Python tutorial

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Follow these links to get started with Python

1 - Introduction

The importance of programming languages is often overstated. What I mean by that is that people who are new to programming tend to worry far too much about what language to…

2 - Manipulating text

Open the first page of a book about learning Python, and the chances are that the first examples of code you’ll see will involve numbers. There’s a good reason for that…

3 - Lists and loops

Think back over the examples that we’ve seen in the previous two pages – they’ve all involved dealing with one bit of information at a time. In the first section, we used…

3 - Working with files

As we start this section, we find ourselves once again doing things in a slightly different order to most programming books. The majority of introductory programming books…

5 - Conditions

If we look back at the examples in previous sections, something that stands out is the lack of decision making. We’ve gone from doing simple calculations on individual bits…

6 - Writing functions

Here’s a piece of code which prints the AT content (the proportion of a DNA sequence which is either A or T) of a given DNA sequence:

7 - Regular expressions

A lot of what we do when writing programs for biology can be described as searching for patterns in strings. The obvious examples come from the analysis of biological…

8 - Dictionaries

Suppose we want to count the number of As in a DNA sequence. Carrying out the calculation is quite straightforward:

9 - Working with the filesystem

Reading from and writing to files was one of the first things we looked at. For some programs, however, we’re not just concerned with the contents of files, but with files…