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Python

In Greek mythology, Python is the name of a a huge serpent and sometimes a dragon. Python had been killed by the god Apollo at Delphi. Python was created out of the slime and mud left after the great flood. He was appointed by Gaia (Mother Earth) to guard the oracle of Delphi, known as Pytho.
The programming language Python has not been created out of slime and mud but out of the programming language ABC. It has been devised by a Dutch programmer, named Guido van Rossum, in Amsterdam.

Origins of Python

Guido van Rossum wrote the following about the origins of Python in a foreword for the book "Programming Python" by Mark Lutz in 1996:
"Over six years ago, in December 1989, I was looking for a "hobby" programming project that would keep me occupied during the week around Christmas. My office (a government-run research lab in Amsterdam) would be closed, but I had a home computer, and not much else on my hands. I decided to write an interpreter for the new scripting language I had been thinking about lately: a descendant of ABC that would appeal to Unix/C hackers. I chose Python as a working title for the project, being in a slightly irreverent mood (and a big fan of Monty Python's Flying Circus)."

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This topic in German / Deutsche Übersetzung: Slots, Vermeidung von dynamisch erzeugten Attributen

Python 2.7

This tutorial deals with Python Version 2.7
This chapter from our course is available in a version for Python3: Slots, Avoiding Dynamically Created Attributes

Classroom Training Courses

This website contains a free and extensive online tutorial by Bernd Klein, using material from his classroom Python training courses.

If you are interested in an instructor-led classroom training course, you may have a look at the Python classes
by Bernd Klein at Bodenseo. © kabliczech - Fotolia.com

Quote of the Day:

"At least for the people who send me mail about a new language that they're designing, the general advice is: do it to learn about how to write a compiler. " (Dennis Ritchie)

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If you have the choice working with Python 2 or Python 3, we recomend to switch to Python 3! You can read our Python Tutorial to see what the differences are.

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Slots

Introduction

The attributes of objects are stored in a dictionary "__dict__". Like any other dictionary, a dictionary used for attribute storage doesn't have a fixed number of elements. In other words, you can add elements to dictionaries after they have been defined, as we have seen in our chapter on dictionaries. This is the reason, why you can dynamically add attributes to objects of classes, you have created.

We recommend to continue with our chapter "Python3 Slots" of our Python3 tutorial. It's compatible with version 2.x anyway.