Python 3 reference · Built-in Functions

Python list() Function

Create a list: an ordered, changeable sequence. Called with an iterable, it copies its items into a new list.

Syntax

list(iterable=())

Parameter	Description
`iterable` optional	Items for the new list.

A new list.

Build a list from an iterableTry it yourself

print(list("abc"))
print(list(range(5)))
print(list({"x": 1, "y": 2}))  # a dict gives its keys

Output

['a', 'b', 'c']
[0, 1, 2, 3, 4]
['x', 'y']

Copy a listTry it yourself

original = [1, 2, 3]
copy = list(original)
copy.append(4)
print(original, copy)

Output

[1, 2, 3] [1, 2, 3, 4]

Turn an iterator into a listTry it yourself

squares = map(lambda n: n * n, [1, 2, 3])
print(squares)        # a lazy map object
print(list(squares))  # materialise it

Output

<map object at 0x1a353e0>
[1, 4, 9]

Version	Change
Python 3.0	Added

tuple() · Create a tuple: an ordered, immutable sequence. Tuples are hashable when their items are, so they can be dict keys.
dict() · Create a dictionary: a mapping of keys to values. Build it from keyword arguments, pairs or another mapping.
set() · Create a set: an unordered collection of unique items with fast membership tests and set operations.
sorted() · Return a new sorted list from any iterable. Supports a key function and reverse order; the original is left unchanged.
len() · Return the number of items in a container: characters in a string, items in a list, keys in a dict, and so on.
Python Lists · tutorial