Checking to see if a file exists is a two step process in Python. Simply import the module shown below and invoke the isfile function:

import os.path
os.path.isfile(fname)

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:

Microsoft has now come up with a surface tablet to compete with the Apple iPad. The Surface is the known as the ‘iPad killer’ and ‘Microsoft iPad’. Microsoft has stuck to production of software till date but this is one of its latest hardware devices that is expected to take over the Apple iPad. This is a new challenge posed by Microsoft to Apple.

            The Microsoft Surface saw its official release on 19^th June in the city of Los Angeles. It has made a great first impression and seems to be beginning a new start in the competition between the best tablets in the international market. It has 10.6’’ screen and a magnetic cover that can be used as a keyboard and also as a kickstand in order to place the device upright on tables. There has been a paradigm shift in Microsoft’s policy when it decided to do away with the tile-based Metro theme for its Desktop that is almost a trademark with it.

            There are many features that make the Surface more like a laptop than like a tablet- the most prominent one being the built- in keyboard that will be useful for business customers. As Microsoft Surface employs Windows 8 as an operating system, which is also used in its computers and laptops, it will be a lot easier for customers to switch among their devices.

            The tablet was announced by Microsoft’s CEO, Steve Ballmer, in Los Angeles at a special press conference. It was hailed to be the first of an entirely new family of a number of devices being created and developed by the company. The Surface has a thickness of 9.3mm and weighs 1.5 pounds. It has a kickstand and keyboard for its cover. It is 0.1 mm thinner than the iPad 3, which is the latest iPad from Apple.

In this tutorial we are going to take a look at how you work with strings in Python. Now, any language worth its salt will have a number of options for working with text and Python is probably one of the best to use when it comes to processing text.

If you are new to programming in general you may be wondering what a string is. In terms of programming, a string is classed as any sequence of characters you can type with your keyboard, and let’s face it, if you want your application to be of any use to yourself or other users then you need it to tell you what it’s doing or to prompt you for an action, and that is where strings come into play.

They are your applications way of communicating with the user. Without the ability to enter and display text or software would be pretty useless.

So, how would you create a string in Python? Take a look at the following code: