raise — Advanced Examples

Throws an exception manually

EasyIntermediateAdvancedExpert

Raise in context managers and generators

Exception interaction with advanced patterns.

python
from contextlib import contextmanager

@contextmanager
def must_not_fail(label):
    try:
        yield
    except Exception as e:
        raise RuntimeError(f"{label} failed") from e

try:
    with must_not_fail("data load"):
        raise ValueError("bad data")
except RuntimeError as e:
    print(f"Caught: {e}")
    print(f"Original: {e.__cause__}")

# Raise in a generator
def safe_divide_gen(pairs):
    for a, b in pairs:
        try:
            yield a / b
        except ZeroDivisionError:
            yield float("inf")

results = list(safe_divide_gen([(10, 2), (5, 0), (9, 3)]))
print(results)
Expected Output
Caught: data load failed
Original: bad data
[5.0, inf, 3.0]

Exceptions raised inside context managers and generators interact with their surrounding protocol (__exit__ and throw()).

Want to try these examples interactively?

Open Advanced Playground
← Intermediate ExamplesExpert Examples →