An Extra 'None'

[leoahum]

I'm trying a piece of script from Magnus Lie Hetland's book. It goes as below.

class Person:
    def setName(self, name):
        self.name = name

    def getName(self):
        return self.name

    def greet(self):
        print ("Hello world, I am %s." % self.name)

bar = Person()

bar.setName('Anakin Skywalker')

print (bar.greet())

When I run this script, besides the expected "Hello world, I am Anakin Skywalker", the "print (bar.greet())" gives me an extra line as "None".
Can someone tell me why there is a None?

[gontajones]

Your line 15 is like a print(print("some text")).
You just need to call bar.greet().

[leoahum]

I'm trying a piece of script from Magnus Lie Hetland's book. It goes as below.

class Person:
    def setName(self, name):
        self.name = name

    def getName(self):
        return self.name

    def greet(self):
        print ("Hello world, I am %s." % self.name)

bar = Person()

bar.setName('Anakin Skywalker')

print (bar.greet())

When I run this script, besides the expected "Hello world, I am Anakin Skywalker", the "print (bar.greet())" gives me an extra line as "None".
Can someone tell me why there is a None?

Oh, thanks!

[volcano63]

I'm trying a piece of script from Magnus Lie Hetland's book. It goes as below.

class Person:
    def setName(self, name):
        self.name = name

    def getName(self):
        return self.name

    def greet(self):
        print ("Hello world, I am %s." % self.name)

bar = Person()

bar.setName('Anakin Skywalker')

print (bar.greet())

When I run this script, besides the expected "Hello world, I am Anakin Skywalker", the "print (bar.greet())" gives me an extra line as "None".
Can someone tell me why there is a None?

Oh, thanks!

I liked the author's middle name Lie - very appropriate . This book - by your short examples - looks like a piece of garbage from a Java convert trying to ride a wave.

Neither names, not implementation of the setter/getter mechhaism (not that it is often used in Python) are Pythonic .

To add insult to injury - old-style formatting

The proper implementation may be something in the style below.

Output:
In [3]: class Person:
   ...:     def __init__(self, name=''):
   ...:         self._name = name
   ...:     
   ...:     @property
   ...:     def name(self):
   ...:         return self._name
   ...:     
   ...:     @name.setter
   ...:     def name(self, name):
   ...:         self._name = name
   ...:   
   ...:     def greet(self):
   ...:         print ("Hello world, I am {}.".format(self.name))
   ...: 
   ...: p = Person('Nobody')
   ...: p.greet()
   ...: p.name = 'Anakin'
   ...: p.greet()
   ...: 
   ...: 
Hello world, I am Nobody.
Hello world, I am Anakin.

I would suggest for ind a book/learning resource by a legitimate Python specialist

[buran]

I would suggest for ind a book/learning resource by a legitimate Python specialist

@volcano: Sometimes it's good to do some research before make statements like this
https://www.python.org/search/?q=Hetland
http://hetland.org/coding/

I guess it's old edition of Hetlands Begining Python book

[volcano63]

I would suggest for ind a book/learning resource by a legitimate Python specialist

@volcano: Sometimes it's good to do some research before make statements like this
https://www.python.org/search/?q=Hetland
http://hetland.org/coding/

I guess it's old edition of Hetlands Begining Python book

From https://www.python.org/dev/peps/pep-0008/

PEP: 8
Title: Style Guide for Python Code
Author: Guido van Rossum <guido at python.org>, Barry Warsaw <barry at python.org>, Nick Coghlan <ncoghlan at gmail.com>
Status: Active
Type: Process
Created: 05-Jul-2001
Post-History: 05-Jul-2001, 01-Aug-2013

The book I found by post-mortem research is dated by 2005.