PHP array_reverse() Function

PHP array_reverse() Function

The array_reverse() function in PHP returns a new array with the elements in the reversed order.

Syntax

array_reverse (array $array [, bool $preserve_keys = FALSE ] )

Parameter

array(required)- This parameter represents the input array

preserve_keys (optional)- This parameter specifies if the function should preserve the keys of the array or not. It takes a Boolean value, and if set to true, the numeric keys are preserved else for Boolean false (default value), the keys are not preserved.

Return

This function returns the reversed array.

Example 1

Output

Array : Array
 (
     [0] => A
     [1] => b
     [2] => c
     [3] => d
 )
 Reversed Array:  
 Array
 (
     [0] => d
     [1] => c
     [2] => b
     [3] => A
 ) 

Example 2

Output

Initialized Array : Array
 (
     [0] => apple
     [1] => banana
     [2] => guava
     [3] => orange
 ) 
 Reversed Array: 
 Array
 (
     [3] => orange
     [2] => guava
     [1] => banana
     [0] => apple
 ) 

Example 3

Output

Initialized Array : Array
 (
     [0] => php
     [1] => Python
     [2] => C#
     [3] => java
     [4] => Array 
         (
             [0] => Spring
             [1] => Hibernate
         )
 )
 Reversed Array:  
 Array
 (
     [4] => Array
         (
             [0] => Spring
             [1] => Hibernate 
         )
     [3] => java
     [2] => C#
     [1] => Python
     [0] => php
 ) 

Example 4

"a",2=>"b",3=>"c");
 echo("Initialized Array : ");
 print_r($array);
 //Return an array with elements in reverse order while setting the preserve_value true
 $reversed_array = array_reverse($array, true);//keys are preserved
 echo("\nReversed Array while preserving the keys: \n"); 
 //printing the reversed array
 print_r($reversed_array);
 //Return an array with elements in reverse order while setting the preserve_value false
 $reversed_array = array_reverse($array, false);//keys are not preserved
 echo("\nReversed Array while not preserving the keys: \n");
 //printing the reversed array 
 print_r($reversed_array);
 ?> 

Output

Initialized Array: Array
 (
     [1] => a
     [2] => b
     [3] => c
 )
 Reversed Array while preserving the keys: 
 Array 
 (
     [3] => c
     [2] => b
     [1] => a
 ) 
 Reversed Array while not preserving the keys: 
 Array
 (
     [0] => c
     [1] => b
     [2] => a
 )