New features of PHP 5.5 with Examples

Following are 5.5 new features.

1. Generators: has been added via the yield keyword.
   Generators provide an easy way to implement simple iterators.
   For Example:

    function xrange($start, $limit, $step = 1) {
       for ($i = $start; $i <= $limit; $i += $step) {
           yield $i;
       }
     }
     
     echo 'List of odd Numbers:';
     
     foreach (xrange(1, 9, 2) as $number) {
         echo "$number ";
     }
     

2. finally: keyword added in try catch.
   In try catch, finally block will be called every time, regardless of whether an exception has been thrown or not.
   For Example:

       
       try {
       //write code here 
     }
     catch (Exception $e) {
         //Exception comes here
     }
     finally {
         echo "I am called everytime";
     } 

3. New password hashing API
   Password hashing API that makes it easier to securely hash and manage passwords using the same crypt() in PHP has been added.
4. foreach now supports list()
   Now in PHP5.5, You can use list function inside foreach function.
   See Example

    $listArray = [
       [10, 20],
       [30, 40],
       [50, 60],
   ];
   
   foreach($listArray as list($a, $b)) {
       echo "A: $a; B: $b";
   } 

5. empty() supports expressions
   Now you can use expression in empty function.
   For Example:

     if(!empty(2*3)){
       echo "Its working";
       }

6. Array and String literal dereferencing.
   String and Array can now be dereferenced directly to access individual elements OR characters.
   For Example

   echo 'Array dereferencing: ';
     echo [10, 02, 30][0];//10
     echo "\n";
     
     echo 'String dereferencing: ';
     echo 'Web Technology'[0]; //W
       

7. Class name resolution via ::class
   ClassName::class to get a fully qualified name of class ClassName.
   For Example

   namespace Foo;
     class Bar {}
      
     echo Bar::class;

8. OPcache extension added
   The Zend Optimiser+ opcode cache has been added to PHP5.5 as the new OPcache extension.
9. foreach now supports non-scalar keys. For non-scalar keys, an Iterator must be used as they cannot occur in native PHP array.
   
10. Apache 2.4 handler supported on Windows
11. Improvements to GD Library.

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