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PHP data type conversion and type detection
- 小云云Original
- 2018-03-27 16:17:101294browse
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()
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