Import numbers from header (.txt file)?

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MLP
MLP on 5 Nov 2021
Commented: MLP on 6 Nov 2021
Hello, I have set up a script that will go through many files containing 3D geometries and is essential that I am able to extract the number of vertices and faces listed in the header of each respective file. How can I access thiese numbers (lines 5 and 9 of the attached file) in order to assign them to a variable?
Thank you in advance!
  2 Comments
Walter Roberson
Walter Roberson on 5 Nov 2021
Do you need only those things for a given pass, or will you happening to be reading the data in as well?
If you are reading in the data at the same time, then some of the convenient methods become worth doing, but if you have "many" files and you only need that header information, then the overhead of the convenient methods could be too much and you might need to switch to less convenient but faster methods.
MLP
MLP on 6 Nov 2021
Edited: MLP on 6 Nov 2021
I need those two numbers from the header but I also need to import the rest of the file. I am currently using readmatrix() for the later. @Walter Roberson

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Accepted Answer

Walter Roberson
Walter Roberson on 6 Nov 2021
filename = 'testMODEL.txt';
S = fileread(filename);
EV = cell2mat(textscan(S, 'element vertex %f', 1, 'HeaderLines', 4));
EF = cell2mat(textscan(S, 'element face %f', 1, 'HeaderLines', 8));
data = cell2mat(textscan(S, '%f %f %f', 'HeaderLines', 11));
This assumes that those items are always on the same line numbers. If not, then modifications would need to be made to the code.
textscan() of a character string is pretty efficient.

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