?: (Elvis Operator)
The elvis operator (?:) is actually a name used for shorthand ternary (which was introduced in PHP 5.3). It has the following syntax:
// PHP 5.3+ expr1 ?: expr2;
This is equivalent to:
expr1 ? expr1 : expr2;
?? (Null Coalescing Operator)
The null coalescing operator (??) was introduced in PHP 7, and it has the following syntax:
// PHP 7+ $x ?? $y;
This is equivalent to:
isset($x) ? $x : $y;
?: vs. ??
The table below shows a side-by-side comparison of the two operators against a given expression:
| Expression | echo ($x ?: 'hello') |
echo ($x ?? 'hello') |
|---|---|---|
$x = ""; |
'hello' |
"" |
$x = null; |
'hello' |
'hello' |
$x; |
'hello'(and Notice: Undefined variable: x) |
'hello' |
$x = []; |
'hello' |
[] |
$x = ['a', 'b']; |
['a', 'b'] |
['a', 'b'] |
$x = false; |
'hello' |
false |
$x = true; |
true |
true |
$x = 1; |
1 |
1 |
$x = 0; |
'hello' |
0 |
$x = -1; |
-1 |
-1 |
$x = '1'; |
'1' |
'1' |
$x = '0'; |
'hello' |
'0' |
$x = '-1'; |
'-1' |
'-1' |
$x = 'random'; |
'random' |
'random' |
$x = new stdClass; |
object(stdClass) |
object(stdClass) |
Hope you found this post useful. It was published (and was last revised ). Please show your love and support by sharing this post.