TIL an easy way to populate an data array

POSTED ON: Jul 05, 2021

TAGS: php javascript

Bonus - I just had to do this in PHP as well, so you get TWO languages for the price of one TIL!
(And I pass the savings on to you!)

Javascript #

Using Fill -- arrays:

let filledArray = new Array(10).fill('hello');

// RESULT:
// ["hello","hello","hello","hello","hello","hello","hello","hello","hello","hello"]

Using Fill -- array with objects:

// referencing the same object
let filledArrayObject = new Array(10).fill({'hello':'goodbye'});

// referencing unique objects
let filledArrayObjectUnique = new Array(10).fill(null).map(()=> ({'hello':'goodbye'}))

// RESULT:
// [
//   { hello: "goodbye"},
//   { hello: "goodbye"},
//    ...
//   { hello: "goodbye"}
// ]

PHP #

Using array_fill
array_fill(int $start_index, int $count, mixed $value)

Php.net manual

$a = array_fill(0, 10, 'hello');

// RESULT:
// Array
// (
//     [0] => hello
//     [1] => hello
//     [2] => hello
//     [3] => hello
//     [4] => hello
//     [5] => hello
//     [6] => hello
//     [7] => hello
//     [8] => hello
//     [9] => hello
// )

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

Php.net manual

$i = 0;
$array = [];
while ($i < 10) {
    $array[] = "hello" . $i;
    $i++;
}

print_r(array_fill_keys($array, 'goodbye'));

// RESULT:
// Array
// (
//     [hello0] => goodbye
//     [hello1] => goodbye
//     [hello2] => goodbye
//     [hello3] => goodbye
//     [hello4] => goodbye
//     [hello5] => goodbye
//     [hello6] => goodbye
//     [hello7] => goodbye
//     [hello8] => goodbye
//     [hello9] => goodbye
// )

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