+ 5

Can you please explain the output of this code?

a = enumerate(range(10)) b = enumerate(range(1,10)) c = list(zip(a,b)) print(c[-1]) Answer is ((8,8),(8,9))

7th Mar 2020, 6:19 PM
APC (Inactive for a while)
APC (Inactive for a while) - avatar
2 odpowiedzi
+ 4
Enumerate takes an iterable and gives an index to each item. That makes looping easier in some situations, because you can access the item *and* index it in the list or whatever. enumerate('abc') ... becomes... (0, 'a'), (1, 'b'), (2, 'c'). The last element of a is (9, 9), the last element of b (8, 9). Zip combines two iterables to tuples, but only reads until one of them ends. So since a is one longer, the last item in the zip situation is (8, 8). So the last tuple from the zip would consist of (8, 8) from a and (8, 9) from b.
7th Mar 2020, 6:43 PM
HonFu
HonFu - avatar
+ 4
Great explanation from Honfu! I just add some information about the generators that are used here. a = enumerate(range(10)) makes a generator of type 'enumerate object'. Also b and c are objects from the same type as a. The special thing about these generator objects is that they can only be used once. So if a is printed with print(list(a)), a is empty after this action and looks like []. The same happend when c is created with: c = list(zip(a,b)). After this action, a and b are empty generators, c can still be printed. But after that it is laso empty. This behavior is the same for all generators.
7th Mar 2020, 8:16 PM
Lothar
Lothar - avatar