Extracting data from messy text file

Question

Alison 2014-7-14

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回答： D. Ali 2019-4-27

Data file attached. There is a header followed by row names. I want to extract the numeric data for Time, and Area and Volume then group them together into a convenient format for analysis. I've tried textscan, sscanf. I haven't regexp because I've never used it before! Many thanks in advance!

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Azzi Abdelmalek 2014-7-14

No file attached

Teresa Tutt 2015-4-14

Yes, please can someone post the "Data.txt" file?

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Answer 1

dpb 2014-7-14

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https://ww2.mathworks.cn/matlabcentral/answers/141797-extracting-data-from-messy-text-file#answer_145055

编辑：dpb 2014-7-14

在 MATLAB Online 中打开

It's just a repetitive application of textscan...

fmt1='Time       [T] %f';
fmt2='Area    [V] %f %f %f Volume  [V] %f %f %f';
fid=fopen('Data.txt');
% read first set as has unique number header lines
time=cell2mat(textscan(fid, fmt1,'headerlines',10));  % 1st time value
data=cell2mat(textscan(fid, fmt2, ...
              'headerlines',3,'collectoutput',true,'delimiter','\n'))
% and second also has unique number to skip...
time=[time; cell2mat(textscan(fid, fmt1,'headerlines',5))];
data=[data; cell2mat(textscan(fid, fmt2, 'headerlines',3, ...
                     'collectoutput',true,'delimiter','\n'))];
while ~feof(fid)
  time=[time; cell2mat(textscan(fid, fmt1,'headerlines',7))];
  data=[data; cell2mat(textscan(fid, fmt2, 'headerlines',3, ...
                        'collectoutput',true,'delimiter','\n'))];
end
fid=fclose(fid);

At the end you'll have a Nx1 vector of time and Nx6 of volumes and areas. You could either concatenate time and data into one array or separate out A and V based on the columns in data; your choice.

At the command line the above gives me

>> [time data]
ans =
 1.0e+04 *
       0    1.7221    1.6475    0.0746    0.0995    0.0987    0.0009
  0.1054    1.7221    1.6475    0.0746    0.1089    0.1081    0.0008
  0.2108    1.7221    1.6475    0.0746    0.1102    0.1093    0.0008
  0.3162    1.7221    1.6475    0.0746    0.1111    0.1103    0.0008
  0.4216    1.7221    1.6475    0.0746    0.1118    0.1110    0.0008
  0.5270    1.7221    1.6475    0.0746    0.1124    0.1116    0.0008
  0.6324    1.7221    1.6475    0.0746    0.1129    0.1120    0.0008
  0.7379    1.7221    1.6475    0.0746    0.1134    0.1126    0.0008
  0.8433    1.7221    1.6475    0.0746    0.1139    0.1130    0.0008
  ...

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dpb 2014-7-14

编辑：dpb 2014-7-14

Oh, I see now...I had just glanced at the first couple and that the other data seemed in the right place and presumed it was ok. I'll have to see if can see what's causing that.

Oh, I see...there are two more lines after T=0 in the output--is that real or are there two lines missing in the first section? Assuming it's real and an artifact of the startup, need to handle the first two separately instead of just the first one. I'll amend the answer in a few minutes...

dpb 2014-7-14

编辑：dpb 2014-7-14

在 MATLAB Online 中打开

...I'm actually looking at Inflow rather than area now.

I didn't try it, I think you'll need to modify fmt to

fmt2=['Area [V] %f %f %f' repmat(%*s,1,5) 'InFlow [V/T] %f %f %f'];

to skip the five string fields in the intermediary line. The alternative is to read the Area line by itself, then another textscan call for the InFlow line w/ another 'headerline', 1 parameter, or just insert a call to fgetl between the two without 'headerline'.

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Answer 2

Joseph Cheng 2014-7-14

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编辑：Joseph Cheng 2014-7-14

在 MATLAB Online 中打开

dpb's solution is much more elegant but thought i'd put what i did so far.

fid = fopen('Data.txt');
nlines = 1;
dashes = [];time=[]; timeline=[];
dataInd = 1;
while 1
    tline = fgetl(fid);
    if ~ischar(tline),break,end
      if ~isempty(tline)& length(tline)>=2
         switch tline(2:3)
             case '--'
                 dashes = [dashes nlines];
             case 'Ti'
                 timeline = [timeline nlines];
                 tTime= sscanf(tline,' Time       [T]     %f');
                 if isempty(tTime),continue, end;
                 Data(dataInd).time = tTime;
                 dataInd = dataInd +1;
             case 'Ar'
                 tArea= sscanf(tline,' Area    [V]          %f%f%f')';
                 Data(dataInd).Area = tArea;
            case 'Vo'
                 tVolume= sscanf(tline,' Volume  [V]          %f%f%f')';
                 Data(dataInd).Area = tArea;
             case 'hM'
                 thmean= sscanf(tline,' hMean   [L]         %f%f%f')';
                 Data(dataInd).hMean = thmean;
         end
      end
      nlines = nlines+1;
  end