Raymond Hettinger added the comment:
This is the expected behavior.
The assignments are made left-to-right.
The first use of L2[1] is updated BEFORE the second use as index.
The assignments are equivalent to:
==
>>> L1 = [1,3,2,4]
>>> L2 = [1,3,2,4]
>>> tup = L2[L
New submission from Hang Liao:
Suppose I have two lists
L1 = [1,3,2,4], L2 = [1,3,2,4]
L1[1], L1[2] = L1[2], L1[1]
This gives me L1 = [1,2,3,4]
However, if I write
L2[1], L2[L2[1] - 1] = L2[L2[1] - 1], L2[1]
This gives me back the same L2 = [1,3,2,4]
I am not sure if this is a mistake ... If it
