What are the classifications of PHP variables?

PHP variables are classified into scalar variables, array variables, object variables, resource variables, NULL variables, etc. Detailed introduction: 1. Scalar variables represent a single value. Scalar variables in PHP include integers, floating point numbers, Boolean values ​​and strings; 2. Array variables can store multiple values ​​and access them in the form of key-value pairs. In PHP The array can be an index array, an associative array or a mixed array; 3. Object variables refer to objects instantiated through classes, and object variables can contain properties and methods; 4. Resource variables, etc.

The operating environment of this tutorial: Windows 10 system, PHP8.1.3 version, Dell G3 computer.

PHP variables can be divided into the following categories:

Scalar Variables: Scalar variables represent a single value. Scalar variables in PHP include integers (int), floating point numbers (float), Boolean values ​​(bool), and strings (string).

Array Variables: Array variables can store multiple values ​​and are accessed in the form of key-value pairs. Arrays in PHP can be indexed arrays, associative arrays, or mixed arrays.

Object Variables: Object variables refer to objects instantiated through classes. Object variables can contain properties and methods.

Resource Variables: Resource variables refer to references to external resources (such as database connections, file handles, etc.). In PHP, resource variables are a special variable type used to manage external resources.

NULL variable: NULL variable represents a null value or undefined variable.

These are common variable classifications in PHP. Understanding the different types of variables can help you better understand and use variables in PHP.

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