How to find same element in txt file (in a coloumn) and find the amount for averaging the value of another coloumn ?

i have a txt file that contain hundreds rows and 7 coloumns

what must i do if i want to find (in coloumn 1) a same number and their amount to calculate the average of coloumn 4, 5, 6, and 7 respectively in those specific rows

the data in rata2_j1.txt

please help, thank a lot

Answer 1

[Are Mjaavatten]

There may be more elegant ways to read the file, but I often prefer to use textscan to read a text file into a cell array of strings. This lets me experiment with parsing to make sure I get it right.

The cyc values vary between 1 and 260, but some values are missing in every set. For every cyc value I select the corresponding lines in the data array and calculate the mean.

fid = fopen('rata2_j1.txt');
lines = textscan(fid,'%s', 'Delimiter', '\n','HeaderLines' ,1);
fclose(fid);
lines = lines{1};  % Cell array of strings, one per line
N = length(lines);
cyc = zeros(N,1);
data = zeros(N,6);
for i = 1:N
  A = sscanf(lines{i},'%f');  % Parse line to array of 7 dounbles
  cyc(i) = A(1);
  data(i,:) = A(2:7);
end
averages = zeros(260,4);
for i = 1:260
  averages(i,:) = mean(data(cyc==i,3:6),1);
end

Note that I have calculated averages for each cyc value and column separately. If you want to average all four columns, add the line:

average = mean(averages,2);

[Agnes Ardianti]

thankyou so much, this answer was very helpful

but, maybe i have to modify some of those to cover the NaN values that appear and sortir some datas that are not even complete

but still thankyou very much

[Are Mjaavatten]

I failed to notice that there are no data for cyc = 178 or cyc = 243. How to handle this would depend on your further use of the data. Sometimes keeping the NaNs is useful, sometimes not.

One way is to remove the NaN averages afterwards:

averages(all(isnan(averages),2),:) = [];

Alternativley, you can calculate averages for only the cyc values that are found in the file:

cyc_values = unique(cyc);
n_cyc = length(cyc_values);
averages = zeros(n_cyc,4);
for i = 1:n_cyc
  averages(i,:) = mean(data(cyc == cyc_values(i),3:6),1);
end

The results are identical. Of course now row 250 of averages will hold the results for cyc = 252.

[Agnes Ardianti]

This is it, it's work more for my intention. Because i don't have to keep the NaN values anymore

Thankyou again, it have made my day through yours