[python] How to add element in Python to the end of list using list.insert?

There is a list, for example,

a=[1,2,3,4]

I can use

a.append(some_value)

to add element at the end of list, and

a.insert(exact_position, some_value)

to insert element on any other position in list but not at the end as

a.insert(-1, 5)

will return [1,2,3,5,4]. So how to add an element to the end of list using list.insert(position, value)?

This question is related to python list insert

The answer is


You'll have to pass the new ordinal position to insert using len in this case:

In [62]:

a=[1,2,3,4]
a.insert(len(a),5)
a
Out[62]:
[1, 2, 3, 4, 5]

list.insert with any index >= len(of_the_list) places the value at the end of list. It behaves like append

Python 3.7.4
>>>lst=[10,20,30]
>>>lst.insert(len(lst), 101)
>>>lst
[10, 20, 30, 101]
>>>lst.insert(len(lst)+50, 202)
>>>lst
[10, 20, 30, 101, 202]

Time complexity, append O(1), insert O(n)


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