What are the common function return value types in PHP?

PHP function return value type determines the data type returned by the function, including scalar types (int, float, string, bool, resource), composite types (array, object) and special types (null, void). In practice, functions can return specific types of return values, such as integers, arrays, or objects, ensuring the correctness and robustness of applications.

Common function return value types in PHP

In PHP, the function return value type determines the type of data returned by the function , which is crucial to ensure the correctness and robustness of the application. The following are some common PHP function return value types:

1. Scalar type

• int: Integer Type
• float: floating point type
• string: string
• bool: Boolean type
• resource: Resource, such as a file handle or database connection

2. Composite type

• array：Array
• object：Object

##3. Special type

• null: means there is no value
• void: means the function does not return any value

Practical case:

1. Get the integer return value

function sum($a, $b) {
  return $a + $b;
}

$result = sum(5, 10);
var_dump($result); // 结果：int(15)

2. Get the array return value

function getUserData($id) {
  // 从数据库获取用户信息
  // ...

  return [
    'name' => 'John Doe',
    'email' => 'john@example.com',
  ];
}

$userData = getUserData(1);
var_dump($userData); // 结果：array(2) { ["name"]=> string(8) "John Doe" ["email"]=> string(19) "john@example.com" }

3 . Get the object return value

class User {
  // ...
}

function createUser() {
  return new User();
}

$user = createUser();
var_dump($user); // 结果：object(User) #1 (0) { }

In addition to the above types, PHP also supports union types (that is, a function can return a union of multiple types) and variable return types (that is, a function returns different types in different situations) return value), providing greater flexibility.

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