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

Question

I've been banging my head against this problem for a while. I feel like it should be simple, but I'm having a hard time coming up with a solution.

I'm looking to pre-populate a database, and I need to create SQL statements with some foreign key values. It would be tedious to hand-code them, so naturally I decided to do it in code.

What I want are series of arrays that have values as such:

[1]
[2]
[3]
[1,1]
[1,2]
[1,3]
[2,1]
[2,2]
...
[1,1,1]
[1,1,2]
[1,1,3]
...
[3,1,1]
...
[3,3,3]

I want to specify the number of values in the array, and the numerical value at which it causes the preceeding value to roll over.

In the example I gave above, it would be like generate(3,3), since the maximum number of elements is 3, and the highest value is 3.

How could I write some code that would give me this series of arrays?

I hope you have tried something. So kindly add your code effort. As you know without code-effort your question may got closed/got down-voted. — Death-is-the-real-truth
– Death-is-the-real-truth, Commented Oct 29, 2020 at 4:22
Hope this will help you:stackoverflow.com/questions/19067556/… the correct answer getting all possible combination based on size. You can take reference of code and convert it to fir your requirement — Death-is-the-real-truth
– Death-is-the-real-truth, Commented Oct 29, 2020 at 4:26

Nick · Accepted Answer · 2020-10-29 04:39:06Z

2

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);

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);

with

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

edited Oct 29, 2020 at 4:39

answered Oct 29, 2020 at 4:30

Nick

147k23 gold badges67 silver badges106 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Jeto · Accepted Answer · 2020-10-29 05:40:09Z

2

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]);
        }
    }
}

Exemple usage + debug/print:

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

Demo

edited Oct 29, 2020 at 5:40

answered Oct 29, 2020 at 5:20

Jeto

15k2 gold badges39 silver badges50 bronze badges

Collectives™ on Stack Overflow

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

2 Answers 2

Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related