What does ?: in this line mean?
$_COOKIE['user'] ?: getusername($_COOKIE['user']); Thank you.
- php.net/manual/en/language.operators.comparison.phpAbhik Chakraborty– Abhik Chakraborty2014-05-20 07:02:48 +00:00Commented May 20, 2014 at 7:02
- ?: means ternary operatoruser3470953– user34709532014-05-20 07:03:51 +00:00Commented May 20, 2014 at 7:03
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4 Answers
It is a shorthand for an if statement.
$username = $_COOKIE['user'] ?: getusername($_COOKIE['user']); Is the same as
if( $_COOKIE['user'] ) { $username = $_COOKIE['user']; } else { $username = getusername($_COOKIE['user']); } see test suite here: https://3v4l.org/6XMc4
But in this example, the function 'getusername' probably doesn't work correct, because it hits the else only when $_COOKIE['user'] is empty. So, the parameter inside getusername() is also kind of empty.
5 Comments
Lewis
if this line is
$username = $_COOKIE['user'] ?: getusername($_COOKIE['user']);. Does that mean if($_COOKIE['user']) { $username = $_COOKIE['user']; } else { $username = getusername($_COOKIE['user']); }?Lewis
I got it now. Thank you.
Tyler V.
Note with the ternary operator that your variable is going to be set to the output of your conditional. So while
$a = $b ?: $c; will set $a to equal either $b or $c in all cases, $a = ($b > 5) ?: $c; then $a will only ever equal true or $c and never $b. It's a tricky nuance.
i336_
Aw, I thought I could use it like
$var = isset($something) ?: $something and I'd get if (isset($result)) { $var = $result } else { $var = false; }. Back to using $var = isset($something) ? $something : null for me... :<
Gavin
FYI if you want to test if a variable, array key, object parameter, etc. exists (same as
isset() or empty()) and if not assign another value you can use the ?? operator instead. For example: $myVar = $varNotExists ?? 'this will be the value of $myVar because $varNotExists does not exist';It is short hand php, for example:
(true == true ? echo "this is true" : "this is false")
Written out this means:
if (true == true) { echo "This is true"; } else { echo "This is false"; } In your example, there is only an else statement.
Comments
It's known as the ternary operator, similar to what's commonly called an inline if. For instance, the following two examples:
a) $genderString = $genderAbbreviation == "M" ? "Male" : "Female";
b)
if ($genderAbbreviation == "M") { $genderString = "Male"; } else { $genderString = "Female"; } Both of these will have the same effect. The statement before the question mark is evaluated to be either true or false, and then if true the statement before the colon is executed, and if false the statement after the colon is executed.
For more information you can check the section titled "Ternary Operator" on the following page of the PHP documentation:
http://www.php.net/manual/en/language.operators.comparison.php
Comments
if $_COOKIE['user'] value is exist then NULL else getusername($_COOKIE['user'] will work
it's a ternary operator in php
1 Comment
Jonathon Reinhart
ternary operator.