match

The expression branches evaluation based on an identity check of a value. Similarly to a statement, a expression has a subject expression that is compared against multiple alternatives. Unlike , it will evaluate to a value much like ternary expressions. Unlike , the comparison is an identity check () rather than a weak equality check (). Match expressions are available as of PHP 8.0.0. match``switch``match``switch``switch``===``==

Voorbeeld: Structure of a expression

<?php
$return_value = match (subject_expression) {
    single_conditional_expression => return_expression,
    conditional_expression1, conditional_expression2 => return_expression,
};
?>

Voorbeeld: Basic usage

<?php
$food = 'cake';

$return_value = match ($food) {
    'apple' => 'This food is an apple',
    'bar' => 'This food is a bar',
    'cake' => 'This food is a cake',
};

var_dump($return_value);
?>

string(19) "This food is a cake"

Voorbeeld: Example of using with comparison operators

<?php
$age = 18;

$output = match (true) {
    $age < 2 => "Baby",
    $age < 13 => "Child",
    $age <= 19 => "Teenager",
    $age >= 40 => "Old adult",
    $age > 19 => "Young adult",
};

var_dump($output);
?>

string(8) "Teenager"

Opmerking: > The result of a expression does not need to be used. match

Opmerking: > When a expression is used as a standalone expression it be terminated by a semicolon . matchmust;

The expression is similar to a statement but has some key differences:

match``switch- A arm compares values strictly () instead of loosely as the switch statement does. match``===

A expression returns a value. match
arms do not fall-through to later cases the way statements do. match``switch
A expression must be exhaustive. match

As statements, expressions are executed match arm by match arm. In the beginning, no code is executed. The conditional expressions are only evaluated if all previous conditional expressions failed to match the subject expression. Only the return expression corresponding to the matching conditional expression will be evaluated. For example:

`switch``match````php

'value', $this->bar() => 'value', // $this->bar() isn't called if foo() === $x $this->baz => beep(), // beep() isn't called unless $x === $this->baz // etc. }; ?>





   expression arms may contain multiple expressions
  separated by a comma.  That is a logical OR, and is a short-hand for multiple
  match arms with the same right-hand side.
 `match`


  
 ```php
<?php
$result = match ($x) {
    // This match arm:
    $a, $b, $c => 5,
    // Is equivalent to these three match arms:
    $a => 5,
    $b => 5,
    $c => 5,
};
?>

A special case is the pattern. This pattern matches anything that wasn't previously matched. For example:

`default````php

foo(), 3, 4 => bar(), default => baz(), }; ?>


> **Opmerking:** > Multiple default patterns will raise a
>      error.
>    `E_FATAL_ERROR`




  A  expression must be exhaustive.  If the
  subject expression is not handled by any match arm an
   is thrown.
 `match``UnhandledMatchError`

**Voorbeeld: Example of an unhandled match expression**

```php
<?php
$condition = 5;

try {
    match ($condition) {
        1, 2 => foo(),
        3, 4 => bar(),
    };
} catch (\UnhandledMatchError $e) {
    var_dump($e);
}
?>

object(UnhandledMatchError)#1 (7) {
  ["message":protected]=>
  string(33) "Unhandled match value of type int"
  ["string":"Error":private]=>
  string(0) ""
  ["code":protected]=>
  int(0)
  ["file":protected]=>
  string(9) "/in/ICgGK"
  ["line":protected]=>
  int(6)
  ["trace":"Error":private]=>
  array(0) {
  }
  ["previous":"Error":private]=>
  NULL
}

Using match expressions to handle non identity checks

It is possible to use a expression to handle non-identity conditional cases by using as the subject expression. match``true

Voorbeeld: Using a generalized match expressions to branch on integer ranges

<?php

$age = 23;

$result = match (true) {
    $age >= 65 => 'senior',
    $age >= 25 => 'adult',
    $age >= 18 => 'young adult',
    default => 'kid',
};

var_dump($result);
?>

string(11) "young adult"

Voorbeeld: Using a generalized match expressions to branch on string content

<?php

$text = 'Bienvenue chez nous';

$result = match (true) {
    str_contains($text, 'Welcome'), str_contains($text, 'Hello') => 'en',
    str_contains($text, 'Bienvenue'), str_contains($text, 'Bonjour') => 'fr',
    // ...
};

var_dump($result);
?>

string(2) "fr"

Vorige ← include Volgende require_once →

match

match

Using match expressions to handle non identity checks

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