Python binary converter.

[Bobie8]

Hello trying to learn python and decided to write a small program that will convert 8 digit binary numbers to base 10. Now I know python has a built in function for this and there are a few other ways of doing this but Im trying to figure out what is going wrong in my solution.

output = 0
data = input("Enter a binary number:")
print (len(data))
print (type(data))
if len(data) < 8 or data.isalpha(): #need to add check for digits that are not 0 or 1
    print("A binary number must be 8 digits long and contain only 1's and 0's")
    
for digit in data:
    if digit == "1":
        if data.index(digit) == (0):
            output = output+128
        elif data.index(digit) == (1):
            output = output+64
        elif data.index(digit) == (2):
            output = output+32
        elif data.index(digit) == (3):
            output = output+16
        elif data.index(digit) == (4):
            output = output+8
        elif data.index(digit) == (5):
            output = output+4
        elif data.index(digit) == (6):
            output = output+2
        elif data.index(digit) == (7):
            output = output+1


print(output)

What I'm trying to achieve is the program goes through the string and checks for a 1 if it finds a 1 then it will add the corresponding value for that index to the total. My code just works if there is only a single 1 in the string but as soon as the is more than 1 it will add 128 for every 1.

Anyone able to point out where I'm going wrong?

 

[PaulStat]

It's because index gives the first index of the argument so if you have "11000000", the index will always be 0 so give an output of 256 instead of 192 for example

So your for loop should actually be something like

for digit in  range(0, len(data)):
    if data[digit] == "1":
        if digit == 0:
            output = output+128
        elif digit == 1:
            output = output+64
        elif digit == (2):
            output = output+32
        elif digit == (3):
            output = output+16
        elif digit == (4):
            output = output+8
        elif digit == (5):
            output = output+4
        elif digit == (6):
            output = output+2
        elif digit == (7):
            output = output+1

 

[Bobie8]

Ok thanks for the help