将数字转换为具有固定长度的二进制数

def decimal_to_binary(num, length):
    binary = ''
    for i in range(length):
        binary = str(num & 1) + binary
        num >>= 1
    return binary

def decimal_to_binary(num, length):
    binary = bin(num)[2:]
    binary = binary.zfill(length)
    return binary