Splitting an iterator in two succeeding iterators in python

Question

I have an iterator that yields a dictionary with several data fields. Is there a way to split this stream of data into two following iterators that each feature only a certain data field of the preceding streamed dictionary?

class Splitter(IteratorBase):
    def __init__(self, iterable):
        super().__init__(iterable)

    def __iter__(self):
        for pt in self.iterable:
            yield pt["field1"], pt["field2"]

does not work, because this just yields tuples with both fields

Answer 1

You can use itertools.tee:

import itertools

# Make iterator for some data
data = [{'field1': 1, 'field2': 2}, {'field1': 3, 'field2': 4}]
it = iter(data)
# Make two iterators out of the first one
it1, it2 = itertools.tee(it)
# Use first iterator for field1
it1 = (elem['field1'] for elem in it1)
# Use second iterator for field2
it2 = (elem['field2'] for elem in it2)
# Print elements of each iterator
print(*it1)
# 1 3
print(*it2)
# 2 4