While Loop not Breaking when Condition is Met

Question

I've got several working while loops in my function but this one I just can't get to work as it's supposed to. I assumed that while($variable == false) would break out of the loop as soon as $variable = true; occurs. Here's a bare bones version, with only two statements inside the loop.

$excluded = false;
while($excluded == false):
    $excluded = in_array(strtolower($extension), $GLOBALS['codexts']) ? true : false;
    $excluded = $file != "." && $file != ".." ? false : true; 
    break;
endwhile;

Inside the loop, the first definition does produce false when it's suppose to, but the loop doesn't break. It goes on to the second one, which returns true. If I change the second one to this:

$excluded = $excluded ? $excluded : ($file != "." && $file != ".." ? false : true);

...then I get the result I want, but only because I'm correcting for the failure of the while loop to break when $excluded is first defined as true. What am I doing wrongly here?

UPDATE I just reread the manual, and apparently I missed this part:

The value of the expression is checked each time at the beginning of the loop, so even if this value changes during the execution of the nested statement(s), execution will not stop until the end of the iteration

That's why the iterations were reverting back to false. I do need to do manual conditional breaks after all.

Are you sure it goes on to the second loop? Your `break;` statement does not have a condition surrounding it, it will be executed whether or not your `$excluded` is true or false. — AyB, Apr 30 '14 at 05:35
The break statement is at the end of the loop, to cover those iterations that never return true, so the loop doesn't get stuck. But I assure you, there are iterations that are returning true on the first statement, but not behaving like they're true, hence that's how I know it's going on to the second statement. The break at the end is not the issue. — Works for a Living, Apr 30 '14 at 05:37

Sajad Karuthedath · Accepted Answer · 2014-04-30T05:55:52.593

3

try

$excluded = false;
while($excluded == false) {
   $excluded = in_array(strtolower($extension), $GLOBALS['codexts']) ? true : false;
   if ($excluded == true) {
     break;
   }
    $excluded = $file != "." && $file != ".." ? false : true; 
    break;
} 
?>

edited Apr 30 '14 at 05:55

answered Apr 30 '14 at 05:31

Sajad Karuthedath

14,987
4
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It took me a minute to see what the difference was. Curly brackets. Well, I tried it. Still not working. Thanks though. – Works for a Living Apr 30 '14 at 05:34
@Thom:do you need the while loop to break if first statement is true ?? – Sajad Karuthedath Apr 30 '14 at 05:40
Yes. That's what while loops are suppose to do. Break when the condition is changed. – Works for a Living Apr 30 '14 at 05:42
I shouldn't have to use break. While loops are supposed to break when the condition is changed. That's what they do. – Works for a Living Apr 30 '14 at 05:46
1

@Thom That's right, you wouldn't need to have a `break;` in your case. One key point is, nothing in your loop is changing, so depending on your values it maybe executed once or infinite. – AyB Apr 30 '14 at 05:52
I take that back, Sajad. You're right. Apparently I misunderstood how the while loop works. If you want to edit your answer to include a break, I'll accept it. Apparently, the while loop continues to the end even if the condition is changed. – Works for a Living Apr 30 '14 at 05:53
Cheezburger: $excluded is changing. From false to true. I'm not sure how you can say that. Regardless, I just reread the manual and I need to do a manual break. That's my answer. – Works for a Living Apr 30 '14 at 05:53
@Thom:is it ok now ? i have added the if statement – Sajad Karuthedath Apr 30 '14 at 05:56
Yup. Thanks for forcing me back to the manual. My $notion was false. – Works for a Living Apr 30 '14 at 05:57
Nuts you need a break statement. Silly PHP – Johnny Rockex Apr 13 '21 at 05:11

score 0 · Answer 2 · answered Apr 30 '14 at 05:37

0

Q: Why don't use use conventional syntax?

Q: Why a redundant "break"?

Q: Why are you setting the expression twice before testing, and do you really need "?:" here? Twice???

Q: Can't you simplify the expression that changes your flag (changes "$excluded")?

SUGGESTION:

$myvar = false;
while(!$myvar) {
  $myvar = << something that sets/clears my flag >>
}

answered Apr 30 '14 at 05:37

FoggyDay

11,962
4
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Q: Which part of my syntax is unconventional? A: The break statement is at the end of the loop, to cover those iterations that never return true, so the loop doesn't get stuck. It's standard protocol. It is NOT redundant. Q: I don't understand your third question: "setting the expression twice before testing." – Works for a Living Apr 30 '14 at 05:39
It doesn't get much simpler than `if in_array() true/false`. – Works for a Living Apr 30 '14 at 05:41
And your suggestion is exactly what I'm doing already. `!$myvar` is the same as `$myvar == false`, and I tried `!$excluded` many times before posting here. – Works for a Living Apr 30 '14 at 05:45
use the wrapped value of $myvar for your while `while !$myvar.wrappedValue {` – theZ3r0CooL Feb 26 '22 at 01:57

While Loop not Breaking when Condition is Met

2 Answers2