PHP data type conversion and type detection

This article mainly shares with you PHP data type conversion and type detection. Although it is the basic knowledge of PHP, it is very useful and I hope it can help everyone.

Implicit conversion (automatic conversion)

Convert to string type

true --> '1'

false, null --> ; Empty string

is converted into a numeric type

starts with a legal value and ends with the first illegal value;

starts with an illegal value and is converted to 0

Convert to Boolean type

0, 0.0, '', "", '0', null, array() is false;

String, integer, float Points, '0.0', 'false', ' ' are true.

Display conversion

Temporary conversion

1. (Variable type)$Variable name

Syntax:

Integer: (int) $Variable name

Floating point type: (float)$Variable name

Character type: (string)$Variable name

Boolean type: (bool)$Variable name

Empty: (unset)$Variable name

Number: (array)$Variable name

Object: (object)$Variable name

2. System Function implementation

intval($variable name) Returns the value of the variable converted to an integer

floatval($variable name) Returns the value of the variable converted to a floating point type

strval( $Variable name) Returns the value of the variable converted to string type

oolval($Variable name) Returns the value of the variable converted to Boolean type

Permanent conversion

settype($ Variable name, 'type') Set the type of the variable

Detect the variable type

Integer type is_int()

Floating point type is_float()

Character String is_string()

Boolean type is_bool()

Scalar type is_scalar()

Empty is_null()

Array is_array()

Object is_object()

Resource is_resource()

Numeric or string value is_numeric()

Implicit conversion (automatic conversion)

Convert to string type

true --> '1'

false, null --> Empty string

Convert to numeric type

Start with a legal value and continue until the first illegal value;

Start with an illegal value and convert it to 0

Convert to Boolean type

0 , 0.0, '', "", '0', null, array() are false;

String, integer, floating point number, '0.0', 'false', ' ' are true.

Display conversion

Temporary conversion

1. (Variable type)$Variable name

Syntax:

Integer: (int) $Variable name

Floating point type: (float)$Variable name

Character type: (string)$Variable name

Boolean type: (bool)$Variable name

Empty: (unset)$Variable name

Number: (array)$Variable name

Object: (object)$Variable name

2. System Function implementation

intval($variable name) Returns the value of the variable converted to an integer

floatval($variable name) Returns the value of the variable converted to a floating point type

strval( $Variable name) Returns the value of the variable converted to string type

oolval($Variable name) Returns the value of the variable converted to Boolean type

Permanent conversion

settype($ Variable name, 'type') Set the type of the variable

Detect the variable type

Integer type is_int()

Floating point type is_float()

Character String is_string()

Boolean type is_bool()

Scalar type is_scalar()

Empty is_null()

Array is_array()

Object is_object()

Resource is_resource()

Numeric or string value is_numeric()

Related recommendations:

JavaScript data type conversion principles detailed explanation

PHP data type conversion conversion

JS data type conversion summary

The above is the detailed content of PHP data type conversion and type detection. For more information, please follow other related articles on the PHP Chinese website!