array_flip

(PHP 4, PHP 5, PHP 7, PHP 8)

array_flipExchanges all keys with their associated values in an array

Опис

function array_flip(array $array): array

array_flip() returns an array in flip order, i.e. keys from array become values and values from array become keys.

Note that the values of array need to be valid keys, i.e. they need to be either int or string. A warning will be emitted if a value has the wrong type, and the key/value pair in question will not be included in the result.

If a value has several occurrences, the latest key will be used as its value, and all others will be lost.

Параметри

array

An array of key/value pairs to be flipped.

Значення, що повертаються

Returns the flipped array.

Приклади

Приклад #1 array_flip() example

<?php
$input = array("oranges", "apples", "pears");
$flipped = array_flip($input);

print_r($flipped);
?>

Поданий вище приклад виведе:

Array
(
    [oranges] => 0
    [apples] => 1
    [pears] => 2
)

Приклад #2 array_flip() example : collision

<?php
$input = array("a" => 1, "b" => 1, "c" => 2);
$flipped = array_flip($input);

print_r($flipped);
?>

Поданий вище приклад виведе:

Array
(
    [1] => b
    [2] => c
)

Прогляньте також

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User Contributed Notes 16 notes

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162
Final
14 years ago
I find this function vey useful when you have a big array and you want to know if a given value is in the array. in_array in fact becomes quite slow in such a case, but you can flip the big array and then use isset to obtain the same result in a much faster way.