array_unique Removes duplicate values from an array arrayarray_unique arrayarray array_unique takes input array and returns a new array without duplicate values. Note that keys are preserved. array_unique sorts the values treated as string at first, then will keep the first key encountered for every value, and ignore all following keys. It does not mean that the key of the first related value from the unsorted array will be kept. Two elements are considered equal if and only if (string) $elem1 === (string) $elem2. In words: when the string representation is the same. The first element will be used. "green", "red", "b" => "green", "blue", "red"); $result = array_unique($input); print_r($result); ?> ]]> This will output: green [0] => red [1] => blue ) ]]> ]]> This script will output: int(4) [2] => string(1) "3" } ]]>