[Python] Python append() vs. += operator on lists, why do these give different results?

Why do these two operations 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 infinite recursion. c[-1] and c are the same. Why is it different with the + operation?

Continue reading...