MATLAB: Re-organize LS-DYNA data from text file removing header and footer

fgetlfgetsread datatextscan

Hello,
I'm trying to extract data from an LS-DYNA output text file and write it into a new file with a new format, but I find the initial format a bit complicated and I have problem getting what I want, which is:
  • Header: keep the same (LS-DYNA keyword … date)
  • One line with the legend of the data, with timestep and time moved to columns 1 and 2, respectively (two new columns should be created)
  • N lines with the actual data
  • No footer
The starting file looks like this:
and I'd like to have it like this
From that point I can use textscan to manipulate the data the way I want.
Numpy library in Python has the command genfromtxt that allows to remove header and footer, then choose which data to extract from a specific column of a specific line. I couln't find such a command in MATLAB, and i tried with a combination of, fgets, fgetl, and textscan, but impossible to achieve what I'm looking for.
Does anyone have an idea of which function would work best?
Thanks a lot!

Best Answer

I understand that you would like to know what MATLAB functions would work best to format your data so it can be easily imported using textscan.
Because your original data file is not formatted the same on each line, you will likely need to call 'fgetl' to read in each line as a character array. Use 'eof' to determine when the end of the file has been reached.
To extract the numerical values from lines that contain many characters, you can first remove the characters by using the 'replace' function.
https://www.mathworks.com/help/matlab/ref/replace.html
Then, you can use 'textscan' on the remaining string to extract the numerical values.
Once you have read the data into MATLAB, you can use a function like 'fprintf' to write the data to another file.
https://www.mathworks.com/help/matlab/ref/fprintf.html
These functions should help you write custom code to achieve the desired format.
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