PHP8.1 new match expression: simplifying multiple condition judgments

PHP is a very popular server-side scripting language that is constantly developing and improving. In the latest version of PHP8.1, an important new feature has been added: match expressions. This new feature makes multiple conditional judgments simpler and easier to read. This article will introduce the use of match expressions and demonstrate it through some code examples.

In PHP, we often need to perform multiple conditional judgments on different variables or expressions. The traditional way is to use a series of if-else statements. The match expression provides us with a more concise way of writing. Let's look at a simple example:

$value = 5;

$result = match($value) {
    1 => 'One',
    2 => 'Two',
    3, 4 => 'Three or Four',
    default => 'Other'
};

echo $result; // 输出：Other

In the above code, we use the match expression to determine the value of the variable $value. The brackets after match are the variables or expressions that need to be judged. After the arrow, we can list the values ​​that need to be matched and follow the corresponding results after the arrow. If no value is matched, we can use the default keyword to specify the default result. In this example, the value of $value is 5, which does not match any of the specified values, so the final result is 'Other'.

In addition to matching single values, we can also use lists for matching. The following is a sample code:

$value = 20;

$result = match($value) {
    in_array($value, [1, 2, 3]) => 'One, Two or Three',
    in_array($value, [4, 5, 6]) => 'Four, Five or Six',
    default => 'Other'
};

echo $result; // 输出：Other

In the above code, we use the in_array function to determine whether $value is in the specified list. If the match is successful, the corresponding result is returned. If no match is found, the default result is returned.

In addition, the match expression also supports the use of other expressions or functions for matching. We can combine and use them according to specific needs. Here is a more complex example:

$value = 100;

$result = match(true) {
    in_array($value, range(1, 10)) => 'One to Ten',
    $value > 10 && $value < 100 => 'Between Ten and One Hundred',
    is_numeric($value) => 'Numeric Value',
    default => 'Others'
};

echo $result; // 输出：Others

In the above code, we determine whether the value of $value is in the range of 1 to 10, and whether it is in the range of 10 to 100 within, and whether it is a number. Match results according to different conditions and return corresponding results.

Through the above examples, we can see that the code of match expression is more concise and easier to read than the traditional if-else statement. It can handle multiple conditions simultaneously and supports matching using various expressions and functions. For multiple conditional judgments, match expressions can provide a more elegant and efficient programming method.

In summary, the new match expression in PHP8.1 makes multiple conditional judgments more simplified and easier to read. By using match expressions, we can transform complex logical judgments into concise code, improving the readability and maintainability of the code. For PHP developers, mastering the use of match expressions will improve development efficiency and make code more concise and elegant.

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