Question about lists

Question

I thought the output would be [3,4,3,1,2], but instead it is [3,4,3,3,4].
When changing x, why would y also change?
Also, how can I make a copy of a list that will not change when the original list changes?

x=[1,2,3,4,5]
y = x
x[0:2]=y[2:4]
x[3:5]=y[0:2]
print(x)
https://code.sololearn.com/cwZKbQMh872P/?ref=app

Answer 1

chunngai chan
y=x
create only shallow copy of the variable you need deep copy of the object and remember y=x[:] KrOW is coded is also shallow copy not a deep copy if your list is nested it will also change.e.g
x=[[1,2],[3,4]]
y=x or y=x[:]
x[1][1]='m'

now when you print y it will also change so try copy module to create deep copy of the variable or object.

import copy
y=copy.deepcopy(x)

now y is independent from x even x in nested.

Answer 2

with

y = x

you assign SAME object (x) to y then any edit on one will reflect on other (i repeat they are SAME).
For get what you want, you have to copy and you can do this so

y = x[:]

Now though x and y will have same items, they are DIFFERENT list objects

Answer 3

thx!

Answer 4

👍👍👍