Python Lists
A list is Python's built-in container for holding an ordered, changeable collection of items in a single variable.
What is a list?
A list stores several values together under one name. You create one by placing comma-separated values inside square brackets. Lists keep the items in the order you write them, and that order stays fixed until you decide to change it, which makes lists a natural fit for anything that has a sequence, such as steps in a recipe or scores in a game.
Creating a list
fruits = ["apple", "banana", "cherry"]
print(fruits)
print(type(fruits))The example above prints the whole list and then confirms its type. Running it shows ['apple', 'banana', 'cherry'] followed by <class 'list'>, so you can see that Python treats the collection as a single object of type list.
Key characteristics
- Ordered: items have a fixed position, and new items are added at the end by default.
- Changeable (mutable): you can add, replace, or delete items after the list is created.
- Allows duplicates: the same value can appear more than once because items are stored by position, not by uniqueness.
- Mixed types: a single list can hold strings, numbers, booleans, and even other lists at the same time.
Mixed data and duplicates
mixed = ["text", 42, True, 3.14, "text"]
print(mixed)
print(len(mixed))Here the list mixes four different data types and repeats the value 'text'. The built-in len() function returns 5, counting every item regardless of type or repetition.
Exercise: Python Lists
What is the key difference between a Python list and a tuple?