php - 哪个更高效 PHP : array_intersect() OR array_intersect_key()

Question

如果键和值具有相同的内容，使用键相交还是使用值相交更有效例如:

Array
(
    [743] => 743
    [744] => 744
    [745] => 745
    [746] => 746
    [747] => 747
    [748] => 748
)

使用具有相同值的一个或另一个在性能上是否有任何差异。类似于使用双引号或单引号的区别？

Answer 1

来自另一篇文章:I have two unordered integer arrays, and i need to know how many integers these arrays have in common

Depending on your data (size) you might want to use array_intersect_key() instead of array_intersect(). Apparently the implementation of array_intersect (testing php 5.3) does not use any optimization/caching/whatsoever but loops through the array and compares the values one by one for each element in array A. The hashtable lookup is incredibly faster than that.