Is there a "superbreak" in Javascript or PHP for loops?

Question

On many of the projects on which I work, I find that I have nested for loops (I will focus on PHP implementation but applies to javascript as well) that take this generic form:

$array1 = array(........);
$count1 = count($array1);

$invalidState = false;//An invalid state will be looked for in the innermost loop, and if found, break all the loops

for($i = 0; $i < $count1; $i++) {
    //parsing, then another loop
    $array2 = explode("needle", $array1[$i]);
    $count2 = count($array2);
    for($j = 0; $j < $count2; $j++) {
        //parsing, then sometimes even another another loop
        $array3 = explode("different-needle", $array2[$j]);
        $count3 = count($array3);
        for($k = 0; $k < $count3; $k++) {
            //check for an invalid state in $array3[$k], and break if invalid state = true; 
        }
        if ($invalidState) break;
    }
    if ($invalidState) break;
}

To reiterate, if an invalid state is found in the innermost loop, then all the loops should break. But as far as I am aware, to break from all the loops, I must set a variable (in this case $invalidState), and check this in all the outer loops, and if true, then break.

Is there any kind of "super-break" where if a condition is met in the innermost loop, all outer loops will be broken?

Yes, you should check this: http://stackoverflow.com/questions/11609532/php-breaking-the-nested-loop — Luis González, Nov 24 '15 at 13:22
And to complement @luigonsec's comment, [here's the javascript way](http://stackoverflow.com/questions/183161/best-way-to-break-from-nested-loops-in-javascript). — James Thorpe, Nov 24 '15 at 13:25
I think this is what you want: http://stackoverflow.com/a/19734110/2018654 — Naruto, Nov 24 '15 at 13:25
I prefer bat break or captain break, but super break is good too — Jaromanda X, Nov 24 '15 at 13:27
@JaromandaX It's a bird ? It's a plane ? No ! It's superbreak ! — Alexandre Beaudet, Nov 24 '15 at 13:28

Luis González · Accepted Answer · 2015-11-24T13:55:17.273

6

Yes, try this:

for($i = 0; $i < $count1; $i++) {
    //parsing, then another loop
    $array2 = explode("needle", $array1[$i]);
    $count2 = count($array2);
    for($j = 0; $j < $count2; $j++) {
        //parsing, then sometimes even another another loop
        $array3 = explode("different-needle", $array2[$j]);
        $count3 = count($array3);
        for($k = 0; $k < $count3; $k++) {
            break 3; 

    }
    if ($invalidState) break;
}
if ($invalidState) break;
}

When you write break n you are breaking n nested loops. However, you can't break $foo, because this ability has been recently removed:

http://php.net/manual/en/control-structures.break.php

edited Nov 24 '15 at 13:55

answered Nov 24 '15 at 13:23

Luis González

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This should be considered as the answer, since it truly give a response, not a workaround (return) – Alexandre Beaudet Nov 24 '15 at 13:28
1

Actually, `break n` was removed from PHP since PHP 5.4 (http://php.net/manual/en/control-structures.break.php) so this example will throw syntax error on PHP 5.4+. – martin Nov 24 '15 at 13:48
@Martin From the link you gave me: `5.4.0 - Removed the ability to pass in variables (e.g., $num = 2; break $num;) as the numerical argument.` but it seems that `break 3` still working – Luis González Nov 24 '15 at 13:50
Ou, you're right, its related to only `break $var` syntax. – martin Nov 24 '15 at 13:57
@Martin thank you for the observation, I learnt something new! – Luis González Nov 24 '15 at 14:00

score 3 · Answer 2 · answered Nov 24 '15 at 13:23

3

Probably most easily just wrap the loop in a function and when you want to use "super-break" just use return.

answered Nov 24 '15 at 13:23

martin

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score 2 · Answer 3 · answered Nov 24 '15 at 13:23

2

I would suggest making your outer loop its own function, and returning explicitly in the center of the loop to hard break from all the nested loops.

answered Nov 24 '15 at 13:23

Devon Parsons

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Atif Tariq · Answer 4 · 2015-11-24T13:30:13.623

2

You should consider this:

break 3; //Breaks 3 levels, so breaks outermost foreach

edited Nov 24 '15 at 13:30

answered Nov 24 '15 at 13:26

Atif Tariq

2,650
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Should be `break 3;` as per the answer from @luigonsec. – Reinstate Monica Cellio Nov 24 '15 at 13:29

score 1 · Answer 5 · answered Nov 24 '15 at 13:23

1

You can use return for this purpose

answered Nov 24 '15 at 13:23

Alexander Elgin

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Is there a "superbreak" in Javascript or PHP for loops?

5 Answers5