Generating a series of sequential arrays of version-like values in PHP

Solution:

This is a recursive function that will generate each of the combinations of the ranges up to the maximum value, with elements in each array from 1 to the number specified:

function generate($elements, $maxvalue) {
    if ($elements == 0) return array();
    $result = array();
    foreach (range(1, $maxvalue) as $el) {
        $result[] = array($el);
    }
    foreach (range(1, $maxvalue) as $el) {
        foreach (generate($elements - 1, $maxvalue) as $arr) {
            $result[] = array($el, ...$arr);
        }
    }
    return $result;
}

$combs = generate(3, 3);
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Output is too long to show here but can be seen in this demo on 3v4l.org

Note for PHP < 7.4, replace

$result[] = array($el, ...$arr);
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with

$result[] = array_merge(array($el), $arr);
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Solution:

Here's a version using generators (which may be slightly easier on memory than pure arrays):

function generate(int $elementsCount, int $maxValue, array $current = []): \Generator
{
    for ($value = 1; $value <= $maxValue; $value++) {
        yield [...$current, $value];
    }
    if ($elementsCount > 1) {
        for ($value = 1; $value <= $maxValue; $value++) {
            yield from generate($elementsCount - 1, $maxValue, [...$current, $value]);
        }
    }
}
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Exemple usage + debug/print:

$combinations = generate(3, 3);
print_r(iterator_to_array($combinations, false));
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