Each of next() and list() iterates over generator with mutable object differently

Question

def generator(dct):
    for i in range(3):
        dct[\'a\'] = i
        yield dct

g = generator({\'a\': None})
next(g) # -> {\'a\': 0}
next(g) # -> {\'a\': 1}
n         


        

Answer 1

They iterate over the iterator identically, but you're checking in at different points. Because dicts are mutable, and you always yield the same dict, you should expect everything you yield to be identical. In your first example, you are looking at the dict as it is changing. Instead consider

g = generator({'a': None})

a = next(g)
b = next(g)
c = next(g)

print(a, b, c)
# {'a': 2} {'a': 2} {'a': 2}