This is a ternary operator, a short version of the if
statement.
This:
$a = $test ? $b : $c;
is the same as:
if($test)
{
$a=$b;
}
else
{
$a=$c;
}
so basically your example is equivalent to:
if(! empty(self::$settings['tax_value'])
{
return self::$settings['tax_value'];
}
else
{
return $value;
}
You can find some more info here, together with some tips for precautions when using ternary operators.
Important note about the difference from other languages
Since the question is marked as a duplicate of another question that deals with ternary operator in Objective-C, I feel this difference needs to be addressed.
The ternary operator in PHP has a different associativity than the one in C language (and all others as far as I know). To illustrate this, consider the following example:
$val = "B";
$choice = ( ($val == "A") ? 1 : ($val == "B") ? 2 : ($val == "C") ? 3 : 0 );
echo $choice;
The result of this code (in PHP) will be 3
, even though it would seem that 2
should be the correct answer. This is due to weird associativity implementation that threats the upper expression as:
( ( ( ($val=="A") ? 1 : ($val=="B") ) ? 2 : ) ($val=="C") ? 3 : 0 )
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