Find the row of a word in a file

Dear all, I have a text file, which has some headers and then 3 lists like the following:

   Region_1
 2.1 3.2 4.3
 3.2 9.3 6.7
 ...
   Region_2
 1.1 1.2 0.3
 5.5 9.7 9.7
 ...

And I want to take the table only for Region_23. How can I do that?

I hope you could help me with this, I didnt manage to find any commands...

All the best,

           Panos

p.s. Every region has different nr of rows. They tables dont have the same size

Answer 1

[Titus Edelhofer]

Hi,

something like the following should do the trick

fid = fopen('yourtextfile.txt', 'rt');
% read the entire file, if not too big
s = textscan(fid, '%s', 'delimiter', '\n');
% search for your Region:
idx1 = find(strcmp(s{1}, 'Region_23'), 1, 'first');
% now search for the next Region:
idx2 = find(strcmp(s{1}, 'Region_24'), 1, 'first');
% and read from s{1}(idx1+1:idx2-1) the values using textscan again ...
fclose(fid);

Not tested but should give you a hint ...

Titus

Answer 2

[Panos]

Hi Titus,

thnx for you answer. It did exactly what I wanted. I d like to ask you something else. How is it possible to read from a file a line removing or ignoring a word, and reading the existing numbers not as comments. Because as it is, it reads the numbers as comments. The line looks like this:

 Total            333.398E-03     5.42046E-03     604.137E-03

I use strrep to remove the 'Total' word. But how do I take the numbers as a table lets say of 3 numbers?

All the best,

        Panos

Answer 3

[Titus Edelhofer]

Hi Panos,

to read a number instead of a string, use textscan again but replace the %s by %f: let's say sFound is the line. Then

sFoundParts = textscan(sFound, '%s %f %f %f');

should give in sFoundParts{1} the "Total" in the other cells the numbers.

Titus

Answer 4

[Tímea]

Hi!

I have a very similar problem, most of the code worked perfect, thanks! I couldn't get this last part you wrote above working though: % and read from s{1}(idx1+1:idx2-1) the values using textscan again ...

My line was this: alpha = textscan(s{1}(idx1+1:idx2-1),'%f32',idx2-idx1-1)

Perhaps I misunderstand how it works with textscan..

What I finally want to do is to copy all the text between (idx1+1:idx2-1) to a vector, as floating point numbers. Do you have a suggestion for that?

Tim

[Cedric]

You could do something like:

 buffer  = s{1}(idx1+1:idx2-1) ;
 dataTxt = sprintf( '%s\n', buffer{:} ) ;

and call TEXTSCAN with dataTxt, e.g.

 data = textscan( dataTxt, '%f %f %f' ) ;

[Tímea]

Thanks! Something happens, but I still can't get the numbers from 'data' out. The structure of the result I get is this:

data = [3112136x1 double]

>>data(1)

ans =

    [3112136x1 double]

Probably it's not the way to do it, but I haven't found any other yet. This is how the code looks now:

if true
  % code
fid = fopen('50.dx','rt');
% read the entire file - s becomes a cell array (12448587x1)
s = textscan(fid,'%s','delimiter','\n');
% search for your region (have to copy the whole row)
idx1 = find(strcmp(s{1},'object "alfa" class array type float rank 0          items  3112136 data follows'),1,'first');
% now search for the next region (-||-)
idx2 = find(strcmp(s{1},'attribute "dep" string "positions"'),1,'last');
% and read from s{1}(idx1+1:idx2-1) the values using textscan again
buffer  = s{1}(idx1+1:idx2-1);
dataTxt = sprintf('%s\n',buffer{:});
% call TEXTSCAN with dataTxt, e.g.
data = textscan(dataTxt,'%f');

fclose(fid); end

(In the original text file I have numbers in one column, corresponding to scalar values for a 3d box domain, which I alter on want to plot.)

Tim

[Cedric]

Check that dataTxt is a string which contains only numbers. It seems that TEXTSCAN outputs a cell array, which is a bit weird if you have only numbers and use the simple '%f' formatSpec. Yet, it's worth checking whether these numbers are what you are looking for.

1. Check that data is a cell array:

 >> class(data)

if this return cell, you are dealing with a cell array. Then just extract the content of cell 1 (content of cells are addressed using curly brackets):

 >> data = data{1} ;

Now data should be a numeric array that you can plot, reshape, etc.

Answer 5

[Tímea]

Ah, the bracket was the trick! Everything worked like you wrote above, data was a cell array. I tried cell2mat before, that didn't worked the way I tried.

Thanks a lot!!

[Cedric]

You're welcome!