Book Image

The Python Apprentice

By : Robert Smallshire, Austin Bingham
Book Image

The Python Apprentice

By: Robert Smallshire, Austin Bingham

Overview of this book

Experienced programmers want to know how to enhance their craft and we want to help them start as apprentices with Python. We know that before mastering Python you need to learn the culture and the tools to become a productive member of any Python project. Our goal with this book is to give you a practical and thorough introduction to Python programming, providing you with the insight and technical craftsmanship you need to be a productive member of any Python project. Python is a big language, and it’s not our intention with this book to cover everything there is to know. We just want to make sure that you, as the developer, know the tools, basic idioms and of course the ins and outs of the language, the standard library and other modules to be able to jump into most projects.
Table of Contents (21 chapters)
Title Page
Credits
About the Authors
www.PacktPub.com
Customer Feedback
Preface
12
Afterword – Just the Beginning

The dict type – associating keys with values


Dictionaries – embodied in the dict type – are completely fundamental to the way the Python language works, and are very widely used. A dictionary maps keys to values, and in some languages it is known as a map or associative array. Let's look at how to create and use dictionaries in Python.

Literal dictionaries are created using curly braces containing key-value pairs. Each pair is separated by a comma, and each key is separated from its corresponding value by a colon. Here we use a dictionary to create a simple telephone directory:

>>> d = {'alice': '878-8728-922', 'bob': '256-5262-124', 
         'eve': '198-2321-787'}

We can retrieve items by key using the square brackets operator:

>>> d['alice']
'878-8728-922'

And we can update the value associated with a particular key by assigning through the square brackets:

>>> d['alice'] = '966-4532-6272'
>>> d
{'bob': '256-5262-124', 'eve': '198-2321-787', 
 'alice': '966...