write data to specific column in text file

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Lalit Patil
Lalit Patil 2012-11-20
I have this text file created from
I = imread('3.jpg');
i = im2bw(I);
m = max(max(i));
[r c] = find(i == m);
fid = fopen('lalit.txt','wt');
for j=1:length(r)
fprintf(fid,'%f %f\n',r(j),c(j));
end
fclose(fid);
Now i want to do
for m = 1:length(r)
z(m) = round((r(m) + c(m))/2);
end
z=z';
Now i want to save this z as third column in the same text file, but without modifying r and c.

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采纳的回答

Walter Roberson
Walter Roberson 2012-11-20
The only way you should seriously consider for modifying data in text files is to read in the file and write the modified version to another file, possibly followed by renaming the new file to the old name. Modifying a text file "in place" is tricky and often not possible anyhow.
  1 个评论
Lalit Patil
Lalit Patil 2012-11-21
clear all; clc; I = imread('1.jpg'); i = im2bw(I); imshow(i); m = max(max(i)); [r c] = find(i == m); a = r; fid = fopen('lalit.txt','wt'); for j=1:length(r) fprintf(fid,'%f %f\n',r(j),c(j)); end fclose(fid);
data = textread('lalit.txt'); a = unique(data); for i=a', maxVal = max(data(a==i,2)); minVal = min(data(a==i,2)); z(i,:) = round((maxVal + minVal)/2); end
fid = fopen('lalit1.txt','wt'); for j=1:length(z) fprintf(fid,'%f\n',z(j)); end fclose(fid);
Thank you.. I got it.. it doesn't matter for me whethere i write data to same file or another file..

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