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I have multiples text files each with a header, 200 data points, and a footer. I'm trying to figure out a way of making a script capable of finding where the datapoints start and stop in each file, and load those data points into a workspace table.

I've attached a text file to make it easier to understand what I'm working with.

Rik
on 19 Aug 2020

Edited: Rik
on 19 Aug 2020

It looks like you can look for the line with '[data]' on it, and continue until the first line that doesn't start with a digit or a minus sign.

The code below takes the scenic route, but it gets there in the end. If you have a very large number of files you may want to consider a more efficient method.

A=readfile('https://www.mathworks.com/matlabcentral/answers/uploaded_files/348641/IN01_SCALED.txt');

n_start=0;n_end=-1;

for n=1:numel(A)

if strcmpi(A{n},'[data]')

n_start=n+1;

end

if n_start>0 && n>=n_start

if ~any(A{n}(1)=='-0123456789')

n_end=n-1;

break

end

end

end

B=A(n_start:n_end);

B=cellfun(@(x) cellfun(@str2double,strsplit(x,',')),B,'UniformOutput',0);

B=cell2mat(B);

Let's stretch the definition of what an earlier release is. I made the above code compatible with just about any Matlab release. I didn't test it, but it should work with releases as far back as R13 (version 6.5). For the modern code I used the solution by Star Strider.

UseFallbackMethod=true;try if ~verLessThan('matlab','9.6'),UseFallbackMethod=false;end,catch,end

if UseFallbackMethod

A=readfile('https://www.mathworks.com/matlabcentral/answers/uploaded_files/348641/IN01_SCALED.txt');

n_start=0;n_end=-1;

for n=1:numel(A)

if strcmpi(A{n},'[data]'),n_start=n+1;end

if n_start>0 && n>=n_start && ~any(A{n}(1)=='-0123456789')

n_end=n-1;break

end

end

B=A(n_start:n_end);

%the loop below is equivalent to:

%B=cellfun(@(x) cellfun(@str2double,strsplit(x,',')),B,'UniformOutput',0);

for n=1:numel(B)

s=strfind(B{n},',');

split=zeros(1,numel(s)+1);

start_index=[s numel(B{n})+1];

stop_index=[0 s];

for m=1:numel(start_index)

str=B{n}((stop_index(m)+1):(start_index(m)-1));

split(m)=str2double(str);

end

B{n}=split;

end

B=cell2mat(B);

else

B = readmatrix('IN01_SCALED.txt');

nonan = ~isnan(B);

B = [B(nonan(:,1),1) B(nonan(:,2),2)];

end

Star Strider
on 19 Aug 2020

Another option:

A1 = readmatrix('IN01_SCALED.txt');

nonan = ~isnan(A1);

A1 = [A1(nonan(:,1),1) A1(nonan(:,2),2)];

This actually takes care of all the header lines itself, and produces the (201x2) array in ‘A1’. The only drawback is that the readmatrix function was introduced in R2019a, so this will not work for earlier releases.

Rik
on 19 Aug 2020

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