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.
Negative indices count from the end: -1 is the last element, -2 the second-to-last, and so on.
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. It is is a method that uses list indices to extract a specific range of elements.
To perform slicing, specify the start and end indices separated by a colon : inside square brackets []. For example, you can slice the fruits list using fruits[0:2].
The start index is included, while the end index is excluded. So, fruits[0:2] returns the first and second elements of the list. The third element, fruits[2], is not included in the result.
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)
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