row by row matrix building

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Colin Edgar
Colin Edgar 2015-11-6
评论： Colin Edgar 2015-11-9
Quick question here I hope. Am modifying some code, can't see why this won't work:
j=1
while ischar (tline);
%define indexes, below as idx, etc etc
tline = fgetl(fid); %reads the next line in input file
dt = textscan(tline,'%s','delimiter',',');
tm = datenum(dt{1}(didx));
d1 = str2double(dt{1}(1idx));
d2 = str2double(dt{1}(2idx));
d3 = str2double(dt{1}(3idx));
mat(j,:) = [tm d1 d2 d3]; ;
j = j+1;
tline = fgetl(fid);
end;
The stumbling block is the mat(j,:) portion. Error message says 'Subscripted assignment dimension mismatch.' Tried different ways of creating mat[] prior to this loop and in different ways but no luck. Could do a whole different approach, but don't want to build a whole new routine.

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回答（1 个）

Image Analyst
Image Analyst 2015-11-7
What is the size of mat? Does it have 4 columns? What is the value of tline and j when the error is thrown? Maybe try preallocating mat before the while loop
mat = zeros(1, 4);
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Image Analyst
Image Analyst 2015-11-7
Well you can't assign 4 numbers to an entire row of 7 columns. If you just want the first 4 columns assigned, you can index it like this:
mat(j,1:4) = [tm d1 d2 d3];
The final 3 columns (columns 5, 6, and 7) will be untouched and remain as zero.
Colin Edgar
Colin Edgar 2015-11-9
I realize that. Sorry my example is smaller than my actual testfile. I still haven't solved this but am doing a workaround. Still interested in a solution. Thx

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