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PHP array_filter() Function with Example

PHP array_filter() Function: Here, we are going to learn about the array_filter() function with example in PHP.
Submitted by IncludeHelp, on February 10, 2019

PHP array_filter() Function

array_filter() function is used to apply a filter on array elements based on the function and returns the array with filtered elements, it accepts an array to be checked and a callback function. The callback function is used to validate the elements in the array.

Syntax:

    array_filter(array,callback_function) : array

Here,

  • array is the input array in which we have to apply the filter.
  • callback_function is the function, in which we write the condition to be validated.

Examples:

    Input:
    $arr = array(10, 20, -10, -20, 50, 0);

    //here we have to filter the positive numbers 
    //the callback function to check the positive number is "isPositive()"
    Function calling: 
    $temp = array_filter($arr, "isPositive");

    Output:
    Array
    (
        [0] => 10
        [1] => 20
        [4] => 50
    )

    So, here 0th , 1st and 4th elements are positive

PHP code 1: Find the positive number from given array of the numbers.

<?php
    //function to check wheather number is positive or not
    function isPositive($val)
    {
        if($val>0)
            return $val;
    }
    
    // array 
    $arr = array(10, 20, -10, -20, 50, 0);
    
    // array with only positive value
    $temp = array_filter($arr, "isPositive");
    
    print_r ($temp);
    
?>

Output

Array
(
    [0] => 10
    [1] => 20
    [4] => 50
)

PHP code 2: Find the persons who are eligible for voting from given array of persons

Here, we also have the "keys" and based on the age key we are checking the voting eligibility.

<?php
    //function to check wheather person is eligible
    //for voting or not?
    function isVoter($val)
    {
        if($val['age']>=18)
            return $val;
    }
    
    // person's array 
    $arr = array(
            array("name" => "Prem", "age" => 28,"city" => "Gwalior",),
            array("name" => "Manju", "age" => 25,"city" => "Gwalior",),
            array("name" => "Radib Kar", "age" => 23,"city" => "Chennai",),
            array("name" => "Prerana", "age" => 17,"city" => "Gwalior",),
        );
    
    // array with voting eligible persons
    $temp = array_filter($arr, "isVoter");
    
    print_r ($temp);
    
?>

Output

Array
(
    [0] => Array
        (
            [name] => Prem
            [age] => 28   
            [city] => Gwalior
        )
         
    [1] => Array          
        (
            [name] => Manju  
            [age] => 25   
            [city] => Gwalior
        )
         
    [2] => Array          
        (
            [name] => Radib Kar 
            [age] => 23   
            [city] => Chennai
        )
         
)






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