How to add new value to a list without using 'append()' and then store the value in a newly created list?

Question

I have been trying this a lot.

>>> x = [4,5]
>>> y = x.append(7)
>>> print y
None
>>>print x
[4, 5, 7]

Answer 1

Because the function append() modifies the list and returns None.

One of the best practices to do what you want to do is by using + operator.

Let's take your example :

>>> x = [4, 5]
>>> y = x + [7]
>>> x
[4, 5]
>>> y
[4, 5, 7]

The + operator creates a new list and leaves the original list unchanged.