PHP ternary operators: if/else if/else with NULL, 0 and 1

Question

I'm trying to simplify this control block:

if (!isset($mobileNumberHF['IS_VALID']) && $mobileNumberHF['IS_VALID'] != 0) {
  echo '<strong class="text-warning">Sin validar</strong>';
} else if ($mobileNumberHF['IS_VALID'] == 0) {
  echo '<strong class="text-danger">Inválido</strong>';
} else {
  echo '<strong class="text-success">Validado</strong>';
}

Like this:

$isValidMobileNum = $mobileNumHF['IS_VALID'];
$mobileNumStatusLabel = ($isValidMobileNum == 1) ? 'Valid' : (!isset($isValidMobileNum)) ? 'Hasn't been validated' : 'Invalid';

The test scenarios are when $isValidMobileNum equals NULL, 0 or 1;

By now, the result varies in a way I'm still trying to understand. Sometimes the output is 'Valid', sometimes 'Invalid' and sometimes 'Hasn't been validated'

For example, for $isValidMobileNum = 1 I'm getting Invalid?

The above control block looks simplified enough. Easier to read too. — Charlotte Dunois
– Charlotte Dunois, Commented Apr 1, 2016 at 21:35
Yes, but I'm using them for mobile, house and other phone numbers. I also want to understand what's happening with the ternary logic. I updated the post with an example of what I'm getting right now. @CharlotteDunois — Gus
– Gus, Commented Apr 1, 2016 at 21:37
!isset($mobileNumberHF['IS_VALID']) && $mobileNumberHF['IS_VALID'] != 0? How can it be not set and have a value != 0? — Don't Panic
– Don't Panic, Commented Apr 1, 2016 at 21:38

RomanPerekhrest · Accepted Answer · 2016-04-01 21:54:26Z

1

It doesn't seem to be a correct logic.
I suppose, I should be as follows:

if (isset($mobileNumberHF['IS_VALID'])) {
  echo ($mobileNumberHF['IS_VALID'] != 0)? '<strong class="text-success">Validado</strong>' : '<strong class="text-danger">Inválido</strong>';
} else {
  echo '<strong class="text-warning">Sin validar</strong>';  
}

As for your ternary operator: you have misplaced parenthesis in the last operand. Also 'Hasn't word has unescaped single quote.

$isValidMobileNum = 1;
$mobileNumStatusLabel = ($isValidMobileNum == 1) ? 'Valid' : (!isset($isValidMobileNum) ? 'Hasn\'t been validated' : 'Invalid');
echo $mobileNumStatusLabel; // "Valid"

answered Apr 1, 2016 at 21:54

RomanPerekhrest

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2 Comments

Gus Over a year ago

You supposed right. This ternary reference worked. Just one question. Why is $mobileNumStatusLabel = $isValidMobileNum ? 'Valid'... not evaluated as true?

RomanPerekhrest Over a year ago

$isValidMobileNum ? as condition expression is always eveluated as boolean value. NULL , "" and 0 will be evaluated as FALSE, and 1 - as TRUE

Dan · Accepted Answer · 2016-04-01 21:55:21Z

0

Put parentheses around your nested ternary statements to make the output more reliable:

$isValidMobileNum = $mobileNumHF['IS_VALID'];
$mobileNumStatusLabel = ($isValidMobileNum == 1) ? 'Valid' : ( (!isset($isValidMobileNum)) ? 'Hasn't been validated' : 'Invalid' );

Here is an alternative that I would use personally (with little justification for why it's better)

$mobilePhone = isset($mobileNumHF['IS_VALID']) ? $mobileNumHF['IS_VALID'] : -1;

$mobileNumStatusLabel = $mobilePhone ? 'Valid' : ($mobilePhone == 0 ? 'Invalid' : 'Hasn\'t been validated');

This way will avoid an illegal offset warning.

edited Apr 1, 2016 at 21:55

answered Apr 1, 2016 at 21:38

Dan

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Comments

brense · Accepted Answer · 2016-04-01 21:57:42Z

Why do you want to use shorthand syntax for this logic? I mean... obviously you're already confused about what your if else statement is doing. How is it simplifying? Nesting shorthand if/else statements... is this called simplifying these days? To me it just looks like you're creating a monster because you want to write less lines of code. Thats not simplifying, its juggling.

But yes... If you want to make it work, you should put parenthesis around your nested if/else.

I would seriously consider using normal if/else though... If you don't, your code will become impossible to maintain... What if you need to add more logic to your if/else later? What if someone stumbles upon this line of code when tracking down a bug?

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