Table Of ContentP y t h o n
P o w e r !
THE COMPREHENSIVE GUIDE
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Matt Telles
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This book is dedicated to the ladies in my life: Teresa, Jenny, Rachel and Sarah.
Acknowledgments
The author would like to acknowledge the aid of the Python community
and Usenet newsgroups in finding answers to all of the questions that
eluded me.
A special thanks to Mike Dawson, who went well above and beyond the
call of duty to help a poor programmer out with this book. Thanks, Mike,
you did a great job!
Also, a small note of thanks to Marta, without whom this book would
never have gotten off the ground. Thank you, dear. Now get back to work.
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About the Author
Matt Telles is a 22-year veteran of the computer wars. Having moved
from the mainframe world, with his beloved DEC 1091, he is now
ensconced in the PC world of Windows and Linux. A long-time C++
programmer, he has since moved on to more modern languages like
C#, Python, and PHP. The high point of his career is in writing his own
biography for books.
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Contents
TABLE OF
CHAPTER 1 About Python ............................................................................................1
What Is Python? ................................................................................................................1
A Brief History of Python ................................................................................................2
Interpreters Versus Compilers .......................................................................................5
When to Use (or Not Use) an Interpreted Language .........................................8
Understanding Bytecodes ......................................................................................10
Why Use Python? ...........................................................................................................11
Object-Oriented ........................................................................................................11
Cross Platform ..........................................................................................................11
Broad User Base .......................................................................................................11
Well Supported in Third-Party Tools ...................................................................12
Good Selection of Tools Available ........................................................................12
Good Selection of Pre-built Libraries ..................................................................12
Where Is Python Used? .................................................................................................13
How Is Python Licensed? ..............................................................................................13
Where Do I Get Python? ...............................................................................................14
Installing Python ............................................................................................................14
Getting Information on Python ..................................................................................16
Python Communities .....................................................................................................17
Other Software ................................................................................................................18
And Now for Something Completely Different… ....................................................18
CHAPTER 2 Python Language Overview .................................................................19
Python Syntax .................................................................................................................20
Comments .................................................................................................................20
Indentation ...............................................................................................................20
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Python Reserved Words ................................................................................................24
Decision Making and Iteration Keywords ..........................................................25
Debugging Keywords ..............................................................................................27
Package and Module Handling Keywords .........................................................27
Exception Handling Keywords ..............................................................................29
General Language Keywords .................................................................................31
Other Keywords ........................................................................................................32
Variable Usage ................................................................................................................34
The Continuation Variable ....................................................................................36
Watching Out for Spelling Mistakes! ..................................................................37
Predicates .........................................................................................................................38
Identifier Scope ...............................................................................................................39
Operators .........................................................................................................................42
Modulo Operator .....................................................................................................44
Exponential Operator .............................................................................................46
Logical Operators ....................................................................................................46
Comparative Operators ..........................................................................................49
Bitwise Operators ....................................................................................................51
Membership Operators and String Operators ..................................................53
Identity Operators ...................................................................................................53
In Conclusion ..................................................................................................................53
CHAPTER 3 Tools ..........................................................................................................55
IDLE ...................................................................................................................................55
File Menu ...................................................................................................................57
The Path Browser Dialog ........................................................................................62
Edit Menu ..................................................................................................................64
Shell Menu .................................................................................................................70
Debug Menu ..............................................................................................................71
The Edit Window ......................................................................................................79
Format Menu ............................................................................................................80
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Command Line Compiler ..............................................................................................90
Creating Python Files ....................................................................................................93
Documentation ...............................................................................................................95
In Conclusion ..................................................................................................................96
CHAPTER 4 Data Types ...............................................................................................97
Numeric Types ................................................................................................................98
Integers ......................................................................................................................98
Demonstrating Long Integers ...............................................................................99
Octal and Hexadecimal ........................................................................................100
Floating Point Numbers .............................................................................................101
Strings ............................................................................................................................103
String Variables .....................................................................................................103
Concatenating Strings .........................................................................................106
Repeating Strings ..................................................................................................107
Substrings ...............................................................................................................108
Slicing ......................................................................................................................110
String Functions ....................................................................................................111
String Constants ....................................................................................................112
Conversion Functions ...........................................................................................114
Search Functions ...................................................................................................118
Formatting Functions ..........................................................................................120
Escape Sequences ..................................................................................................121
Sequences ......................................................................................................................122
Lists ..........................................................................................................................123
Shared References .................................................................................................128
Tuples .......................................................................................................................128
Dictionaries ............................................................................................................132
Advanced Type .............................................................................................................136
Classes and Objects ..............................................................................................136
Complex Type .........................................................................................................137
Generator Type ......................................................................................................138
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