Reading data row by row into matlab.
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Jorge Guzman
am 21 Feb. 2019
Kommentiert: Yasir Iqbal
am 16 Nov. 2021
I need to read a text file, row by row, into different variables for the first 5 rows. Afterwards an N x M matrix needs to be read in. Is there a simple way to do this? I've tried to use textrfead, fopen, etc, but can't figure out how to get just the numbers I need.
this would be a sample file:
8
10
12 15 12 18 17 19 14 16
200 155 487 632 526 321 845 80
52 41 78 62 32 45 67 85 29 10 15
followed by a matrix of size 8 x10 (the matrix will always be size of the first two inputs)
Sorry, I uploaded two sample files. I know how to read in everything but the matrix at the end. That's what I need help retrieving from the files.
2 Kommentare
Kevin Chng
am 22 Feb. 2019
It is a bit confusing about
for the first 5 rows. After words an N x M matrix needs to be read in.
I guess you are only wanted to read certain line in your text file.
If you could upload your text file, and let us know which line you want to read, i can try to write the code for you here.
Akzeptierte Antwort
Stephen23
am 22 Feb. 2019
Bearbeitet: Stephen23
am 22 Feb. 2019
Why not just use dlmread ?:
>> M = dlmread('test.txt','',2,0)
M =
12 15 12 18 17 19 14 16 0 0 0
200 155 487 632 526 321 845 80 0 0 0
52 41 78 62 32 45 67 85 29 10 15
I had to create my own test file (attached) based on your description because you did not provide one. If you upload a sample file then it makes it easier for us to help you, and faster for you to get the results that you want.
Weitere Antworten (1)
Are Mjaavatten
am 22 Feb. 2019
I often find it useful to read the file into a cell array of strings using textscan. Then I can easily experiment with how to best parse each line. In your case, this resulted in:
fid = fopen(filename);
lines = textscan(fid,'%s','delimiter','\n');
fclose(fid);
lines = lines{1};
n = sscanf(lines{1},'%d');
m = sscanf(lines{2},'%d');
% parse lines 3-5
M = zeros(n,m);
for i = 1:n
M(i,:) = sscanf(lines{5+i},'%f')';
% Alternatively:
% M(i,:) = str2num(lines{5+i});
end
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