## Fix Python – Python append() vs. + operator on lists, why do these give different results?

Why do these two operations (append() resp. +) give different results?

>>> c = [1, 2, 3]

>>> c

[1, 2, 3]

>>> c += c

>>> c

[1, 2, 3, 1, 2, 3]

>>> c = [1, 2, 3]

>>> c.append(c)

>>> c

[1, 2, 3, […]]

>>>

In the last case there’s actually an infinite recursion. c[-1] and c are the same. Why is it different with the + operation?

….