all Python 3Exceptionsexception

RuntimeError

built-in exceptions

A generic runtime error that doesn't fit other categories.

Syntax

raise RuntimeError

Using it as a catch-all is a trap: RecursionError and NotImplementedError are subclasses, so except RuntimeError swallows them too. It also arrives from very concrete situations — dictionary changed size during iteration when you mutate a dict inside a loop over it, or generator raised StopIteration. Raise your own only when no more specific exception class fits.

Examples

try:
    raise RuntimeError
except RuntimeError as e:
    print(type(e).__name__)   # → RuntimeError

See also

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