Question

I’m a casual gamer and hobbyist programmer who knows a bit of Python. I’m trying to make a simple text adventure game engine, so I need to get raw input from the player.

This is Python 3.2.2, so my line is this:

var = input("What do you want to do? ").lower()

And that line works, but rather than typing that whole line I’d like to make it into a function (something like “getinput()”). From what I’ve read about input() and functions I’m looking for a function that doesn’t return anything, but changes another variable’s state (here “var”) as a “side effect.”

I do have a working function “halt()” that takes no arguments:

def halt():
    input("(Press Enter to continue...) ")
    print("")

Calling “halt()” gives the prompt, waits for Enter, then prints a blank line and moves on, which I intended.

The function I’m trying to get to work looks like this:

def getinput(x):
    x = input("What do you want to do? ").lower()
    print("")

After defining getinput(x):

var = ""
getinput(var)
print(var)

That snippet does not print the user’s input, and I’m confused as to why. What do I need to do to make this work in the intended fashion?

Is what I’m trying to do impossible with a function, or is there just something I don’t know about scope? Should I be at codereview?

Answer 1

You are right that the issue is about scope. The x in this line:

x = input("What do you want to do? ").lower()

Does not change the value that is passed to it- it creates a new variable (also called x) in the local scope of the function.

The right way to do this would be:

def getinput():
    return input("What do you want to do? ").lower()

x = getinput()
print(x)