This section of our beginning python training class always stumps students.  Firstly, because they need to know the difference between a function and a method.  Secondly, they need to understand object oriented programming concepts.  Thirdly, they need to realize that python has three types of methods.  Then they need to know how to use each method, which means they need to know the purpose of each method type.  Then they have to understand mutable versus non-mutable types.  The list goes on.  As part of our python tutorial, I hope to shed some light on this confusing topic.

To begin, the difference between a function and a method in python is that a method is defined within a class.  Here is an illustration:

#function

	def greeting():
	                print "Hello, I hope you're having a great day!"

	class HSGPrinter(object):
	                #method
	                def greeting(self): 
	                                print "Hello, I hope you're having a great day!"

As should be obvious, the second definition of greeting is encapsulated within the HSGPrinter class and is , therefore, refered to as a method.

The astute reader will notice that the greeting method contains one parameter named self.  For those who know C++ , Java or C#, self is equivalent to this i.e. it is a reference to the invoking object:

Businesses “Going Green” is so commonplace now it’s more than just an encouraging a trend; it’s become expected of companies big and small. In fact, consumers frequently place more of an obligation on companies to go green than they do themselves. The last few years—the infancy of what may turn out to be a green revolution—have really proven that there are many ways to go green, and that some of these ways are much more financially sound than others. But rather than providing a cut and dry list of green options and their pros and cons, I’d like to take a look at the bigger picture incentives for businesses going green and how consumers are responding.

What does it mean to be green?

In Python, we can create three types of methods in a class:  instance or regular method, classmethod and staticmethod.  Instance methods are associated, as the name infers, with an instance or object of the class and take self as the first parameter.  Classmethods take a reference to the class, cls, as the first parameter of the class.  Staticmethods, for the most part, are convenience methods that could be declared as functions since they really do not have much to do with the class itself.  They were probably added at some time after the advent of Python in order to make the language more object oriented i.e. minimize the number of free floating functions. 

Refer the our article static, class and regular methods in Python for a detailed explanation on this subject.

Jeff Nelson, a former Googler and inventor of Chromebook says on Quora, “One habit I've clung to is writing small prototypes when I'm trying to learn new concepts.
For example, I'll sit down with a book or a web page, and over the course of a few hours, write 30 or 40 programs all of them only a few dozen lines long.  Each program intended to demonstrate some simple concept. This prototyping makes it very easy to try out many concepts in a short period of time.”

Miguel Paraz, Software Engineering Student habit is to “keep a log in a text file or document on my work computer. Before trying to solve a problem, I write it down first. And then I describe the details as they happen.”