What are the types of PHP function return values, and what are their respective usage scenarios?

PHP functions can return values ​​of various data types, including scalar types (bool, int, float, string, null), composite types (array, object) and special types (mixed, void). This determines the nature of the data returned by the function and the operations allowed. Scalar types are used for basic data processing, composite types are used for storing and processing complex data, and special types are used to represent unknown or variable return values ​​or no return value.

PHP function return value type

In PHP, functions can return values ​​of various data types. These value types determine the nature of the data returned by the function and the operations allowed. Let’s explore function return value types in PHP and their common usage scenarios:

1. Scalar types

2. Composite type

Example 1: Return a Boolean value to determine the condition (bool

function is_odd($number) {
  return $number % 2 === 1;
}

if (is_odd(15)) {
  echo "15 是奇数";
}

function calculate_area($radius) {
  return 3.14 * $radius ** 2;
}

$area = calculate_area(5);
echo "半径为 5 的圆的面积为 $area";

function get_student_data($id) {
  return [
    'name' => 'John Doe',
    'age' => 25,
    'address' => '123 Main Street'
  ];
}

$student_data = get_student_data(1);
echo "学生姓名：{$student_data['name']}";

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