Store and manage data with lists

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A list is an ordered collection of values, written inside square brackets [] with items separated by commas. Lists are one of the most commonly used data structures in Python because they can hold any type of value and can be modified after creation.

Creating a list

colors = ["red", "green", "blue"]
scores = [95, 82, 76, 91]

Lists can hold any data type, and can even mix types—although keeping one type per list makes your code easier to reason about.

Accessing items by index

Each item in a list has a numbered position called an index, starting at 0:

colors = ["red", "green", "blue"]
print(colors[0])  # Output: red
print(colors[2])  # Output: blue

You can also use negative indexes to count from the end:

print(colors[-1])  # Output: blue  (last item)
print(colors[-2])  # Output: green

Common list operations

Lists can be modified after creation. Here are the operations you'll use most often:

Operation	What it does
len(list)	Returns the number of items
list.append(value)	Adds an item to the end of the list
list.remove(value)	Removes the first matching item
list[i] = value	Overwrites the item at index i
list.pop()	Removes and returns the last item
list.sort()	Sorts the list in place

colors = ["red", "green", "blue"]

print(len(colors))        # Output: 3
colors.append("yellow")   # Adds "yellow" to the end
print(colors)             # Output: ['red', 'green', 'blue', 'yellow']

colors.remove("red")      # Removes "red"
print(colors)             # Output: ['green', 'blue', 'yellow']

colors[0] = "purple"      # Replaces "green" with "purple"
print(colors)             # Output: ['purple', 'blue', 'yellow']

Iterating over a list

Lists work naturally with for loops:

scores = [95, 82, 76, 91]

for score in scores:
    print(score)

Output:

95
82
76
91