Python Cookbook, 2nd Edition

Chapter 3. Time and Money

Introduction

Credit: Gustavo Niemeyer, Facundo Batista

Today, last weekend, next year. These terms sound so common. You have probably wondered, at least once, about how deeply our lives are involved in the very idea of time. The concept of time surrounds us, and, as a consequence, it’s also present in the vast majority of software projects. Even very simple programs may have to deal with timestamps, delays, timeouts, speed gauges, calendars, and so on. As befits a general-purpose language that is proud to come with “batteries included,” Python’s standard library offers solid support for these application needs, and more support yet comes from third-party modules and packages.

Computing tasks involving money are another interesting topic that catches our attention because it’s so closely related to our daily lives. Python 2.4 introduced support for decimal numbers (and you can retrofit that support into 2.3, see http://www.taniquetil.com.ar/facundo/bdvfiles/get_decimal.html), making Python a good option even for computations where you must avoid using binary floats, as ones involving money so often are.

This chapter covers exactly these two topics, money and time. According to the old saying, maybe we should claim the chapter is really about a single topic, since after all, as everybody knows—time is money!

The time Module

Python Standard Library’s time module lets Python applications access a good portion of the time-related functionality offered by the platform ...