将数字索引数组转换为由这些索引编制索引的关联对象数组中的有序元素数组

Question

Note: I should be clear my desire is to do this functionally, in one statement. I can do this easily with loops but that's not what I'm interested in.

I have two arrays: a numeric array of indexes, A, and an associative array, B, of objects O indexed by the elements of array A.

I want to produce an array of O in the order of the elements of A--in other words, map the indexes into real objects, based on the associative array B.

For example:

A = [ 3, 4, 2, 1 ];
B = [ 1=>"one", 2=>"two", 3=>"three", 4=>"four" ]

I want:

[ "three", "four", "two", "one" ]

Also, incidentally I'm also curious to learn what this concept is called. It's kind of like mapping, but specifically involves indexes into another array, as opposed to a function.

Answer 1

NullUserException posted the answer in a comment:

array_map(function ($v) use ($b) { return $b[$v]; }, $a);