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array_mapApplies the callback to the elements of the given arrays Description
array array_map(callablenull
$callback , array $array , array ...$arrays )
array_map returns an array containing
the results of applying the Parameters
Return Values
Returns an array containing the results of applying the The returned array will preserve the keys of the array argument if and only if exactly one array is passed. If more than one array is passed, the returned array will have sequential integer keys. Changelog
Examples
Example #1 array_map example
This makes $b have: Array ( [0] => 1 [1] => 8 [2] => 27 [3] => 64 [4] => 125 )
Example #2 array_map using a lambda function
Array ( [0] => 2 [1] => 4 [2] => 6 [3] => 8 [4] => 10 )
Example #3 array_map - using more arrays
The above example will output: // printout of $c Array ( [0] => The number 1 is called uno in Spanish [1] => The number 2 is called dos in Spanish [2] => The number 3 is called tres in Spanish [3] => The number 4 is called cuatro in Spanish [4] => The number 5 is called cinco in Spanish ) // printout of $d Array ( [0] => Array ( [1] => uno ) [1] => Array ( [2] => dos ) [2] => Array ( [3] => tres ) [3] => Array ( [4] => cuatro ) [4] => Array ( [5] => cinco ) ) Usually when using two or more arrays, they should be of equal length because the callback function is applied in parallel to the corresponding elements. If the arrays are of unequal length, shorter ones will be extended with empty elements to match the length of the longest.
An interesting use of this function is to construct an array of arrays,
which can be easily performed by using
Example #4 Performing a zip operation of arrays
The above example will output: Array ( [0] => Array ( [0] => 1 [1] => one [2] => uno ) [1] => Array ( [0] => 2 [1] => two [2] => dos ) [2] => Array ( [0] => 3 [1] => three [2] => tres ) [3] => Array ( [0] => 4 [1] => four [2] => cuatro ) [4] => Array ( [0] => 5 [1] => five [2] => cinco ) )
Example #5
The above example will output: array(3) { [0]=> int(1) [1]=> int(2) [2]=> int(3) }
Example #6 array_map - with string keys
The above example will output: array(1) { ["stringkey"]=> array(1) { [0]=> string(5) "value" } } array(1) { [0]=> array(2) { [0]=> string(5) "value" [1]=> string(5) "value" } } array(1) { ["stringkey"]=> string(5) "value" } array(1) { [0]=> array(2) { [0]=> string(5) "value" [1]=> string(5) "value" } } Example #7 array_map - associative arrays While array_map does not directly support using the array key as an input, that may be simulated using array_keys.
The above example will output: array(3) { [0]=> string(24) "v1 was the First release" [1]=> string(25) "v2 was the Second release" [2]=> string(24) "v3 was the Third release" } See Also
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