array_unique

    (PHP 4 >= 4.0.1, PHP 5, PHP 7, PHP 8)

    array_unique — Removes duplicate values from an array

    Description

    function array_unique(array $array, int $flags = SORT_STRING): array

    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 flags, then the key and value of the first equal element will be retained.

    Note:

    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.

    Parameters

    array

    The input array.

    flags

    The optional second parameter flags may be used to modify the comparison behavior using these values:

    Comparison type flags:

    • SORT_REGULAR - compare items normally (don't change types)

      Note:

      When combining SORT_REGULAR with arrays mixing numeric and non-numeric strings, the sort-then-compare algorithm may not place equal elements adjacent, which can leave duplicates in the result. Use SORT_STRING to avoid this.

    • SORT_NUMERIC - compare items numerically

    • SORT_STRING - compare items as strings

    • SORT_LOCALE_STRING - compare items as strings, based on the current locale.