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How to use modern loop in php

I need to create an array like this:

['A1','A2','A3','A4','B1','B2','B3','B4','C1','C2','C3','C4'];

In php you can do this:

$letters = ['A', 'B', 'C'];
$arr = [];
foreach($letters as $l){
    for($i=1;$i<=4;$i++){
        $str = $l . '' . $i;
        array_push($arr, $str);
    }
}

Isn’t there a cleaner way to do this?

Tags:

3

Answers


  1. 0

    Sure, array_push is pretty old school 😛 This is cleaner.

    $letters = ['A', 'B', 'C'];
$arr = [];

foreach($letters as $l){
    for($i = 1; $i <= 4; $i++){
        $arr[] = $l . $i;
    }
}

print_r($arr);
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  2. 0

    It is not much cleaner, but I could come up with this:

    $arr = [];

foreach ($letters as $letter) {
    for ($i = 1; $i <= 4; $i++) {
        $arr[] = "{$letter}{$i}";
    }
}
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  3. 0

    For sure! To avoid pushing elements in a mutable array, you could do this :

    $letters = ['A', 'B', 'C'];

$arr = array_merge(
    ...array_map(
        function(string $letter): array {
            return array_map(
                fn(string $v, int $k): string => $v . $k + 1,
                array_fill(0, 4, $letter),
                array_keys(array_fill(0, 4, null))
            );
        },
        $letters
    )
);

    See ? So functional, so elegant.

    No, your way is better. Maybe get rid of the unneeded $str variable, but otherwise it’s about as readable as it could be.

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