SESSION 5 Lists and Tuples

 List:

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

friends = [‘a’, ‘b’, ‘c’, 7, False]

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

List Indexing

A list can be index just like a string. (For string and string slicing revise previous topic).

L1 = [5, 9, ‘mustajab’]

L1[0] – 5

L1[1] – 9

L1[70] – Error

L1[0:2] – [5,9]         (This is known as List Slicing)

List Methods

Consider the following list:

L1 = [1, 8, 7, 2, 21, 15]

1. sort() – updates the list to [1,2,7,8,15,21]
2. reverse() – reverse the list to [15,21,2,7,8,1]
3. append(11) – adds 11 at the end of the list
4. insert(3,0) – This will add 0 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

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

Tuple methods:

Consider the following tuple,

a = (1, 5, 2)

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.

 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. Calculate its Computational time.
4. Write a program to sum a list with 4 numbers.
5. Generate list using random module. 
6. Write a program to count the number of zeros in the following tuple:

a = (5, 0, 8, 0, 0, 9)