Lists
In this class, we will learn about lists, which are one of the most important data structures in Python.
What are lists? Link to heading
Lists are ordered collections of elements that can be any type of data. They can be used to store a variety of data, such as names, numbers, dates, etc.
How are lists created? Link to heading
Lists are created using ([]) square brackets and separating elements with commas.
Example: Link to heading
# List of names
names = ["Ana", "John", "Peter"]
#List of numbers
numbers = [1, 2, 3, 4, 5]
# Mixed list
mixed = ["Hello", 10, True]
Access list items Link to heading
Elements in a list can be accessed using their index. The index of an element is its position within the list, starting at 0.
Example Link to heading
# Print first name
print(names[0])
# Print the third number
print(numbers[2])
# Print the last element of the mixed list
print(mixed[-1])
Add items to list Link to heading
Elements can be added to the end of the list using the append() method.
Example: Link to heading
names.append("Mary")
print(names)
Delete items from the list Link to heading
Elements can be removed from the list using the remove() method or the del operator.
Example: Link to heading
# Delete the second element
names.remove("John")
# Delete the last element
of names[-1]
print(names)
Change list items Link to heading
You can change list elements using their index.
Example: Link to heading
# Change first name
names[0] = "Camila"
print(names)
Search for elements Link to heading
You can search for an element in a list using the index() method or the in operator.
Example: Link to heading
# Find the index of the first appearance of "Ana"
index = names.index("Ana")
print(index)
# Search if "Peter" is in the list
print("Pedro" in names)
Exercise Link to heading
Copy the following lists and add a new element to each with .append(), then, using the [] indices, print at least 3 elements. Finally, perform a search where you print elements of the list using the search with index() or with the in operator.
names = ['Arturo', 'Laura', 'Carlos', 'Martha']
ages = [25, 36, 53, 78]