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50 lines
1.5 KiB
Python
50 lines
1.5 KiB
Python
hex_table = {hex(i)[2:]: i for i in range(16)} # Use [:2] to strip off the leading '0x'
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def hex_to_decimal(hex_string: str) -> int:
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"""
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Convert a hexadecimal value to its decimal equivalent
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#https://www.programiz.com/python-programming/methods/built-in/hex
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>>> hex_to_decimal("a")
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10
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>>> hex_to_decimal("12f")
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303
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>>> hex_to_decimal(" 12f ")
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303
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>>> hex_to_decimal("FfFf")
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65535
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>>> hex_to_decimal("-Ff")
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-255
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>>> hex_to_decimal("F-f")
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Traceback (most recent call last):
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...
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ValueError: Non-hexadecimal value was passed to the function
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>>> hex_to_decimal("")
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Traceback (most recent call last):
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...
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ValueError: Empty string was passed to the function
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>>> hex_to_decimal("12m")
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Traceback (most recent call last):
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...
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ValueError: Non-hexadecimal value was passed to the function
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"""
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hex_string = hex_string.strip().lower()
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if not hex_string:
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raise ValueError("Empty string was passed to the function")
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is_negative = hex_string[0] == "-"
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if is_negative:
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hex_string = hex_string[1:]
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if not all(char in hex_table for char in hex_string):
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raise ValueError("Non-hexadecimal value was passed to the function")
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decimal_number = 0
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for char in hex_string:
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decimal_number = 16 * decimal_number + hex_table[char]
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return -decimal_number if is_negative else decimal_number
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if __name__ == "__main__":
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from doctest import testmod
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testmod()
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