Python - output from functions?

Question

I have a very rudimentary question.

Assume I call a function, e.g.,

def foo():
    x = 'hello world'

How do I get the function to return x in such a way that I can use it as the input for another function or use the variable within the body of a program?

When I use return and call the variable within another functions I get a NameError.

Answer 1

def foo():
    x = 'hello world'
    return x  # return 'hello world' would do, too

foo()
print x    # NameError - x is not defined outside the function

y = foo()
print y    # this works

x = foo()
print x    # this also works, and it's a completely different x than that inside
           # foo()

z = bar(x) # of course, now you can use x as you want

z = bar(foo()) # but you don't have to

Answer 2

>>> def foo():
    return 'hello world'

>>> x = foo()
>>> x
'hello world'

Answer 3

You can use global statement and then achieve what you want without returning value from the function. For example you can do something like below:

def foo():
    global x 
    x = "hello world"

foo()
print x

The above code will print "hello world".

But please be warned that usage of "global" is not a good idea at all and it is better to avoid usage that is shown in my example.

Also check this related discussion on about usage of global statement in Python.