The python keyword global is used in a function to distinguish a local representation of a variable with the same name. 

glbvar = 0

def setglbvar():
    global glbvar # include this declaration so that updates to glbvar are NOT LOCAL to this function
    glbvar = 1

def printglbvar():
    print glbvar     # No need for global declaration to read value of globvar

setglbvar()
printglbvar()       # Prints 1

Yahoo answers abstract.

Overview:

·         Virus is a piece of code that is secretly introduced into a system in order to corrupt it or destroy data

Python is an incredibly powerful and useful computer programming language that many of the biggest websites in the world rely on for their foundation. Python provides reliable results that are functional and involve a variety of dynamic scripted and non-scripted contexts. And because it is free and open source, it has remained a popular choice for a variety of different developers who are looking to build new sites on one of the most reliable languages available. Here is a look at 10 of the most famous software programs that are written in Python and what they do.

YouTube
If you love watching hours of homemade and professional quality video clips on YouTube, you can thank Python for giving you that option. The foundation for Python helped YouTube integrate streaming videos into their pages, as well as the ability to like videos and embed certain information. YouTube is one of the most popular sites on the Internet, and it runs off of one of the most powerful languages in Python.

DropBox
What started as a powerful app, DropBox is now used by a variety of individuals, businesses, companies, organizations and more. This program lets you save files to a cloud-based service, that you can then access from anywhere in the world. With Python at the root of DropBox, there is no longer a need for USB sticks or blank CDs, since you can now save and share everything with your cloud-based account.

Google
It takes a lot of power to be able to handle the most popular search engine in the entire world. That is why Google uses Python for its mainframe foundation, as well as in addition to various apps that it runs in conjunction with the main site. The ease that Google provides for finding certain information, would be impossible without Python at the core.

Quora
Got a question? Ask it on Quora. This site compiles a list of questions and answers that come from a community of individuals. Those questions are then organized by various members of the community, which puts the most relevant information at the top. The creators of Quora, who happened to be former Facebook employees, decided to use Python to help them create the world’s best Magic 8 ball in Quora.

Instagram
If you love taking photos of your food or a new outfit and posting it online for all of your friends to see, you can thank Python for that ability. Granted, Instagram has both a very powerful app and a website, but the latter runs on Python language. The system allows for users to browse, find and post pictures that they like on the site.

BitTorrent
BitTorrent has evolved quite a bit in recent years, but its foundation and earlier years were built on Python. When it comes to one of the largest databases of knowledge, media and content, BitTorrent is the way to go. But you wouldn’t be able to get any of those lectures or other legal stuff that you are downloading from BitTorrent, if it wasn’t for Python.

Spotify
Spotify changed the music game when it allowed you to listen to ad-free music of your choice. This wasn’t a program where you got to select a playlist, but rather full songs that you love, on repeat as many times as you can imagine, if you so desire. But whether you are rocking out to the latest K-Pop song from Psy or a classic jazz tune, you are doing so because Spotify was built on Python.

Reddit
Reddit is one of the biggest open communities on the web. You have a question, want to talk about something in specific, or find tons of information regarding a particular topic, you can just look on Reddit. The site relies on Python to help them store user names, categorize subreddits, upload links to GIFs and, of course, award gold to valued posters.

Yahoo Maps
Much like Google, Yahoo also uses Python for a variety of different resources. Most valued may be Yahoo Maps. The API and programming behind the maps program, which is built with Python, allows for users to find locations, get directions and even find reviews about local places.

Hipmunk
If you love to travel, you have likely come across Hipmunk. And while the site lets you save money on booking your itinerary through Hipmunk, it is Python that keeps everything organized. Python also helps sort the best discounts and rates, so you can get the best packages available.

Python is an incredibly powerful tool for web development. More and more sites rely on it, including 10 of the most powerful sites in the world that are listed here.

Related:

Current Active List of Organizations that use Python 

Working With Lists In Python

Many individuals are looking to break into a video game designing career, and it's no surprise. A $9 billion industry, the video game designing business has appeal to gamers and non-gamers alike. High salaries and high rates of job satisfaction are typical in the field.

In order to design video games, however, you need a certain skill set. Computer programming is first on the list. While games are made using almost all languages, the most popular programming language for video games is C++, because of its object-oriented nature and because it compiles to binary. The next most popular languages for games are C and Java, but others such as C# and assembly language are also used. A strong background in math is usually required to learn these languages. Individuals wishing to design games should also have an extensive knowledge of both PCs and Macs.

There are many colleges and universities that offer classes not only in programming but also classes specifically on game design. Some of these schools have alliances with game developing companies, leading to jobs for students upon graduation. Programming video games can be lucrative. The average game designer's salary is $62,500, with $55,000 at the low end and $85,000 at the high end.

Programmers are not the only individuals needed to make a video game, however. There are multiple career paths within the gaming industry, including specialists in audio, design, production, visual arts and business.

Designing a video game can be an long, expensive process. The average budget for a modern multiplatform video game is $18-$28 million, with some high-profile games costing as much as $40 million. Making the game, from conception to sale, can take several months to several years. Some games have taken a notoriously long time to make; for example, 3D Realms' Duke Nukem Forever was announced in April 1997 and did not make it to shelves until July 2011.

Video game programmers have a high level of job satisfaction. In a March 2013 survey conducted by Game Developer magazine, 29 percent of game programmers were very satisfied with their jobs, and 39 percent were somewhat satisfied.

If you're interested in a game development career, now's the time to get moving. Take advantage of the many online resources available regarding these careers and start learning right away.