As of PHP 7.1, there are real private constants.

    private const PRIVATE_CONST = 0;

See the [Class Constant Visibility RFC][1] for more information.


  [1]: https://wiki.php.net/rfc/class_const_visibility

Use `private static` properties.

In that case you will have the same variable throughout all objects and if you want to extend its scope to nested, you can expose a getter method to get its value and restrict variables settings.


I&#39;ve been playing around with a system I&#39;m developing and managed to get it to cause this:

&gt; Fatal error: Maximum execution time of 30 seconds exceeded

It happened when I was doing something unrealistic, but nevertheless it could happen with a user.

Does anyone know if there is a way to catch this exception? I&#39;ve read around but everyone seems to suggest upping the time allowed.

How to catch the fatal error: Maximum execution time of 30 seconds exceeded in PHP

Is it possible to create a CSS rule that would apply a style to any IMG tag with a SRC that contained a specific string, say &quot;hideme&quot;?  For instance, if I had the following 3 images on a page it would hide the second one?

    &lt;img src=&quot;images/test1.png&quot;&gt;
    &lt;img src=&quot;images/hideme.gif&quot;&gt;
    &lt;img src=&quot;images/test3.jpg&quot;&gt;

CSS hide all images with matching SRC attribute

I have a class that benefits from the use of constants in its internal implementation, but I would like to limit visibility of these constants. Why doesn&#39;t PHP permit private constants?  Is there another way to achieve this or is PHP trying to discourage some type of design misstep I am ignorant of?

Why doesn&#39;t PHP permit private const?

<p>I have a class that benefits from the use of constants in its internal implementation, but I would like to limit visibility of these constants. Why doesn't PHP permit private constants?  Is there another way to achieve this or is PHP trying to discourage some type of design misstep I am ignorant of?</p>


Any way to return PHP `json_encode` with encode UTF-8 and not Unicode?

    $arr=array(&#39;a&#39;=&gt;&#39;&#225;&#39;);
    echo json_encode($arr);

`mb_internal_encoding(&#39;UTF-8&#39;);`and `$arr=array_map(&#39;utf8_encode&#39;,$arr);` does not fix it.


Result: `{&quot;a&quot;:&quot;\u00e1&quot;}`

**Expected result: `{&quot;a&quot;:&quot;&#225;&quot;}`**

Any way to return PHP `json_encode` with encode UTF-8 and not Unicode?

I need to check in PHP if user entered a decimal number (US way, with decimal point: X.XXX)

Any reliable way to do this?

Check if number is decimal

I have an array which is multidimensional for no reason

    /* This is how my array is currently */
    Array
    (
    [0] =&gt; Array
        (
            [0] =&gt; Array
                (
                    [plan] =&gt; basic
                )
 
            [1] =&gt; Array
                (
                    [plan] =&gt; small
                )
 
            [2] =&gt; Array
                (
                    [plan] =&gt; novice
                )
 
            [3] =&gt; Array
                (
                    [plan] =&gt; professional
                )
 
            [4] =&gt; Array
                (
                    [plan] =&gt; master
                )
 
            [5] =&gt; Array
                (
                    [plan] =&gt; promo
                )
 
            [6] =&gt; Array
                (
                    [plan] =&gt; newplan
                )
 
        )
 
     )

 
I want to convert this array into this form

    /*Now, I want to simply it down to this*/
    Array (
	[0] =&gt; basic
	[1] =&gt; small
	[2] =&gt; novice
	[3] =&gt; professional
	[4] =&gt; master
	[5] =&gt; promo
	[6] =&gt; newplan
    )

Any idea how to do this? 

Convert multidimensional array into single array

I&#39;m trying to set the width of a cell in an Excel document generated with PHPExcel with:

    $objPHPExcel-&gt;getActiveSheet()-&gt;getColumnDimensionByColumn(&#39;C&#39;)-&gt;setWidth(&#39;10&#39;);
    $objPHPExcel-&gt;getActiveSheet()-&gt;getColumnDimensionByColumn(&#39;C&#39;)-&gt;setAutoSize(false);

but that does not works.

What is the method that I need to call here?

Setting width of spreadsheet cell using PHPExcel

I downloaded symfony2 and I am able to run it starting from app_dev.php.

But when I start from app.php, then I get an error page 404.

app.php though is of course there and it gets executed.

The error happens apparently somewhere after the last line of code in app.php:

    $kernel-&gt;handle(Request::createFromGlobals())-&gt;send();

I guess there is a switch somewhere I have to configure.

**EDIT**:

As suggested by GeLo I added the routing for the production version to app/config/routing.yml. 

    _welcome:
        resource: &quot;@AcmeDemoBundle/Resources/config/routing.yml&quot;
        prefix:     /

I created src/Acme/DemoBundle/Resources/config/routing.yml with content:

    bla:
        pattern: /
        defaults: {_controller:AcmeDemoBundle:Demo:index}

In `DemoController::indexAction()` I placed a `die(__FILE__)`;

nothing; I still get 404 from app.php !?

**EDIT regarding the answer:**

    ./app/console --env=prod cache:clear

did the trick. mind the env-parameter.

symfony2 - how to switch from &quot;dev&quot; to &quot;prod&quot;?

So far I have a `PHP` class with the constructor

    public function __construct ($identifier = NULL)
    {
     // Return me.
    if ( $identifier != NULL )
    {
      $this-&gt;emailAddress = $identifier;
      if ($this-&gt;loadUser() )
	    return $this;      
      else
      {
	// registered user requested , but not found ! 
	return false;
      }
    }

the functionality of `loadUser` is to look up the database for a particular email address. 
When i set the identifier to some email that i&#39;m sure it&#39;s not in the database; the first IF is get passed, and goes to the first ELSE. here the constructor should return FALSE; but instead, it returns an object of the class with all NULL values ! 

how do i prevent this? thanks 


EDIT:

thank you all for the answers. that was quite fast ! I see that the OOP way is to throw an Exception. So a throw one, my question changes that what should i do with the exception?? 
php.net&#39;s manual is pretty confusing ! 

		// Setup the user ( we assume he is a user first. referees, admins are   considered users too )
		try { $him = new user ($_emailAddress);
		} catch (Exception $e_u) { 
		  // try the groups database
		  try { $him = new group ($_emailAddress); 
		  } catch (Exception $e_g) {
		      // email address was not in any of them !!  
		    }
		}

Returning a value in constructor function of a class

Let&#39;s say you have the below code:

    function A() {
        function modify() {
           x = 300;
           y = 400;
        }

        var c = new C();
    }

    function B() {
        function modify(){
           x = 3000;
           y = 4000;
        }

        var c = new C();
    }

    C = function () {
       var x = 10;
       var y = 20;
       
       function modify() {
          x = 30;
          y = 40;
       };
    
       modify();
       alert(&quot;The sum is: &quot; + (x+y));
    }

Now the question is, if there is any way in which I can override the method `modify` from `C` with the methods that are in `A` and `B`. In Java you would use the `super`-keyword, but how can you achieve something like this in JavaScript?

JavaScript override methods

When discussing metaclasses, [the docs][1] state:

&gt; You can of course also override other class methods (or add new
&gt; methods); for example defining a custom `__call__()` method in the
&gt; metaclass allows custom behavior when the class is called, e.g. not
&gt; always creating a new instance.

*[Editor&#39;s note: This was removed from the docs in 3.3. It&#39;s here in 3.2: [Customizing class creation](https://docs.python.org/3.2/reference/datamodel.html#customizing-class-creation)]*

My questions is: suppose I want to have custom behavior when the class is called, for example caching instead of creating fresh objects. I can do this by overriding the `__new__` method of the class. When would I want to define a metaclass with `__call__` instead? What does this approach give that isn&#39;t achievable with `__new__`?

  [1]: http://docs.python.org/reference/datamodel.html

Using the __call__ method of a metaclass instead of __new__?

In C# (and many other languages) it&#39;s perfectly legitimate to access private fields of other instances of the same type. For example:

    public class Foo
    {
        private bool aBool;

        public void DoBar(Foo anotherFoo)
        {
            if (anotherFoo.aBool) ...
        }
    }

As the [C# specification](http://msdn.microsoft.com/en-us/vcsharp/aa336809) (sections 3.5.1, 3.5.2) states access to private fields is on a type, not an instance. I&#39;ve been discussing this with a colleague and we&#39;re trying to come up with a reason why it works like this (rather than restricting access to the same instance).

The best argument we could come up with is for equality checks where the class may want to access private fields to determine equality with another instance. Are there any other reasons? Or some golden reason that absolutely means it must work like this or something would be completely impossible?

Why are private fields private to the type, not the instance?

When someone talks about hydrating an object, what does that mean?

I see a Java project called Hydrate on the web that transforms data between different representations (RDMS to OOPS to XML). Is this the general meaning of object hydration; to transform data between representations? Could it mean reconstructing an object hierarchy from a stored representation?


What does it mean to hydrate an object?

I have Constants NSString, that I want to call like:

    [newString isEqualToString:CONSTANT_STRING];

Any wrong code here?

I got this warning:

&gt; sending &#39;const NSString *&#39; to parameter of type &#39;NSString *&#39; discards qualifiers

How should these be declared?

&quot;sending &#39;const NSString *&#39; to parameter of type &#39;NSString *&#39; discards qualifiers&quot; warning

I would like to put a constant date time in an attribute parameter, how do i make a constant datetime? It&#39;s related to a `ValidationAttribute` of the EntLib Validation Application Block but applies to other attributes as well.

When I do this:

    private DateTime _lowerbound = new DateTime(2011, 1, 1);
    [DateTimeRangeValidator(_lowerbound)]

I&#39;ll get:

    An object reference is required for the non-static field, method, or property _lowerbound

And by doing this

    private const DateTime _lowerbound = new DateTime(2011, 1, 1);
    [DateTimeRangeValidator(_lowerbound)]

I&#39;ll Get:

&gt;The type &#39;System.DateTime&#39; cannot be declared const

Any ideas? Going this way is not preferable:

    [DateTimeRangeValidator(&quot;01-01-2011&quot;)]



Constant DateTime in C#

Container requirements have changed from C++03 to C++11. While C++03 had blanket requirements (e.g. copy constructibility and assignability for vector), C++11 defines fine-grained requirements on each container operation (section 23.2).

As a result, you can e.g. store a type that is copy-constructible but not assignable - such as a structure with a const member - in a vector as long as you only perform certain operations that do not require assignment (construction and `push_back` are such operations; `insert` is not).

What I&#39;m wondering is: does this mean the standard now allows `vector&lt;const T&gt;`? I don&#39;t see any reason it shouldn&#39;t - `const T`, just like a structure with a const member, is a type that is copy constructible but not assignable - but I may have missed something.

(Part of what makes me think I may have missed something, is that gcc trunk crashes and burns if you try to instantiate `vector&lt;const T&gt;`, but it&#39;s fine with `vector&lt;T&gt;` where T has a const member).

Does C++11 allow vector&lt;const T&gt;?

Most of the models in my iOS app query a web server. I would like to have a configuration file storing the base URL of the server. It will look something like this:

    // production
    // static NSString* const baseUrl = &quot;http://website.com/&quot;
    
    // testing
    static NSString* const baseUrl = &quot;http://192.168.0.123/&quot;

By commenting out one line or the other, I can instantly change which server my models point to. My question is, what&#39;s the best practice for storing global constants in iOS? In Android programming, we have this built-in [strings resource file][1]. In any [Activity][2] (the equivalent of a [UIViewController][3]), we can retrieve those string constants with:

    String string = this.getString(R.string.someConstant);

I was wondering if the iOS SDK has an analogous place to store constants. If not, what is the best practice in Objective-C to do so?  

  [1]: https://developer.android.com/guide/topics/resources/string-resource.html
  [2]: https://developer.android.com/reference/android/app/Activity.html
  [3]: https://developer.apple.com/documentation/uikit/uiviewcontroller

Where to store global constants in an iOS application?

Lets say I have an array as:

`int a[]={4,5,7,10,2,3,6}`

when I access an element, such as `a[3]`, what does actually happen behind the scenes?
Why do many algorithm books (such as the Cormen book...) say that it takes a constant time? 

(I&#39;m just a noob in low-level programming so I would like to learn more from you guys)

why does accessing an element in an array take constant time?

If a variable is declared as `public static varName;`, then I can access it from anywhere as `ClassName.varName`. I am also aware that static members are shared by all instances of a class and are not reallocated in each instance.

Is declaring a variable as `private static varName;` any different from declaring a variable `private varName;`?

In both cases it cannot be accessed as `ClassName.varName` or as `ClassInstance.varName` from any other class.

Does declaring the variable as static give it other special properties?

What is the use of a private static variable in Java?

How do I create a private constructor which should be called only by the static function of the class and not from else where?


Private Constructor in Python

As far as I know, `private` is the default *everywhere* in C# (meaning that if I don&#39;t write `public`, `protected`, `internal`, etc. it will be `private` by default). (Please correct me if I am wrong.)

So, what&#39;s the reason to write that keyword, or why does it even exist for members?

For example, when an event handler is auto-generated it looks like this:

    private void RatTrap_MouseEnter(object sender, CheeseEventArgs e)
    {
        
    }

But why does it even write private if that&#39;s implied and default? Just so that novice developers (who don&#39;t know it&#39;s the C# default) know that it&#39;s private? Or is there a difference for the compiler?

Moreover, is there a case where writing &quot;private&quot; (alone) *will* change the accessibility of the member?


Any reason to write the &quot;private&quot; keyword in C#?

Someone gave me access to one of their private repo on Github. What I want to do is to fork that project into my own account, so I could make use of Github&#39;s pull request feature.

I only have a basic account on Github, so I cannot make private repos on my own, but if I fork someone else&#39;s private repo into my account, is it going to appear in my account as public?

If I fork someone else&#39;s private Github repo into my account, is it going to appear in my account as a public repo?

In Java, it&#39;s taught that variables should be kept private to enable better encapsulation, but what about static constants? This:

    public static final int FOO = 5;

Would be equivalent in result to this:

    private static final int FOO = 5;
    ...
    public static getFoo() { return FOO; }
But which is better practice?

&#39;public static final&#39; or &#39;private static final&#39; with getter?

I want to hide public methods from the IntelliSense member list.  I have created an attribute that, when applied to a method, will cause the method to be called when its object is constructed.  I&#39;ve done this to better support partial classes.  The problem is that in some environments (such as Silverlight), reflection cannot access private members, even those of child classes.  This is a problem since all of the work is done in a base class. I have to make these methods public, but I want them to be hidden from IntelliSense, similar to how the `Obsolete` attribute works.  Frankly, because I am anal about object encapsulation. I&#39;ve tried different things, but nothing has actually worked.  The method still shows up in the member drop-down.

**How do I keep public methods from showing up in IntelliSense when I don&#39;t want them to be called by clients?** How&#39;s that for a _real_ question, Philistines! This can also apply to MEF properties that have to be public though sometimes you want to hide them from clients.

**Update:**
I have matured as a developer since I posted this question. Why I cared so much about hiding interface is beyond me.

How to hide public methods from IntelliSense

&gt; **Interviewer:** What is encapsulation and how do you achieve it in Java?
&gt; 
&gt; **Me:**  Encapsulation is a mechanism to hide information from the client. The information may be data or implementation or algorithm. We
&gt; achieve this using access modifiers. 
&gt; 
&gt; 
&gt; **Interviewer:** This is data hiding. How do we achieve encapsulation in Java?
&gt; 
&gt; **Me**: uummmm



**Concrete Question:** Other than &#39;Access Modifiers&#39;, what is the way to implement Encapsulation in Java?

Encapsulation vs Data Hiding - Java

I had an interview today. I had a question from **OOP**, about the difference between **Encapsulation** &amp; **Abstraction**?
 
I replied her to my knowledge that **Encapsulation** is basically to bind data members &amp; member functions into a single unit called **Class**. Whereas **Abstraction** is basically to hide complexity of implementation &amp; provide ease of access to the users. I thought she would be fine with my answer. But she queried, if the purpose of both are to hide information then what is the actual difference between these two? I could not give any answer to her.

Before asking this question, I read other threads on StackOverFlow about the difference between these two **OOP**s concepts. But I am not finding my self in a position to convince the interviewer.

Can anyone please justify it with a simplest example? 

Difference between Encapsulation and Abstraction

Learning OOP concepts especially interested to understand Abstraction and Encapsulation in depth.

Checked out the below already

https://stackoverflow.com/questions/24626/abstraction-vs-information-hiding-vs-encapsulation

https://stackoverflow.com/questions/742341/difference-between-abstraction-and-encapsulation

I found very hard to understand those concepts with out a real and simple example class/code snippet.

&gt; One of my colleagues said abstraction is nothing but creating abstract
&gt; class and normal class that protects its member variable with scope is
&gt; called Encapsulation.

Is there a simple way I can understand and help others to understand what exactly they are, rather than repeating the below?

&gt; Abstraction and encapsulation are complementary concepts: abstraction
&gt; focuses on the observable behavior of an object... encapsulation
&gt; focuses upon the implementation that gives rise to this behavior...
&gt; encapsulation is most often achieved through information hiding, which
&gt; is the process of hiding all of the secrets of object that do not
&gt; contribute to its essential characteristics.

Simple way to understand Encapsulation and Abstraction

Let&#39;s say I have a need for a simple private helper method, and intuitively in the code it would make sense as an extension method. Is there any way to encapsulate that helper to the only class that actually needs to use it?

For example, I try this:

    class Program
    {
        static void Main(string[] args)
        {
            var value = 0;
            value = value.GetNext(); // Compiler error
        }

        static int GetNext(this int i)
        {
            return i + 1;
        }
    }

The compiler doesn&#39;t &quot;see&quot; the `GetNext()` extension method.  The error is:

 &gt; Extension method must be defined in a non-generic static class

Fair enough, so I wrap it in its own class, but still encapsulated within the object where it belongs:

    class Program
    {
        static void Main(string[] args)
        {
            var value = 0;
            value = value.GetNext(); // Compiler error
        }

        static class Extensions
        {
            static int GetNext(this int i)
            {
                return i + 1;
            }
        }
    }

Still no dice.  Now the error states:

 &gt; Extension method must be defined in a top-level static class; Extensions is a nested class.

Is there a compelling reason for this requirement?  There are cases where a helper method really should be privately encapsulated, and there are cases where the code is a lot cleaner and more readable/supportable if a helper method is an extension method.  For cases where these two intersect, can both be satisfied or do we have to choose one over the other?

Content Type	Original Author	Original Content on Stackoverflow
Question	leo	View Question on Stackoverflow
Solution 1 - Php	Jeroen De Dauw	View Answer on Stackoverflow
Solution 2 - Php	sudhir chauhan	View Answer on Stackoverflow

Why doesn't PHP permit private const?

Php Problem Overview

Php Solutions

Solution 1 - Php

Solution 2 - Php

CSS hide all images with matching SRC attribute

How to catch the fatal error: Maximum execution time of 30 seconds exceeded in PHP

Attributions