Parse Boolean Strings

Convert a messy boolean string into a Python bool, handling True/False/Yes/No/1/0 case-insensitively.

strings boolean parsing conditional

Write a function `parse_bool(value: str) -> bool` that converts a string representation of a boolean into a Python `bool`. The function should accept the following inputs (case-insensitive): "true", "false", "yes", "no", "1", "0". For any other input, raise a `ValueError` with the message `"Invalid boolean string: {value}"` (replace `{value}` with the actual input). The function must treat "true", "yes", "1" as `True`, and "false", "no", "0" as `False`.

Constraints

Input is a string. Length of string is between 1 and 20. The function must be case-insensitive. The function must raise `ValueError` for invalid inputs. Allowed time complexity: O(n), where n is the length of the string.

Example

>>> parse_bool("True")
True
>>> parse_bool("false")
False
>>> parse_bool("YES")
True
>>> parse_bool("0")
False
>>> try: parse_bool("maybe")
... except ValueError as e: print(e)
Invalid boolean string: maybe

10 points ~10 min

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Hints

Convert the input string to lowercase to handle case-insensitivity.

Use a dictionary or set to map the accepted true and false values.

Remember to raise ValueError with the exact message format when the input is not recognized.

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