Sample code for the iterators and iterables article

Author: lpozo

python-iterators-iterables/README.md

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+# Iterators and Iterables in Python: Run Efficient Iterations
+
+This folder provides the code examples for the article [Iterators and Iterables in Python: Run Efficient Iterations](https://realpython.com/python-iterators-iterables/).

python-iterators-iterables/async_iter.py

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+import asyncio
+from random import randint
+
+
+class AsyncIterable:
+    def __init__(self, stop):
+        self.stop = stop
+        self.index = 0
+
+    def __aiter__(self):
+        return self
+
+    async def __anext__(self):
+        if self.index >= self.stop:
+            raise StopAsyncIteration
+        await asyncio.sleep(value := randint(1, 3))
+        self.index += 1
+        return value
+
+
+async def main():
+    async for num in AsyncIterable(4):
+        print(num)
+
+
+asyncio.run(main())

python-iterators-iterables/fib_gen.py

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+# def fibonacci_generator(stop):
+#     previous, next = 0, 1
+#     for _ in range(0, stop):
+#         fib_number = previous
+#         previous, next = next, previous + next
+#         yield fib_number
+
+
+def fibonacci_generator(stop=100):
+    previous, next = 0, 1
+    index = 0
+    while True:
+        if index == stop:
+            return
+        index += 1
+        fib_number = previous
+        previous, next = next, previous + next
+        yield fib_number
+
+
+print("Fibonacci Generator")
+for fib in fibonacci_generator(10):
+    print(fib)

python-iterators-iterables/fib_iter.py

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+class Fibonaccier:
+    def __init__(self, stop=10):
+        self._stop = stop
+        self._index = 0
+        self._previous = 0
+        self._next = 1
+
+    def __iter__(self):
+        return self
+
+    def __next__(self):
+        if self._index >= self._stop:
+            raise StopIteration
+        self._index += 1
+        fib_number = self._previous
+        self._previous, self._next = self._next, self._previous + self._next
+        return fib_number

python-iterators-iterables/inf_int.py

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+class InfIntegers:
+    def __init__(self):
+        self._number = 0
+
+    def __iter__(self):
+        return self
+
+    def __next__(self):
+        number = self._number
+        self._number += 1
+        return number

python-iterators-iterables/resettable_iter.py

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+class ResettableRange:
+    def __init__(self, start=0, end=None, step=1, *, resettable=False):
+        if end is None:
+            end, start = start, 0
+        self._start = start
+        self._end = end
+        self._step = step
+        self._resettable = resettable
+
+    def __iter__(self):
+        return self
+
+    def __next__(self):
+        if self._start >= self._end:
+            if self._resettable:
+                self._start = 0
+            raise StopIteration
+        value = self._start
+        self._start += self._step
+        return value

python-iterators-iterables/sequence_iter.py

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+class SequenceIterator:
+    def __init__(self, sequence):
+        self._sequence = sequence
+        self._index = 0
+
+    def __iter__(self):
+        return self
+
+    def __next__(self):
+        if self._index < len(self._sequence):
+            item = self._sequence[self._index]
+            self._index += 1
+            return item
+        else:
+            raise StopIteration
+
+
+class Iterable:
+    def __init__(self, sequence):
+        self.sequence = sequence
+
+    def __iter__(self):
+        return SequenceIterator(self.sequence)

python-iterators-iterables/square_gen.py

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+def square_generator(sequence):
+    for item in sequence:
+        yield item**2

python-iterators-iterables/square_iter.py

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+class SquareIterator:
+    def __init__(self, sequence):
+        self._sequence = sequence
+        self._index = 0
+
+    def __iter__(self):
+        return self
+
+    def __next__(self):
+        if self._index < len(self._sequence):
+            square = self._sequence[self._index] ** 2
+            self._index += 1
+            return square
+        else:
+            raise StopIteration

python-iterators-iterables/square_list.py

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+def square_list(sequence):
+    squares = []
+    for item in sequence:
+        squares.append(item**2)
+    return squares
+
+
+# def square_list(sequence):
+#     return [item**2 for item in sequence]