Javadoubts

Python List

Python Lists store multiple values in a single variable. In the same list variable, list items values can be of the same or different type. Each list item can be defined within double quotes separated by commas. The list allows ordered, duplicate, and changeable values.

Example:

list1 = [“HTML”, “CSS”, “Java”];

list2 = [1, 2, 3, 4, 5, 6];

List items can be access using index, it always starts from 0.

Defining a list listOne with four list items HTML, CSS, JavaScript and Java as show below:

listOne = [“HTML”, “CSS”, “JavaScript”, “Java”];

listOne[0] → HTML,
listOne[1] → CSS,
listOne[3] → Java

There are some other methods provided by Python to access list elements:

listOne[0:3] → [‘HTML’, ‘CSS’]

Note: Point to be noted, in above example first item as 0 represents the index number and second item as 3 is number of items.

Example: Below example is all about access, update and delete list items.

listOne = ["HTML", "CSS", "JavaScript", "Java"];

# Accssing single list Item from list
print(listOne[0])

# Accessing multiple list items from
# 0 index and number of items as 3
print(listOne[0:3])

# Updating an element at index in list
listOne[1] = "CSS3";

# Print list items
print(listOne);

#Delete list time at index 2
del listOne[2];

# Print list items
print(listOne);

OUTPUT:
     ['HTML', 'CSS', 'JavaScript']
     ['HTML', 'CSS3', 'JavaScript', 'Java']
     ['HTML', 'CSS3', 'Java']

Sort and Create Copy

Below example to sort and create copy of list.

listOne = ["HTML", "CSS", "JavaScript", "Java"];

// sort the list, by default ascending
listOne.sort()
print(listOne);

// sort the list in descending
listOne.sort(reverse = True)
print(listOne);

// Create list copy
listTwo = listOne.copy();
print(listTwo);


OUTPUT:
['CSS', 'HTML', 'Java', 'JavaScript']
['JavaScript', 'Java', 'HTML', 'CSS']
['JavaScript', 'Java', 'HTML', 'CSS']