What are the eight major data types in PHP?

The definition of a data type in a data structure is the collective name of a set of values ​​with the same properties and a set of operations defined on this set of values. Let's summarize the eight major data types of PHP for everyone.

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##Four scalar types:

Boolean (Boolean type) : This is the simplest type, with only two values, which can be TRUE/true or FALSE/false, and are not case-sensitive. For details, please see: PHP Boolean type (boolean)

integer (integer) : Its valid range in 32-bit operating systems is: -2 147 483 648~ 2 147 483 647 . Integer values ​​can be expressed in decimal, hexadecimal or octal notation and may be preceded by an optional sign (- or ). Octal represents a number that must be preceded by 0 (zero), and hexadecimal represents a number that must be preceded by 0x. For details, please see: PHP integer data (Integer)

Float (floating point type, also called double): The valid range in 32-bit operating systems is: 1.7E-308 ~1.7E 308. For details, please see: PHP floating point type (float)

String (string) : Character variables are different from other programming languages ​​in that they are divided into characters and strings. In PHP, they are unified Use character variables to define characters or strings. For details, please see: PHP string type (string)

Two composite types:

　

array (array) : Array variable is a special variable type, which will be explained in detail in subsequent chapters.

　

object (object): Object is also a special data type. To create an object variable, use the new keyword. For details, please see: PHP object type (object)

Finally, there are two special types:

Resource (resource) : Source is a special variable that holds a reference to an external resource. Resources are created and used through specialized functions. For details, please see: PHP resource type (resource)

NULL (NULL) : Indicates that a variable has no value. The only possible value of type NULL is NULL.

Note:

You may also read some references to the "double" type. In fact, double and float are the same, and for some historical reasons, these two names existed at the same time.

The type of a variable is usually not set by the programmer, but is determined by PHP at runtime based on the context in which the variable is used. In other words, PHP is a weakly typed language. Programmers do not need to declare the variable type when declaring variables, and the PHP interpreter will automatically recognize it.

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