How can I break a loop which has a condition in it? (PHP)

问题

I need to break a loop which has a condition inside it, on any circumstance which the condition meets the exception

like this:

for($l=0; $l<$subject_count; $l++){
    for($a=0; $a<$term_relatives_id_array_count; $a++){
        if($subject_array[$l]['id'] == $term_relatives_id_array[$a]['subject_id']){
            $subject_echo = true;
            break;
        }
        echo 'a';
    }
    if(!$subject_echo){
        echo '<li class="selectable_item" id="'.$subject_array[$l['id'].'">'.$subject_array[$l]['name_fa'];
        echo '</li>';
    }
}

I used echo 'a'; to see if break; works, but it doesn't break the inside loop what can I do?

回答1:

break ends execution of the current for, foreach, while, do-while or switch structure.

So in your case, check if you want to end the execution for both for loops, use break 2;

For more reference, refer break

And it may be that if condition is not met,so break may not be executed. So check the values also.

回答2:

Use break 1; to exit the current loop and break 2; out of 2.

回答3:

Do you need to break both the inner and outer loops? In this case you should use break 2;

回答4:

break accepts an optional numeric argument which tells it how many nested enclosing structures are to be broken out of.

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

Example took from the above link:

<?php 
$i = 0;
while (++$i) {
    switch ($i) {
    case 5:
        echo "At 5<br />\n";
        break 1;  /* Exit only the switch. */
    case 10:
        echo "At 10; quitting<br />\n";
        break 2;  /* Exit the switch and the while. */
    default:
        break;
    }
}
?>

来源：https://stackoverflow.com/questions/17475470/how-can-i-break-a-loop-which-has-a-condition-in-it-php