What are the main data types of PHP?

There are three main data types in PHP:

1. Scalar data types

Scalar data types include the following. (Recommended learning: PHP video tutorial)

(1) boolean: Boolean type

Boolean variables are the simplest of PHP variables. It holds a True or False value. Where True or False is an internal keyword of PHP. To set a Boolean variable, just assign True or False to the variable

(2) string: String

A string is a continuous sequence of characters. Each character in the string characters occupy only one byte. In PHP, there are three ways to define strings:

single quote method,

double quote method,

Heredoc method.

(3) integer: integer

The integer data type can only contain integers. These data types can be positive or negative numbers. In 32-bit operating systems, the valid range is 2 147 483 648 ~ 2 147 483 647.

(4)double: floating point number

The floating point data type can be used to store numbers or decimals. The precision it provides is not much larger than integers. In 32-bit operating systems, the valid range is 1.7E-308 ~ 1.7E 308.

2. Composite data types

Compound data types include the following two types.

(1) array: Array

can be two-dimensional, three-dimensional or multi-dimensional. Each element in the array can be string, integer or double, or it can be an array.

(2) object: object type

3． Special data types

Special data types include the following two types.

(1) resource: Resource

Resources are special data types required by several functions in PHP and are allocated by programmers.

(2) null: Null value

Null value is the simplest data type. Indicates that no value is set for the variable. In addition, null values ​​(NULL) are not case-sensitive.

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