Please Explain This Python Code

Question

a = 'Apoorve kumar verma'
b = [11,12,13]
c = 55
x = [a,b,c]
u = x[:]
b[1] = 10
print(x[1][1]) #print 10
print(u[1][1]) #print 10

a1 = 'Apoorve kumar verma'
b1 = [11,12,13]
c1 = 55
x1 = [a1,b1,c1]
u1 = x1[:]
b1 = [11,14,13]
print(x1[1][1]) #print 12
print(u1[1][1]) #print 12

<h2>why it is happend?<h2>

Answer 1

The first case - you changed an element of the b list, so whenever it's referenced to, it returns the new value of 10. Now x contains b explicitly and u is its shallow copy (preserves references rather than values), so behaves the same.

The second case is similar, but you change the reference of the whole list, not just its element. Now both x1 and u1 point to the elements of the "old" b1, but b1 itself has been re-assigned and has nothing in common with its own copy anymore.

It is well-explained and graphically illustrated here:
https://www.python-course.eu/deep_copy.php

Answer 2

I would also like to know 😗

Answer 3

Please put in playground