Code Completion 5 Challenges

Complete the Python iterators code

Practice creating and advancing iterators, implementing the iterator protocol, and stopping a callable iterator with a sentinel.

Intermediate ~8 min read

Complete the code so iterator receives an iterator over numbers.

python Your answer

numbers = [10, 20, 30]
iterator = 

print(next(iterator))

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Get the next value from the iterator.

python Your answer

iterator = iter(["red", "green"])
first = 

print(first)

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Complete iter so this iterator returns itself.

python Your answer

class CountDown:
    def __next__(self):
        raise StopIteration

    def __iter__(self):

iterator = CountDown()
print(iterator is iter(iterator))

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Signal that this iterator has no more values.

python Your answer

class OneValue:
    def __next__(self):
        if self.done:
            
        self.done = True
        return 1

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Use the callable-and-sentinel form of iter() to read each line until stream.readline() reaches end-of-file.

python Your answer

from io import StringIO

stream = StringIO("red\ngreen\n")
lines = list()
print([line.strip() for line in lines])

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