Find a word in a file then pick the value next to it

Good morning everyone,

I am trying to open a file, find a keyword and pick the value next to it. I tried using the command regexp but I don't have the good result.

Here is my file :

*SET,MAX_ANCRAGE_X_6881,  185.5679805275    
*SET,MAX_ANCRAGE_X_6952,  332.0771666276    
*SET,MAX_ANCRAGE_X_6968,  194.5047935943    
*SET,MAX_ANCRAGE_X_7011,  321.4175275594    
*SET,MAX_ANCRAGE_Y_6881,  412.8217963186    
*SET,MAX_ANCRAGE_Y_6952,  202.2417053201    
*SET,MAX_ANCRAGE_Y_6968,  580.6889503183    
*SET,MAX_ANCRAGE_Y_7011,  165.7298365705    
*SET,MAX_ANCRAGE_Z_6881,  3354.728736175    
*SET,MAX_ANCRAGE_Z_6952,  4722.802350600    
*SET,MAX_ANCRAGE_Z_6968,  3274.569376437    
*SET,MAX_ANCRAGE_Z_7011,  3042.275382807    
*SET,MAX_DEPLACEMENT, 0.1533135713205E-02
*SET,MAX_DISPLACEMENT, 0.1905912931085E-05
*SET,MAX_VM  ,  39323548.00000    
*SET,MODULE_YOUNG,  210000000000.0    
*SET,MODULE_YOUNG_RIGIDE, 0.2100000000000E+15

I would like to perform a loop as

for i=[6881 6952 6968]
find the value next to MAX_ANCRAGE_X_i and store it into a matrix (3*3) 
then do the same with MAX_ANCRAGE_Y_i
then do the same with MAX_ANCRAGE_Z_i
end

My objective is to have

(Max_Ancrage_X_6881 Max_Ancrage_Y_6881 Max_Ancrage_Z_6881)
(Max_Ancrage_X_6952 Max_Ancrage_Y_6952 Max_Ancrage_Z_6952)
(Max_Ancrage_X_6968 Max_Ancrage_Y_6968 Max_Ancrage_Z_6968)

Thanks you really much for your help !

Thibaut

[Johannes Rebling]

Could you post your code using regexp?

[Thibaut]

This is what I tried but I don't understand how to use these commands. I don't know what expression to use to pick the value next to the keyword

[Johannes Rebling]

So the final result should be:

(185.5679805275 412.8217963186 3354.728736175) etc?

[Thibaut]

yes exactly !

Answer 1

[Johannes Rebling]

One way would be regexp, another would be strfind, see doc strfind.

str =  '*SET,MAX_ANCRAGE_X_6881,  185.5679805275';
i = 6881;
searchStr = sprintf('MAX_ANCRAGE_X_%04i',i);
strStartIdx = strfind(str,searchStr);
numberStartIdx = strStartIdx + numel(searchStr) + 3
numberStr = str(numberStartIdx:end);
value = str2double(numberStr)

Answer 2

[dpb]

buf=importdata('thibaut.dat');       % get the data in; how is your choice...importdata leaves .text, .data
ix=contains(buf.textdata(:,2),'ANCRAGE');  % splits at comma delimiter so is in second column
nodes=str2double(extractAfter(text,max(strfind(text(1),'_'))));  % extract the node numbers for info
iWant=[6881 6952 6968];                     % the desired subset
xyz=zeros(numel(iWant),3);                  % preallocate the output array
for i=1:numel(iWant)
  xyz(i,:)=buf.data(ismember(nodes,iWant(i))).';
end

Results in

>> format bank
>> xyz
xyz =
        185.57        412.82       3354.73
        332.08        202.24       4722.80
        194.50        580.69       3274.57
>> 

Have the nodes array to go with to identify which is which...using lookup in an array is much simpler than coding explicit variable names containing metadata--that way "there be dragons!"

[Thibaut]

Thank you really much !

Answer 3

[Stephen23]

>> str = fileread('test.txt');
>> rgx = 'MAX_ANCRAGE_[XYZ]_(?:6881|6952|6968),\s+(\d+\.?\d*)';
>> tkn = regexp(str,rgx,'tokens');
>> mat = reshape(str2double([tkn{:}]),[3,3])
mat =
       185.57       412.82       3354.7
       332.08       202.24       4722.8
        194.5       580.69       3274.6

[Thibaut]

Thank you really much !

Answer 4

[TADA]

You've got the right idea. Regular expressions can be confusing at times I tested the regexp, the rest of the code is not tested but I trust you to make it work

data = fileread('whatever file name');

% this is the regexp pattern, we use 
% sprintf to insert the x/y/z and 
% number later. 
% This is why the backslash is escaped
pattern = 'MAX_ANCRAGE_%s_%d,\\s*(\\d*\\.?\\d*)';

ids = [6881 6952 6968];
varNames = {'X', 'Y', 'Z'};
out = zeros(numel(ids), numel(varNames));

for i = 1:numel(ids)
    for j = 1:numel(varNames)
        tok = regexp(sprintf(pattern, varNames{j}, ids(i)), 'tokens');
        val = tok{1};
        out(i,j) = str2double(val{1});
    end
end

[Thibaut]

Thank you really much !

[TADA]

Cheers