Takes an 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 i.e. when the string representation is the same, the first element will be used.
The input array.
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.
Returns the filtered array.
Changed the default value of sort_flags
back to SORT_STRING
.
Added the optional sort_flags
defaulting to SORT_REGULAR
. Prior to 5.2.9, this function used to sort the array with SORT_STRING
internally.
<?php $input = array("a" => "green", "red", "b" => "green", "blue", "red"); $result = array_unique($input); print_r($result); ?>
The above example will output:
Array ( [a] => green [0] => red [1] => blue )
<?php $input = array(4, "4", "3", 4, 3, "3"); $result = array_unique($input); var_dump($result); ?>
The above example will output:
array(2) { [0] => int(4) [2] => string(1) "3" }
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