PHP 中的集合运算
A∩B
array_intersect
example:
$array1 = array("a" => "green", "red", "blue");
$array2 = array("b" => "green", "yellow", "red");
$result = array_intersect($array1, $array2);
print_r($result);
output
Array
(
[a] => green
[0] => red
)
A-B & B-A
<?php
$array1 = array("a" => "green", "red", "blue", "red");
$array2 = array("b" => "green", "yellow", "red");
$result = array_diff($array1, $array2);
print_r($result);
?>
output
Array
(
[1] => blue
)
A∪B
array_unique
array_unique(array_merge($array1, $array2));
首先通过 array_merge
将两个数组进行合并,之后使用 array_unique
去掉数组中的重复项。