Python Struggling to Understand difference between return and print

Question

I'm working on creating a function that returns the last_name, followed by a comma, a space, first_name another space, and finally last_name.

The below code gives me the correct answer:

def introduction(first_name, last_name):
  return last_name + ", " + first_name + " " + last_name

print(introduction("James", "Bond"))
Bond, James Bond

However, if I use print, I get the following:

def introduction(first_name, last_name):
  print(last_name + ", " + first_name + " " + last_name)

print(introduction("James", "Bond"))

Bond, James Bond
None
Angelou, Maya Angelou
None

Where does the none come from when using the print instead of return? I have looked around and I can't seem to tell which to use.

Answer 1

None is what is returned by the function "print". That is, print sends something to stdout and then returns a None. You can verify this by explicitly returning the value and checking:

x = print('something')
print(x)

You introduction statement is returning a None, hence your statement

Print(introduction('James','Bond'))

First runs the introduction(,) which itself has a print statement that prints the name, but then returns a None, from which the print above prints.