PHP Velho Oeste 2024

array_uintersect

(PHP 5, PHP 7, PHP 8)

array_uintersect计算数组的交集,用回调函数比较数据

说明

array_uintersect(array $array, array ...$arrays, callable $value_compare_func): array

array_uintersect() 返回一个数组,该数组包含了所有在 array1 中也同时出现在所有其它参数数组中的值。数据比较是用回调函数进行的。 此比较是通过用户提供的回调函数来进行的。如果认为第一个参数小于,等于,或大于第二个参数时必须分别返回一个小于零,等于零,或大于零的整数。

参数

array

第一个数组。

arrays

要比较的数组。

value_compare_func

在第一个参数小于,等于或大于第二个参数时,该比较函数必须相应地返回一个小于,等于或大于 0 的整数。

callback(mixed $a, mixed $b): int
警告

从比较函数中返回非整数值,例如 float,将导致内部强制转换为 callback 返回值为 int。因此,诸如 0.990.1 之类的值都将被转换为整数值 0,将这些值比较的话将会是相等。

警告

排序回调必须以任意顺序处理任意数组中的任意值,无论它们最初提供的顺序如何。这是因为每个单独的数组在与其他数组进行比较之前首先进行排序。例如:

<?php
$arrayA
= ["string", 1];
$arrayB = [["value" => 1]];
// $item1 和 $item2 可以是“string”、1 或 ["value" => 1]
$compareFunc = static function ($item1, $item2) {
$value1 = is_string($item1) ? strlen($item1) : (is_array($item1) ? $item1["value"] : $item1);
$value2 = is_string($item2) ? strlen($item2) : (is_array($item2) ? $item2["value"] : $item2);
return
$value1 <=> $value2;
};
?>

返回值

返回一个数组,数组中包含了 array 中在所有的参数中都存在的值。

示例

示例 #1 array_uintersect() 示例

<?php
$array1
= array("a" => "green", "b" => "brown", "c" => "blue", "red");
$array2 = array("a" => "GREEN", "B" => "brown", "yellow", "red");

print_r(array_uintersect($array1, $array2, "strcasecmp"));
?>

以上示例会输出:

Array
(
    [a] => green
    [b] => brown
    [0] => red
)

参见

add a note

User Contributed Notes 4 notes

up
17
Nate at RuggFamily dot com
17 years ago
I want to stress that in the user function, you do need to return either a 1 or a -1 properly; you cannot simply return 0 if the results are equal and 1 if they are not.

The following code is incorrect:

<?php
function myfunction($v1,$v2)
{
if (
$v1===$v2)
{
return
0;
}
return
1;
}

$a1=array(1, 2, 4);
$a2=array(1, 3, 4);
print_r(array_uintersect($a1,$a2,"myfunction"));
?>

This code is correct:

<?php
function myfunction($v1,$v2)
{
if (
$v1===$v2)
{
return
0;
}
if (
$v1 > $v2) return 1;
return -
1;
}
$a1=array(1, 2, 4);
$a2=array(1, 3, 4);
print_r(array_uintersect($a1,$a2,"myfunction"));
?>
up
5
Ryan C
1 year ago
If you're rolling your own comparison function, keep in mind that the spaceship operator (i.e. <=>) can be your best friend. It's been around since PHP7. https://www.php.net/manual/en/language.operators.comparison.php

So, for instance, instead of a clunky function like:

<?php
function myFunction($v1, $v2) {
if (
$v1 === $v2) {
return
0;
}
if (
$v1 > $v2) return 1;
return -
1;
}
?>

You can simplify it to:

<?php
function myFunction($v1, $v2) {
return
$v1 <=> $v2;
}
?>
up
2
rob dot c dot ruiz at gmail dot com
5 years ago
When trying to do a case insensitive comparison between arrays of words, the strcasecmp function works very nicely with this one like so:

$arr1 = array('blue', 'green', 'red');

$arr2 = array('BLUE', 'Purple', 'Red');

$loose_matches = array_uintersect($arr1, $arr2, 'strcasecmp');

print_r($loose_matches) // array('blue', 'red');
up
2
Hayley Watson
6 years ago
As for the other "compare function" callbacks, the return value from the callback function doesn't need to be -1, 0, or 1.

cmp($a,$b) just needs to be <0, =0, or >0 depending on whether $a<$b, $a=$b, or $a>$b.
To Top