Point out my mistake in code:

Question

Q=[]
r=[1, 2]
i=0
while i<3:
j=r
j.insert(i, 3)
Q.append(j)
i=i+1
print(Q)

My desire output is :
>>
[[3,1,2],[1,3,2],[1,2,3]]
>>

Which can be obtained by:
Q=[]
i=0
while i<3:
j=[1, 2]
j.insert(i, 3)
Q.append(j)
i=i+1
print(Q)

Answer 1

you can solve the problem by adding an
import copy
and replacing
j=r
with
j=copy.copy(r)

(btw 100th post)

Answer 2

The problem is that j is always referring to the same list, so it always adds the 3 to the same list

Answer 3

instead of using the copy module, you could also do
j=r[:]

Answer 4

Here
https://code.sololearn.com/cdp2ySjFpoHb/?ref=app