What does this PHP line mean?

Question

Can someone explain to me what this PHP line is doing?

$fileName = (isset($_POST[self::$PARAM_FILE_NAME])) ? $_POST[self::$PARAM_FILE_NAME] : null;

if the $PARAM_FILE_NAME parameter has been set by POST request, assign its value to $fileName else assign null to $fileName — Satya, Nov 25 '14 at 03:53
http://php.net/manual/en/language.operators.comparison.php#language.operators.comparison.ternary <-- the ternary operator. Example in the docs is equivalent to yours. — Michael Berkowski, Nov 25 '14 at 03:53
https://stackoverflow.com/questions/889373/quick-php-syntax-question — Felix Kling, Nov 25 '14 at 03:56

score 0 · Answer 1 · answered Nov 25 '14 at 03:54

$fileName = (isset($_POST[self::$PARAM_FILE_NAME])) ? $_POST[self::$PARAM_FILE_NAME] : null;

It sets the variable named $fileName to either the value of $_POST[self::$PARAM_FILE_NAME] or to null. Another way to write it is:

if (isset($_POST[self::$PARAM_FILE_NAME]))
    $fileName = $_POST[self::$PARAM_FILE_NAME];
else
    $fileName = null;

This avoids a warning if the key in $_POST isn't set, which would you get with the more straightforward version:

$fileName = $_POST[self::$PARAM_FILE_NAME];

score 0 · Accepted Answer · edited Nov 25 '14 at 04:05

0

That line is simply a shorthand php if|else statement.

Expanded, it would look like this:

if(isset($_POST[self::$PARAM_FILE_NAME])) {
    $fileName = $_POST[self::$PARAM_FILE_NAME];
} else {
    $fileName = null;
}

You can read more about it here.

It is basically a shorter assigning of the variable.

edited Nov 25 '14 at 04:05

scrowler

answered Nov 25 '14 at 03:55

Darren

2 Answers2