Comprehensions & generators
List/dict/set comprehensions, generator expressions, and lazy iteration.
How to Close a Generator and Handle GeneratorExit in Python
This Python code demonstrates how to explicitly close a generator using the close() method and handle the GeneratorExit exception through a finally block to run cleanup logic.
def countdown(n):
try:
while n > 0:
yield n
n -= 1
finally:
print(f"Generator closed after countdown completed")
if __name__ == "__main__":
gen = countdown(5)
print(next(gen))
print(next(gen))
gen.close()
print("Generator closed explicitly")How to Throw an Exception into a Python Generator
This code demonstrates how to use the .throw() method on a generator to inject an exception at its current yield point and let it recover gracefully.
def demo_throw_into_generator():
"""Demonstrate throwing an exception into a running generator."""
def counter():
"""Generator that counts until interrupted."""
try:
i = 0
while True:
yield i
i += 1
except ValueError as e:
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Comprehensions & generators — Python code examples
What you will find here
This page collects comprehensions & generators snippets — short, copy-ready Python you can paste into our free online IDE and run without installing anything. Each sample includes a plain-English explanation and the full source code.
Samples vs tutorials and challenges
Samples are quick reference — one concept per page. For step-by-step teaching, use our Python tutorials. To test yourself, try quizzes or coding challenges. Clean up style with the Python formatter.