indices and values

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huda nawaf
huda nawaf 2011-11-22
HI,
If I have this txt file(indices and values),and need read it into array without using for loop. Is there command do that?
(1,2) 3
(2,3) 4
thanks
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huda nawaf
huda nawaf 2011-11-22
sorry ,I were not clear.
I mean a command place each element in it's index
where the above file be :
0 3 0
0 0 4

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回答（3 个）

Walter Roberson
Walter Roberson 2011-11-22
textscan(fid, '%*c%f%*c%f%*c%f')
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显示 4更早的评论
Andrei Bobrov
Andrei Bobrov 2011-11-23
a = accumarray([w,w1],w2,[],[],[],true)
Walter Roberson
Walter Roberson 2011-11-23
Interesting, Andrei; I had quite forgotten that flag.
I am, however, not convinced at the moment that the array really is sparse; Huda earlier (in a different Question on this same topic) made reference to the array indices being sequential.

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Fangjun Jiang
Fangjun Jiang 2011-11-22
[I,J,V]=textread('test.txt','(%f,%f) %f');
A=zeros(2,3);
A(sub2ind(size(A),I,J))=V
Andrei Bobrov
Andrei Bobrov 2011-11-23
[EDIT]
fid = fopen('nameyourfile.txt','r');
c = textscan(fid, '(%f,%f)%f','collectoutput',true);
fclose(fid)
a = accumarray(c{1}(:,1:2),c{1}(:,3),[],[],[],true)
[ADD] 22:32MSD
fid = fopen('nameyourfile.txt','r');
c1 = textscan(fid, '(%f,%f)%f');
fclose(fid);
a = sparse(c1{:});
  2 个评论
huda nawaf
huda nawaf 2011-11-23
I got this error when ran it:
??? Function 'accumarray' is not defined for values of class 'int32'.
Error in ==> accumarray at 73
[varargout{1:nargout}] = builtin('accumarray', varargin{:});
huda nawaf
huda nawaf 2011-11-23
I got this error when use cellfun
c = cellfun(@(x)double(x),c,'un',0);
??? Too many inputs.

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