PHP array_filter（）函数与示例

PHP array_filter()函数 (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.

array_filter()函数用于基于该函数在数组元素上应用过滤器，并返回带有已过滤元素的数组，它接受要检查的数组和回调函数。回调函数用于验证数组中的元素。

Syntax:

句法：

    array_filter(array,callback_function) : array

Here,

这里，

array is the input array in which we have to apply the filter.
数组是我们必须在其中应用过滤器的输入数组。
callback_function is the function, in which we write the condition to be validated.
callback_function是函数，我们在其中编写要验证的条件。

Examples:

例子：

    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 0^th , 1^st and 4^th elements are positive

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

PHP代码1：从给定的数字数组中找到正数。

<?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

输出量

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

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

PHP代码2：从给定的一组人员中找到有资格投票的人员

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

在这里，我们还有“键”，并且根据年龄键，我们正在检查投票资格。

<?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

输出量

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
)
)