typepy 0.3.1

A Python library for variable type checker/validator/converter at a run time.

typepy

Table of Contents

• Summary

• Features

• Usage

  • Type Check Method

  • Type Validation Method

  • Type Conversion Methods

  • For more information

• Installation

• Dependencies

  • Optioal dependencies

  • Test dependencies

• Documentation

Summary

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:

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

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.

Installation

pip install typepy

Install additional dependency packages with the following command if using typepy.DateTime class

pip install typepy[datetime]

Dependencies

Python 2.7+ or 3.4+

• mbstrdecoder

• six

Optioal dependencies

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

• python-dateutil

• pytz

Test dependencies

• pytest

• pytest-runner

• tox

Documentation

https://typepy.rtfd.io/