2.2 Itse1359-1220-operators

Table of contents

• Preface
  • What you have learned
  • What you will learn
  • Viewing tip
    • Figures
    • Listings
• Operators
  • Arithmetic operators
  • Relational operators
  • Logical operators
  • Bit shift operators
  • Miscellaneous operators
• Discussion and sample code
• Miscellaneous

Preface

This module is one in a collection of modules on Python designed for teaching ITSE 1359 Introduction to Scripting Languages: Python at Austin Community College in Austin, TX.

What you have learned

Early modules in this collection included instruction on the following topics:

• numbers
• variables
• identifiers
• strings
• scripts
• lists

This instruction has prepared you to use Python as a very fancy desk calculator.

A more recent module provided instruction on the concepts of repetition and decision logic using the while loop as an example.

What you will learn

Prior to encountering the conditional clause in the while loop, all of the code involving operators was fairly self explanatory:

• addition
• subtraction
• multiplication
• division
• assignment

However, when examining the while loop, we were confronted with an operator that was less self explanatory -- the l ess than or equal operator. This suggests that this is the point in this collection where we need to describe all, or at least most of the operatorsused in Python. That is the purpose of this module.

Viewing tip

I recommend that you open another copy of this module in a separate browser window and use the following links to easily find and view the Figuresand the Listings while you are reading about them.

(Note to blind and visually impaired students: all of the Figures and the Listings inthis module are presented in plain text format and should be accessible using an audio screen reader or a braille display. Note however that the requiredindentation may not be properly represented by an audio screen reader.)

Figures

• Figure 1 . Arithmetic operators.
• Figure 2 . Relational operators.
• Figure 3 . Logical operators.
• Figure 4 . Bit shift operators.
• Figure 5 . Miscellaneous operators.

Listings

• Listing 1 . Logical operators "and", "or", and "not".

Operators

The material on operators contained in this module was mainly extracted from 10.3.1. Mapping Operators to Functions in The Python Standard Library .

Arithmetic operators

As the name implies, the arithmetic operators are used for performing arithmetic. However, some of the operators are "overloaded" meaning that thebehavior of the operator depends on the types of the operands. For example, as you learned in an earlier module, the (+) operator is used both forarithmetic addition and string concatenation.

Figure 1 shows all or at least most of the arithmetic operators.