这篇文章主要介绍了php array_walk array_map array_filter区别案例详解,本篇文章通过简要的案例,讲解了该项技术的了解与使用,以下就是详细内容,需要的朋友可以参考下
php 开发经常遇到数组处理，会涉及到题目中这几个函数。这个函数功能类似，很多时候容易混淆。
array_walk — 使用用户自定义函数对数组中的每个元素做回调处理
<?php
$fruits = array("d" => "lemon", "a" => "orange", "b" => "banana", "c" => "apple");function test_alter(&$item1, $key, $prefix)
{
$item1 = "$prefix: $item1";
}echo "Before ...:\n";
array_walk($fruits, 'test_print');array_walk($fruits, 'test_alter', 'fruit');
echo "... and after:\n";array_walk($fruits, 'test_print');
?>//运行结果Before …:d. lemona. orangeb. bananac. apple … and after:d. fruit: lemona. fruit: orangeb. fruit: bananac. fruit: apple
更多信息参考官方文档：http://php.net/manual/zh/function.array-walk.php
array_maparray_map — 为数组的每个元素应用回调函数
Example #1：
<?php
$func = function($value) {
return $value * 2;
};print_r(array_map($func, range(1, 5)));
?>//运行结果
Array([0] => 2[1] => 4[2] => 6[3] => 8[4] => 10
)Example #3：
<?php
function show_Spanish($n, $m)
{
return("The number $n is called $m in Spanish");
}function map_Spanish($n, $m)
{
return(array($n => $m));
}$a = array(1, 2, 3, 4, 5);
$b = array("uno", "dos", "tres", "cuatro", "cinco");$c = array_map("show_Spanish", $a, $b);
print_r($c);$d = array_map("map_Spanish", $a , $b);
print_r($d);
?>
//运行结果
// printout of $cArray([0] => The number 1 is called uno in Spanish[1] => The number 2 is called dos in Spanish[2] => The number 3 is called tres in Spanish[3] => The number 4 is called cuatro in Spanish[4] => The number 5 is called cinco in Spanish)
// printout of $dArray([0] => Array([1] => uno)
[1] => Array
([2] => dos)
[2] => Array
([3] => tres)
[3] => Array
([4] => cuatro)
[4] => Array
([5] => cinco)
更多信息参考官方文档：http://php.net/manual/zh/function.array-map.php
array_filter
Example 1:
<?php
function odd($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);
$array2 = array(6, 7, 8, 9, 10, 11, 12);echo "Odd :\n";
print_r(array_filter($array1, "odd"));
echo "Even:\n";
print_r(array_filter($array2, "even"));
?>
//运行结果Array
(
[0] => foo[2] => -1
)
Example #3：
<?php
$arr = ['a' => 1, 'b' => 2, 'c' => 3, 'd' => 4];
var_dump(array_filter($arr, function($k) {
return $k == 'b';
}, ARRAY_FILTER_USE_KEY));
var_dump(array_filter($arr, function($v, $k) {
return $k == 'b' || $v == 4;
}, ARRAY_FILTER_USE_BOTH));
?>
//运行结果
array(1) {
[“b”]=>
int(2)
}
array(2) {
[“b”]=>
int(2)
[“d”]=>
int(4)
)
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