1.31 Itse1359-1110-nested tuples

Table of contents

• Preface
  • Viewing tip
    • Figures
    • Listings
• Introduction
• What is a tuple?
• Sample program
  • Create two tuples
  • Nesting the tuples
  • Get the length of the new tuple
• Complete program listing
• Visualization of the tuples
• Run the program
• 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.

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 Listings while you are reading about them.

(Note to blind and visually impaired students: most of the Figures all of the Listings in this module are presented in plain text format and should be accessible using anaudio screen reader or a braille display.)

Figures

• Figure 1 . Output from the code in Listing 1.
• Figure 2 . Output from the code in Listing 2.
• Figure 3 . Output from the code in Listing 3.
• Figure 4 . Output from the code in Listing 4.
• Figure 5 . Visualization of the tuples

Listings

• Listing 1 . Beginning of the program.
• Listing 2 . Nesting the tuples.
• Listing 3 . Get the length of the new tuple.
• Listing 4 . Complete program listing.

Introduction

Previous modules have introduced you to lists, subscriptions, sequences, mutable sequences, mappings, slicings, and tuples.

The earlier module titled Itse1359-1100-Indexing and Slicing Tuples showed you:

• How to create a tuple.
• How to access a tuple item using indexing.
• How to slice a tuple.

This module will expand your knowledge of tuples by teaching you about nesting tuples within other tuples.

What is a tuple ?

To briefly repeat part of what you learned in the earlier module, a tuple is like a list whose values cannot be modified. In other words, a tuple is immutable.

• Tuples are normally written as a sequence of items contained in (optional) matching parentheses.
• A tuple is an immutable sequence.
• Items in a tuple are accessed using a numeric index.

Tuples can contain other compound objects, including lists, dictionaries, and other tuples. Hence, tuples can be nested inside of other tuples.

Sample program

Listing 4 shows a complete listing of a Python program that

• Creates two tuples.
• Nests them in a third tuple.
• Determines the length (number of items) in the tuple containing the two nested tuples.
• Prints various items of information along the way.

A visualization of the tuples in this program is provided in Figure 5 .

Create two tuples

The beginning of the program is shown in Listing 1 .

The code in Listing 1 creates and displays the two tuples.

Figure 1 shows the output produced by the code fragment in Listing 1 .