Searching for values that a particular variable takes in a single text file

Hello,

I need to work on the values that a particular variable takes up at different times in a particular text file. I need these values so that I can compare them with a certain threshold level that I will set in the program. I am a new to MATLAB. Please help.

Thank you.

[Azzi Abdelmalek]

What do you mean by at different times? can you provide a short example with expected result?

[Abhishek]

For example: A variable average= 200, 550, 125, etc. based on the dataset it is working on. But all these values of "average" appear in the same text file.

[Cedric]

Please post a copy/past of part of the file (e.g. 10-20 lines) so we can see the format.

[Abhishek]

This is how the text file looks. I need to check if the AvgValue is greater than or lesser than a particular threshold everytime, the counter encounters the AvgValue.

   44  20   4    516
 45  20   4    515
 43  21   4    554
 42  22   4    578
 43  22   4    540
 41  23   4    576
 41  24   4    426
 41  25   4    300
 47  25   4    302
 41  26   4    285
 45  26   4    177
 46  26   4    136
 47  26   4    337
 48  26   4    343
 41  27   4    349
 47  27   4    380
 48  27   4    533
 49  27   4     92
 41  28   4    374
 42  28   4    178
 43  28   4    156
 44  28   4    154
 46  28   4    315
 47  28   4    478
 48  28   4    558
 40  29   4    444
 44  29   4    266
 45  29   4    452
 46  29   4    496
AvgValue: 378.000000

ROI:         2
NrOfVoxels:  34
45  37   5    395
46  37   5    331
44  38   5    506
45  38   5    480
46  38   5    412
42  39   5    529
43  39   5    566
45  39   5    554
46  39   5    495
40  40   5    557
43  40   5    587
44  40   5    564
46  40   5    463
47  40   5    416
48  40   5    221
40  41   5    574
46  41   5    452
47  41   5    431
48  41   5    128
43  42   5    525
45  42   5    439
46  42   5    374
42  43   5    532
43  43   5    485
44  43   5    478
45  43   5    367
46  43   5    406
47  43   5    295
43  44   5    503
44  44   5    522
45  44   5    507
46  44   5    564
45  45   5    606
45  46   5    687
AvgValue: 469.000000

Answer 1

[Azzi Abdelmalek]

If your text file contains only numbers, you can use

M=dlmread('YourFilename.txt')

[Abhishek]

It contains text too. I submitted a part of the readings in the file.

[Azzi Abdelmalek]

You can use fgetl to read your file then parse the result with regexp

[Abhishek]

Thank you for your help.

Answer 2

[Cedric]

I would go for something like:

 buffer = fileread('data.txt') ;
 match  = regexp(buffer, '(?<=AvgValue:\s*)[\d\.]+', 'match') ;
 avgValue = str2double(match) ;

and then analyze avgValue which is a numeric array.

[Abhishek]

Thank you. It's working. The only problem is the huge size of the file. But nothing can possibly be done about it. Thus, its taking almost 20 minutes to print the result. But thanks for the solution.

[Cedric]

How large is your file? There are more efficient approaches, but I proposed this one because it solves your problem with 3 lines of code.

[Abhishek]

The file size is around 688 kB. The number of occurrences of AvgValue is 546 times.

[Cedric]

If it is really 688kB (and not MB), could you email me the file please so I can perform some tests? This is a small file actually, so its processing shouldn't take more than a few seconds.

[Cedric]

Ok, the positive look-behind takes time. Please, try the following:

 buffer   = fileread('feedback0005_plots_Aphasia.ert') ;
 tokens   = regexp(buffer, 'AvgValue:\s*([\d\.]+)', 'tokens') ;
 avgValue = str2double([tokens{:}]) ;