I just did Exercise 1.7 (in http://ocw.mit.edu/courses/electrical-engineering-and-computer-science/6-189-a-gentle-introduction-to-programming-using-python-january-iap-2011/assignments/MIT6_189IAP11_hw1.pdf ) which is a Rock, Paper, Scissors game.

My question is, when you have a series of if/elif conditionals, is it good practice to have an extra else at the end to catch any unexpected conditions? Or is that unnecessary or confusing?

You can see my code at https://gist.github.com/3781336

Question

I just did Exercise 1.7 (in http://ocw.mit.edu/courses/electrical-engineering-and-computer-science/6-189-a-gentle-introduction-to-programming-using-python-january-iap-2011/assignments/MIT6_189IAP11_hw1.pdf ) which is a Rock, Paper, Scissors game. 

My question is, when you have a series of if/elif conditionals, is it good practice to have an extra else at the end to catch any unexpected conditions? Or is that unnecessary or confusing?

You can see my code at https://gist.github.com/3781336

anonymous · Answer

If you guarantee that only allowed answers are given, then account for each of those answers, there should be no need for the extra else at the end. Having said that, I did added it anyway, just in case. As long as the if/elif conditions account for all possibilities, you should be good.

anonymous · Answer

I should add that sometimes your last elif can be replaced with else, since at that point you've exhausted all the possibilities--assuming you have controlled the input, which it looks like you have.

rsmith6559 · Answer

Users have an amazing ability to screw up.  Having that extra else gives your program a fighting chance.  IMO, do it.