# Bit xor of two binary strings and conversion into decimal

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lilly lord on 19 Jun 2020
Commented: lilly lord on 21 Jun 2020
Hi, I have two large binary strings (e.g 256 bits each), then how to perform bit Xor operation and then convert the answer into decimal number.
str1='11010011110111110000110110111111';
str2='00011111001101011010001111100001';
str3=bitxor(str1,str2);
%%getting error in str3

James Tursa on 19 Jun 2020
To be clear, you want a decimal number that can't be represented in any native integer type? A 256-bit integer? Or did you just mean you want the result as a vector of 0's and 1's but not character?
lilly lord on 19 Jun 2020
I want to divide the string into 8 bit chunks and need decimal value between 0-255.
James Tursa on 19 Jun 2020

James Tursa on 19 Jun 2020
Edited: James Tursa on 19 Jun 2020
The xor part as a logical vector result
result = str1 ~= str2;
Or if you wanted it as char:
str3 = char((str1 ~= str2) + '0');
For 8-bit chunks turned into decimal numbers:
result = 2.^(7:-1:0) * reshape(str1 ~= str2,8,[]);

lilly lord on 19 Jun 2020
Is there a way in which i can use the output string only.
James Tursa on 20 Jun 2020
So, can you tell me what exactly you have as inputs (size and class) and what exactly you want as an output (size and class)?
lilly lord on 21 Jun 2020
I was workig on random bits generating and try different methods. Your both answer solved my problem . Thanks once again
%%%%Test random bit generation
I2=imresize(I,[128 128]);figure;imshow(I2)
R=I2(:,:,1);G=I2(:,:,2);
R_r=reshape(R,1,[]);
G_row=reshape(G,1,[]);
G_bits=dec2bin(G_row,8);
R_bits=dec2bin(R_r,8);
Red_bits=R_bits(:)';
Gr_bits=G_bits(:)';
%Extract last four bits
R_newbit=R_bits(:,5:end);
R_finabit=R_newbit(:)';
G_newbit=G_bits(:,5:end);
G_finalbit=G_newbit(:)';
s1=length(R_finabit);%check the size of both strings
s2=length(G_finalbit);
%bit Xor g final bit and r final bit and give the answer in dec number
result = 2.^(7:-1:0) * reshape(R_finabit ~= G_finalbit,8,[]);

David Hill on 19 Jun 2020
Use java BigInteger
import java.math.*;
a=BigInteger(str1,2);
b=BigInteger(str2,2);
c=a.xor(b);%c will be the decimal BigInteger

#### 1 Comment

lilly lord on 19 Jun 2020
It gives a big number Sir