Integer array to binary array

Question

I have an integer array:

a=[3,4,5,6,7];

I want to convert it to a binary array with four bits each. For the above integer array I would like get the following binary array:

abinary=[0,0,1,1, 0,1,0,0, 0,1,0,1, 0,1,1,0, 0,1,1,1];

Is there any fast way to do it?

Solution 1

Matlab has the built-in function DEC2BIN. It creates a character array, but it's easy to turn that back to numbers.

%# create binary string - the 4 forces at least 4 bits
bstr = dec2bin([3,4,5,6,7],4)

%# convert back to numbers (reshape so that zeros are preserved)
out = str2num(reshape(bstr',[],1))'

Solution 2

You can use the BITGET function:

abinary = [bitget(a,4); ...  %# Get bit 4 for each number
           bitget(a,3); ...  %# Get bit 3 for each number
           bitget(a,2); ...  %# Get bit 2 for each number
           bitget(a,1)];     %# Get bit 1 for each number
abinary = abinary(:)';      %'# Make it a 1-by-20 array

Solution 3

A late answer I know, but MATLAB has a function to do this directly de2bi

out = de2bi([3,4,5,6,7], 4, 'left-msb');

Comments

[Jonas]

I didn't even know about bitget. I'd make a loop to construct abinary, though, in order to be able to use this for any number of bits. +1 anyway.

[nekomatic]

de2bi is only available in the Communications System Toolbox. A similar function decimalToBinaryVector exists in the Data Acquisition Toolbox.

[Shreta Ghimire]

Do you have something similar to python?