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How can the original iterator object instance be preserved while implementing chain iterators?

asked 2022-11-06 11:00:00 +0000

lakamha gravatar image

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answered 2022-11-13 20:00:00 +0000

bukephalos gravatar image

To preserve the original iterator object instance while implementing chain iterators, you can create a wrapper object that keeps track of the original iterator object and the current position within it. This wrapper object can then be used to create chain iterators that pass through the original iterator first before moving on to the next iterator in the chain.

Here is an example implementation of a chain iterator using a wrapper object:

class IteratorWrapper:
    def __init__(self, iterator):
        self.iterator = iterator
        self.position = 0

    def __iter__(self):
        return self

    def __next__(self):
        try:
            item = self.iterator[self.position]
            self.position += 1
            return item
        except IndexError:
            raise StopIteration

def chain_iterators(*iterators):
    for iterator in iterators:
        yield from IteratorWrapper(iterator)

Here, the IteratorWrapper class initializes with the original iterator object and a position of 0. The __iter__ and __next__ methods allow for iteration over the original iterator object while keeping track of the current position.

The chain_iterators function takes any number of iterators as arguments and returns a generator that yields items from each original iterator in turn. The yield from statement iterates over the IteratorWrapper for each original iterator, preserving the original iterator object instance while still allowing for chaining.

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Asked: 2022-11-06 11:00:00 +0000

Seen: 1 times

Last updated: Nov 13 '22