I have a question if whether the following code is executed in place or has extra space complexity. Given that sentence was a string initially. Thanks appreciate the help
sentence = "hello world"
sentence = sentence.split()
In python strings are immutable objects, which means that they cannot change at all "in-place". All actions on them essentially take up new memory space, and hopefully, the old unused ones are deleted by python's garbage collecting process (if there are no more references to those objects). One method to see it for yourself is this:
>>> a = 'hello world'
>>> id(a)
1838856511920
>>> b = a
>>> id(b)
1838856511920
>>> a += '!'
>>> id(a)
1838856512944
>>> id(b)
1838856511920
As you can see, when b and a are referring to the same underlying objects, their id in memory is the same, but as soon as one of them changes, it now has a new id - a new space in memory. The object that was left unchanged (b) still has the same place-id.
To check it in your example:
>>> sentence = "hello world"
>>> id(sentence)
1838856521584
>>> sentence = sentence.split()
>>> id(sentence)
1838853280840
We can once again see that those objects are not taking the same memory. We can further explore just how much space they take up:
>>> import sys
>>> sentence = "hello world"
>>> sys.getsizeof(sentence)
60
>>> sentence = sentence.split()
>>> sys.getsizeof(sentence)
160