in_array Checks if a value exists in an array boolin_array mixedneedle arrayhaystack boolstrict Searches haystack for needle and returns &true; if it is found in the array, &false; otherwise. If the third parameter strict is set to &true; then the in_array function will also check the types of the needle in the haystack. If needle is a string, the comparison is done in a case-sensitive manner. In PHP versions before 4.2.0 needle was not allowed to be an array. ]]> The second condition fails because in_array is case-sensitive, so the program above will display: ]]> This will display: ]]> Outputs: See also array_search, array_key_exists, and isset.