PHP array function array_map() notes_PHP tutorial

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Release: 2016-07-13 10:17:15
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PHP array function array_map() notes

Definition and usage

The array_map() function returns the array after the user-defined function is applied. The callback function should accept the same number of arguments as the number of arrays passed to the array_map() function.

Grammar

array_map(function,array1,array2,array3...)

参数 描述
function 必需。用户自定义函数的名称,或者是 null。
array1 必需。规定数组。
array2 可选。规定数组。
array3 可选。规定数组。

Example 1

<?php
function myfunction($v) {
	if ($v === "Dog") {
		return "Fido";
	}
	return $v;
}

$a = array("Horse", "Dog", "Cat");
print_r(array_map("myfunction", $a));
?>
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Output:

Array ( [0] => Horse [1] => Fido [2] => Cat )

Example 2

Use multiple parameters:

<?php
function myfunction($v1, $v2) {
	if ($v1 === $v2) {
		return "same";
	}
	return "different";
}

$a1 = array("Horse", "Dog", "Cat");
$a2 = array("Cow", "Dog", "Rat");
print_r(array_map("myfunction", $a1, $a2));
?>
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Output:

Array ( [0] => different [1] => same [2] => different )

Example 3

Please see what happens when the custom function name is set to null:

<?php
$a1 = array("Dog", "Cat");
$a2 = array("Puppy", "Kitten");
print_r(array_map(null, $a1, $a2));
?>
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Output:

Array (
[0] => Array ( [0] => Dog [1] => Puppy )
[1] => Array ( [0] => Cat [1] => Kitten )
)

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www.bkjia.comtruehttp: //www.bkjia.com/PHPjc/894201.htmlTechArticlePHP array function array_map() notes definition and usage array_map() function returns the array after the user-defined function is applied. The number of arguments accepted by the callback function should be the same as the number of arguments passed to the array_map() function...
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