How to Utilize Values in a List
To utilize values within a list, you use an index that starts from 0.
The index of the first element is 0, the second element is 1, and it increases sequentially after that.
The index of the last element is -1, the second-to-last is -2, decreasing sequentially.
fruits = ["Apple", "Banana", "Grape", "Cherry"]
# First element
first_fruit = fruits[0]
# "Apple"
print("first_fruit:", first_fruit)
# Second element
second_fruit = fruits[1]
# "Banana"
print("second_fruit:", second_fruit)
# Last element
last_fruit = fruits[-1]
# "Cherry"
print("last_fruit:", last_fruit)
Slicing to Retrieve a Portion of a List
To retrieve a portion of a list, we use slicing.
Slicing is a technique that uses list indices to extract a desired portion.
To slice a list, specify the start and end indices separated by a colon : inside the square brackets [].
For example, you can slice the fruits list with fruits[0:2].
The start index is included, but the end index is not.
For example, fruits[0:2] extracts from the first element to the second element.
The third element, fruits[2], is not included in the result of the slice.
fruits = ["Apple", "Banana", "Grape", "Cherry"]
# From the first element to the second element
first_two_fruits = fruits[0:2]
# fruits[2] is not included
print("first_two_fruits:", first_two_fruits)
# ['Apple', 'Banana']
Nested Lists
A nested list is a list that contains other lists as its elements.
This allows you to represent complex data structures like multidimensional arrays or matrices.
# Create a 2D list
nested_list = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
# First element of the nested list
print(nested_list[0])
# Output: [1, 2, 3]
# Specific element of a nested list
print(nested_list[0][1])
# Output: 2 (2nd element of the 1st list)
Want to learn more?
Join CodeFriends Plus membership or enroll in a course to start your journey.