project

To install the plugin manually, try:

  1. Download Lombok zip file (ensure Lombok matches the IDE version).
  2. Select Preferences Plugins Install Plugins from Disk.

IntelliJ Plugin Preferences Dialog

AngularJS $http, CORS and http authentication

No you don't have to put credentials, You have to put headers on client side eg:

 $http({
        url: 'url of service',
        method: "POST",
        data: {test :  name },
        withCredentials: true,
        headers: {
                    'Content-Type': 'application/json; charset=utf-8'
        }
    });

And and on server side you have to put headers to this is example for nodejs:

/**
 * On all requests add headers
 */
app.all('*', function(req, res,next) {


    /**
     * Response settings
     * @type {Object}
     */
    var responseSettings = {
        "AccessControlAllowOrigin": req.headers.origin,
        "AccessControlAllowHeaders": "Content-Type,X-CSRF-Token, X-Requested-With, Accept, Accept-Version, Content-Length, Content-MD5,  Date, X-Api-Version, X-File-Name",
        "AccessControlAllowMethods": "POST, GET, PUT, DELETE, OPTIONS",
        "AccessControlAllowCredentials": true
    };

    /**
     * Headers
     */
    res.header("Access-Control-Allow-Credentials", responseSettings.AccessControlAllowCredentials);
    res.header("Access-Control-Allow-Origin",  responseSettings.AccessControlAllowOrigin);
    res.header("Access-Control-Allow-Headers", (req.headers['access-control-request-headers']) ? req.headers['access-control-request-headers'] : "x-requested-with");
    res.header("Access-Control-Allow-Methods", (req.headers['access-control-request-method']) ? req.headers['access-control-request-method'] : responseSettings.AccessControlAllowMethods);

    if ('OPTIONS' == req.method) {
        res.send(200);
    }
    else {
        next();
    }


});

Where does Oracle SQL Developer store connections?

If you have previously installed SQL Developer then it will store the connection details in the 'connection.xml' which will be located in below mentioned path.

C:\Users\Username\AppData\Roaming\SQL Developer\system3.1.07.42\o.jdeveloper.db.connection.11.1.1.4.37.59.48

Once you get that 'connection.xml' try to import it into SQLDeveloper by right clicking to CONNECTIONS.

Design Patterns web based applications

A bit decent web application consists of a mix of design patterns. I'll mention only the most important ones.


Model View Controller pattern

The core (architectural) design pattern you'd like to use is the Model-View-Controller pattern. The Controller is to be represented by a Servlet which (in)directly creates/uses a specific Model and View based on the request. The Model is to be represented by Javabean classes. This is often further dividable in Business Model which contains the actions (behaviour) and Data Model which contains the data (information). The View is to be represented by JSP files which have direct access to the (Data) Model by EL (Expression Language).

Then, there are variations based on how actions and events are handled. The popular ones are:

  • Request (action) based MVC: this is the simplest to implement. The (Business) Model works directly with HttpServletRequest and HttpServletResponse objects. You have to gather, convert and validate the request parameters (mostly) yourself. The View can be represented by plain vanilla HTML/CSS/JS and it does not maintain state across requests. This is how among others Spring MVC, Struts and Stripes works.

  • Component based MVC: this is harder to implement. But you end up with a simpler model and view wherein all the "raw" Servlet API is abstracted completely away. You shouldn't have the need to gather, convert and validate the request parameters yourself. The Controller does this task and sets the gathered, converted and validated request parameters in the Model. All you need to do is to define action methods which works directly with the model properties. The View is represented by "components" in flavor of JSP taglibs or XML elements which in turn generates HTML/CSS/JS. The state of the View for the subsequent requests is maintained in the session. This is particularly helpful for server-side conversion, validation and value change events. This is how among others JSF, Wicket and Play! works.

As a side note, hobbying around with a homegrown MVC framework is a very nice learning exercise, and I do recommend it as long as you keep it for personal/private purposes. But once you go professional, then it's strongly recommended to pick an existing framework rather than reinventing your own. Learning an existing and well-developed framework takes in long term less time than developing and maintaining a robust framework yourself.

In the below detailed explanation I'll restrict myself to request based MVC since that's easier to implement.


Front Controller pattern (Mediator pattern)

First, the Controller part should implement the Front Controller pattern (which is a specialized kind of Mediator pattern). It should consist of only a single servlet which provides a centralized entry point of all requests. It should create the Model based on information available by the request, such as the pathinfo or servletpath, the method and/or specific parameters. The Business Model is called Action in the below HttpServlet example.

protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    try {
        Action action = ActionFactory.getAction(request);
        String view = action.execute(request, response);

        if (view.equals(request.getPathInfo().substring(1)) {
            request.getRequestDispatcher("/WEB-INF/" + view + ".jsp").forward(request, response);
        }
        else {
            response.sendRedirect(view); // We'd like to fire redirect in case of a view change as result of the action (PRG pattern).
        }
    }
    catch (Exception e) {
        throw new ServletException("Executing action failed.", e);
    }
}

Executing the action should return some identifier to locate the view. Simplest would be to use it as filename of the JSP. Map this servlet on a specific url-pattern in web.xml, e.g. /pages/*, *.do or even just *.html.

In case of prefix-patterns as for example /pages/* you could then invoke URL's like http://example.com/pages/register, http://example.com/pages/login, etc and provide /WEB-INF/register.jsp, /WEB-INF/login.jsp with the appropriate GET and POST actions. The parts register, login, etc are then available by request.getPathInfo() as in above example.

When you're using suffix-patterns like *.do, *.html, etc, then you could then invoke URL's like http://example.com/register.do, http://example.com/login.do, etc and you should change the code examples in this answer (also the ActionFactory) to extract the register and login parts by request.getServletPath() instead.


Strategy pattern

The Action should follow the Strategy pattern. It needs to be defined as an abstract/interface type which should do the work based on the passed-in arguments of the abstract method (this is the difference with the Command pattern, wherein the abstract/interface type should do the work based on the arguments which are been passed-in during the creation of the implementation).

public interface Action {
    public String execute(HttpServletRequest request, HttpServletResponse response) throws Exception;
}

You may want to make the Exception more specific with a custom exception like ActionException. It's just a basic kickoff example, the rest is all up to you.

Here's an example of a LoginAction which (as its name says) logs in the user. The User itself is in turn a Data Model. The View is aware of the presence of the User.

public class LoginAction implements Action {

    public String execute(HttpServletRequest request, HttpServletResponse response) throws Exception {
        String username = request.getParameter("username");
        String password = request.getParameter("password");
        User user = userDAO.find(username, password);

        if (user != null) {
            request.getSession().setAttribute("user", user); // Login user.
            return "home"; // Redirect to home page.
        }
        else {
            request.setAttribute("error", "Unknown username/password. Please retry."); // Store error message in request scope.
            return "login"; // Go back to redisplay login form with error.
        }
    }

}

Factory method pattern

The ActionFactory should follow the Factory method pattern. Basically, it should provide a creational method which returns a concrete implementation of an abstract/interface type. In this case, it should return an implementation of the Action interface based on the information provided by the request. For example, the method and pathinfo (the pathinfo is the part after the context and servlet path in the request URL, excluding the query string).

public static Action getAction(HttpServletRequest request) {
    return actions.get(request.getMethod() + request.getPathInfo());
}

The actions in turn should be some static/applicationwide Map<String, Action> which holds all known actions. It's up to you how to fill this map. Hardcoding:

actions.put("POST/register", new RegisterAction());
actions.put("POST/login", new LoginAction());
actions.put("GET/logout", new LogoutAction());
// ...

Or configurable based on a properties/XML configuration file in the classpath: (pseudo)

for (Entry entry : configuration) {
    actions.put(entry.getKey(), Class.forName(entry.getValue()).newInstance());
}

Or dynamically based on a scan in the classpath for classes implementing a certain interface and/or annotation: (pseudo)

for (ClassFile classFile : classpath) {
    if (classFile.isInstanceOf(Action.class)) {
       actions.put(classFile.getAnnotation("mapping"), classFile.newInstance());
    }
}

Keep in mind to create a "do nothing" Action for the case there's no mapping. Let it for example return directly the request.getPathInfo().substring(1) then.


Other patterns

Those were the important patterns so far.

To get a step further, you could use the Facade pattern to create a Context class which in turn wraps the request and response objects and offers several convenience methods delegating to the request and response objects and pass that as argument into the Action#execute() method instead. This adds an extra abstract layer to hide the raw Servlet API away. You should then basically end up with zero import javax.servlet.* declarations in every Action implementation. In JSF terms, this is what the FacesContext and ExternalContext classes are doing. You can find a concrete example in this answer.

Then there's the State pattern for the case that you'd like to add an extra abstraction layer to split the tasks of gathering the request parameters, converting them, validating them, updating the model values and execute the actions. In JSF terms, this is what the LifeCycle is doing.

Then there's the Composite pattern for the case that you'd like to create a component based view which can be attached with the model and whose behaviour depends on the state of the request based lifecycle. In JSF terms, this is what the UIComponent represent.

This way you can evolve bit by bit towards a component based framework.


See also:

src absolute path problem

I think because C would be seen the C drive on the client pc, it wont let you. And if it could do this, it would be a big security hole.

How to use protractor to check if an element is visible?

The correct way for checking the visibility of an element with Protractor is to call the isDisplayed method. You should be careful though since isDisplayed does not return a boolean, but rather a promise providing the evaluated visibility. I've seen lots of code examples that use this method wrongly and therefore don't evaluate its actual visibility.

Example for getting the visibility of an element:

element(by.className('your-class-name')).isDisplayed().then(function (isVisible) {
    if (isVisible) {
        // element is visible
    } else {
        // element is not visible
    }
});

However, you don't need this if you are just checking the visibility of the element (as opposed to getting it) because protractor patches Jasmine expect() so it always waits for promises to be resolved. See github.com/angular/jasminewd

So you can just do:

expect(element(by.className('your-class-name')).isDisplayed()).toBeTruthy();

Since you're using AngularJS to control the visibility of that element, you could also check its class attribute for ng-hide like this:

var spinner = element.by.css('i.icon-spin');
expect(spinner.getAttribute('class')).not.toMatch('ng-hide'); // expect element to be visible

Handling exceptions from Java ExecutorService tasks

From the docs:

Note: When actions are enclosed in tasks (such as FutureTask) either explicitly or via methods such as submit, these task objects catch and maintain computational exceptions, and so they do not cause abrupt termination, and the internal exceptions are not passed to this method.

When you submit a Runnable, it'll get wrapped in a Future.

Your afterExecute should be something like this:

public final class ExtendedExecutor extends ThreadPoolExecutor {

    // ...

    protected void afterExecute(Runnable r, Throwable t) {
        super.afterExecute(r, t);
        if (t == null && r instanceof Future<?>) {
            try {
                Future<?> future = (Future<?>) r;
                if (future.isDone()) {
                    future.get();
                }
            } catch (CancellationException ce) {
                t = ce;
            } catch (ExecutionException ee) {
                t = ee.getCause();
            } catch (InterruptedException ie) {
                Thread.currentThread().interrupt();
            }
        }
        if (t != null) {
            System.out.println(t);
        }
    }
}

Get the difference between dates in terms of weeks, months, quarters, and years

Here's a solution:

dates <- c("14.01.2013", "26.03.2014")

# Date format:
dates2 <- strptime(dates, format = "%d.%m.%Y")

dif <- diff(as.numeric(dates2)) # difference in seconds

dif/(60 * 60 * 24 * 7) # weeks
[1] 62.28571
dif/(60 * 60 * 24 * 30) # months
[1] 14.53333
dif/(60 * 60 * 24 * 30 * 3) # quartes
[1] 4.844444
dif/(60 * 60 * 24 * 365) # years
[1] 1.194521

'profile name is not valid' error when executing the sp_send_dbmail command

You need to grant the user or group rights to use the profile. They need to be added to the msdb database and then you will see them available in the mail wizard when you are maintaining security for mail.

Read up the security here: http://msdn.microsoft.com/en-us/library/ms175887.aspx

See a listing of mail procedures here: http://msdn.microsoft.com/en-us/library/ms177580.aspx

Example script for 'TestUser' to use the profile named 'General Admin Mail'.


USE [msdb]
GO
CREATE USER [TestUser] FOR LOGIN [testuser]
GO
USE [msdb]
GO
EXEC sp_addrolemember N'DatabaseMailUserRole', N'TestUser'
GO

EXECUTE msdb.dbo.sysmail_add_principalprofile_sp
    @profile_name = 'General Admin Mail',
    @principal_name = 'TestUser',
    @is_default = 1 ;

How can I decrypt a password hash in PHP?

Bcrypt is a one-way hashing algorithm, you can't decrypt hashes. Use password_verify to check whether a password matches the stored hash:

<?php
// See the password_hash() example to see where this came from.
$hash = '$2y$07$BCryptRequires22Chrcte/VlQH0piJtjXl.0t1XkA8pw9dMXTpOq';

if (password_verify('rasmuslerdorf', $hash)) {
    echo 'Password is valid!';
} else {
    echo 'Invalid password.';
}

In your case, run the SQL query using only the username:

$sql_script = 'SELECT * FROM USERS WHERE username=?';

And do the password validation in PHP using a code that is similar to the example above.

The way you are constructing the query is very dangerous. If you don't parameterize the input properly, the code will be vulnerable to SQL injection attacks. See this Stack Overflow answer on how to prevent SQL injection.

Str_replace for multiple items

I had a situation whereby I had to replace the HTML tags with two different replacement results.

$trades = "<li>Sprinkler and Fire      Protection Installer</li>
<li>Steamfitter </li>
<li>Terrazzo, Tile and Marble      Setter</li>";

$s1 =  str_replace('<li>', '"', $trades);

$s2 = str_replace('</li>', '",', $s1);

echo $s2;

result

"Sprinkler and Fire Protection Installer", "Steamfitter ", "Terrazzo, Tile and Marble Setter",

Charts for Android

SciChart for Android is a relative newcomer, but brings extremely fast high performance real-time charting to the Android platform.

SciChart is a commercial control but available under royalty free distribution / per developer licensing. There is also free licensing available for educational use with some conditions.

Some useful links can be found below:

enter image description here

Disclosure: I am the tech lead on the SciChart project!

Create a .csv file with values from a Python list

Here is working copy-paste example for Python 3.x with options to define your own delimiter and quote char.

import csv

mylist = ['value 1', 'value 2', 'value 3']

with open('employee_file.csv', mode='w') as employee_file:
    employee_writer = csv.writer(employee_file, delimiter=',', quotechar='"', quoting=csv.QUOTE_ALL)
    employee_writer.writerow(mylist)

This will generate employee_file.csv that looks like this:

"value 1","value 2","value 3"

NOTE:

If quoting is set to csv.QUOTE_MINIMAL, then .writerow() will quote fields only if they contain the delimiter or the quotechar. This is the default case.

If quoting is set to csv.QUOTE_ALL, then .writerow() will quote all fields.

If quoting is set to csv.QUOTE_NONNUMERIC, then .writerow() will quote all fields containing text data and convert all numeric fields to the float data type.

If quoting is set to csv.QUOTE_NONE, then .writerow() will escape delimiters instead of quoting them. In this case, you also must provide a value for the escapechar optional parameter.

SQL - HAVING vs. WHERE

You can not use where clause with aggregate functions because where fetch records on the basis of condition, it goes into table record by record and then fetch record on the basis of condition we have give. So that time we can not where clause. While having clause works on the resultSet which we finally get after running a query.

Example query:

select empName, sum(Bonus) 
from employees 
order by empName 
having sum(Bonus) > 5000;

This will store the resultSet in a temporary memory, then having clause will perform its work. So we can easily use aggregate functions here.

Why maven settings.xml file is not there?

settings.xml is not required (and thus not autocreated in ~/.m2 folder) unless you want to change the default settings.

Standalone maven and the maven in eclipse will use the same local repository (~/.m2 folder). This means if some artifacts/dependencies are downloaded by standalone maven, it will not be again downloaded by maven in eclipse.

Based on the version of Eclipse that you use, you may have different maven version in eclipse compared to the standalone. It should not matter in most cases.

Making a <button> that's a link in HTML

IMPORTANT: <button> should never be a descendent of <a>.

Try <a href="http://stackoverflow.com"><button>Link Text</button></a> in any html validator like https://validator.w3.org and you'll get an error. There's really no point in using a button if you're not using the button. Just style the <a> with css to look like a button. If you're using a framework like Bootstrap, you could apply the button style(s) btn, btn-primary etc.

jsfiddle : button styled link

_x000D_
_x000D_
.btnStack {_x000D_
  font-family: Oswald;_x000D_
  background-color: orange;_x000D_
  color: white;_x000D_
  text-decoration: none;_x000D_
  display: inline-block;_x000D_
  padding: 6px 12px;_x000D_
  margin-bottom: 0;_x000D_
  font-size: 14px;_x000D_
  font-weight: normal;_x000D_
  line-height: 1.428571429;_x000D_
  text-align: center;_x000D_
  white-space: nowrap;_x000D_
  vertical-align: middle;_x000D_
  cursor: pointer;_x000D_
  border: 1px solid transparent;_x000D_
  border-radius: 4px;_x000D_
  -webkit-user-select: none;_x000D_
  -moz-user-select: none;_x000D_
  -ms-user-select: none;_x000D_
  -o-user-select: none;_x000D_
  user-select: none;_x000D_
}_x000D_
_x000D_
a.btnStack:hover {_x000D_
  background-color: #000;_x000D_
}
_x000D_
<link href='https://fonts.googleapis.com/css?family=Oswald:400' rel='stylesheet' type='text/css'>_x000D_
<a href="http://stackoverflow.com" class="btnStack">stackoverflow.com</a>
_x000D_
_x000D_
_x000D_

Get content of a DIV using JavaScript

You need to set Div2 to Div1's innerHTML. Also, JavaScript is case sensitive - in your HTML, the id Div2 is DIV2. Also, you should use document, not Document:

var MyDiv1 = document.getElementById('DIV1');
var MyDiv2 = document.getElementById('DIV2');
MyDiv2.innerHTML = MyDiv1.innerHTML; 

Here is a JSFiddle: http://jsfiddle.net/gFN6r/.

ImportError: numpy.core.multiarray failed to import

I used Anaconda environment and had the same issue. I tried all the aforementioned approaches and, alas, it didn't help me. Accumulated the suggestions, here the way which helped me:

  1. Delete all NumPy folders in the virtual environment or in the system if you don't use a virtual environment, for example in my case:

    ~/home/anaconda3/envs//lib/python/site-packages/numpy

    ~/home/anaconda3/envs//lib/python/site-packages/numpy.libs

    ~/home/anaconda3/envs//lib/python/site-packages/numpy-.dist-info

  2. Install new Numpy with:

    pip install numpy -U

Hope, it could help in the same case

Redis: How to access Redis log file

vi /usr/local/etc/redis.conf

Look for dir, logfile

# The working directory.
#
# The DB will be written inside this directory, with the filename specified
# above using the 'dbfilename' configuration directive.
#
# The Append Only File will also be created inside this directory.
#
# Note that you must specify a directory here, not a file name.
dir /usr/local/var/db/redis/



# Specify the log file name. Also the empty string can be used to force
# Redis to log on the standard output. Note that if you use standard
# output for logging but daemonize, logs will be sent to /dev/null 
logfile "redis_log"

So the log file is created at /usr/local/var/db/redis/redis_log with the name redis_log

You can also try MONITOR command from redis-cli to review the number of commands executed.

Sorted collection in Java

TreeMap and TreeSet will give you an iteration over the contents in sorted order. Or you could use an ArrayList and use Collections.sort() to sort it. All those classes are in java.util

Combining two lists and removing duplicates, without removing duplicates in original list

resulting_list = list(first_list)
resulting_list.extend(x for x in second_list if x not in resulting_list)

Windows batch: formatted date into variable

If you don't mind an one-time investment of 10 to 30 minutes to get a reliable solution (that doesn't depend on Windows' region settings), please read on.

Let's free our minds. Do you want to simplify the scripts to just look like this? (Assume you wants to set the LOG_DATETIME variable)

FOR /F "tokens=* USEBACKQ" %%F IN (`FormatNow "yyyy-MM-dd"`) DO (
  Set LOG_DATETIME=%%F
)

echo I am going to write log to Testing_%LOG_DATETIME%.log

You can. Simply build a FormatNow.exe with C# .NET and add it to your PATH.

Notes:

  1. You can use any Visual Studio edition, such as Visual Studio Express, to build the FormatNow.exe.
  2. In Visual Studio, choose the "Console Application" C# project, not "Windows Forms Application" project.
  3. Common sense: the built FormatNow.exe will need .NET Framework to run.
  4. Common sense: after adding FormatNow.exe to PATH variable, you need to restart CMD to take effect. It also applies to any change in environment variables.

Benefits:

  1. It's not slow (finishes within 0.2 seconds).
  2. Many formats are supported https://msdn.microsoft.com/en-us/library/8kb3ddd4(v=vs.110).aspx e.g. FormatNow "ddd" to get only the day of week, FormatNow "yyyy" to get only the year
  3. It doesn't depend on Windows' region settings, so its output is much more reliable. On the other hand, %date% doesn't give a consistent format over different computers, and is not reliable.
  4. You don't need to create so many CMD variables and pollute the variable namespace.
  5. It would require 3 lines in the batch script to invoke the program and get the results. It should be reasonably short enough.

Source code of FormatNow.exe which I built with Visual Studio 2010 (I prefer to build it myself to avoid the risk of downloading an unknown, possibly malicious program). Just copy and paste the codes below, build the program once, and then you have a reliable date formatter for all future uses.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Globalization;

namespace FormatNow
{
    class Program
    {
        static void Main(string[] args)
        {
            try
            {
                if (args.Length < 1)
                {
                    throw new ArgumentException("Missing format");
                }
                string format = args[0];
                Console.Write(DateTime.Now.ToString(format, CultureInfo.InvariantCulture.DateTimeFormat));
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.ToString());
            }
        }

    }
}

In general, when dealing with complicated logics, we can make it simpler for by building a very small program and calling the program to capture the output back to a batch script variable instead. We are not students and we're not taking exams requiring us to follow the batch-script-only rule to solve problems. In real working environment, any (legal) method is allowed. Why should we still stick to the poor capabilities of Windows batch script that needs workarounds for many simple tasks? Why should we use the wrong tool for the job?

How/when to generate Gradle wrapper files?

  1. You generate it once, and again when you'd like to change the version of Gradle you use in the project. There's no need to generate is so often. Here are the docs. Just add wrapper task to build.gradle file and run this task to get the wrapper structure.

    Mind that you need to have Gradle installed to generate a wrapper. Great tool for managing g-ecosystem artifacts is SDKMAN!. To generate a gradle wrapper, add the following piece of code to build.gradle file:

    task wrapper(type: Wrapper) {
       gradleVersion = '2.0' //version required
    }
    

    and run:

    gradle wrapper
    

    task. Add the resulting files to SCM (e.g. git) and from now all developers will have the same version of Gradle when using Gradle Wrapper.

    With Gradle 2.4 (or higher) you can set up a wrapper without adding a dedicated task:

    gradle wrapper --gradle-version 2.3
    

    or

    gradle wrapper --gradle-distribution-url https://myEnterpriseRepository:7070/gradle/distributions/gradle-2.3-bin.zip
    

    All the details can be found here

From Gradle 3.1 --distribution-type option can be also used. The options are binary and all and bin. all additionally contains source code and documentation. all is also better when IDE is used, so the editor works better. Drawback is the build may last longer (need to download more data, pointless on CI server) and it will take more space.

  1. These are Gradle Wrapper files. You need to generate them once (for a particular version) and add to version control. If you need to change the version of Gradle Wrapper, change the version in build.gradle see (1.) and regenerate the files.

  2. Give a detailed example. Such file may have multiple purposes: multi-module project, responsibility separation, slightly modified script, etc.

  3. settings.gradle is responsible rather for structure of the project (modules, names, etc), while, gradle.properties is used for project's and Gradle's external details (version, command line arguments -XX, properties etc.)

Return a string method in C#

These answers are all way too complicated!

The way he wrote the method is fine. The problem is where he invoked the method. He did not include parentheses after the method name, so the compiler thought he was trying to get a value from a variable instead of a method.

In Visual Basic and Delphi, those parentheses are optional, but in C#, they are required. So, to correct the last line of the original post:

Console.WriteLine("{0}", x.fullNameMethod());

jQuery trigger file input

My problem was a little bit different on iOS 7. Turns out FastClick was causing problems. All I had to do was add class="needsclick" to my button.

How to take screenshot of a div with JavaScript?

After hours of research, I finally found a solution to take a screenshot of an element, even if the origin-clean FLAG is set (to prevent XSS), that´s why you can even capture for example Google Maps (in my case). I wrote a universal function to get a screenshot. The only thing you need in addition is the html2canvas library (https://html2canvas.hertzen.com/).

Example:

getScreenshotOfElement($("div#toBeCaptured").get(0), 0, 0, 100, 100, function(data) {
    // in the data variable there is the base64 image
    // exmaple for displaying the image in an <img>
    $("img#captured").attr("src", "data:image/png;base64,"+data);
});

Keep in mind console.log() and alert() won´t generate output if the size of the image is great.

Function:

function getScreenshotOfElement(element, posX, posY, width, height, callback) {
    html2canvas(element, {
        onrendered: function (canvas) {
            var context = canvas.getContext('2d');
            var imageData = context.getImageData(posX, posY, width, height).data;
            var outputCanvas = document.createElement('canvas');
            var outputContext = outputCanvas.getContext('2d');
            outputCanvas.width = width;
            outputCanvas.height = height;

            var idata = outputContext.createImageData(width, height);
            idata.data.set(imageData);
            outputContext.putImageData(idata, 0, 0);
            callback(outputCanvas.toDataURL().replace("data:image/png;base64,", ""));
        },
        width: width,
        height: height,
        useCORS: true,
        taintTest: false,
        allowTaint: false
    });
}

How to access pandas groupby dataframe by key

gb = df.groupby(['A'])

gb_groups = grouped_df.groups

If you are looking for selective groupby objects then, do: gb_groups.keys(), and input desired key into the following key_list..

gb_groups.keys()

key_list = [key1, key2, key3 and so on...]

for key, values in gb_groups.iteritems():
    if key in key_list:
        print df.ix[values], "\n"

Xcode 10: A valid provisioning profile for this executable was not found

Did you maybe change your developing device? It happened to me when I bought a new iPhone and gave it the same name with my previous device. A clean build however fixed the issue.

Correct way to quit a Qt program?

If you're using Qt Jambi, this should work:

QApplication.closeAllWindows();

Query to display all tablespaces in a database and datafiles

In oracle, generally speaking, there are number of facts that I will mention in following section:

  • Each database can have many Schema/User (Logical division).
  • Each database can have many tablespaces (Logical division).
  • A schema is the set of objects (tables, indexes, views, etc) that belong to a user.
  • In Oracle, a user can be considered the same as a schema.
  • A database is divided into logical storage units called tablespaces, which group related logical structures together. For example, tablespaces commonly group all of an application’s objects to simplify some administrative operations. You may have a tablespace for application data and an additional one for application indexes.

Therefore, your question, "to see all tablespaces and datafiles belong to SCOTT" is s bit wrong.

However, there are some DBA views encompass information about all database objects, regardless of the owner. Only users with DBA privileges can access these views: DBA_DATA_FILES, DBA_TABLESPACES, DBA_FREE_SPACE, DBA_SEGMENTS.

So, connect to your DB as sysdba and run query through these helpful views. For example this query can help you to find all tablespaces and their data files that objects of your user are located:

SELECT DISTINCT sgm.TABLESPACE_NAME , dtf.FILE_NAME
FROM DBA_SEGMENTS sgm
JOIN DBA_DATA_FILES dtf ON (sgm.TABLESPACE_NAME = dtf.TABLESPACE_NAME)
WHERE sgm.OWNER = 'SCOTT'

How to force table cell <td> content to wrap?

If you are using Bootstrap responsive table, just want to set the maximum width for one particular column and make text wrapping, making the the style of this column as following also works

max-width:someValue;
word-wrap:break-word

Tools for creating Class Diagrams

Some time ago I used DIA - free and platform-independent. It was ok. Now I use Enterprise Architect but it's not free.

Install Node.js on Ubuntu

Install Node.js on Ubuntu 12.10 (Quantal Quetzal) or Ubuntu 14.04 LTS (Trusty Tahr) or Ubuntu 16.04.1 LTS (Xenial Xerus).

Please avoid installing Node.js with apt-get on Ubuntu. If you already installed Node.js with the built-in package manager, please remove that. (sudo apt-get purge nodejs && sudo apt-get autoremove && sudo apt-get autoclean)

The installation process on Linux is the same as on OS X. With the provided script:

$ curl -o- https://raw.githubusercontent.com/creationix/nvm/v0.31.3/install.sh | bash

$ nvm list
$ nvm ls-remote
$ nvm install 6.4.0
$ nvm use 6.4.0
$ nvm alias default 6.4.0
$ node -v
$ npm install -g npm
$ npm -v

One more thing! Don’t forget to run the following command, which increases the amount of inotify watches.

$ echo fs.inotify.max_user_watches=524288 | sudo tee -a /etc/sysctl.conf && sudo sysctl -p

Is there a command like "watch" or "inotifywait" on the Mac?

This is just to mention entr as an alternative on OSX to run arbitrary commands when files change. I find it simple and useful.

How to Convert a Text File into a List in Python

Maybe:

crimefile = open(fileName, 'r')
yourResult = [line.split(',') for line in crimefile.readlines()]

Oracle SELECT TOP 10 records

You get an apparently random set because ROWNUM is applied before the ORDER BY. So your query takes the first ten rows and sorts them.0 To select the top ten salaries you should use an analytic function in a subquery, then filter that:

 select * from 
     (select empno,
             ename,
             sal,
             row_number() over(order by sal desc nulls last) rnm
    from emp) 
 where rnm<=10

How to open a specific port such as 9090 in Google Compute Engine

I had to fix this by decreasing the priority (making it higher). This caused an immediate response. Not what I was expecting, but it worked.

How can I get the MAC and the IP address of a connected client in PHP?

I don't think you can get MAC address in PHP, but you can get IP from $_SERVER['REMOTE_ADDR'] variable.

Text file with 0D 0D 0A line breaks

Apple mail has also been known to make an encoding error on text and csv attachments outbound. In essence it replaces line terminators with soft line breaks on each line, which look like =0D in the encoding. If the attachment is emailed to Outlook, Outlook sees the soft line breaks, removes the = then appends real line breaks i.e. 0D0A so you get 0D0D0A (cr cr lf) at the end of each line. The encoding should be =0D= if it is a mac format file (or any other flavour of unix) or =0D0A= if it is a windows format file.

If you are emailing out from apple mail (in at least mavericks or yosemite), making the attachment not a text or csv file is an acceptable workaround e.g. compress it.

The bug also exists if you are running a windows VM under parallels and email a txt file from there using apple mail. It is the email encoding. Form previous comments here, it looks like netscape had the same issue.

iOS 7: UITableView shows under status bar

This is how to write it in "Swift" An adjustment to @lipka's answer:

tableView.contentInset = UIEdgeInsetsMake(20.0, 0.0, 0.0, 0.0)

Why am I getting the message, "fatal: This operation must be run in a work tree?"

Same issue i got, i did following steps,

  1. git init
  2. git add .
  3. git commit -m"inital setup"
  4. git push -f origin master

then it work starts working.

What are some alternatives to ReSharper?

There is BrockSoft VSAid. This is mainly used for finding files in a solution.

NUnit vs. MbUnit vs. MSTest vs. xUnit.net

I wouldn't go with MSTest. Although it's probably the most future proof of the frameworks with Microsoft behind it's not the most flexible solution. It won't run stand alone without some hacks. So running it on a build server other than TFS without installing Visual Studio is hard. The visual studio test-runner is actually slower than Testdriven.Net + any of the other frameworks. And because the releases of this framework are tied to releases of Visual Studio there are less updates and if you have to work with an older VS you're tied to an older MSTest.

I don't think it matters a lot which of the other frameworks you use. It's really easy to switch from one to another.

I personally use XUnit.Net or NUnit depending on the preference of my coworkers. NUnit is the most standard. XUnit.Net is the leanest framework.

Pip Install not installing into correct directory?

I've tried this and it worked for me,

curl -O  https://files.pythonhosted.org/packages/c0/4d/d2cd1171f93245131686b67d905f38cab53bf0edc3fd1a06b9c667c9d046/boto3-1.14.29.tar.gz

tar -zxvf boto3-1.14.29.tar.gz

cd boto3-1.14.29/

Replace X with your required python interpreter, for mine it was python3

sudo pythonX setup.py install

Working with $scope.$emit and $scope.$on

<!DOCTYPE html>
<html>

<head>
<script src= "http://ajax.googleapis.com/ajax/libs/angularjs/1.3.14/angular.min.js"></script>
<script>
var app = angular.module('MyApp',[]);
app.controller('parentCtrl',function($scope){
  $scope.$on('MyEvent',function(event,data){    
    $scope.myData = data;
  });
 });

app.controller('childCtrl',function($scope){
  $scope.fireEvent = function(){ 
  $scope.$emit('MyEvent','Any Data');
  }  
 });
</script>
</head>
<body ng-app="MyApp">
<div ng-controller="parentCtrl" ng-model="myName">

{{myData}}

 <div ng-controller="childCtrl">
   <button ng-click="fireEvent()">Fire Event</button>
 </div>

</div>
</body>
</html>

How to count the number of true elements in a NumPy bool array

boolarr.sum(axis=1 or axis=0)

axis = 1 will output number of trues in a row and axis = 0 will count number of trues in columns so

boolarr[[true,true,true],[false,false,true]]
print(boolarr.sum(axis=1))

will be (3,1)

How do I center text horizontally and vertically in a TextView?

Try this:

<TextView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center" />

Using a Glyphicon as an LI bullet point (Bootstrap 3)

If you want happen to be using LESS it can be achieved like so:

li {
    .glyphicon-ok();

    &:before {            
        .glyphicon();            
        margin-left:-25px;
       float:left;
    }
}

Read the package name of an Android APK

You can install the apk on your phone, then

connect using adb, you can launch adb shell and execute pm list packages -f, which shows the package name for each installed apk.

This taken from Find package name for Android apps to use Intent to launch Market app from web

Use jQuery to change an HTML tag?

Here's an extension that will do it all, on as many elements in as many ways...

Example usage:

keep existing class and attributes:

$('div#change').replaceTag('<span>', true);

or

Discard existing class and attributes:

$('div#change').replaceTag('<span class=newclass>', false);

or even

replace all divs with spans, copy classes and attributes, add extra class name

$('div').replaceTag($('<span>').addClass('wasDiv'), true);

Plugin Source:

$.extend({
    replaceTag: function (currentElem, newTagObj, keepProps) {
        var $currentElem = $(currentElem);
        var i, $newTag = $(newTagObj).clone();
        if (keepProps) {//{{{
            newTag = $newTag[0];
            newTag.className = currentElem.className;
            $.extend(newTag.classList, currentElem.classList);
            $.extend(newTag.attributes, currentElem.attributes);
        }//}}}
        $currentElem.wrapAll($newTag);
        $currentElem.contents().unwrap();
        // return node; (Error spotted by Frank van Luijn)
        return this; // Suggested by ColeLawrence
    }
});

$.fn.extend({
    replaceTag: function (newTagObj, keepProps) {
        // "return" suggested by ColeLawrence
        return this.each(function() {
            jQuery.replaceTag(this, newTagObj, keepProps);
        });
    }
});

What does hash do in python?

The Python docs for hash() state:

Hash values are integers. They are used to quickly compare dictionary keys during a dictionary lookup.

Python dictionaries are implemented as hash tables. So any time you use a dictionary, hash() is called on the keys that you pass in for assignment, or look-up.

Additionally, the docs for the dict type state:

Values that are not hashable, that is, values containing lists, dictionaries or other mutable types (that are compared by value rather than by object identity) may not be used as keys.

Python Pandas : group by in group by and average?

I would simply do this, which literally follows what your desired logic was:

df.groupby(['org']).mean().groupby(['cluster']).mean()

How to loop through elements of forms with JavaScript?

You need to get a reference of your form, and after that you can iterate the elements collection. So, assuming for instance:

<form method="POST" action="submit.php" id="my-form">
  ..etc..
</form>

You will have something like:

var elements = document.getElementById("my-form").elements;

for (var i = 0, element; element = elements[i++];) {
    if (element.type === "text" && element.value === "")
        console.log("it's an empty textfield")
}

Notice that in browser that would support querySelectorAll you can also do something like:

var elements = document.querySelectorAll("#my-form input[type=text][value='']")

And you will have in elements just the element that have an empty value attribute. Notice however that if the value is changed by the user, the attribute will be remain the same, so this code is only to filter by attribute not by the object's property. Of course, you can also mix the two solution:

var elements = document.querySelectorAll("#my-form input[type=text]")

for (var i = 0, element; element = elements[i++];) {
    if (element.value === "")
        console.log("it's an empty textfield")
}

You will basically save one check.

Why is my toFixed() function not working?

I tried function toFixed(2) many times. Every time console shows "toFixed() is not a function".

but how I resolved is By using Math.round()

eg:

if ($(this).attr('name') == 'time') {
    var value = parseFloat($(this).val());
    value = Math.round(value*100)/100; // 10 defines 1 decimals, 100 for 2, 1000 for 3
    alert(value);
}

this thing surely works for me and it might help you guys too...

Hashing with SHA1 Algorithm in C#

I'll throw my hat in here:

(as part of a static class, as this snippet is two extensions)

//hex encoding of the hash, in uppercase.
public static string Sha1Hash (this string str)
{
    byte[] data = UTF8Encoding.UTF8.GetBytes (str);
    data = data.Sha1Hash ();
    return BitConverter.ToString (data).Replace ("-", "");
}
// Do the actual hashing
public static byte[] Sha1Hash (this byte[] data)
{
    using (SHA1Managed sha1 = new SHA1Managed ()) {
    return sha1.ComputeHash (data);
}

Android: adb: Permission Denied

Run your cmd as administrator this will solve my issues. Thanks.

VideoView Full screen in android application

DisplayMetrics metrics = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(metrics);
android.widget.LinearLayout.LayoutParams params = (android.widget.LinearLayout.LayoutParams) mVideoView.getLayoutParams();
params.width = (int) metrics.widthPixels;
params.height = (int) metrics.heightPixels;
mVideoView.setLayoutParams(params);

playVideo();
aspectRatio = VideoInfo.AR_4_3_FIT_PARENT;
mVideoView.getPlayer().aspectRatio(aspectRatio);

How to delete a file after checking whether it exists

Use System.IO.File.Delete like so:

System.IO.File.Delete(@"C:\test.txt")

From the documentation:

If the file to be deleted does not exist, no exception is thrown.

Check if property has attribute

This is a pretty old question but I used

My method has this parameter but it could be built:

Expression<Func<TModel, TValue>> expression

Then in the method this:

System.Linq.Expressions.MemberExpression memberExpression 
       = expression.Body as System.Linq.Expressions.MemberExpression;
Boolean hasIdentityAttr = System.Attribute
       .IsDefined(memberExpression.Member, typeof(IsIdentity));

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

I would definitely suggest using element.getBoundingClientRect().

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

Summary

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

Syntax

var rectObject = object.getBoundingClientRect();

Returns

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

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

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

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

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

You can use it like this:

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

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

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

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

Note:

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

The name 'ViewBag' does not exist in the current context

You need to add the MVC-specific Razor configuration to your web.config. See here: Razor HtmlHelper Extensions (or other namespaces for views) Not Found

Use the MVC 3 upgrade tool to automatically ensure you have the right config values.

How to use foreach with a hash reference?

In Perl 5.14 (it works in now in Perl 5.13), we'll be able to just use keys on the hash reference

use v5.13.7;

foreach my $key (keys $ad_grp_ref) {
    ...
}

sql like operator to get the numbers only

With SQL 2012 and later, you could use TRY_CAST/TRY_CONVERT to try converting to a numeric type, e.g. TRY_CAST(answer AS float) IS NOT NULL -- note though that this will match scientific notation too (1+E34). (If you use decimal, then scientific notation won't match)

OSError: [WinError 193] %1 is not a valid Win32 application

I solved this by Following steps:

  1. Uninstalled python
  2. removed Python37 Folder from C/program files/ and user/sukhendra/AppData
  3. removed all python37 paths

then only Anaconda is remaining in my PC so opened Anaconda and then it's all working fine for me

Vue-router redirect on page not found (404)

I think you should be able to use a default route handler and redirect from there to a page outside the app, as detailed below:

const ROUTER_INSTANCE = new VueRouter({
    mode: "history",
    routes: [
        { path: "/", component: HomeComponent },
        // ... other routes ...
        // and finally the default route, when none of the above matches:
        { path: "*", component: PageNotFound }
    ]
})

In the above PageNotFound component definition, you can specify the actual redirect, that will take you out of the app entirely:

Vue.component("page-not-found", {
    template: "",
    created: function() {
        // Redirect outside the app using plain old javascript
        window.location.href = "/my-new-404-page.html";
    }
}

You may do it either on created hook as shown above, or mounted hook also.

Please note:

  1. I have not verified the above. You need to build a production version of app, ensure that the above redirect happens. You cannot test this in vue-cli as it requires server side handling.

  2. Usually in single page apps, server sends out the same index.html along with app scripts for all route requests, especially if you have set <base href="/">. This will fail for your /404-page.html unless your server treats it as a special case and serves the static page.

Let me know if it works!

Update for Vue 3 onward:

You'll need to replace the '*' path property with '/:pathMatch(.*)*' if you're using Vue 3 as the old catch-all path of '*' is no longer supported. The route would then look something like this:

{ path: '/:pathMatch(.*)*', component: PathNotFound },

See the docs for more info on this update.

How does an SSL certificate chain bundle work?

You need to use the openssl pkcs12 -export -chain -in server.crt -CAfile ...

See https://www.openssl.org/docs/apps/pkcs12.html

How do I find the current executable filename?

I think this should be what you want:

System.Reflection.Assembly.GetEntryAssembly().Location

This returns the assembly that was first loaded when the process started up, which would seem to be what you want.

GetCallingAssembly won't necessarily return the assembly you want in the general case, since it returns the assembly containing the method immediately higher in the call stack (i.e. it could be in the same DLL).

What is the difference between "Class.forName()" and "Class.forName().newInstance()"?

Class.forName() gets a reference to a Class, Class.forName().newInstance() tries to use the no-arg constructor for the Class to return a new instance.

Echo equivalent in PowerShell for script testing

It should also be mentioned, that Set-PSDebug is similar to the old-school echo on batch command:

Set-PSDebug -Trace 1

This command will result in showing every line of the executing script:

When the Trace parameter has a value of 1, each line of script is traced as it runs. When the parameter has a value of 2, variable assignments, function calls, and script calls are also traced. If the Step parameter is specified, you're prompted before each line of the script runs.

You must enable the openssl extension to download files via https

Late answer but adding so other can learn the reason.

You also need to edit the php.ini file in the "wamp\bin\php\php-X.Y.Z" location.

Display rows with one or more NaN values in pandas dataframe

Use df[df.isnull().any(axis=1)] for python 3.6 or above.

Must declare the scalar variable

Here is a simple example :

Create or alter PROCEDURE getPersonCountByLastName (
@lastName varchar(20),
@count int OUTPUT
)
As
Begin
select @count = count(personSid) from Person where lastName like @lastName
End;

Execute below statements in one batch (by selecting all)

1. Declare @count int
2. Exec getPersonCountByLastName kumar, @count output
3. Select @count

When i tried to execute statements 1,2,3 individually, I had the same error. But when executed them all at one time, it worked fine.

The reason is that SQL executes declare, exec statements in different sessions.

Open to further corrections.

Convert character to ASCII numeric value in java

Just cast the char to an int.

char character = 'a';
int number = (int) character;

The value of number will be 97.

C#: List All Classes in Assembly

Use Assembly.GetTypes. For example:

Assembly mscorlib = typeof(string).Assembly;
foreach (Type type in mscorlib.GetTypes())
{
    Console.WriteLine(type.FullName);
}

How can I String.Format a TimeSpan object with a custom format in .NET?

I used the code below. It is long, but still it is one expression, and produces very friendly output, as it does not outputs days, hours, minutes, or seconds if they have value of zero.

In the sample it produces output: "4 days 1 hour 3 seconds".

TimeSpan sp = new TimeSpan(4,1,0,3);
string.Format("{0}{1}{2}{3}", 
        sp.Days > 0 ? ( sp.Days > 1 ? sp.ToString(@"d\ \d\a\y\s\ "): sp.ToString(@"d\ \d\a\y\ ")):string.Empty,
        sp.Hours > 0 ? (sp.Hours > 1 ? sp.ToString(@"h\ \h\o\u\r\s\ ") : sp.ToString(@"h\ \h\o\u\r\ ")):string.Empty,
        sp.Minutes > 0 ? (sp.Minutes > 1 ? sp.ToString(@"m\ \m\i\n\u\t\e\s\ ") :sp.ToString(@"m\ \m\i\n\u\t\e\ ")):string.Empty,
        sp.Seconds > 0 ? (sp.Seconds > 1 ? sp.ToString(@"s\ \s\e\c\o\n\d\s"): sp.ToString(@"s\ \s\e\c\o\n\d\s")):string.Empty);

Page redirect with successful Ajax request

I think you can do that with:

window.location = "your_url";

How does a Java HashMap handle different objects with the same hash code?

It gonna be a long answer , grab a drink and read on …

Hashing is all about storing a key-value pair in memory that can be read and written faster. It stores keys in an array and values in a LinkedList .

Lets Say I want to store 4 key value pairs -

{
“girl” => “ahhan” , 
“misused” => “Manmohan Singh” , 
“horsemints” => “guess what”, 
“no” => “way”
}

So to store the keys we need an array of 4 element . Now how do I map one of these 4 keys to 4 array indexes (0,1,2,3)?

So java finds the hashCode of individual keys and map them to a particular array index . Hashcode Formulae is -

1) reverse the string.

2) keep on multiplying ascii of each character with increasing power of 31 . then add the components .

3) So hashCode() of girl would be –(ascii values of  l,r,i,g are 108, 114, 105 and 103) . 

e.g. girl =  108 * 31^0  + 114 * 31^1  + 105 * 31^2 + 103 * 31^3  = 3173020

Hash and girl !! I know what you are thinking. Your fascination about that wild duet might made you miss an important thing .

Why java multiply it with 31 ?

It’s because, 31 is an odd prime in the form 2^5 – 1 . And odd prime reduces the chance of Hash Collision

Now how this hash code is mapped to an array index?

answer is , Hash Code % (Array length -1) . So “girl” is mapped to (3173020 % 3) = 1 in our case . which is second element of the array .

and the value “ahhan” is stored in a LinkedList associated with array index 1 .

HashCollision - If you try to find hasHCode of the keys “misused” and “horsemints” using the formulae described above you’ll see both giving us same 1069518484. Whooaa !! lesson learnt -

2 equal objects must have same hashCode but there is no guarantee if the hashCode matches then the objects are equal . So it should store both values corresponding to “misused” and “horsemints” to bucket 1 (1069518484 % 3) .

Now the hash map looks like –

Array Index 0 –
Array Index 1 - LinkedIst (“ahhan” , “Manmohan Singh” , “guess what”)
Array Index 2 – LinkedList (“way”)
Array Index 3 – 

Now if some body tries to find the value for the key “horsemints” , java quickly will find the hashCode of it , module it and start searching for it’s value in the LinkedList corresponding index 1 . So this way we need not search all the 4 array indexes thus making data access faster.

But , wait , one sec . there are 3 values in that linkedList corresponding Array index 1, how it finds out which one was was the value for key “horsemints” ?

Actually I lied , when I said HashMap just stores values in LinkedList .

It stores both key value pair as map entry. So actually Map looks like this .

Array Index 0 –
Array Index 1 - LinkedIst (<”girl” => “ahhan”> , <” misused” => “Manmohan Singh”> , <”horsemints” => “guess what”>)
Array Index 2 – LinkedList (<”no” => “way”>)
Array Index 3 – 

Now you can see While traversing through the linkedList corresponding to ArrayIndex1 it actually compares key of each entry to of that LinkedList to “horsemints” and when it finds one it just returns the value of it .

Hope you had fun while reading it :)

Get the first N elements of an array?

You can use array_slice as:

$sliced_array = array_slice($array,0,$N);