Example of new features in PHP8: How to use match expressions and code to simplify conditional judgment?

PHP8 is an important version of the PHP programming language that introduces many new features and improvements. One of the new features is match expressions, which can help developers simplify conditional judgment code. In this article, we will introduce how to use match expressions to simplify the process of conditional judgment and give some practical examples.

In PHP7 and previous versions, we often use switch statements or a series of if-else statements to make conditional judgments. These statements can achieve the same function, but will cause code duplication and poor readability. The introduction of match expressions is precisely to solve these problems.

The syntax of the match expression is very similar to the switch statement. It can execute the corresponding code block based on the value of an expression. The difference is that the match expression is an expression rather than a statement, and it can return a value. This allows us to assign it directly to a variable or as the return value of a function.

The following is a simple example that shows how to use match expressions to determine which range a number belongs to and return the corresponding numerical type.

function getType(int $number) {
    return match (true) {
        $number < 0 => 'negative',
        $number == 0 => 'zero',
        $number > 0 => 'positive',
    };
}

echo getType(-5);  // 输出: negative
echo getType(0);   // 输出: zero
echo getType(10);  // 输出: positive

In the above example, we defined a function named getType, which accepts an integer as a parameter. In the match expression, we use true as the condition because we want to perform multiple conditional judgments instead of a single judgment. We then associate each condition with the corresponding numeric type using the arrow operator =>.

In actual use, we can add more conditions and perform different operations as needed. The match expression will be evaluated in sequence according to the conditions until a matching condition is found or the default condition is reached.

function getPrice(string $productType) {
    return match ($productType) {
        'book' => 20,
        'clothes' => 50,
        'electronics' => 100,
        default => 0,
    };
}

echo getPrice('book');          // 输出: 20
echo getPrice('clothes');       // 输出: 50
echo getPrice('electronics');   // 输出: 100
echo getPrice('unknown');       // 输出: 0

In the above example, we defined a function called getPrice, which accepts a string parameter representing the product type. Depending on the product type, we return the corresponding price. If the product type cannot match any criteria, a default value of 0 is returned.

In addition to the basic usage in the above examples, match expressions also provide other functions, such as using logical operators to combine conditions, using anonymous functions, etc. These features can further improve the flexibility and readability of our code.

To sum up, PHP8’s new feature match expression provides us with a way to simplify conditional judgment, making our code more concise and readable. By using match expressions, we can avoid cumbersome if-else statements and repeated code, improving development efficiency and code quality. I hope the examples in this article can help you better understand and apply match expressions.

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