How to create a nested list from another list?

Question

list1=[1, 2, 3, 4, 5]

I want to create a list [[1, 2, 3, 4, 5]] from list1. I tried list(list1) but it's showing only [1, 2, 3, 4, 5] instead of [[1, 2, 3, 4, 5]].

Answer 1

One line solution :

list1=[1, 2, 3, 4, 5]

print([[nested_list for nested_list in list1]])

or just use:

list1=[1, 2, 3, 4, 5]

nested_list=[list1]

Answer 2

This works for me

list1=list([list1])

Answer 3

Just initialise a new list which has a sub-list that is list1.

This is done with:

[list1]

which will give:

[[1, 2, 3, 4, 5]]

Or alternatively, when you are defining list1, you can define it already nested inside another list:

list1 = [[1, 2, 3, 4, 5]]

---

Note that when you were trying to nest the original list inside another list, using list() will not work.

If you read the documentation:

The constructor builds a list whose items are the same and in the same order as iterable’s items. iterable may be either a sequence, a container that supports iteration, or an iterator object. If iterable is already a list, a copy is made and returned, similar to iterable[:]. For example, list('abc') returns ['a', 'b', 'c'] and list( (1, 2, 3) ) returns [1, 2, 3]. If no argument is given, the constructor creates a new empty list, [].

The key thing mentioned here is that list creates a list from an iterable. As list1 is a list already, it is an iterable. This means that the list() constructor will treat as an iterable and create a new list from the elements inside list1 - creating a copy of it. So that is why it wasn't working as you expected it to.

Answer 4

You'll have to put it in another list using. When you declare a list, you put them in two square brackets. If you want to make a list of lists, you'll have to use them twice.

lis = [your_list]

Answer 5

Have you tried?

list2 = [list1]