Lists and Tuples

Lists and Tuples

Python Lists are containers to store a set of values of any data type.

friends = [‘Apple’, ‘Akash’, ‘Rohan’, 7, False]

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The list can contain different types of elements such as int, float, string, Boolean, etc. Above list is a collection of different types of elements.

List Indexing

A list can be index just like a string.

L1 = [7, 9, ‘alok’]

 

L1[0] – 7

 

L1[1] – 9

 

L1[70] – Error

 

L1[0:2] – [7,9]         (This is known as List Slicing)

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List Methods

Consider the following list:

L1 = [1, 8, 7, 2, 21, 15]

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1.     sort() – updates the list to [1,2,7,8,15,21]

2.     reverse() – updates the list to [15,21,2,7,8,1]

3.     append(8) – adds 8 at the end of the list

4.     insert(3,8) – This will add 8 at 3 index

5.     pop(2) – It will delete the element at index 2 and return its value

6.     remove(21) – It will remove 21 from the last

Tuples in Python:

A tuple is an immutable (can’t change or modified) data type in Python.

a = ()              #It is an example of empty tuple

 

a = (1,)           #Tuple with only one element needs a comma

 

a = (1, 7, 2)   #Tuple with more than one element

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Once defined, tuple elements can’t be manipulated or altered.

Tuple methods:

Consider the following tuple,

a = (1, 7, 2)

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1.     count(1) – It will return the number of times 1 occurs in a.

2.     index(1) – It will return the index of the first occurrence of 1 in a.

Chapter 4 – Practice Set

1.     Write a program to store seven fruits in a list entered by the user.

2.     Write a program to accept the marks of 6 students and display them in a sorted manner.

3.     Check that a tuple cannot be changed in Python.

4.     Write a program to sum a list with 4 numbers.

5.     Write a program to count the number of zeros in the following tuple:

a = (7, 0, 8, 0, 0, 9)

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