Error message saying variable not defined when it is. Python

Question

I am trying to create a simple encryption program in python using functions but am having a problem where I get an error message when I run the program saying (\'msgReversed\' i

Answer 1

In your last line you pass a variable called 'msgReversed' into your 'encript' function. However: msgReversed is only locally defined inside your 'reverseMsg' function. Variables can either be local variables that only live inside of a function. Or global variables, that live in the entire script. A simple workaround would be to make your msgReversed a global variable, by simply adding 'global' in front of the first line of your 'reverseMsg' function. Another solution in your first to last line: msgReversed = reverseMsg(plaintext)

A simplified tutorial on this matter: http://www.python-course.eu/global_vs_local_variables.php

Added a simple example:

myname = "Marc"

def printName():
    myname = "Sonder"
    print (myname)

printName()
print (myname)

Outside of the function, the 'myname' function will yield "Marc". However inside the function, myname will yield "Sonder". If you would delete the first line, and try to execute the last line, to print the global version of 'myname', you will get the exact same error as you have got right now.

To grasp this I would copy this script, and see what changes when you comment certain parts out.