check cell's contents and convert to matrix

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ben harper
ben harper el 27 de Mayo de 2011
i have a data cell as below:
when i use
param1=cell2mat(data(:,2));
param2=cell2mat(data(:,6));
param3=cell2mat(data(:,7));
it gives error:
??? Error using ==> cell2mat at 47
All contents of the input cell array must be of the same data type.
So, every time there is a string in cell matrix MATLAB Gives error and i correct it by hand.
Is there a method that makes this:
param1=cell2mat(data(:,2));
If one of the members of cell is string, than assign that to value of zero??
Thank you very much
  5 comentarios
Walter Roberson
Walter Roberson el 27 de Mayo de 2011
For me it appears in the section underneath "click to add tags". I had to temporarily allow tinypic.com but I did not have to allow any of the other sites the page wants (photobucket, gigya, z25, or others.)
http://oi56.tinypic.com/33ylu1z.jpg
should be the direct link.
Jan
Jan el 28 de Mayo de 2011
Thanks Walter! Following your link I can see the table without any tricks. This is another argument to host pictures on a Mathworks server.

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Respuesta aceptada

Laura Proctor
Laura Proctor el 27 de Mayo de 2011
The following code will find any strings in your input data and replace them with NaN values then converts the cell array to a matrix. You can use any value to replace the strings... it's just that NaN may be appropriate for this case.
c = { 1; 2 ; 3 ; 'aa ' ; 4 ; 10 ; ' '};
ival = cellfun(@ischar,c)
c(ival) = {NaN}
b = cell2mat(c)
  1 comentario
Jan
Jan el 27 de Mayo de 2011
The OP asked for zeros explicitely. CELLFUN(@ischar, C) and CELLFUN('isclass', C, 'char') is equivalent.

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Más respuestas (6)

Jan
Jan el 27 de Mayo de 2011
data(cellfun('isclass', data, 'char')) = {0}

Walter Roberson
Walter Roberson el 27 de Mayo de 2011
param1 = cellfun(@(c) isnumeric(c) * c(1),data(:,2))
  1 comentario
Walter Roberson
Walter Roberson el 27 de Mayo de 2011
Note: this also does the conversion from cell to array.

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Andrei Bobrov
Andrei Bobrov el 28 de Mayo de 2011
idx = find(cellfun('isclass',data,'char'));
data(idx) = data(idx-1)
  1 comentario
Walter Roberson
Walter Roberson el 28 de Mayo de 2011
Close, but that won't work if there are several strings in a row.

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ben harper
ben harper el 28 de Mayo de 2011
Thank you for answers.. What if i try to change the string cell to the prvious cell's value, not zero??
I mean
for i=1:size(data,1)
if data(i,2) is string
data(i,2)=data(i-1,2)
end
end
convert column to array with cell2mat
----------
Like this picture:

ben harper
ben harper el 29 de Mayo de 2011
I wrote a solution as below: Can you recommend me if you know a shorter solution. Because in my code i must do this multiple times. Thank you all.
indices=cellfun('isclass', data(:,2), 'char');
for i=1:size(indices,1)
if indices(i)==1
if i>1
data(i,2)=data(i-1,2);
elseif i==1
data(i,2)=data(i+1,2);
end
end
end
data_new=cell2mat(data(:,2));

Laura Proctor
Laura Proctor el 31 de Mayo de 2011
Are you guaranteed that there will not be two adjacent string values in the input matrix?
If so, then this should work for you:
if indices(1)
data(1,2) = data(2,2);
indices(1) = 0;
end
data(indices) = data([indices(2:end) 0]);

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