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 one type to the other type

The correspondence between Python types and typepy classes are as follows:

Supported Types

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

• Python 3.7+
• Python package dependencies (automatically installed)

Optional dependencies

These packages can be installed via pip install typepy[datetime]:

• python-dateutil
• pytz

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 was 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 class constructors as an argument. More information can be found in the API reference.

Documentation

https://typepy.rtfd.io/