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Extract column from text file

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Suuz HMS
Suuz HMS on 12 Jun 2023
Commented: Suuz HMS on 13 Jun 2023
Hi, for my research project I have to analyze a certain output. The output gives a lot of measurements (also a lot of data I don't need), but I don't know how to extract the specific column of data that I do need. The data looks like this:
P1,R0,14:17:36.779,47,0.01421266,[-0.03077913; 0.3226232; -0.4286367],[0; 0; 0],[-0.4424625; 0.120887; -0.9627059],[-0.03836464; 0.5967162; 0.3170188],[-6.699989; -7.350024; 5.199996],50.48101,0.7456555,0,0,0,-5.2,0
P0,R0,14:17:36.823,47,0.01403595,[-0.03077913; 0.3226232; -0.4286367],[0; 0; 0],[-0.4424625; 0.120887; -0.9627059],[-0.03836464; 0.5967162; 0.3170188],[-6.699989; -7.350024; 5.199996],50.48101,0.7456555,0.08738,0.6293842,17.97661,-5.2,0
But I only need the first number between brackets (value -0.03077913 here). How do I do this?
  2 Comments
the cyclist
the cyclist on 12 Jun 2023
The best method will depend on exactly what format of file you have. (For example, is it Excel, a CSV, etc.?) Can you upload the file (using the paper clip icon from the INSERT area of the toolbar), or at least a few representative lines?
Suuz HMS
Suuz HMS on 13 Jun 2023
The file gets downloaded as a txt-file, but can also be saved as a .m file.

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Answers (2)

Kautuk Raj
Kautuk Raj on 13 Jun 2023
To extract the first number between the brackets in the data provided, we can use regular expressions in MATLAB.
This regular expression pattern \[([-0-9\.]+);([-0-9\.]+);([-0-9\.]+)\] will match the three numbers between the brackets and captures them in separate groups.

Stephen23
Stephen23 on 13 Jun 2023
Fake data (you would use FILEREAD):
S = sprintf('%s\n','P1,R0,14:17:36.779,47,0.01421266,[-0.03077913; 0.3226232; -0.4286367],[0; 0; 0],[-0.4424625; 0.120887; -0.9627059],[-0.03836464; 0.5967162; 0.3170188],[-6.699989; -7.350024; 5.199996],50.48101,0.7456555,0,0,0,-5.2,0','P0,R0,14:17:36.823,47,0.01403595,[-0.03077913; 0.3226232; -0.4286367],[0; 0; 0],[-0.4424625; 0.120887; -0.9627059],[-0.03836464; 0.5967162; 0.3170188],[-6.699989; -7.350024; 5.199996],50.48101,0.7456555,0.08738,0.6293842,17.97661,-5.2,0')
S =
'P1,R0,14:17:36.779,47,0.01421266,[-0.03077913; 0.3226232; -0.4286367],[0; 0; 0],[-0.4424625; 0.120887; -0.9627059],[-0.03836464; 0.5967162; 0.3170188],[-6.699989; -7.350024; 5.199996],50.48101,0.7456555,0,0,0,-5.2,0 P0,R0,14:17:36.823,47,0.01403595,[-0.03077913; 0.3226232; -0.4286367],[0; 0; 0],[-0.4424625; 0.120887; -0.9627059],[-0.03836464; 0.5967162; 0.3170188],[-6.699989; -7.350024; 5.199996],50.48101,0.7456555,0.08738,0.6293842,17.97661,-5.2,0 '
C = regexp(S,'(?<=\[)(-|+)?\d+\.?\d*','match')
C = 1×10 cell array
{'-0.03077913'} {'0'} {'-0.4424625'} {'-0.03836464'} {'-6.699989'} {'-0.03077913'} {'0'} {'-0.4424625'} {'-0.03836464'} {'-6.699989'}
V = str2double(C)
V = 1×10
-0.0308 0 -0.4425 -0.0384 -6.7000 -0.0308 0 -0.4425 -0.0384 -6.7000

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