Python/maths/decimal_to_fraction.py

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def decimal_to_fraction(decimal: float | str) -> tuple[int, int]:
"""
Return a decimal number in its simplest fraction form
>>> decimal_to_fraction(2)
(2, 1)
>>> decimal_to_fraction(89.)
(89, 1)
>>> decimal_to_fraction("67")
(67, 1)
>>> decimal_to_fraction("45.0")
(45, 1)
>>> decimal_to_fraction(1.5)
(3, 2)
>>> decimal_to_fraction("6.25")
(25, 4)
>>> decimal_to_fraction("78td")
Traceback (most recent call last):
ValueError: Please enter a valid number
"""
try:
decimal = float(decimal)
except ValueError:
raise ValueError("Please enter a valid number")
fractional_part = decimal - int(decimal)
if fractional_part == 0:
return int(decimal), 1
else:
number_of_frac_digits = len(str(decimal).split(".")[1])
numerator = int(decimal * (10**number_of_frac_digits))
denominator = 10**number_of_frac_digits
divisor, dividend = denominator, numerator
while True:
remainder = dividend % divisor
if remainder == 0:
break
dividend, divisor = divisor, remainder
numerator, denominator = numerator / divisor, denominator / divisor
return int(numerator), int(denominator)
if __name__ == "__main__":
print(f"{decimal_to_fraction(2) = }")
print(f"{decimal_to_fraction(89.0) = }")
print(f"{decimal_to_fraction('67') = }")
print(f"{decimal_to_fraction('45.0') = }")
print(f"{decimal_to_fraction(1.5) = }")
print(f"{decimal_to_fraction('6.25') = }")
print(f"{decimal_to_fraction('78td') = }")