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:

Checking to see if a directory exists and then creating it if it is not present requires a few lines of code.  Isn't Python great.   Begin by importing the os module and use the exists and makedirs functions.

import os

if os.path.exists(somedirectory):
   os.makedirs(somedirectory)

The importance of variables in any programming language can’t be emphasised enough. Even if you are a novice, the chances are good that you will have been using variables for quite a while now.

They are the cornerstone of any language and without them we would not be able to accomplish much of anything. However, most of you up until this point have probably only been working with standard variables, variables which can hold single values such as an integer, a single character, or a string of text.

In this tutorial we are going to take a look at a more special type of variable called an array. Arrays can seem quite daunting at first glance but once you get used to working with them you will wonder how you ever managed to program without them.

The reason arrays are special is because they can hold more than one value. Think about this: say you create a variable which contains a line of text like the code below:

Viruses, trojans, and other malicious programs are everywhere. There's always a new threat to your computer's security, and many of these threats invade your computer without you even knowing. Most viruses aren't going to loudly announce themselves, so it's important to know the hidden ways in which your computer can become infected.


Infected Files from Other Computers

Whether you're borrowing someone's flash drive or grabbing a file from their computer, your computer can become infected if the file or device you're using already contains a virus, trojan, or other form of malware.

This is a very common issue, and you won't even know there's a problem most of the time. For example, if your computer is connected to other devices on a network, and you decide to pull an important file off of another computer on the network, your computer will become infected if the file you took has a virus attached to it.

Also, if you forgot your flash drive, and you need to use your friend or coworker's device for the day, then even plugging the device into your computer can cause the infection in the flash drive to be transmitted.


Downloading Legitimate Programs

Another way your computer can be secretly infected is when you download a legitimate program and run it. There are numerous legitimate programs on the internet that can help you in many ways. The programs themselves could be infected, though.

Also, one of the most common ways your computer can become infected is when you don't read the fine print before you download a program. Some of them may insist that you install another small program in addition to the one you initially chose. The boxes that you are supposed to click to give your consent may already be clicked.

This small extra program is the one that may carry an infection that will spread to your computer when you run the main program. You may get a lot of good use out of the legitimate program, but the virus attached to the extra hidden program can cause you a lot of trouble.


Using Vulnerable Applications

Security is a serious matter. If even one of the applications you use on your computer is vulnerable to becoming hacked or infected, then your entire computer is at risk and could become secretly infected. Anything from PDF viewing applications to your operating system can become infected if you don't download the latest security patches and keep everything up-to-date.


Not Using Antivirus Software

Antivirus software can protect your computer from a number of viruses, trojans, and other problems. Your computer can become infected in a number of ways, so you need to have good antivirus software to provide strong protection from hidden attacks.


Viruses, trojans, and other malware can infect your computer in a variety of hidden ways. To prevent infection and problems, you need to be careful about what you download, and you should keep your applications secure. Also, find reliable antivirus software to help.

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