MATLAB: How to extract line numbers of text data

extract line numbersline numbersread line numbers

Hello everyone. I have attached a .txt file (portion.txt) which contains a portion of my data. What I need is to create a script which will identify strings that correspond to pairs of x-y coordinates and return their line numbers. For instance, in the .txt file the first set of coordinates begins at line 3 and ends at line 138 (the number of those pairs is written above each set of coordinates, which at this case is 136). So the script should return those two numbers. Then this process should be done for the whole file. I suppose that the process can be repeated with loop since every next set of coordinates begins after 2 lines from the previous one. How can this be done? Thanks in advance.

Best Answer

str=[]
fid=fopen('portion.txt')
l=fgetl(fid)
while ischar(l)
  str{end+1,1}=l;
  l=fgetl(fid);
end
fclose(fid)
str
idx=str(cellfun(@numel,regexp(str,'[\d\.]+'))==2)

Related Solutions

MATLAB: Concatenate data using fgets

You are closing the file in the loop. close the file after the loop. I assume the below should work.

function read_datapattern(filename)
fid = fopen(filename,'rt');
if fid < 0
  error('error opening file %s\n\n',filename);
end
pattern = fgets(fid);
for n = 1:32767
  nextline = fgets(fid);
  pattern = strcat(pattern, nextline);
fprintf(pattern);
fprintf('\n');
end
fclose(fid);

MATLAB: How to import specific part of text file when you do not known the size and which lines is the one you want to import

OK, here's a basic function to read any section of the file returning the data in that section plus optionally the X,Y coordinate vectors to go with it...

function [data,x,y]=readAnna(fname,section)
% returns desired sectional data from file 

% alternate returns of X,Y coordinates if desired

%

% [data,x,y]=readAnna(fname,'Dose Interpolated')

%   will return the interpolated dose section 

    fid=fopen(fname, 'r');
    [r,c]=getrowcol(fid);                     % go get the row, col sizes

    [data,x,y]=readsection(fid,section,r,c);  % get desired data section

    fid=fclose(fid);                          % close the file

  end
function [r,c]=getrowcol(fid)
  while ~feof(fid)                  % find the Rows: line
    l=fgetl(fid);
    if ~isempty(strfind(l,'Rows:')),break,end
  end
  r=sscanf(l,'Rows: %d');           % read the value from string

  c=fscanf(fid,'Cols: %d');         % get column numbers next record

end
function [d,x,y]=readsection(fid,section,r,c)
  while ~feof(fid)
    l=fgetl(fid);
    if ~isempty(strfind(l,section)),break,end
  end
  fgetl(fid);                              % skip the header record

  d=fscanf(fid,'%f',[(c+2),r]).';          % read data including y,rec

  y=d(:,1);                                % y is first column

  d=d(:,3:end);                            % save only data

  l=fgetl(fid);                            % resynch to begin next record

  x=cell2mat(textscan(fid,['%*s' repmat('%f',1,c)],'headerlines',1)).';          % read the x coords
end

This can be called in a routine to process whatever file(s) are chosen; data storage for multiple files would be handled at that level; one alternative would be 3D array.

ADDENDUM

Slightly cleaned-up version replacing multiple lookup loops with function...

function [data,x,y]=readAnna(fname,section)
% returns desired sectional data from file 
% alternate returns of X,Y coordinates if desired
%
% [data,x,y]=readAnna(fname,'Dose Interpolated')
%   will return the interpolated dose section 
    fid=fopen(fname, 'r');                    % open requested file
    [r,c]=getrowcol(fid);                     % go get the row, col sizes
    [data,x,y]=readsection(fid,section,r,c);  % get desired data section
    fid=fclose(fid);                          % close the file
  end
function [r,c]=getrowcol(fid)
  l=locaterecord(fid,'Rows:');      % get to proper record
  r=sscanf(l,'Rows: %d');           % read the value from string
  c=fscanf(fid,'Cols: %d');         % get column numbers next record
end
function [d,x,y]=readsection(fid,section,r,c)
  l=locaterecord(fid,section);          % find beginning of section
  fgetl(fid);                           % skip the header record
  d=fscanf(fid,'%f',[(c+2),r]).';       % read data including y,rec
  y=d(:,1);                             % y is first column
  d=d(:,3:end);                         % save only data
  l=fgetl(fid);                         % resynch to begin next record
  x=cell2mat(textscan(fid,['%*s' repmat('%f',1,c)],'headerlines',1)).';
end
function l=locaterecord(fid,str)
% find record in open file containing str; return as character string
  while ~feof(fid)                  
    l=fgetl(fid);
    if ~isempty(strfind(l,str)),break,end
  end
end

Best Answer

Related Solutions

MATLAB: Concatenate data using fgets

MATLAB: How to import specific part of text file when you do not known the size and which lines is the one you want to import

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