# convert binary to charaacter

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Abirami am 15 Aug. 2014
Bearbeitet: Azzi Abdelmalek am 16 Aug. 2014
hello,
i have a binary sequnce 10110001. and i want to encode based on the following rule
A=00
C=01
T=10
G=11
and the answer i get will be something like TGAC.
i want to do it for a 256*256 matrix each element having an 8bit binary sequence..i have generated the matrix by using the following code
>>disp(a);
>>imshow(a);
>>for i=1:1:256
>>for j=1:1:256
>>b{i,j,1} = dec2bin(a(i,j),8);
>>end
>>end
>>disp(b)
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### Akzeptierte Antwort

Guillaume am 15 Aug. 2014
Bearbeitet: Guillaume am 15 Aug. 2014
Personally, if I was going to do that encoding several times, I would precompute the encoding for all the possible values (there's only 256 of them) and use the precomputed array to do the conversion using basic matrix indexing. Thus the expensive calculation you only do once and the conversion from matrix to sequence is a simple array lookup, thus very fast.
You can precompute the array many different ways. A fairly simple one:
sequences = 'ACTG'; %in the order 0,1,2,3
seqbase4 = dec2base(0:255, 4); %convert integer 0-255 to a sequence of 0123
int2sequence = num2cell(sequences(seqbase4-'0'+1), 2); %represents integer 0-255 as cell array of ACTG
Whenever you want to convert a matrix, it's then as simple as:
s=int2sequence(a+1); %+1 because matlab indexes start at 1
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Andrei Bobrov am 15 Aug. 2014
+1

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### Weitere Antworten (1)

Azzi Abdelmalek am 15 Aug. 2014
Bearbeitet: Azzi Abdelmalek am 15 Aug. 2014
str='10110001'
c='ACTG'
b={'00','01','10','11'}
ss=regexp(str,'.{2}','match')
[ii,jj]=ismember(ss,b)
out=c(jj)
%or
str='10110001'
c='ACTG'
out=c(bin2dec(regexp(str,'.{2}','match'))+1)
%or
str='10110001'
c='ACTG'
out=c(bin2dec(reshape(str,2,[])')+1)
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Guillaume am 16 Aug. 2014
Have you tried what I wrote in my answer? Does it not work for you? If it doesn't, which step is the problem?
Azzi Abdelmalek am 16 Aug. 2014
Bearbeitet: Azzi Abdelmalek am 16 Aug. 2014
[n,m]=size(a);
b=arrayfun(@(x) dec2bin(x,8),a,'un',0);
c='ACTG';
out=cellfun(@(x) c(bin2dec(reshape(x,2,[])')+1),b,'un',0)
Note that Guillaume's method is faster, and do not need to convert your matrix from decimal to binary

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