Why it's True False False?

Question

Plaese take a look at my Python code. Can you explain me the 'is' operator in this case?

https://code.sololearn.com/c88nbF0EdLW2/?ref=app

Answer 1

list1 = [1,2]
>create a list and store it in list1

list2 = list1
>assign list1 to list2..meaning list2 is also pointing to same object(i think python call value as object)..so there are both pointing to same thing

list3 = list2[:]
>that[:] in list will return a new list..it will have same value as list2 but it is a new one..

"is" keyword will only return true if u compare two variable that point to same object

Answer 2

The id is different, it is another object, try this adding to your code.

print (id(list1))
print (id(list2))
print (id(list3))

Answer 3

Okay Lily Mea final test:
L1 = [[1,1],[1,2]]
L2 =L1[:]
L1[0][0]=3

What is L2 now and why?

Answer 4

Additionally to HonFu s great tutorial I would propose that you read all functions for a list object
(Sort,reverse,....) and find out if the result creates a new reference or works on list itself(inplace).

Answer 5

After reading this, all of that sort of questions should become clear... I hope.

https://code.sololearn.com/c89ejW97QsTN/?ref=app

Answer 6

Lily Mea
Now I understand the 'is' operator.
It compares the ID of the variable
and not its value.

Thanks for explanation to all answers