# 1.29 Itse1359-1100-indexing and slicing tuples

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This module and several modules that follow will use sample programs to show you a variety of ways to manipulate and use tuples.

## 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 Figures and the Listingswhile you are reading about them.

(Note to blind and visually impaired students: most of the Figures and 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 . Visualization of a tuple.
• Figure 2 . Output from code in Listing 6.

## Introduction

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

Those modules showed you some of the ways that you can manipulate lists. The discussion was illustrated using sample programs.

The introduction to tuples in previous modules was very brief. This and several future modules will use sample programs to show you a variety of waysto manipulate and use tuples.

## Description of a tuple

As a practical matter, a tuple is like a list whose values cannot be modified. In other words, a tuple is immutable .

According to Lutz and Ascher, Learning Python from O'Reilly, tuples are "Ordered collections of arbitrary objects."

Again according to Lutz and Ascher, "They work exactly like lists, except that tuples can't be changed in place (they're immutable)..."

Unlike lists, however, tuples don't use square brackets for containment. Rather, they are normally written as a sequence of items contained inparentheses.

Like a string or a list, a tuple is a sequence . Like a string (but unlike a list) , a tuple is an immutable sequence.

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

## An array of references

One way to think of a tuple is to consider it to be an array of references to other objects.

For example, Figure 1 shows a visualization of the tuple from Listing 6 . As you can see, each element in the tuple object at the bottom right contains a reference or apointer to another object.

Figure 1. Visualization of a tuple.

While the tuple itself cannot be changed in place, the values contained in the objects that are referred to by the contents of the tuple can be changed (assuming that those objects are mutable) .

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it is a goid question and i want to know the answer as well
Maciej
Do somebody tell me a best nano engineering book for beginners?
what is fullerene does it is used to make bukky balls
are you nano engineer ?
s.
what is the Synthesis, properties,and applications of carbon nano chemistry
Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
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Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
for screen printed electrodes ?
SUYASH
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of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
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Cied
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what's the easiest and fastest way to the synthesize AgNP?
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Cied
types of nano material
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
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Porter
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Yasmin
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Uday
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preparation of nanomaterial
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Stotaw
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Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
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Azam
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Prasenjit
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Damian
silver nanoparticles could handle the job?
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Azam
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Uday
I'm interested in Nanotube
Uday
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how did you get the value of 2000N.What calculations are needed to arrive at it
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