PHP数组的交集array_intersect()，array_intersect_assoc()，array_inter_key()函数详解

求两个数组的交集问题可以使用 array_intersect()，array_inersect_assoc，array_intersect_key来实现，其中 array_intersect()函数是求两个数的交集，返回一个交集共有元素的数组（只是数组值得比较）、 array_intersect_assoc()函数是将键和值绑定，一起比较交集部分、array_intersect_key()函数是将两个数组的键值进行比较，返回键值交集的数组。

但实际应用中也遇到了一些小问题，正如下：

实例：

<?php
$array = array(
	"red"		=> "Red",
	"green"		=> "red4",
	"Red15"		=> "Red",
	7			=> "Level",
	"Width"		=> "Red",
	"azzzz1"	=> "art",
	"peak"		=> 158
);
$array1 = array(
	"red"		=> "Red2",
	"greena"	=> "red",
	"Red15"		=> "Red",
	7			=> "Level",
	"Width"		=> "Red",
	"azzzz"		=> "art",
	"peak"		=> 158
);
$num = array_intersect($array, $array1);
print_r ($num);
echo "<br />";
$num = array_intersect_assoc($array, $array1);
print_r($num);
echo "<br />";
$num = array_intersect_key($array, $array1);
print_r ($num);
?>

运行结果：

Array ( [red] => Red [Red15] => Red [7] => Level [Width] => Red [azzzz1] => art [peak] => 158 )
Array ( [Red15] => Red [7] => Level [Width] => Red [peak] => 158 )
Array ( [red] => Red [Red15] => Red [7] => Level [Width] => Red [peak] => 158 )

总结：

1.array_intersect()函数进行的比较只有数组值的比较，而且存在如”Red“和”Red2“比较时会返回"Red"，反之则不会返回"Red2";

2.array_intersect_assoc()函数是将数组的值与键值一起比较，而且不会存在array_intersect的情况，适用于较严格的比较；

3.array_intersect_key()函数适用于比较两个数组键值的交集，返回的并不只有键值，而是键值和对应的数组值。