typepy
Summary
typepy is a Python library for variable type checker/validator/converter at a run time.
Features
- checking a value type
- validate a value for a type
- convert a value from a type to the other type
The correspondence between Python types and typepy classes are as follows:
| Python Type | typepy: Type Class |
|---|---|
bool |
Bool |
datetime |
DateTime |
dict |
Dictionary |
float/decimal.Decimal (not infinity/NaN) |
RealNumber |
float/decimal.Decimal (infinity) |
Infinity |
float/decimal.Decimal (NaN) |
Nan |
int |
Integer |
list |
List |
None |
None |
str (not null) |
String |
str (null) |
NullString |
str (IP address) |
IpAddress |
Installation
Installation: pip
pip install typepy
Install additional dependency packages with the following command if using typepy.DateTime class
pip install typepy[datetime]
Installation: conda
conda install -c conda-forge typepy
Installation: apt
sudo add-apt-repository ppa:thombashi/ppa sudo apt update sudo apt install python3-typepy
Dependencies
Optioal dependencies
These packages can be installed via pip install typepy[datetime]:
Usage
Type Check Method
| Examples: | >>> from typepy import Integer
>>> Integer(1).is_type()
True
>>> Integer(1.1).is_type()
False |
|---|
Type Validation Method
| Examples: | >>> from typepy import Integer
>>> Integer(1).validate()
>>> try:
... Integer(1.1).validate()
... except TypeError as e:
... # validate() raised TypeError when the value unmatched the type class
... print(e)
...
invalid value type: expected=INTEGER, actual=<type 'float'> |
|---|
Type Conversion Methods
convert method
| Examples: | >>> from typepy import Integer, TypeConversionError
>>> Integer("1").convert()
1
>>> try:
... Integer(1.1).convert()
... except TypeConversionError as e:
... # convert() raised TypeConversionError when conversion failed
... print(e)
...
failed to convert from float to INTEGER |
|---|
try_convert method
| Examples: | >>> from typepy import Integer
>>> Integer("1").try_convert()
1
>>> print(Integer(1.1).try_convert()) # try_convert() returned None when conversion failed
None |
|---|
force_convert
| Examples: | >>> from typepy import Integer, TypeConversionError
>>> Integer("1").force_convert() # force_convert() forcibly convert the value
1
>>> Integer(1.1).force_convert()
1
>>> try:
... Integer("abc").force_convert()
... except TypeConversionError as e:
... # force_convert() raised TypeConversionError when the value not convertible
... print(e)
...
failed to force_convert to int: type=<class 'str'> |
|---|
For more information
Type check/validate/convert results differed according to
strict_level value which can pass to typepy classes constructors as an argument.
More information can be found in the
API reference.