Python 3 reference · List Methods

Python List insert() Method

Insert an item at a given position, shifting later items to the right. Index 0 adds to the front.

Syntax

list.insert(index, item)

Parameter	Description
`index`	Position to insert before; past the end appends, negative counts from the end.
`item`	The value.

None.

Insert at the front and endTry it yourself

queue = ["b", "c"]
queue.insert(0, "a")
queue.insert(len(queue), "d")
print(queue)

Output

['a', 'b', 'c', 'd']

Many inserts at the front? Use dequeTry it yourself

from collections import deque
q = deque(["b", "c"])
q.appendleft("a")   # fast for adding to the front
print(list(q))

Output

['a', 'b', 'c']

Inserting near the front of a long list is slow (every later item moves). For queues, use collections.deque.

Version	Change
Python 3.0	Added

list.append() · Add one item to the end of a list, changing the list in place. Returns None.
list.pop() · Remove and return the item at a position, the last item by default. Raises IndexError on an empty list.
list.extend() · Add every item from an iterable to the end of the list, in place. Like append() for many items at once.
Python Lists · tutorial