MATLAB: Find index of cell array

cell arrays

Hello all, suppose i have cell array 6×1 which contains abstracts of articles, so each row of the cell contains 800 character. if i wan to find the position of str='b e h i n d' from that cell array,only b will be generated, so what is wrong my code. the cell arrays data is in the attachment or myabs.mat

load ('myabs.mat');
mydata=X;
[row,column]=size(mydata);
distance=zeros(row,column);
str='behind using a cover';
j=1;
for n=1:row
          gec=char(mydata{n});
          %for j=1:length(str)

          for m=1:800
          while j<length(str)
          %for j=1:length(str)
          if (gec(m)==str(j))
          indexx(j)=m;
          distance(n,m)=indexx(j);
          end
          break;
j=j+1;
         end
    end
end

Best Answer

There might be simpler ways to achieve this task, but this seems to work:

str = 'behind';
load myabs
for m = 1:numel(X)
    Y = bsxfun(@eq,X{m}(:),str);
    for n = 2:size(Y,2)
        Y(:,n) = Y(:,n) & cumsum(Y(:,n-1))>0;
    end
    Z = find(any(diff([false(size(str));cumsum(Y)>0],1),2))
end

and when run it prints this in the command window:

Related Solutions

MATLAB: Find index of cells containing a string

The problem is not with your search expression, which works fine, but the fact that the exact string 'CERT' is not present in your cell array.

>>double(s{7, 2})
ans = 
    67    69    82    84   160   160

Notice the two 160 characters at the end of the string ([67 69 82 84] are the character codes for CERT). In my version of matlab, char(160) renders as a blank space (depending on your locale it may render differently).

In fact, if you look through your whole matrix, there are a fair number of strings where the character 160 appears. It seems that it's the only character outside the ASCII range, as well:

cellfun(@(s) double(s(s>127)), text, 'UniformOutput', false) %show characters outside ASCII

Probably, the simplest thing is to remove these characters (which I assume you did not want in the first place):

text = cellfun(@(s) s(s<128), text, 'UniformOutput', false);

Your search expression will then work:

>>[row, col] = find(cellfun(@(s) strcmp(s, 'CERT'), text))
row =
   7
col =
   2

MATLAB: When the secret text contain pair(doubke) character like ‘dd’,mm’ ,’ll’, the Y vector reswtores as Nan

I think you just need to preallocate the cell array, and then index into it inside the loop:

str = 'steganography is the art and science of covered or hidden';
X = {'as modeling of changes in backbone conformation still lacks a computationally efficient solution, we developed a discretisation of the conformational states accessible to the protein backbone similar to the successful rotamer approach in side chains. The BriX fragment database, consisting of fragments from 4 to 14 residues long, was realized through identification of recurrent backbone fragments from a non-redundant set of high-resolution protein structures. brix contains an alphabet of more than 1,000 frequently observed conformations per peptide length for 6 different variation levels. analysis of the performance of brix revealed an average structural coverage of protein structures of more than 99 percent within a root mean square distance of 1 angstrom. globally, we are able to reconstruct protein structures with an average accuracy of 0.48 angstrom rmsd. as expected, regular structures are well covered, but, interestingly, many loop regions that appear irregular at first glance are also found to form a recurrent structural motif, albeit with lower frequency of occurrence than regular secondary  structures. larger loop regions could be completely reconstructed from smaller recurrent elements, between 4 and 8 residues long. finally, we observed that a significant amount of short sequences tend to display strong structural ambiguity between alpha helix and extended conformations. when the sequence length increases, this so-called sequence plasticity is no longer observed, illustrating the context dependency of polypeptide structures.'};
Z = cell(size(X));
for m = 1:numel(X)
    Y = bsxfun(@eq,X{m}(:),str);
    for n = 2:size(Y,2)
        Y(:,n) = Y(:,n) & cumsum(Y(:,n-1))>0;
    end
    Z{m} = find(any(diff([false(size(str));cumsum(Y)>0],1),2));
end

EDIT: improved code that takes into account repeated characters (see the comments):

    m = 1;
    str = 'communication';
    X = {'computers memory unites collection demarcation'};
    Y = bsxfun(@eq,X{m}(:),str);
    for n = 2:size(Y,2)
        Y(:,n) = Y(:,n) & [false;cumsum(Y(1:end-1,n-1))>0];
    end
    find(any(Y & cumsum(Y)<2, 2))

Best Answer

Related Solutions

MATLAB: Find index of cells containing a string

MATLAB: When the secret text contain pair(doubke) character like ‘dd’,mm’ ,’ll’, the Y vector reswtores as Nan

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