Is there a way to enforce the type of a variable in a python function ? Or at least, give an indication of what it should be ? I already saw things like :
var -> int But I don't know the name of that syntax, nor its use.
Thanks
6
- there is not, python is not strictly typedSasha– Sasha2018-06-13 11:28:30 +00:00Commented Jun 13, 2018 at 11:28
- so what does this syntax means ? a:var->int ? And I know it is not stricly typed but my question is : or, is there a way to give an indication?John Doe– John Doe2018-06-13 11:29:41 +00:00Commented Jun 13, 2018 at 11:29
- and I don't know why someone would feel the urge to downvote the question.. I am just looking for the vocabulary involved to be able to search the PEP for advice.John Doe– John Doe2018-06-13 11:33:33 +00:00Commented Jun 13, 2018 at 11:33
- Check out docs.python.org/3/library/typing.htmltwolffpiggott– twolffpiggott2018-06-13 11:35:35 +00:00Commented Jun 13, 2018 at 11:35
- Possible duplicate of What does -> mean in Python function definitions?bipll– bipll2018-06-13 11:35:57 +00:00Commented Jun 13, 2018 at 11:35
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1 Answer
It's called Type Hints, has been introduced in Python 3.5 and is described here: https://docs.python.org/3/library/typing.html
See also PEP 484: https://www.python.org/dev/peps/pep-0484/
Example:
def greeting(name: str) -> str: return 'Hello ' + name Note that this will not enforce the type.
From the PEP:
While these annotations are available at runtime through the usual
__annotations__attribute, no type checking happens at runtime. Instead, the proposal assumes the existence of a separate off-line type checker which users can run over their source code voluntarily.
1 Comment
alec_djinn
To enforce the type, just add ad an assertion in your function
assert type(name) is str