What is the purpose of using " -> int" after a function def in Python? [duplicate]

Question

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

This is function name and this format is used in python. I am confused why we are using this arrow and why we are using int inside paranthesis after s. Can someone explain please?

See stackoverflow.com/q/51639332/3001761. Note that "this" is a pretty terrible description for a title. — jonrsharpe
– jonrsharpe, Commented Mar 30, 2020 at 20:38
In the future, please use the generic [python] tag for all python related questions. Use a version-specific tag at your discretion — juanpa.arrivillaga
– juanpa.arrivillaga, Commented Mar 30, 2020 at 20:45

jonrsharpe · Accepted Answer · 2020-03-30 20:42:11Z

3

They are function annotations.

-> marks the return function annotation indicating the function returns an int.

The : str indicates a string argument.

You can read more about them here.

Or, SO: What does -> mean in Python function definitions?

edited Mar 30, 2020 at 20:42

jonrsharpe

123k31 gold badges277 silver badges488 bronze badges

answered Mar 30, 2020 at 20:39

Sanil

3742 silver badges7 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Charles Duffy Over a year ago

Questions that you know to be duplicative should be closed, not answered. See the "Answer Well-Asked Questions" section of How to Answer, including the bullet point regarding questions that "have already been asked and answered many times before".

Collectives™ on Stack Overflow

What is the purpose of using " -> int" after a function def in Python? [duplicate]

1 Answer 1

1 Comment

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Linked

Related