Spaceship, Ternary and Null Coalescing operators in PHP: Quick examples

These are so simple concepts, but sometimes forgotten by PHP developers. In order to quick introduce and explain how to use there three types of comparison operators in PHP, I've decided to share the simple codes bellow.

If you need further information, please check the official Comparison Operators documentation page.

Spaceship Operator

This:

$result = ($expr1) <=> ($expr2);

Is the same of:

if ($expr1 < $expr2) {
    $result = -1;
} else if ($expr1 == $expr2) {
    $result = 0;
} else if ($expr1 > $expr2) {
    $result = 1;
}

Ternary Operator

This:

$result = ($expr1) ? ($expr2) : ($expr3); 

Is the same of:

if (true == $expr1) {
  $result = $expr2;
} else {
  $result = $expr3;
}

And this:

$result = ($expr1) ?: ($expr3);

Is the same of:

if (true == $expr1) {
  $result = $expr1;
} else {
  $result = $expr3;
}

Null Coalescing Operator

This:

$result = ($expr1) ?? ($expr3);

Is the same of:

if (null !== $expr1) {
  $result = $expr1;
} else {
  $result = $expr3;
}

You can play with here: https://3v4l.org/SWfOt