Which is more efficent PHP: array_intersect() OR array_intersect_key()

Is it more efficient to use the key intersect or the value intersect if both key and value have the same contents for example:

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

Is there any difference in performance in using one or the other with the same v开发者_运维问答alues. Similar to the difference of using double or single quotes?

From another post: 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.