In the tutorial there is an example iterator class that revesrses the
string given to the constructor. The problem is that this class works
only once, unlike built-in types like string. How to modify it that it
could work several times? I have tried two approaches. They both work,
but which of them is stylistically better?
class Reverse: #original one
"Iterator for looping over a sequence backwards"
def __init__(self, data):
self.data = data
self.index = len(data)
def __iter__(self):
return self
def next(self):
if self.index == 0:
raise StopIteration
self.index = self.index - 1
return self.data[self.index]
class Reverse: #1st approach
"Reuseable Iterator for looping over a sequence backwards"
def __init__(self, data):
self.data = data
self.index = len(data)
def __iter__(self):
return self
def next(self):
if self.index == 0:
self.index = len(self.data) #Reset when previous
#
iterator goes out
raise StopIteration
self.index = self.index - 1
return self.data[self.index]
class Reverse: #2nd approach
"Reuseable Iterator for looping over a sequence backwards"
def __init__(self, data):
self.data = data
def __iter__(self):
self.index = len(self.data) #Reset as a part of iterator
# creation
return self
def next(self):
if self.index == 0:
raise StopIteration
self.index = self.index - 1
return self.data[self.index]
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