How to convert binary elements of a cell into decimal number

Hello, I have a cell of binary elements with 0's and 1's of size 1*1624..now i have to convert every 8 binary elements from 1624 elements into a decimal number and store in an array..so,the final output must be of size 1*203(each element in 203 must consists of the value of each 8 binary elements...can anyone help me please

[Stephen23]

Original question:

https://www.mathworks.com/matlabcentral/answers/323562-how-to-get-row-vector-for-a-folder-of-text-files

Answer 1

[Jan]

In  = {0,1,1,1,0,0,1,0, 1,0,1,1,0,1,0,1};   % 1 x 16
M   = reshape([In{:}], 8, []);
Out = [128, 64, 32, 16, 8, 4, 2, 1] * M;

[Guillaume]

Ah, yes, even simpler with matrix multiplication.

[Jyothi Alugolu]

one more question...i have 4 binary(0's and 1's ) cells of sizes 1*1120,1*1344,1*868,1*812...now, i need to split or do partition on each cell i.e the entire cell must divide into each 8 bits,so that output of cell's must be of size first cell:8*140, second cell: 8*168, third cell must be 8*109..109 because 108 columns contains 108*8=864 binary numbers,and there will remain 4 binary number's..these 4 binary numbers must store in another column i.e 109th column..so third cell size must be 8*109..and fourth cell size must be 8*102 ...and finally i need to calculate decimal value for each splitted file..in case of 3rd cell,the 109th column contains 4 elements,these 4 elements also must convert into decimal value...final decimal vector must contain size of 1*140,1*168,1*109,1*102....

Answer 2

[Thibaut Jacqmin]

Here I create a cell of size 16 (and not 1624) as an example

a = {1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 1, 0, 0, 1, 1, 1};

Reshape the cell in a 8xN cell (N = 203 in your case)

a = reshape(a, [8, length(a)/8]);

Convert each column of 8 binary in a decimal number and store it in res

res = [];
for i = 1:size(a, 2)
   res(end+1) = bi2de([a{:, i}]);
end

[Jyothi Alugolu]

i am getting wrong results when i calculated manually..after reshaping a cell again why you are assigning to a variable?

[Jyothi Alugolu]

sorry what i mean is..you have reshaped the cell 'a' and again assigned to 'a' variable??? i dont understand...and also in for loop i have to write 203 instead of 2(bcz 1624/8=203)..when i written 203,i am not getting entire output...please help me

[Thibaut Jacqmin]

You can assign it to a new variable if you want/need. I did that because it uses less memory than creating a new variable. You can name it 'b' if you want. Then you will have to replace 'a' by 'b' eveywhere in the following code lines.

[Thibaut Jacqmin]

You don't have to write 203 in the for loop. Indeed size(a, 2) already equals to 203 after reshaping.

[Jyothi Alugolu]

if suppose, if the binary text file with 0's and 1's is of size 1*1624.now i need to reshape this 1624 binary elements into 16 *N (N=1624),then i will have 16*101 cell and 8 bits will be remaining..these 8 bits must store in another cell..so,finally the output must be 16*102..since 101 columns will have each 16 bit values and 102th column must have remaining 8 bits..now i need to convert these 102 column values into decimal values...the final output must be a row vector of size 1*102..how to do this?

Answer 3

[Alexandra Harkai]

Considering it's a 1*1624 numeric array you have in the cell A, you can utilise bin2dec to do it after converting the numeric values to a string representation with num2str:

{bin2dec(num2str(reshape(A{:}, 8, size(A{:},2)/8)'))}'

[Jyothi Alugolu]

can you explain it properly??

Answer 4

[Guillaume]

Question: Why is the data in a cell array when a normal matrix would work just as well and make the code simpler? That is instead of:

binaryvector = {1, 0, 0, 1, 0, 1, 1, ...};

Have

binaryvector = [1, 0, 0, 1, 0, 1, 1, ...];

You also haven't told us which bit (1st or 8th) is the LSB and MSB.

Anyway, another way, probably the fastest, to convert your array:

binaryvector = num2cell(randi([0 1], 1, 1624));  %create a cell array of random bits for demonstration only. Use your own data

binaryvector = cell2mat(binaryvector);  %convert cell array into matrix as cell array is pointless and just makes manipulating the bits harder
%in version R2016b ONLY:
decimalvector = sum(2.^(7:-1:0)' .* reshape(binaryvector, 8, []));
%in version prior to R2016b:
decimalvector = sum(bsxfun(@times, 2.^(7:-1:0)', reshape(binaryvector, 8, [])));

The above assumes the LSB is the 8th bit, if it's the first bit replace the 7:-1:0 by 0:7

[Jan]

You can omit the sum(), when you use a matrix multiplication.