PHP: Find dynamic element from nested associated array

Question

I'm working on a function that looks like this:

public function myfunction($mainArr, $keys) {
    // $mainArr: a nested associative array
    // $keys: a simple array of strings, example: array('string_1', 'string_2', 'string_3')
    $totalKeys = count(keys);
    if(totalKeys == 1) {
        return mainArr[keys[0]];
    } else if(totalKeys == 2) {
        return mainArr[keys[0]][keys[1]];
    } else if(totalKeys == 3) {
        return mainArr[keys[0]][keys[1]][keys[2]];
    } else if(totalKeys == 4) {
        return mainArr[keys[0]][keys[1]][keys[2]][keys[3]];
    } else if(totalKeys == 5) {
        return mainArr[keys[0]][keys[1]][keys[2]][keys[3]][keys[4]];
    }
    // the same pattern continues..
}

I want to change this function into something more dynamic rather than a big list of "if" conditions, is it possible somehow?

you're missing the function keyword

djthoms
– djthoms

2013-06-13 16:27:34 +00:00
Commented Jun 13, 2013 at 16:27 — djthoms
– djthoms, Commented Jun 13, 2013 at 16:27

Jon · Accepted Answer · 2013-06-13 16:37:58Z

1

You can do it for example this way:

function get_value(array $source, array $keys) {
    foreach ($keys as $key) {
        if (isset($source[$key])) {
            $source = $source[$key];
        }
        else {
            return null;
        }
    }

    return $source;
}

If $keys describes an invalid path inside $source then null will be returned.

answered Jun 13, 2013 at 16:37

Jon

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2 Comments

evilReiko Over a year ago

Works perfectly! I spent an hour just thinking of a solution, and you solved it in few seconds! You're a genius!

Jon Over a year ago

@evilReiko: I 'm no genius, just spent lots of time programming. As you learn you always find that yesterday's difficult task is today's easy thingy. This is true for everyone.

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