How to use Match expression to judge conditions more concisely in PHP8?

How to use Match expression to judge conditions more concisely in PHP8?

In PHP8, a new conditional judgment syntax - Match expression is introduced, which allows us to judge multiple conditions and execute the corresponding code block in a more concise way. Match expressions are similar to switch statements, but are more concise and easier to read than switch.

The syntax for using Match expressions is as follows:

$result = match ($value) {
    value1 => expression1,
    value2 => expression2,
    value3 => expression3,
    ...
    default => expression
};

In this syntax, $value is the value to be judged, followed by a series of conditional values ​​and expressions. When the value of $value matches a certain condition value, the corresponding expression will be executed.

Next, we will use specific code examples to demonstrate how to use Match expressions to determine conditions more concisely in PHP8.

First, consider a simple example. We need to determine which age group the user belongs to based on his age and print the corresponding message. The traditional approach may be to use if statements, the code is as follows:

$age = 20;
if ($age >= 18 && $age <= 25) {
    echo "你是青年人";
} elseif ($age > 25 && $age <= 35) {
    echo "你是中年人";
} elseif ($age > 35) {
    echo "你是老年人";
} else {
    echo "你还是未成年人";
}

Using Match expression, we can implement the above code more concisely, as shown below:

$age = 20;
$result = match (true) {
    $age >= 18 && $age <= 25 => "你是青年人",
    $age > 25 && $age <= 35 => "你是中年人",
    $age > 35 => "你是老年人",
    default => "你还是未成年人"
};
echo $result;

From the above code can As you can see, we use Match expressions to map conditions and corresponding expressions in the form of key-value pairs. When the value of $value meets a certain condition, the corresponding expression is executed and the result is assigned to the $result variable.

In addition, we can also use function expressions in Match expressions to further simplify the code. Consider the following example, where we want to determine the user's permission level in the system based on his role and return the corresponding text message. The traditional approach may be to use a switch statement, the code is as follows:

$role = "admin";
$permission = "";
switch ($role) {
    case "admin":
        $permission = "完全权限";
        break;
    case "moderator":
        $permission = "部分权限";
        break;
    case "user":
        $permission = "只读权限";
        break;
    default:
        $permission = "未知权限";
}
echo "您的权限级别为：" . $permission;

Using Match expression, we can implement the above code more concisely, as shown below:

$role = "admin";
$result = match ($role) {
    "admin" => "完全权限",
    "moderator" => "部分权限",
    "user" => "只读权限",
    default => "未知权限"
};
echo "您的权限级别为：" . $result;

As can be seen from the above example It turns out that Match expressions can easily replace traditional conditional judgment syntax, making the code more concise and readable. It provides a more intuitive and efficient way to handle multiple conditional branches. When we need to judge multiple conditions, using Match expressions can make the code more elegant and improve the maintainability of the code.

Summary:
In PHP8, a new conditional judgment syntax - Match expression is introduced, which can judge conditions more concisely and execute the corresponding code block. Using Match expressions, we can implement multi-condition judgments with less code and improve the readability of the code. In actual development, we can learn and master the use of Match expressions through specific code examples so that we can apply them to actual projects and improve development efficiency and code quality.

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