1. typepy¶

2. Summary¶

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

3. 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

4. Installation¶

4.1. Installation: pip¶

pip install typepy

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

pip install typepy[datetime]

4.2. Installation: conda¶

conda install -c conda-forge typepy

4.3. Installation: apt¶

sudo add-apt-repository ppa:thombashi/ppa
sudo apt update
sudo apt install python3-typepy

5. Dependencies¶

Python 3.7+
Python package dependencies (automatically installed)

5.1. Optional dependencies¶

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

6. Usage¶

6.1. Type Check Method¶

Examples

>>> from typepy import Integer
>>> Integer(1).is_type()
True
>>> Integer(1.1).is_type()
False

6.2. 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'>

6.3. Type Conversion Methods¶

6.3.1. 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

6.3.2. 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

6.3.3. 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'>

6.4. 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.