Book Image

Modern Python Standard Library Cookbook

By : Molina
Book Image

Modern Python Standard Library Cookbook

By: Molina

Overview of this book

The Python 3 Standard Library is a vast array of modules that you can use for developing various kinds of applications. It contains an exhaustive list of libraries, and this book will help you choose the best one to address specific programming problems in Python. The Modern Python Standard Library Cookbook begins with recipes on containers and data structures and guides you in performing effective text management in Python. You will find Python recipes for command-line operations, networking, filesystems and directories, and concurrent execution. You will learn about Python security essentials in Python and get to grips with various development tools for debugging, benchmarking, inspection, error reporting, and tracing. The book includes recipes to help you create graphical user interfaces for your application. You will learn to work with multimedia components and perform mathematical operations on date and time. The recipes will also show you how to deploy different searching and sorting algorithms on your data. By the end of the book, you will have acquired the skills needed to write clean code in Python and develop applications that meet your needs.
Table of Contents (16 chapters)

Reading lines of text


When working with text files, the easiest way to process them is usually by line; each line of text is a separate entity and we can build them back by joining all lines by '\n' or '\r\n' depending on the system, thus it would be very convenient to have all the lines of a text file available in a list.

There is a very convenient way to grab lines out of a text file that Python makes instantly available.

How to do it...

As the file object itself is an iterable, we can directly build a list out of it:

with open('/var/log/install.log') as f:
    lines = list(f)

How it works...

open acts as a context manager, returning the resulting object file. It's very convenient to rely on the context manager as, when we are done with our file, we need to close it and using open as a context manager will actually do that for us as soon as we quit the body of with.

The interesting part is that file is actually an iterable. When you iterate over a file, you get back the lines that are contained...