Introduction to PHP data types and data type detection

This article brings you an introduction to PHP data types and data type detection. It has certain reference value. Friends in need can refer to it. I hope it will be helpful to you. .

Data type

Data types are divided into three types: scalar type, composite type, special type
Scalar type:

boolean(Boolean type) integer(integer type)
float(floating point type) string(string type)

composite type

array( Array) object(object)

Special type

resource(resource) Nnull(null value)

Data type detection

The data type of a variable in PHP is usually not set by the developer, but is determined at runtime based on the context in which the variable is used.
In order to detect whether the value of the expression is the data type you want, PHP provides a set of built-in functions
If the detected value matches the detected data type, it will return true, otherwise it will return false

Data type conversion

When operating two variables, if the data types are different, data type conversion is required, which is usually divided into automatic type conversion and forced type. Conversion

Automatic type conversion: certain values ​​will be automatically converted during operation and judgment
When a Boolean value of true participates in the operation, it will become an integer type 1, and false will become an integer type
Characters of integer or floating-point type at the beginning of the string will be converted to the corresponding type for operation
Forced type conversion: manual conversion of the data type, adding "(target type)" before the data or variable to be converted Just

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