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# array_unique

(PHP 4 >= 4.0.1)

array_unique -- Removes duplicate values from an array

## Description

array array_unique ( array array)

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.

> Note: 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.

Warning
This was broken in PHP 4.0.4!

Example 1. array_unique() example

    $input = array ("a" => "green", "red", "b" => "green", "blue", "red");
    $result = array_unique ($input);
    print_r($result);

This will output:

    Array
    (
        [b] => green
        [1] => blue
        [2] => red
    )

Example 2. array_unique() and types

    $input = array (4,"4","3",4,3,"3");
    $result = array_unique ($input);
    var_dump($result);

The printout of the program above will be (PHP 4.0.6):

    array(2) {
      [3]=>
      int(4)
      [4]=>
      int(3)
    }

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