How to write a simple recursive function?
[removed]
Posted Oct 27, 2016, 3:19 PM UTC
07
This is an example of a recursive way of testing if a string is the same reversed or not. Try to work off of this:
def reverse(s):
if len(s) == 1 or len(s) == 0:
return True
if s[0] == s[-1]:
return reverse(s[1:-1])
else:
return False
2
this doesn't output anything, I think it is stuck in a loop. would removing the else retunr false fix the problem
1
Sorry, the stopping conditions should have been if len(s) == 1 or 0. I made the edit.
I will also suggest you write out how this function works on paper or something. Removing the "else: return False" statement would destroy this function. The recursion occurs at the line
return reverse(s[1:-1])
So focus your attention on what is happening there.
1
Ask this in r/learnpython. As the sidebar says:
If you are about to ask a question, please
consider [r/learnpython](/r/learnpython). Homework-style
questions will be removed, and you'll be
encouraged to post there instead.
1
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1
r/learnpython
I think you need to research the word 'recursion' a bit, enough to define it at least.
I get recursive functions call themselves and keep running until the process is complete. I'd like to learn how to reverse a string using recursion, i know how to use the [::-1], but that's not what I am looking for. We're going over it in class right now, and I don't really understand the logic of it so I thought seeing it on an example problem we were given would be useful