PHP - same code on one or multiple lines

Question

This are two lines of codes. Could anyone tell me what the difference is between the first way and the second? I'd like both to do exactly the same thing.

   $test = isset($_POST['test'])?$_POST['test']:[];

if(isset($_POST['test'])){
    $test[] = $_POST['test'];
}

Thanks !

they are completely different. – Karoly Horvath Sep 15 '13 at 16:50 — Karoly Horvath, Sep 15 '13 at 16:50
What exactly do you want to achieve? – Pekka Sep 15 '13 at 16:50 — Pekka, Sep 15 '13 at 16:50

Dave Chen · Accepted Answer · 2013-09-15T16:58:58.840

4

First one sets $test to an empty array if $_POST['test'] is unset. However, the second one does not set $test to a default value. In fact, if $_POST['test'] was unset, $test would be un-existent/undefined/etc.

You would need to run $test = []; at the beginning of the second one to archive the exact same result.

edited Sep 15 '13 at 16:58

answered Sep 15 '13 at 16:50

Dave Chen

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After the second one, `$test` isn't even null - it's undefined. – George Brighton Sep 15 '13 at 16:54
I'd also like to point at [this comment](http://stackoverflow.com/questions/6933345/php-what-is-the-meaning-of#comment26432372_6933366). – Dave Chen Sep 15 '13 at 16:54
Thanks, that's exactly what I wanted to know. Thanks. – Yannick Bloem Sep 15 '13 at 16:56
@DaveChen What does $test = []; mean ?? – Charaf JRA Sep 15 '13 at 17:06
`$test = []` means `$test = array()`, with PHP versions above 5.3. – Dave Chen Sep 15 '13 at 19:50

score 0 · Answer 2 · answered Sep 15 '13 at 16:53

0

the top line would be equivalent to

if(isset($_POST['test'])){
     $test = $_POST['test'];
}else{
     $test = [];
}

answered Sep 15 '13 at 16:53

djbrick

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1
4

score 0 · Answer 3 · answered Sep 15 '13 at 16:53

The first uses a ternary operator, which is a shorthand for if (X) then $a = b else $a = c, which sets $test to $_POST['test'] if it isn't empty, or $test to an empty array.

The second example doesn't have the else case, so it will leave $test undefined if $_POST['test'] is empty.

See also the ternary operator section of this page in the PHP manual http://www.php.net/manual/en/language.operators.comparison.php.

PHP - same code on one or multiple lines

3 Answers3