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7 PYTHON LISTS
Chapter Outline
7.1 Lists 7.2 List Assignment
7.3 Traversing a List 7.4 Nested Lists
7.5 Heterogeneous List 7.6 More Operations on Lists
7.7 List Methods
Introduction
In the last chapter, we learnt about control structures. In this chapter, we will discuss the mutable type of object, lists.
Elements of a list may be of arbitrary types. Like strings, objects in a list appear in sequence and can be accessed using
indexes.
7.1 Lists
A list comprises a comma-separated sequence of objects enclosed in square brackets []. The elements of a list may be
accessed using indexing. Let us begin by creating a list of colours.
>>> colors = ['red', 'green', 'blue', 'pink', 'orange', 'white', 'black']
>>> colors
['red', 'green', 'blue', 'pink', 'orange', 'white', 'black']
Non-negative 0 1 2 3 4 5 6
indices
'red' 'green' 'blue' 'pink' 'orange' 'white' 'black'
Negative -7 -6 -5 -4 -3 -2 -1
indices
The strings 'red', 'green', 'blue', 'pink', 'orange', 'white', and 'black' are stored at
index 0, 1, 2, 3, 4, 5, and 6 respectively. The indexes 0, 1, 2, 3, 4, 5, and 6, correspond to the negative
indexes -7, -6, -5, -4, -3, -2, and -1, respectively. To access an element in a list, the list object is followed by an opening
square bracket, the index to be accessed, and a closing square bracket.
Python Lists 171

