How to find a number in a large array?

Question

PHP

Hello. There is an array, for example, for 1000 elements, all numbers are different, but one matches with whatever, how best to search for this element?

Answer 1

Or even simpler: in_array
If you need to search several times in the same array, then it's better to first make it an array_flip, and then use isset

Answer 2

As an option:

$a = [ 1, 2, 3, 3, 4, 5 ];
$n = array_search(2, array_count_values($a));
echo($n);

Result: 3

Answer 3

If the numbers are in order, then using the sum of an arithmetic progression.