Extracting numerical results from a text file at different positions

I have a number of output files to process, written out from Finite Element Analysis software, from which I need to extract data.

I need to extract data under 2 different "headings" from each of the files. However, each of the files has these headings at different rows. I have attached a "zipped" file with 2 files indicating this problem.

The following screenshots show the "headings" highlighted and the numerical data to be extracted, shown inside a "box":

First Heading

Second Heading

I have tried a number of options in Matlab, but I am overwhelmed as I am new to Matlab and programming.

Any assistance and guidance, would be much appreciated.

[darova]

read about fileread, regexp

Answer 1

[Gareth]

good catch, my bad:) it was late at night. This should work. In either case if you are learning MATLAB, regexp are very powerful. They exist in many languages, it is worth understanding them:)

a = fileread('0295_PhD_AB~Analysis 1.txt');

% find ( H A R M O N I C =    \d )
[b,c] = regexp(a,'( H A R M O N I C =    \d )','tokens');

result = table();
% find the 2nd and the 6th number in the table
for i = 1:length(c)
    aux = (a(c(i)+586:c(i)+700));
    d = regexp(aux,'([0-9.E-+]*)','tokens');
    result = [result;table(repmat(b{i},2,1),[d{2};d{6}])];
end
result.Var2 = str2double(result.Var2);

[GS76]

Thank you GT!

This worked out excellently.

I will continue learning and practising "regexp". Thank you for all your help and tips.

Answer 2

[Gareth]

There is probably an easier way to do this... but this should help. (I am using R2018b).

a = fileread('0295_PhD_AB~Analysis 1.txt');

% find ( H A R M O N I C =    \d )
[b,c] = regexp(a,'( H A R M O N I C =    \d )','tokens');

result = table();
% find
for i = 1:length(c)
    aux = (a(c(i)+586:c(i)+700));
    d = regexp(aux,'([0-9.E-]*)','tokens');
    result = [result;table(repmat(b{i},2,1),[d{2};d{7}])];
end

result

[Gareth]

You can always convert the last column into doubles...

result.Var2 = str2double(result.Var2);

[GS76]

Hi GT,

Thank you very much for this help. This is exactly what I was hoping to achieve.

However, I found the following error whereby the code is extracting the last value from the second column and not the first, when extracting for "HARMONIC = 2". Please see the attached screenshot:

Could you assist me to correct this small problem in the code.

Thank you again for your assistance.