In a Twig template {{0 in ['a', 'b', '99']}} returns 1. WHY?

Question

Question heading already asks it:

In a Twig template {{0 in ['a', 'b', '99']}} prints 1. WHY? I have '0' as a value and I can't check it against arrays, as that value always pops up as existing. And at the end of the day: How do I achieve the goal of checking zero against the array of strings, in Twig?

@Rizier123 thanks, but that Q&A doesn't provide me with a solution on how to achieve my goal in Twig. I got the reasons for this, but also need a solution. — Shahriyar Imanov, Jun 21 '16 at 14:57

Matt S · Answer 1 · 2017-03-16T18:39:39.517

1

PHP's type coercion for comparisons goes to integers when necessary. You're checking if an integer is in the array. (int) 'a' is coerced to 0 for this comparison. So 0 is seen as being in the array.

To avoid this, you can use in_array with the strict option:

in_array('0', ['a', 'b', '99'], true)

edited Mar 16 '17 at 18:39

answered Jun 21 '16 at 14:43

Matt S

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With this in mind, I believe ```var_dump(in_array(0, ['1','2']))``` should yield ```true```, correct? It yields ```false``` though (in PHP 7 at least). Same goes for ```var_dump(in_array(0, [1,2]))``` So why? – Shahriyar Imanov Jun 21 '16 at 14:44
1

Because the string `'1'` is coerced to `1`. Character strings are coerced to `0` when compared with any integer. – Matt S Jun 21 '16 at 14:46
Ok, so how do we compare against integer zero then, in Twig of course? – Shahriyar Imanov Jun 21 '16 at 14:49
For an array of integers (or integer string), use `in`. For an array with a mix of integers and character strings, my answer is above: `in_array` with the strict option. – Matt S Jun 21 '16 at 15:02
Twig has ```in_array``` function? – Shahriyar Imanov Jun 21 '16 at 15:06
Not directly, you'll have to create an extension or use an existing one. – Matt S Jun 21 '16 at 15:11

In a Twig template {{0 in ['a', 'b', '99']}} returns 1. WHY?

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