array_unique Removes duplicate values from an array &reftitle.description; arrayarray_unique arrayarray intsort_flagsSORT_STRING Takes an input array and returns a new array without duplicate values. Note that keys are preserved. If multiple elements compare equal under the given sort_flags, then the key and value of the first equal element will be retained. Two elements are considered equal if and only if (string) $elem1 === (string) $elem2 i.e. when the string representation is the same, the first element will be used. &reftitle.parameters; array The input array. sort_flags The optional second parameter sort_flags may be used to modify the sorting behavior using these values: Sorting type flags: SORT_REGULAR - compare items normally (don't change types) SORT_NUMERIC - compare items numerically SORT_STRING - compare items as strings SORT_LOCALE_STRING - compare items as strings, based on the current locale. &reftitle.returnvalues; Returns the filtered array. &reftitle.changelog; &Version; &Description; 7.2.0 If sort_flags is SORT_STRING, formerly array has been copied and non-unique elements have been removed (without packing the array afterwards), but now a new array is built by adding the unique elements. This can result in different numeric indexes. &reftitle.examples; "green", "red", "b" => "green", "blue", "red"); $result = array_unique($input); print_r($result); ?> ]]> &example.outputs; green [0] => red [1] => blue ) ]]> ]]> &example.outputs; int(4) [2] => string(1) "3" } ]]> &reftitle.seealso; array_count_values &reftitle.notes; Note that array_unique is not intended to work on multi dimensional arrays.