Linking of lists

If we use

a=[1,2,4]
b=a
a.append(5)
print(b)

here a and b are linked so changes in a are reflected in a
to make a list unlinked, there are several methods

a=list(b)
a=b[:]

one imp question that can be used to understand this

L4 = [[9,8],[7,6]] 
L5 = L4[:] 
L5 [0] = [5,4] 
L5 [1] [1] = 3 
print (L4[0])#----->[9,8]
print(L4[1][1])#---->3

this is because changing L5[0] made it point to a new list but the second statement changed the first element of the list it was pointing at which L4 was also pointing at so it also changed

python
lists
col1000