With a positive index, we insert at an index that begins from the start of the list. So 0 is the first element. With a negative value, the index is from the list's end.
Insert example. Here we invoke the insert() method. The index 1 indicates the second element location. Lists are indexed starting at zero—they are zero-based.
Tip To insert at the first index, pass the value 0 to insert. This will create a new first element in the list.
list = ["dot", "perls"]
# Insert at index 1.
list.insert(1, "net")
print(list)['dot', 'net', 'perls']
Insert, negative index. Sometimes we wish to insert based on a relative position from the end of a list. We can use a negative index for this. With -1, insert 1 from the last position.
Tip To add an element at the last position in the list, use append() not insert.
ids = [1000, 1001, 1002, 1003]
print(ids)
# Pass a negative index to insert from the last index.# ... So -1 is the second to last position.
ids.insert(-1, 0)
print(ids)[1000, 1001, 1002, 1003]
[1000, 1001, 1002, 0, 1003]
A review. We invoked the insert() method on lists with a positive and negative index value. The first argument is the index we wish the new element to have.
Dot Net Perls is a collection of tested code examples. Pages are continually updated to stay current, with code correctness a top priority.
Sam Allen is passionate about computer languages. In the past, his work has been recommended by Apple and Microsoft and he has studied computers at a selective university in the United States.
This page was last updated on Aug 22, 2021 (image).
