PHP Conditional Assignment Operators

The PHP conditional assignment operators are used to set a value depending on conditions:

Operator    Name         Example                       Result
?:          Ternary      $x = expr1 ? expr2 : expr3    Returns the value of $x.
                                                       The value of $x is expr2 if expr1 = TRUE.
                                                       The value of $x is expr3 if expr1 = FALSE    
??       Null coalescing    $x = expr1 ?? expr2        Returns the value of $x.
                                                       The value of $x is expr1 if expr1 exists, and is not NULL.
                                                       If expr1 does not exist, or is NULL, the value of $x is expr2.
                                                       Introduced in PHP 7