What are the special types of data that PHP functions return?

PHP functions return special types of data

In PHP, functions can return special types of data, including:

• Null value (null): Indicates an undefined or non-existent value.
• Boolean value (boolean): A value that represents true or false.
• Integer type (integer): Represents an integer, which can be a positive number, a negative number or zero.
• Floating point type (float): Represents a floating point number, which can be a positive number, a negative number or zero, and there can be decimal places after the decimal point.
• String (string): Represents a sequence of characters, which can be enclosed in single quotes (') or double quotes (").
• Array(array): Represents a collection of stored values, which can be ordered (index array) or unordered (associative array)
• Object (object) : Represents an instance of a class (class template), with state (properties) and behavior (methods)
• Resource (resource): Represents a pointer to an external resource (such as a file, database connection, or resource). Image) pointer

Practical case

// 返回空值
$var = null;

// 返回布尔值
$is_true = true;

// 返回整型
$age = 30;

// 返回浮点型
$balance = 255.5;

// 返回字符串
$name = "John Doe";

// 返回数组
$arr = [1, 2, 3];

// 返回对象
class Person {
    public $name;
    public $age;

    public function __construct($name, $age) {
        $this->name = $name;
        $this->age = $age;
    }
}

$person = new Person("John Doe", 30);

// 返回资源
$file = fopen('test.txt', 'w');

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