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PHP

Posted by jason chan
jason chan
31,009 Points

using ternary operator

if(isset($_POST["username"])) {
        $username = $_POST["username"]; 
        } else {
         $username = "";
        }
        if(isset($_POST["password"])) {
        $password = $_POST["password"];
        } else {
        $password = "";
        }

vs

// I don't know what's happening down here.
$username = isset($_POST['username']) ? $_POST['username'] : "";
$password = isset($_POST['password']) ? $_POST['password'] : "";

echo "{$username}: {$password}";

So what't he difference?

1 Answer

Brian Pohuski
Brian Pohuski
5,386 Points 
isset($_POST['username'])

In your example, this is asking the question "Is $_POST['username'] set?" and this part is known as the "condition".

?

Conditional Operator

$_POST['username'] : "";

This is giving two outcomes. The left of the colon will be the result if the logic results in true. The right will be the result if the logic results in false

//Example resulting in true
$a = 1;
$b = 1;
$result = $a === $b ? true : false;

//Example resulting in false
$a = 1;
$b = 2;
$result = $a === $b ? true : false;

//Example returning false
$result = isset($a) ? "this exists!" : "it does not exist!";

//Example returning true
$a = 1;
$result = isset($a) ? "this exists!" : "it does not exist!";

So as you can see, using a ternary operator is a shorthand way to do a standard "if else" statement. They are considered harder to read, so only use them when they are appropriate and not too complex.

Examples David Walsh example, and another example from stack overflow