Class return statement not printing any output

Question

I'm learning about Classes and am having a problem with the return statement (is it a statement? I hope so), the program prints out nothing, it just ends without doing anything.

class className:
    def createName(self, name):
        self.name = name
    def displayName(self):
        return self.name
    def saying(self):
        print("Hello %s" % self.name)

first = className()
second = className()

first.createName("Jack")
second.createName("Joy")

first.displayName()
second.displayName()

I know I'm doing something so obviously wrong but I really don't know what. I'd appreciate some help.

Looking briefly at the code it looks like you are calling first.displayName() which simply returns the name. If you want to print something you would either need to call: first.saying() or print("Hello %s" % first.displayName()) — Roger, Aug 09 '12 at 03:45
I see, but isn't return supposed to return whatever is in self.name? — Hyzenthlay, Aug 09 '12 at 04:14
yes it is, but you aren't printing it out anywhere right? You are just returning it. — Roger, Aug 09 '12 at 04:18

score 7 · Accepted Answer · edited May 23 '17 at 12:31

To answer your question - return does not print anything, but it is slightly confusing, since the interactive python prompt does print out the value of the last statement e.g.:

Python 2.7.2 (default, Jun 20 2012, 16:23:33) 
[GCC 4.2.1 Compatible Apple Clang 4.0 (tags/Apple/clang-418.0.60)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> 1+1
2

But if you create a file with contents 1+1 and run it as a python script, nothing is printed.

Since you say that you are a newbie, I'll give you a few pointers on how to improve your code.

class className:
    def createName(self, name):
        self.name = name
    def displayName(self):
        return self.name
    def saying(self):
        print("Hello %s" % self.name)

className has redundancy, you should rename your class just Name - also new style classes should always inherit object, so let's change your definition a bit:

class Name(object):
    def createName(self, name):
        self.name = name
    def displayName(self):
        return self.name
    def saying(self):
        print("Hello %s" % self.name)

Creating something is done automatically by overriding the classes __init__() method. e.g:

class Name(object):
    def __init__(self, name):
        self.name = name
    def displayName(self):
        return self.name
    def saying(self):
        print("Hello %s" % self.name)

this way you can already initialize your name when instantiating your class, e.g.

first = Name("Jack")

Second, display is handled idiomatically by overriding the method __repr__ e.g.

class Name(object):
    def __init__(self, name):
        self.name = name
    def __repr__(self):
       return self.name
    def saying(self):
        print("Hello %s" % self.name)

This way, you only need to do two things:

>>> n = Name("Jack")
>>> print n
Jack

Class return statement not printing any output

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