how to extract data from an text file?
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Commented: Walter Roberson on 14 Feb 2020
I have two files, one in excel and one in a text file, how would i obtain column data from the text file even though i did it from an excel file.
filename = 'mct.xlsx'
data = xlsread(filename, 'mct', 'A:D');
Phase1 = data(data(:4)==1,:);
how would i be able to extract this from a text file?
fred ssemwogerere on 3 Feb 2020
Hello, there are a number of ways to go about this. Please refer to the following links:
More Answers (3)
fred ssemwogerere on 4 Feb 2020
% what does the 'w' mean?
'w' gives write access permission to the file
% also, what does ''%4.4f\n'' mean?
This is a formatting operator that prints each input as a fixed point number having field width of 4, and the number of digits after the decimal point of 4, before proceeding to a new line ("\n").
Walter Roberson on 5 Feb 2020
Sometimes you can use textscan CommentStyle to ignore headers if they always have the same start and stop. Otherwise sometimes you end up looping textscan, especially if you want the blocks to be separated in output.
Another method that can be very useful is to fileread() the entire file as a character vector, and then use a combination of regexp and regexprep to extract parts of it, possibly then passing the resulting characters into textscan.
isamh on 12 Feb 2020
Edited: isamh on 12 Feb 2020
Walter Roberson on 14 Feb 2020
result = ;
tline = fgetl(fid);
if ~ischar(tline); break; end %end of file
if isempty(tline); continue; end %empty line
celldata = textscan(tline,'%f %f %f %f %f %f');
matdata = cell2mat(celldata);
% match fails for text lines, textscan returns empty cells
result = [result ; matdata];
What is your file format? It appears that you have text at the beginning of some of the lines, and you are doing this looping so that you can ignore those lines? There are usually easier ways to deal with such files.
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