Mutability of Lists

Question

When a list is sorted, perhaps in ascending numerical order (for integer only list) or alphabetical order in case of strings (for string only list), can I say that the list is mutated, considering the fact that the index number of the items in the list have been changed? For example:

x = ["Alexa", "Siri", "Cortana"]
x_sorted = sorted (x)
print (x_sorted)
# ["Alexa", "Cortana", "Siri"]
print (x)
# ["Alexa", "Siri", "Cortana"]

You haven't mutated the list though, you've created a copy with items in a different order. If you did `x.sort()`, that would be mutating x. — Daniel Roseman, Oct 10 '16 at 13:13

score 3 · Accepted Answer · answered Oct 10 '16 at 13:12

It depends how you do the sort. If your initial list is

>>> x = ["Alexa", "Siri", "Cortana"]

using sorted will create a new list, and will leave the original unmutated

>>> sorted(x)
['Alexa', 'Cortana', 'Siri']
>>> x
['Alexa', 'Siri', 'Cortana']

However the sort method will sort the list in-place, and therefore does mutate the list in doing so

>>> x.sort()
>>> x
['Alexa', 'Cortana', 'Siri']

Mutability of Lists

1 Answers1