How to read and manipulate binary numbers?

Hi,

Im currently working with binary numbers within matlab, however they are read into my code as single numbers eg. 10001011 etc. However, I need to break up the code so I can examine different parts. Is there a way of breaking a single number into a 2 or more cell array.

For Example, starting with 10001011

 broken up to a 1x4 array of [10 00 10 11]

Id appreciate any help, Thanks! Mark

[Chad Gilbert]

I'm having trouble imagining why you would need to do this. Are you sure there's no place in your code earlier on (say, when you're reading these data) when it makes more sense to format these? E.g. "a = fscanf(fid,'%c%c',2);" or something of the sort?

[Mark]

Its involved in the crossover over section of a genetic algorithm where the binary coding is used to represent an individual chromosome and the splicing of two chromosomes can be used to create new 'children'

Answer 1

[Chad Gilbert]

Strictly speaking, this should do it:

   >> a = [1 0 0 0 1 0 1 1];
   >> b = 10*a(1:2:end) + a(2:2:end)

   b =

       10     0    10    11

Or, if you've got a string of 1's and 0's:

   >> a = '10001011';
   >> arrayfun(@(i)a(i:i+1),1:2:length(a),'uniformoutput',false)
   ans = 

       '10'    '00'    '01'    '11'

Note: both of these solutions assume that you have an even number of digits. They'll croak if you pass in an odd number of digits.

[Mark]

The first idea nearly works, though as you can see you lose a digit in the second cell because in Matlabs mind its a nil value so 00 isn't required where since im using binary it kinda does...

[Muthu Annamalai]

@Chad croaking is fixed (untested!) if you modify the line,

arrayfun(@(i)a(i:min(i+1,end)),1:2:length(a),'uniformoutput',false)

[Chad Gilbert]

@Mark The first idea handles and outputs actual numeric values. Your interest in the "first digit of the second cell" makes me think you're actually interested in strings. In which case, the second answer might be more appropriate.

@Muthu - nice! A quick test confirms that your fix works.

Answer 2

[Kevin]

a = [1 0 0 0 1 0 1 1]

for p=1:(size(a)-1)
  b = [b strcat(num2str(a(p)),num2str(a(p+1)))]
end

That should feed zeros as double zeros

KD

Answer 3

[Mark]

Cheers guys