Reading in data from text file in a certain format

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Hello, I have a set of text file data that are structured in the following way:
header1
header2
5 columns by N rows (data set 1)
header3
header4
5 columns by M rows (data set 2)
header5
header6
5 columns by K rows (data set 3)
this structure repeats for an arbitrary number of data set, how should I read in these sets of data one by one? I tried
importdata('file.txt')
but it only reads the first set and ignored the rest.
Any help would be appreciated!

Accepted Answer

Star Strider
Star Strider on 16 Aug 2021
A similar problem presented itself in Reorganization of experimental data and that solution could be adapted to your problem. It uses textscan because I have used it successfully with similar problems.
So long as the number of columns does not change between the data segments you want to read, adapting it should be straightforward. The number of rows is irrelevant, and the approach adapts to them.
.
  2 Comments
J T
J T on 16 Aug 2021
Hello, I attempted textscan but it still only returns the first set of date and ignored the rest, here is the code I tried:
fidi = fopen('file.txt','rt');
C = textscan(fidi, '%f%f%f%f%f', 'HeaderLines',2,'EmptyValue',0);
M = cell2mat(C);
fclose(fidi);
Star Strider
Star Strider on 16 Aug 2021
In order to read a segmented file, the textscan call needs to be in a loop as in the example code. Also, checking for the empty matrix is essential in order to avoid an infinite loop if the file does not have a valid end-of-file indicator, so all you should need to do is to change the format descriptor and the 'HeaderLines' value for it to work with your file.
.

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