in_array Return &true; 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: // This will output: 'ph' is found 'o' is found ]]> See also array_search.