3.12. Typing Annotated

Note

ValueRange, ctype, MatchesRegex, MaxLen does not exist in Python. It is used only as an example both here and in PEP 593.

3.12.1. SetUp

>>> from typing import Annotated

3.12.2. Numeric

>>> digit = Annotated[int, ValueRange(0,9)]  
>>> int8 = Annotated[int, ValueRange(-128, 127), ctype('int8')]  
>>> uint8 = Annotated[int, ValueRange(0, 255), ctype('uint8')]    
>>> kelvin = Annotated[float, ValueRange(0.0, float('inf'))]  
>>> vector = Annotated[list[int], MaxLen(3)]

3.12.3. Character

>>> firstname = Annotated[str, MaxLen(10)]  
>>> lastname = Annotated[str, MinLen(2), MaxLen(10)]

3.12.4. Patterns

>>> jira_issuekey = Annotated[str, MatchesRegex('^[A-Z]{2,10}-[0-9]{1,6}$')]  
>>> email = Annotated[str, MatchesRegex('^[a-z]{1,20}@nasa.gov$')]

3.12.5. Use Case - 0x01

>>> 
... EmailAddress = Annotated[str, MatchesRegex('^[a-z]{1,20}@nasa.gov$')]
...
... def send_email(recipient: EmailAddress):
...     ...
...
...
... send_email('mwatney@nasa.gov')  # ok
... send_email('avogel@esa.int')    # error

3.12.6. Use Case - 0x02

>>> 
... IssueKey = Annotated[str, MatchesRegex('^[A-Z]{2,10}-[0-9]{1,6}$')]
...
... def comment(issuekey: IssueKey, text: str):
...     ...
...
...
... comment('MYPROJ-1337', 'Issue was resolved successfully.')