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)

It is rather unfortunate that in the ever changing and rapidly improving world of technology, we hardly remember the geniuses who through their inventions laid the foundation for many of the conveniences and features we now enjoy in our favorite communication devices.

This article is a tribute to the ten people who made these discoveries and an attempt to bring their achievements into the limelight.

1.      Marty Cooper

Did you know that Cooper was the first to file the patent in 1973, when he was already working for Motorola for the “radio telephone system”. The Cooper’s Law is his brainchild and to think that he himself was inspired to come out with the patent was Star Trek and its Captain Kirk is indeed revealing.

2. Mike Lazardidis
 

There has been and continues to be a plethora of observational studies by different researchers in the publishing industry focused on how e-books have affected hard-copy book sales. Evidence from these studies has indicated that there is a significant and monumental shift away from hard-copy books to e-books.[1]These findings precipitate fears that hard-copy books might become more expensive in the near future as they begin to be less available.  This scenario could escalate to the point where only collectors of hard-copy books are willing to pay the high price for ownership.

The founder of Amazon, Jeff Bezos, made a statement in July 2010 that sales of digital books had significantly outstripped U.S. sales of hard-copy. He claimed that Amazon had sold 143 digital books for its e-reader, the Kindle, for every 100 hard-back books over the past three months. The pace of this change was unprecedented;  Amazon said that in the four weeks of June 2010, the rate of sales had reached 180 e-books for every 100 hard-backs sold. Bezos said sales of the Kindle and e-books had reached a "tipping point", with five authors including Steig Larsson, the writer of Girl with a Dragon Tattoo, and Stephenie Meyer, who penned the Twilight series, each selling more than 500,000 digital books.[2] Earlier in July 2010, Hachette said that James Patterson had sold 1.1m e-books to date.

According to a report made by Publishers Weekly, for the first quarter of 2011, e-book sales were up 159.8%; netting sales of $233.1 million. Although adult hard-cover and mass market paperback hard-copies had continued to sell, posting gains in March, all the print segments had declined for the first quarter with the nine mass market houses that report sales. Their findings revealed a 23.4% sales decline, and that children’s paper-back publishers had also declined by 24.1%.[3] E-book sales easily out-distanced mass market paperback sales in the first quarter of 2011 with mass market sales of hard-copy books falling to $123.3 million compared to e-books’ $233.1 million in sales.

According to .net sales report by the March Association of American Publishers (AAP) which collected data and statistics from 1,189 publishers, the adult e-Book sales were $282.3 million in comparison to adult hard-cover book sales which counted $229.6 million during the first quarter of 2012. During the same period in 2011, eBooks revenues were $220.4 million.[4] These reports indicate a disconcerting diminishing demand for hard-copy books.

If you are interested in using java tutorials to educate yourself from home, you are probably interested in learning how to tell the difference between valuable resource materials, and those which are outdated or incorrect.  Learning to evaluate the quality of available tutorials is both an art and a science, and is best accomplished by paying attention to some of the individual components which make up a quality tutorial.  We will take a look at four of the most important:

·         Good organization – The tutorial needs to have a well-developed structure, which comprehensively details the content it will deliver, and is very easy for users to navigate.  A good organizational structure is indicative of a polished educational thought process, and is more important than you may think in the development of a good tutorial.

·         Valuable content – For good java tutorials, the content should be structured around accomplishing individual tasks.  It should do so by providing clear instruction to the reader, and be concise and to the point as well.  The delivery of quality content is the primary purpose of any tutorial.

·         Attractive appearance – Attention needs to be paid to the manner in which the tutorial is presented.  They should always strive to be visually appealing and not overly busy, so as to distract from communicating the message.  A clean and simple presentation also helps to emphasize the content.