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In this source code example, we will write a code to convert a decimal number to its binary equivalent in Python.

Python - Convert Decimal to Binary Example

# Function to convert a Decimal Number to a Binary Number.

def decimal_to_binary(num: int) -> str:

    if isinstance(num, float):
        raise TypeError("'float' object cannot be interpreted as an integer")
    if isinstance(num, str):
        raise TypeError("'str' object cannot be interpreted as an integer")

    if num == 0:
        return "0b0"

    negative = False

    if num < 0:
        negative = True
        num = -num

    binary: list[int] = []
    while num > 0:
        binary.insert(0, num % 2)
        num >>= 1

    if negative:
        return "-0b" + "".join(str(e) for e in binary)

    return "0b" + "".join(str(e) for e in binary)


if __name__ == "__main__":

    # Convert an Integer Decimal Number to a Binary Number as str.
    print(decimal_to_binary(0))
    
    print(decimal_to_binary(2))
    
    print(decimal_to_binary(7))
    
    print(decimal_to_binary(35))
    
    # negatives work too
    print(decimal_to_binary(-2))
    '-0b10'

Output: