how can I convert binary to decimal without using bin method

user_15171886 0
Viewed 68

whenever I run my code I get a TypeError saying "not all arguements converted during string formatting" and I tried using str() around what didn't get converted but I ran into more errors.

Here is my code:

def decimalToBinary(num):

bits = " "

while(num > 0):
   
    bits = str(num%2) + bits
    num = num//2
    
    return bits

def binaryToDecimal(bits):

    deciNum = 0
    powers = 0

    for i in reversed(bits):
    
        deciNum = 2 **powers** (bits % 10)
        bits /=  10
        powers += 1
    
        return deciNum

#program tester
for i in range(135, 146):
x = decimalToBinary(i)
deciNum = binaryToDecimal(x)
print(str(decimal))+ ' is '+ ' in Binary.'

I get this TypeError on the line that says "deciNum = 2 ** powers ** (bits%10)

decimal binary type-conversion python
2 Answers

Try this:

def binaryToDecimal(b_num: str) -> int:
    d_num = 0
    for i in range(len(b_num)):
        digit = b_num.pop()
        if digit == '1':
            d_num = d_num + 2**i
    return d_num

Note that b_num is a string, not an int. So you need to use this function in this way binaryToDecimal('101') (and not in this way binaryToDecimal(101)).

user_52961060

To answer the title of the post and to keep the types consistent with your program:

import math

def binaryToDecimal(bits):

    # Initialize integer for number.
    num = 0

    # For each bit, multiply by power of 2 corresponding to its position.
    #  Then, add that power of 2 to the total counter.
    for i in range(len(bits)):
        num += int(bits[i]) * (2 ** (len(bits)-i-1))

    # Return integer type.
    return str(num)

def decimalToBinary(num):

    # Determine how many bits represent the decimal number.
    num_of_bits = int(math.log(num, 2)) + 1

    bits = ''

    # Shift the number over 1 more place to the right in each iteration.
    #  Then test the sign of the bit with AND.
    for i in reversed(range(num_of_bits)):
        bits += str(int(1&(num>>i)))
    
    return bits


for i in range(135, 146):
    x = decimalToBinary(i)
    deciNum = binaryToDecimal(x)
    print(str(deciNum)+ ' is '+ str(x)+' in Binary.')
user_152794600
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