[Solved] effect of .append() method on a list in a for loop.

Question

Hello dear friends, can you please explain the output of "b" in this code?
I thought "b" and "c" should look like the same but they're not!
This is the code:

a = list()
b = dict()
c = dict()
for n in range(3):
a.append(n)
b[n] = a
c[n] = list(a)

print(b) # {0 : [0,1,2], 1 : [0,1,2], 2 : [0,1,2]}
print(c) # {0 : [0], 1 : [0,1], 2 : [0,1,2]}

Thank you for your time guys. 🙏

Answer 1

list(a) creates a new object. So in your loop you add the same object (which itself gets modified in each iteration) three times to b, but three different objects to c.