StopIteration — Intermediate Examples

Raised by next() to signal that an iterator is exhausted

EasyIntermediateAdvancedExpert

Exception chaining with StopIteration

Using 'raise from' to chain StopIteration with other exceptions.

python
# Exception chaining
class ApplicationError(Exception):
    pass

try:
    try:
        it = iter([]); next(it)
    except StopIteration as original:
        raise ApplicationError("Operation failed") from original
except ApplicationError as e:
    print(f"App error: {e}")
    print(f"Caused by: {e.__cause__}")

Exception chaining preserves the original error context, making debugging easier.

StopIteration in context managers

Handling StopIteration within context managers.

python
# Using context managers with exception handling
class SafeOperation:
    def __enter__(self):
        print("Starting operation")
        return self

    def __exit__(self, exc_type, exc_val, exc_tb):
        if exc_type is StopIteration:
            print(f"Handled {exc_type.__name__}: {exc_val}")
            return True  # Suppress the exception
        return False

with SafeOperation():
    it = iter([]); next(it)
print("Continued after handled exception")

Context managers can catch and handle exceptions in their __exit__ method.

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