Conversion from binary to octal in python

Python program for Conversion from binary to octal. Here more solutions.

#  Python 3 program for
#  Convert Binary number into Octal number
class Convert :
    # Convert decimal number into octal
    def  octal(self, number) :
        result = 0
        multiplier = 1
        remainder = 0
        while (number != 0) :
            remainder = number % 8
            result = (remainder * multiplier) + result
            multiplier *= 10
            number = int(number / 8)
        return result
    def binaryToOctal(self, num) :
        if (len(num) == 0) :
            # When empty binary number
            return
        # Some useful variable
        flag = False
        decimalNo = 0
        counter = 0
        index = len(num) - 1
        # We Assume that given binary number is valid
        # Here - indicates negative binary number
        # First convert binary to decimal
        # Example = 10111 => 23
        while (index >= 0) :
            if (num[index] == '1') :
                decimalNo += (1 << counter)
            elif(num[index] != '0') :
                    if (index == 0 and num[index] == '-') :
                        # When get negative number
                        flag = True
                    else :
                        # Not a valid binary number
                        return
            counter += 1
            index -= 1
        # When given number is 
        output = self.octal(decimalNo)
        if (flag == True) :
            output = -output
        # Display given number
        print("Binary :",num," Octal :",output)


if __name__=="__main__":
    task = Convert()
    # Test Case
    task.binaryToOctal("1111")
    task.binaryToOctal("10111")
    task.binaryToOctal("101011")
    task.binaryToOctal("11011")
    task.binaryToOctal("-1000110")

Output

Binary : 1111  Octal : 17
Binary : 10111  Octal : 27
Binary : 101011  Octal : 53
Binary : 11011  Octal : 33
Binary : -1000110  Octal : -106