Returning A Value From A Function To Be Used Outside The Function in Python 3

Functions are really useful for doing stuff for you in a program. But the hardest thing for me to work out was how to use what ever they did in the rest of my program.

Problem
Let's say I wanted to make a function to convert my string to lowercase. My program would look a little like this:

# Returns a string in lowercase


def Make_Lowercase(cmt):


      cmt = cmt.lower()




comment = "My name is SCOTT."


print ("Commment without lowercase formatting:")


print (comment)


print("")

 


#Replace the old variable with the lowercase one created in the function

print ("Comment run through function to make it lowercase:")


print (cmt)

 Here I am trying to get the new comment, cmt, but when I run the program it yells at me with:

Traceback (most recent call last):

  File "C:/Users/Im/Batman/Python3/ReturnFunction.py", line 13, in <module>

    print(cmt)

NameError: name 'cmt' is not defined

Boo! I can't access the local variable inside the Make_Lowercase function.

Solution
To fix this, we need to return the variable inside the function and place the result back into the original (or a new variable. Up to you.) variable.

Here is an example:

	###Using a variable in a function from outside the function###
	###Returning a value from a function to be used outside the function.###
	# Returns a string in lowercase
	def Make_Lowercase(cmt):
	cmt = cmt.lower()
	return cmt
	comment = "My name is SCOTT."
	print ("Commment without lowercase formatting:")
	print (comment)
	print("")
	#Replace the old variable with the lowercase one created in the function
	comment = Make_Lowercase(comment)
	print ("Comment run through function to make it lowercase:")
	print (comment)

view raw ReturnFunction.py hosted with ❤ by GitHub

Now we can use the results from the function outside of the function and in the rest of the program. Yay!