comparing arrays in php, without caring for the order

Question

I have two arrays, $a and $b here, and need to check if they contain exactly the same elements (independently of the order). I am thinking of using

if (sizeo         


        

Answer 1

If you think of the arrays as sets:

Then your approach is almost correct (you need to drop the equality test for the element count).

If it matters that the arrays contain multiple copies of the same element:

Then your approach is not correct. You need to sort the arrays with sort and then compare them with ===. This should be faster, as it can abort the comparison the moment it sees one difference without going over the whole arrays.

Update:

Clarified exactly when the OP's approach would be correct or not, also incorporated the suggestion that sort would be probably better than asort here.