Strange class declaration I found in Python

Question

So I was trying to do a bit of programming problems on LeetCode and I saw a method of class declaration that I'm not so familiar with. This was how it was:

class Solution:
    def romanToInt(self, s: str) -> int:

And what I'm used to is something more like:

class Solution:
    def romanToInt(self, s):

Is there a difference between the two?

https://stackoverflow.com/questions/14379753/what-does-mean-in-python-function-definitions — omercotkd, Mar 25 '22 at 13:29
Does this answer your question? [What does -> mean in Python function definitions?](https://stackoverflow.com/questions/14379753/what-does-mean-in-python-function-definitions) — EJZ, Mar 27 '22 at 20:31

Ben · Accepted Answer · 2022-03-25T15:22:42.490

3

It is a type annotation that has no runtime significance (in the absence of other libraries like Pydantic), but allows for some static type checking.

In this case, it simply means that the type of s is a string, and that the method returns an int

edited Mar 25 '22 at 15:22

answered Mar 25 '22 at 14:47

Ben

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Strange class declaration I found in Python

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