PHP 8.0.24 Released!

array_fill_keys

(PHP 5 >= 5.2.0, PHP 7, PHP 8)

array_fill_keysFill an array with values, specifying keys

Description

array_fill_keys(array $keys, mixed $value): array

Fills an array with the value of the value parameter, using the values of the keys array as keys.

Parameters

keys

Array of values that will be used as keys. Illegal values for key will be converted to string.

value

Value to use for filling

Return Values

Returns the filled array

Examples

Example #1 array_fill_keys() example

<?php
$keys 
= array('foo'510'bar');
$a array_fill_keys($keys'banana');
print_r($a);
?>

The above example will output:

Array
(
    [foo] => banana
    [5] => banana
    [10] => banana
    [bar] => banana
)

See Also

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User Contributed Notes 10 notes

up
64
sergli at nigma dot ru
10 years ago
<?php
$a
= array("1");

var_dump(array_fill_keys($a, "test"));
?>

array(1) {
  [1]=>
  string(4) "test"
}

now string key "1" become an integer value 1, be careful.
up
26
atul dot kr_singh at hotmail dot com
9 years ago
If an associative array is used as the second parameter of array_fill_keys, then the associative array will be appended in all the values of the first array.
e.g.
<?php
$array1
= array(
   
"a" => "first",
   
"b" => "second",
   
"c" => "something",
   
"red"
);

$array2 = array(
   
"a" => "first",
   
"b" => "something",
   
"letsc"
);

print_r(array_fill_keys($array1, $array2));
?>

The output will be
Array(
    [first] => Array(
        [a] => first,
        [b] => something,
        [0] => letsc
    ),
    [second] => Array(
        [a] => first,
        [b] => something,
        [0] => letsc
    ),
    [something] => Array(
        [a] => first,
        [b] => something,
        [0] => letsc
    ),
    [red] => Array(
        [a] => first,
        [b] => something,
        [0] => letsc
    )
)
up
0
ray.paseur sometimes uses gmail
4 months ago
Get an associative array of zeros for counting letter frequency

<?php
$ltrs
= array_fill_keys( range('a', 'z'), 0 );
up
1
Scratchy
14 years ago
RE: bananasims at hotmail dot com

I also needed a work around to not having a new version of PHP and wanting my own keys. bananasims code doesn't like having an array as the second parameter...

Here's a slightly modified version than can handle 2 arrays as inputs:

//we want these values to be keys
$arr1 = (0 => "abc", 1 => "def");
/we want these values to be values
$arr2 = (0 => 452, 1 => 128);

function array_fill_keys($keyArray, $valueArray) {
    if(is_array($keyArray)) {
        foreach($keyArray as $key => $value) {
            $filledArray[$value] = $valueArray[$key];
        }
    }
    return $filledArray;
}

array_fill_keys($arr1, $arr2);

returns:
abc => 452, def =>128
up
-1
manavchugh988 at gmail dot com
3 months ago
see array_fill_keys are basically used to make a new array from a pre-existing array in a form that the value of the pre-existing array will now be the key of the new Array .And there value will be same That we had given in the 2nd parameter . Example Below---->>>

<?php
       
//pre existing array
       
$a = array("a","b","c","d","e");

       
//new array with a single same value

       
$newArray = array_fill_keys($a, "Testing");

       
//printing the array

       
echo "<pre>";
       
print_r($newArray);
        echo
"</pre>";
?>
output;
    Array
(
    [a] => Testing
    [b] => Testing
    [c] => Testing
    [d] => Testing
    [e] => Testing
)
up
-3
bananasims at hotmail dot com
15 years ago
Some of the versions do not have this function.
I try to write it myself.
You may refer to my script below

function array_fill_keys($array, $values) {
    if(is_array($array)) {
        foreach($array as $key => $value) {
            $arraydisplay[$array[$key]] = $values;
        }
    }
    return $arraydisplay;
}
up
-5
matrebatre
14 years ago
This function does the same as:
<?php
$array
= array_combine($keys,array_fill(0,count($keys),$value));
?>
up
-4
phydeaux
14 years ago
Scratchy's version still doesn't work like the definition describes.  Here's one that can take a mixed variable as the second parameter, defaulting to an empty string if it's not specified.  Don't know if this is exactly how the function works in later versions but it's at least a lot closer.

function array_fill_keys($target, $value = '') {
    if(is_array($target)) {
        foreach($target as $key => $val) {
            $filledArray[$val] = is_array($value) ? $value[$key] : $value;
        }
    }
    return $filledArray;
}

This works for either strings or numerics, so if we have

$arr1 = array(0 => 'abc', 1 => 'def');
$arr2 = array(0 => 452, 1 => 128);
$arr3 = array(0 => 'foo', 1 => 'bar');

then

array_fill_keys($arr1,$arr2)
returns: [abc] => 452, [def] => 128

array_fill_keys($arr1,0)
returns: [abc] => 0, [def] => 0

array_fill_keys($arr2,$arr3)
returns: [452] => foo, [128] => bar

array_fill_keys($arr3,'BLAH')
returns: [foo] => BLAH, [bar] => BLAH

and array_fill_keys($arr1)
returns: [abc] =>, [def] =>
up
-5
ntd at entidi dot it
6 years ago
To remove arbitrary keys from an associative array:

<?php

function nuke_keys($keys, $array) {
    return
array_diff_key($array, array_fill_keys($keys, 0));
}

$array = array('blue'  => 1, 'red'  => 2, 'green'  => 3, 'purple' => 4);
$keys  = array('red', 'purple');

print_r(nuke_keys($keys, $array));
?>

The above snippet will return:

Array
(
    [blue] => 1
    [green] => 3
)
up
-17
taylanaktepe at yahoo dot com
8 years ago
$keys = array(1, 2, 3);

// Fill it with value.
$keys = array_fill_keys($keys, 'banana');
print_r($keys);

// Fill it different value.
$apples = array_fill_keys(array_keys($keys), 'apple');
print_r($apples);

// Output:
Array (
[1] => banana
[2] => banana
[3] => banana
)
Array (
[1] => apple
[2] => apple
[3] => apple
)
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