Question

See the following program

class MyIterator:
    cur_word = ''
    def parse(self):
        data = [('one', 1), ('two', 2), ('three', 3), ('four', 4), ('five', 5)]
        for index in range(1,3):
            (word, num) = data[index]
            cur_word = word
            yield self.unique_str(num)

    def unique_str(self, num):
        data = ['a', 'b']
        for d in data:
            yield "%s-%d-%s" % (self.cur_word, num, d)


miter = MyIterator()
parse = miter.parse()
for ustrs in parse:
    for ustr in ustrs:
        print ustr

Output of this code is

-2-a
-2-b
-3-a
-3-b

But I want it to be

two-2-a
two-2-b
three-3-a
three-3-b

Yes I know I can run yield self.unique_str(word, num). But the code I am using its not allowed. So I used an instance member to pass the data.

Answer 1

MyIterator.parse doesn’t change the instance’s current word.

This works:

class MyIterator:
    cur_word = ''
    def parse(self):
        data = [('one', 1), ('two', 2), ('three', 3), ('four', 4), ('five', 5)]
        for index in range(1,3):
            (word, num) = data[index]
            self.cur_word = word
            yield self.unique_str(num)

    def unique_str(self, num):
        data = ['a', 'b']
        for d in data:
            yield "%s-%d-%s" % (self.cur_word, num, d)


miter = MyIterator()
parse = miter.parse()
for ustrs in parse:
    for ustr in ustrs:
        print ustr

(I just changed cur_word = word to self.cur_word = word in parse)