CODEWITHSUNDEEP
pythonfunction
Blaine
Blaine

Reputation: 21

function either returns None or says "maximum recursion depth exceeded"

I am trying to create a program that will take two sets of random integers, and print a statement based on the results of those two sets of integers. However, when I call the method, I either receive "None" or an error stating "maximum recursion depth exceeded". I can't seem to figure out how to structure my return statements within these methods so that this works properly.

def genre(a,b):
    genreType = random.randint(a,b)

    if genreType == '1':
        genreType = "Fantasy"
        return genre()
    elif genreType == '2':
        genreType = "Sci-Fi"
        return genre()

def medium():
    mediumType = random.randint(1,2)

    if mediumType == '1':
        genre = genre(1,2)
        print("Play a " + genre + "game")
        return medium()
    elif mediumType == '2':
        genre = genre(1,2)
        print("Watch a " + genre + "anime")
        return medium()

Upvotes: 2

Views: 78

Answers (1)

Oleg Pyzhcov
Oleg Pyzhcov

Reputation: 7353

First, if a function has a branch without a return, it will return None, e.g.:

def something():
    if False:
        return "Thing"
    # There is no return in "else"

print(something()) # None

Second, comparing numbers to strings never succeeds:

print(1 == 1) # True
print(1 == '1') # False

So the example you've provided can only always return None

Third, you are not returning anything meaningful from your functions:

def genre(a,b):
    genreType = random.randint(a,b)

    if genreType == '1':
        genreType = "Fantasy"
        return genre() # call this function again, but with no parameters, why?!

If the condition had a chance of being true, you would be getting 

TypeError: genre() missing 2 required positional arguments: 'a' and 'b'

I can only guess that you meant to do this:

    if genreType == 1:
        genreType = "Fantasy"
        return genreType

Or, shorter and arguably more readable:

def genre(a,b):
    genreType = random.randint(a,b)

    if genreType == 1:
        return "Fantasy"
    elif genreType == 2:
        return "Sci-Fi"
    # And you can add your own error to know what exactly went wrong
    else:
       raise Exception("Genre bounds must be between 1 and 2")

Upvotes: 2

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