php中array_filter()函数总结

首先，看php官网的说明：

(PHP 4 >= 4.0.6, PHP 5)

array_filter — Filters elements of an array using a callback function

Report a bug

 Description

array array_filter ( array $input [, callable $callback = "" ] )

Iterates over each value in the input array passing them to the callback function. If the callback function returns true, the current value from input is returned into the result array. Array keys are preserved.

例子1：

<?php
function func_odd($var)
{
    // returns whether the input integer is odd
    return($var & 1);
}

function even($var)
{
    // returns whether the input integer is even
    return(!($var & 1));
}

$array1 = array("a"=>1, "b"=>2, "c"=>3, "d"=>4, "e"=>5);
$array2 = array(6, 7, 8, 9, 10, 11, 12);

echo "Odd :
";
print_r(array_filter($array1, "func_odd"));//回调函数
echo "Even:
";
print_r(array_filter($array2, "even"));
?>

结果：注意数组实际下标并没有改变！

例子2：

$arr = array("a","b","c","d");
去除$arr里的b值;

$arr = array("a","b","c","d");
function isHave($var){
    if($var!="b") return true;
}
array_filter($arr,"isHave");