iterable shine kome da zake iya yi loop (jeri, zarna, dict); iterator shine abin da ke yi ainihin iteration, samar da ƙimomi daya-daya kuma neman mahimmin sa. Bambanci nan ya fi asali kamar yadda for madauki ke aiki a Python.
Iterable → has __iter__() → returns an iterator
Iterator → has __next__() → returns the next value (and __iter__ returning itself)
# this for loop...
for x in [1, 2, 3]:
print(x)
# ...is roughly equivalent to:
it = iter([1, 2, 3]) # __iter__ → get an iterator from the iterable
while True:
try:
x = next(it) # __next__ → get the next value
print(x)
except StopIteration: # raised when exhausted → loop ends
break
for loop yana kira iter() don samun iterator, sannan yana sake kiran next() har StopIteration yana tohu wajen karshe. Wannan protocol ne ke bubutar kome iterable don iya yi loop.
nums = [1, 2, 3] # an ITERABLE (a list)
it = iter(nums) # an ITERATOR over it
next(it) # 1
next(it) # 2
next(it) # 3
next(it) # StopIteration
# the list is REUSABLE (get a fresh iterator each loop);
# an iterator is CONSUMED ONCE — exhausted after one pass
list(it) # [] — already used up
Masoyin bambanci: iterable (jeri) na iya yi loop sau da yawa (kowane for yana samun sabuwar iterator); iterator shine one-time — da aka gama, babu komai.
class Countdown:
def __init__(self, start): self.n = start
def __iter__(self): return self # the iterable returns itself as iterator
def __next__(self):
if self.n <= 0:
raise StopIteration # signal the end
self.n -= 1
return self.n + 1
for x in Countdown(3): # 3, 2, 1
print(x)
def gen(): yield 1; yield 2 # a generator function returns an iterator automatically
Generators shine sauki hanyar gina iterators — yield yana azaltar __next__/StopIteration ka gida.
Iterable/iterator bambanci yana bayyana kamar yadda for loops ke aiki a Python kuma kamar yadda iteration ake tarayya a tsakanin jemi duka (jeri, dicts, fayil, generators) ta hanyar iterator protocol.
Samuwa da shi yana bayyana ainihin hali — me yasa iterator za a iya amfani da shi jiya-jiya (gida gani: yi loop generator/zip sau biyu sannan babu kome na biyu), me yasa generators su ne iterators, kuma kamar yadda za ku bubutar abubuwan kanku iterable.
Annin protocol shine tushe na kyakkyawan, daidai-daidai iteration model na Python kuma dole ne don aiki da generators, lazy evaluation, da aji masu iterable na kakansu.