Import and find a specific number from a text file

hey, i am trying to take out a specific value from a text file.

Let say, i want to get the absolute maximum value (Max and Min) from UX column only. Since the NODE column and LC column will vary for each analysis output, hence i would like to avoid to scan it by line number.

Thank you for your help,

Adrian

________________________________________________

 NODE DISPLACEMENT AND ROTATIONS DEFAULT PRINTOUT                       Unit System : kgf , cm
__________________________________________________

 NODE       LC               UX          UY          UZ          RX          RY          RZ
------ -------- ---- ----------- ----------- ----------- ----------- ----------- -----------

    01     0.1g  Max       0.410       0.000       0.012         0.0         0.0         0.0
                 Min      -0.364       0.000      -0.011        -0.0        -0.0         0.0

           0.2g  Max       0.795       0.000       0.022         0.0         0.0         0.0
                 Min      -0.683       0.000      -0.020        -0.0        -0.0         0.0

           0.3g  Max       1.137       0.000       0.031         0.0         0.0         0.0
                 Min      -1.003       0.000      -0.028        -0.0        -0.0         0.0
...
...
    98     0.1g  Max       0.549       0.000       0.035         0.0         0.0         0.0
                 Min      -0.493       0.000      -0.038        -0.0        -0.0         0.0

           0.2g  Max       1.047       0.000       0.061         0.0         0.0         0.0
                 Min      -0.911       0.000      -0.068        -0.0        -0.0         0.0

           0.3g  Max       1.495       0.000       0.088         0.0         0.0         0.0
                 Min      -1.328       0.000      -0.096        -0.0        -0.0         0.0
________________________________________________

 BEAM ELEMENT FORCES & MOMENTS DEFAULT PRINTOUT                         Unit System : kgf , cm
________________________________________________

ELEM   MAT    SEC        BC      PT      AXIAL    SHEAR-y    SHEAR-z    TORSION   MOMENT-y   MOMENT-z

[Walter Roberson]

I would be curious to see what readtable() would do to your file. Would it be possible to attach a sample data file for testing? You might need to zip it and attach that.

[Stephen23]

@Adrian Ulza: please edit your question and upload the file by clicking on the paperclip button.

[Adrian Ulza]

hey, sorry. i've just attached the file.

[Guillaume]

You may be able to wangle it by reading the whole text file and using some clever regexes but to do the job properly you're going to have to write your own parser.

That text format is not really designed to be read by a computer. If the program you're using has an alternative output format (binary would be better) that is documented, I'd consider using that instead.

Answer 1

[David J. Mack]

Try use regexp:

file='c:\Users\David J. Mack\Desktop\test.txt';
numFormat1 = {'[ ]{1,7}(\-?\d+\.\d{3})'}; %e.g. %12.3f
numFormat2 = {'[ ]{1,9}(\-?\d+\.\d{1})'}; %e.g. %12.1f
%                        ---NODE----------------- ---LC----------------- ------------  ---UX/UY/UZ--------- ---RX/RY/RZ--------- ---EOL
C=regexp(fileread(file),['[ ]{0,6}([1-9]+\d{0,5})?[ ]{1,9}(\d+\.\d{1}g)?  (Min|Max)' [numFormat1{[1 1 1]} numFormat2{[1 1 1]}] '\r\n'],'tokens');
C=vertcat(C{:});
absMax = max(abs(str2num(char(C(:,4))))); % Compute abs. max over min/max.

If the format of the file is fixed like that, absMax contains the abs. max. of min & max. The regex pattern simply defines the numbers with spaces.

As pointed out by Guillaume, this will fail if there are more tables with the same format in your file. Greetings, David

EDIT: Added suggestions by Guillaume

P.S.: If you want to do some processing on your data, modify the following hack>

    tbl = C;
    isEmpt = cellfun(@isempty,tbl(:,2));
    tbl(isEmpt,2) = tbl(~isEmpt,2); % Assume every other row is empty
    tbl(:,2) = strrep(tbl(:,2),'g','');

    tbl = cell2table(tbl,'VariableNames',{'Node','LC','Type','UX','UY','UZ','RX','RY','RZ'});
    tbl.Node = cumsum(~cellfun(@isempty,tbl.Node));
    tbl.Type = categorical(tbl.Type);
    for var = {'LC','UX','UY','UZ','RX','RY','RZ'}
      tbl.(var{:}) = str2num(char(tbl.(var{:})));
    end

[Guillaume]

You're reading the file twice!

You're going to need a more complex pattern to match each number as at the moment it fails to match negative numbers.

Probably a better pattern for numbers:

[+-]\d+.\d+  %instead of [ 0-9]{x}

Also because of ([ \.0-9]{7})g the pattern will fail to match the Min lines.

This also assumes that the UX column always follow Min/Max and that no other table in the file has numbers after the Min/Max column. It appears to be the case as the other (non UX) tables have a letter in the column after the Min/Max column but you need to be sure that it's always the case.

This pattern may or may not work:

regexp(fileread(file), '(?<=Min|Max)\s+([+-]?\d+.\d+)', 'match')

[David J. Mack]

My bad! That was just for the testing. Removed the first (unnecessary call). Also updated the numbers. Thanks for the hint (will use the \d+\.\d+ otherwise you would match any char between the numbers.

As I wrote, this will work only if the file is in the format as specified (where no other table has a similar format).