PHP match Expression

The PHP Match Expression

The match expression provides a new way to handle multiple conditional checks (like the switch statement).

The match expression evaluates an expression against multiple alternatives (using strict comparison) and returns a value. 

Here are the key differences between match and switch:

• A match expression has a more readable syntax than switch
• A match expression returns a value, while switch does not
• A match expression breaks automatically after a match, while switch requires break;
• A match expression has strict comparison (===), while switch uses loose comparison (==)

Syntax for match

$result = match($expression) {
  condition1 => returnvalue1,
  condition2 => returnvalue2,
  condition3, condition4 => returnvalue3,
  default => defaultvalue,
}

Tip: The default arm catches all expressions that are not matched.

The following example is equal to the example on the switch page, but here we use the the match expression:

$favcolor = "red";

$text = match($favcolor) {
  "red" => "Your favorite color is red!",
  "blue" => "Your favorite color is blue!",
  "green" => "Your favorite color is green!",
  default => "Your favorite color is neither red, blue, nor green!",
};

echo $text;

Match Multiple Values

If you want the match expression to match multiple values for the same code block, you can group them with commas, like this:

$d = 3;

$text = match($d) {
  1, 2, 3, 4, 5 => "The week feels so long!",
  6, 0 => "Weekends are best!",
  default => "Invalid day",
};

echo $text;

The default Keyword

In a match expression, there must be a condition that matches the expression, or a default case, to handle it.

If there are no matches, and no default case, the match expression throws an UnhandledMatchError exception.

$favcolor = "pink"; // no conditions will match this

try {
  $text = match($favcolor) {
    "red" => "Your favorite color is red!",
    "blue" => "Your favorite color is blue!",
    "green" => "Your favorite color is green!",
  };
} catch (\UnhandledMatchError $e) {
  var_dump($e);
}

echo $text;