Table of contents
- Preface
- Introduction
- What is a tuple?
- Sample program
- 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 .
Listing 1 . Beginning of the program. |
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# Illustrates creating and displaying nested tuples
#--------------------------------------------------print("Create/print one tuple")
t1 = 1,2print(t1)
print("Create/print another tuple")t2 = "a","b"
print(t2) |
The code in Listing 1 creates and displays the two tuples.
Figure 1 shows the output produced by the code fragment in Listing 1 .
Figure 1 . Output from the code in Listing 1. |
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Create/print one tuple
(1, 2)Create/print another tuple
('a', 'b') |