how to extract data from an text file?
144 vues (au cours des 30 derniers jours)
Afficher commentaires plus anciens
isamh
le 3 Fév 2020
Commenté : Walter Roberson
le 14 Fév 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.
code is:
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?
0 commentaires
Réponse acceptée
fred ssemwogerere
le 3 Fév 2020
Hello, there are a number of ways to go about this. Please refer to the following links:
1 commentaire
Plus de réponses (3)
fred ssemwogerere
le 4 Fév 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").
8 commentaires
Walter Roberson
le 5 Fév 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
le 12 Fév 2020
Modifié(e) : isamh
le 12 Fév 2020
3 commentaires
Walter Roberson
le 14 Fév 2020
result = [];
fid=fopen('MCT_Data.txt');
tic
while 1
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];
end
toc
fclose(fid);
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.
Voir également
Catégories
En savoir plus sur Text Data Preparation dans Help Center et File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!