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1210559deb
* updating DIRECTORY.md
* refactor(decimal-to-binary): Consolidate implementations
* updating DIRECTORY.md
* refactor(decimal-to-binary): Rename main and helper recursive
---------
Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>
110 lines
3.3 KiB
Python
110 lines
3.3 KiB
Python
"""Convert a Decimal Number to a Binary Number."""
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def decimal_to_binary_iterative(num: int) -> str:
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"""
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Convert an Integer Decimal Number to a Binary Number as str.
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>>> decimal_to_binary_iterative(0)
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'0b0'
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>>> decimal_to_binary_iterative(2)
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'0b10'
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>>> decimal_to_binary_iterative(7)
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'0b111'
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>>> decimal_to_binary_iterative(35)
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'0b100011'
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>>> # negatives work too
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>>> decimal_to_binary_iterative(-2)
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'-0b10'
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>>> # other floats will error
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>>> decimal_to_binary_iterative(16.16) # doctest: +ELLIPSIS
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Traceback (most recent call last):
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...
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TypeError: 'float' object cannot be interpreted as an integer
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>>> # strings will error as well
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>>> decimal_to_binary_iterative('0xfffff') # doctest: +ELLIPSIS
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Traceback (most recent call last):
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...
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TypeError: 'str' object cannot be interpreted as an integer
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"""
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if isinstance(num, float):
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raise TypeError("'float' object cannot be interpreted as an integer")
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if isinstance(num, str):
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raise TypeError("'str' object cannot be interpreted as an integer")
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if num == 0:
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return "0b0"
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negative = False
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if num < 0:
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negative = True
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num = -num
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binary: list[int] = []
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while num > 0:
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binary.insert(0, num % 2)
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num >>= 1
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if negative:
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return "-0b" + "".join(str(e) for e in binary)
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return "0b" + "".join(str(e) for e in binary)
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def decimal_to_binary_recursive_helper(decimal: int) -> str:
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"""
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Take a positive integer value and return its binary equivalent.
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>>> decimal_to_binary_recursive_helper(1000)
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'1111101000'
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>>> decimal_to_binary_recursive_helper("72")
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'1001000'
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>>> decimal_to_binary_recursive_helper("number")
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Traceback (most recent call last):
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...
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ValueError: invalid literal for int() with base 10: 'number'
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"""
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decimal = int(decimal)
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if decimal in (0, 1): # Exit cases for the recursion
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return str(decimal)
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div, mod = divmod(decimal, 2)
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return decimal_to_binary_recursive_helper(div) + str(mod)
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def decimal_to_binary_recursive(number: str) -> str:
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"""
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Take an integer value and raise ValueError for wrong inputs,
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call the function above and return the output with prefix "0b" & "-0b"
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for positive and negative integers respectively.
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>>> decimal_to_binary_recursive(0)
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'0b0'
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>>> decimal_to_binary_recursive(40)
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'0b101000'
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>>> decimal_to_binary_recursive(-40)
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'-0b101000'
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>>> decimal_to_binary_recursive(40.8)
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Traceback (most recent call last):
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...
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ValueError: Input value is not an integer
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>>> decimal_to_binary_recursive("forty")
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Traceback (most recent call last):
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...
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ValueError: Input value is not an integer
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"""
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number = str(number).strip()
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if not number:
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raise ValueError("No input value was provided")
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negative = "-" if number.startswith("-") else ""
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number = number.lstrip("-")
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if not number.isnumeric():
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raise ValueError("Input value is not an integer")
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return f"{negative}0b{decimal_to_binary_recursive_helper(int(number))}"
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if __name__ == "__main__":
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import doctest
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doctest.testmod()
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print(decimal_to_binary_recursive(input("Input a decimal number: ")))
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