Explain how you reverse a generator?

Question

I confused because its not reversed(), but how?

Answer 1

You cannot reverse a generator in any generic way except by casting it to a sequence and creating an iterator from that. Later terms of a generator cannot necessarily be known until the earlier ones have been calculated.

Even worse, you can’t know if your generator will ever hit a StopIteration exception until you hit it, so there’s no way to know what there will even be a first term in your sequence.

The best you could do would be to write a reversed_iterator function:

def reversed_iterator(iter):
return reversed(list(iter))

You could also, of course, replace reversed in this with your imap based iterative version, to save one list creation.

Answer 2

def reversed_iterator(iter):
return reversed(list(iter))

Answer 3

Is this the sort of thing you mean:-
def rev_gen():
for x in range(100, 0, -1):
yield x

for x in rev_gen():
print(x)

Answer 4

Use imap is what I'd do.

Answer 5

Don't spam Guna please!

Answer 6

ghj