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Extracting data from messy text file

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Alison on 14 Jul 2014
Answered: D. Ali on 27 Apr 2019
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!


dpb on 14 Jul 2014
Data file attached....
'Cepting it ain't... :)
Teresa Tutt
Teresa Tutt on 14 Apr 2015
Yes, please can someone post the "Data.txt" file?

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Accepted Answer

dpb on 14 Jul 2014
Edited: dpb on 14 Jul 2014
It's just a repetitive application of textscan...
fmt1='Time [T] %f';
fmt2='Area [V] %f %f %f Volume [V] %f %f %f';
% read first set as has unique number header lines
time=cell2mat(textscan(fid, fmt1,'headerlines',10)); % 1st time value
data=cell2mat(textscan(fid, fmt2, ...
% and second also has unique number to skip...
time=[time; cell2mat(textscan(fid, fmt1,'headerlines',5))];
data=[data; cell2mat(textscan(fid, fmt2, 'headerlines',3, ...
while ~feof(fid)
time=[time; cell2mat(textscan(fid, fmt1,'headerlines',7))];
data=[data; cell2mat(textscan(fid, fmt2, 'headerlines',3, ...
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


Show 2 older comments
Alison on 14 Jul 2014
Thanks again dpb. When I run your script, it does actually work in the sense that I get what you get but time values are missing from your results. It seems to be skipping several 'sections' of the data.
So time values are: 0, 1054.08, 2108.1599...and so on but the third time value you have is 0.5207, which is a few sections down the line.
dpb on 14 Jul 2014
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 on 14 Jul 2014
...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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More Answers (2)

Joseph Cheng
Joseph Cheng on 14 Jul 2014
Edited: Joseph Cheng on 14 Jul 2014
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;
nlines = nlines+1;


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D. Ali
D. Ali on 27 Apr 2019
I have similar question where I need to extarct all MCAP amples with time they occured on in separat file and plot if possilbe
I attached the file


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