How can I export only specific data from a text file to a matrix?
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I'm need to import only the numeric data of the attached .txt file into a 9x8 matrix and I'm not sure how to do this. Any help is greatly appreciated!
3 Comments
dpb
on 24 Jul 2019
What Adam said...
But, it's generally simpler to read what section of a file contains the info of interest and then just throw out what you don't need than it is to specifically hunt and peck through a file reading a bit here and there.
But, it certainly isn't at all clear what you want to retrieve from this file given the question wording...
Accepted Answer
Jan
on 25 Jul 2019
Edited: Jan
on 26 Jul 2019
With some guessing, that you want the part behind ':Solar_Radio_Flux:' :
Key = ':Solar_Radio_Flux:';
Str = fileread(FileName);
C = strsplit(Str, newline);
index = find(strncmp(C, Key, numel(Key)));
Block = C(index+3:index+11);
BlockStr = sprintf('%s ', Block{:}); % Horizontal concatenation
% Data = sscanf(BlockStr, '%g ', [9, 8]); [EDITED:]
Data = sscanf(BlockStr, '%g ', [8, 9])'; % Thanks Adam
This can be expanded e.g. to read the 2 header lines also or to accept any block of numbers until the next comment line.
2 Comments
More Answers (1)
Adam Danz
on 25 Jul 2019
rows = 11:19; % NUMERIC ROWS IN TEXT FILE TO IMPORT
nColumns = 8; % NUMBER OF COLUMNS OF TEXT
file = 'Testdata.txt'; % THE FULL PATH WOULD BE BETTER
opts = delimitedTextImportOptions('NumVariables',nColumns,'DataLines',rows([1,end]),'Delimiter', " ", ...
'VariableTypes',repmat({'double'},1,nColumns),'ConsecutiveDelimitersRule','join',...
'LeadingDelimitersRule','ignore');
Testdata = readtable(file, opts);
Testdata = table2array(Testdata);
Result
Testdata =
245 14 12 11 -1 -1 -1 -1
410 25 28 26 -1 -1 -1 -1
610 34 -1 34 -1 -1 -1 -1
1415 45 49 55 -1 -1 -1 -1
2695 104 -1 68 -1 -1 -1 -1
2800 -1 -1 -1 68 68 -1 -1
4995 107 113 126 -1 -1 -1 -1
8800 223 230 218 -1 -1 -1 -1
15400 519 549 496 -1 -1 -1 -1
5 Comments
Adam Danz
on 25 Jul 2019
Edited: Adam Danz
on 25 Jul 2019
@madhan ravi, it's the same. That's the only line in the table2array function. Matlab's import data tool uses table2array() which is why I ended up using it, too. But I agree that Testdata{:,:} is more direct.
Jeremy Hughes
on 25 Jul 2019
Or if you have R2019a
Testdata = readtable(file, opts);
Testdata = table2array(Testdata);
can just be
A = readmatrix(file,opts)
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