Bulba! wrote:
Hello Mr Everyone,
From:
http://docs.python.org/tut/node11.html#SECTION0011900000000000000000
"Define a __iter__() method which returns an object with a next()
method. If the class defines next(), then __iter__() can just return
self:"
The thing is, I tried to define __iter__() directly without explicit
defining next (after all, the conclusion from this passage should
be that it's possible).
class R:
def __init__(self, d):
self.d=d
self.i=len(d)
def __iter__(self):
if self.i == 0:
raise StopIteration
self.i -= 1
return self.d[self.i]
Here's one way: # (Make __iter__ an iterator)
Py> class R1(object):
def __init__(self, data):
self.data = data
self.i = len(data)
def __iter__(self):
while self.i > 0:
self.i -= 1
yield self.data[self.i]
Py> s=R1('spam')
Py> list(s)
['m', 'a', 'p', 's']
Py> list(s)
[]
Py> s.i = 3
Py> list(s)
['a', 'p', 's']
Here's another way: # (Return something with __iter__ and next methods)
Py> class R2(object):
def __init__(self, data):
self.d = data
self.i = len(data)
def __iter__(self):
return iter(self.d)
Py> s = R2('spam')
Py> list(s)
['s', 'p', 'a', 'm']
Py> list(s)
['s', 'p', 'a', 'm']
--Scott David Daniels
[EMAIL PROTECTED]
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