Book Image

Modern Python Standard Library Cookbook

By : Alessandro Molina
Book Image

Modern Python Standard Library Cookbook

By: Alessandro 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 (21 chapters)
Title Page
Copyright and Credits
Packt Upsell
Contributors
Preface
Index

Code evaluation


Python is an interpreted language, and the interpreter features are exposed in the standard library too.

This means that we can evaluate expressions and statements coming from files or text sources and have them run as Python code within Python code itself.

It's also possible to evaluate code in a fairly safe way that allows us to create objects from expressions but prevents the execution of any function.

How to do it...

The steps for this recipe are as follows:

  1. The eval, exec, and ast functions and modules provide most of the machinery needed for execution of code from strings:
import ast

def run_python(code, mode='evalsafe'):
    if mode == 'evalsafe':
        return ast.literal_eval(code)
    elif mode == 'eval':
        return eval(compile(code, '', mode='eval'))
    elif mode == 'exec':
        return exec(compile(code, '', mode='exec'))
    else:
        raise ValueError('Unsupported execution model 
                         {}'.format(mode))
  1. The run_python function in evalsafe...