MATLAB: Extract a specific line in text files

specific line in many text files

how are you best community :

I have about 6000 text files each of them has 11 lines as shown next :

COM: IFN/ENIT-database truth (label) file
COM: http://www.ifnenit.com
COM: IfN, TU-BS
COM: ae07_001.tif coming from pa021_0.tif
X_Y: 449 119
BDR: begin data record
LBL: ZIP:1251;AW1:ÇáÔÑÇíÚ;AW2:aaA|laB|shM|raE|aaA|yaB|ayE|;QUA:YB2;ADD:P4
CHA: 7
BLN: 82,78
TLN: 32,62
EDR: end of data record

i want to extract from the seventh line only the text

"aaA|laB|shM|raE|aaA|yaB|ayE|"

( the part i want to extract does not has the same size from file to file )and put all of them in a new array with same size of files numbers .

how can i do it

any answer will be appreciated .

thank you

Best Answer

Use fileread() to read the file into a single string. Use regexp() to match the portions of it you want. For example

regexp(TheString, '(?<=COM:\s+)\S+(?=\s+coming)', 'match')

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MATLAB: Extract numbers or string after specific symbol from a text file

dinfo = dir('*.txt');
nfiles = length(dinfo);
filenames = fullfile({dinfo.folder}, {dinfo.name});
IDs = cell(nfiles,1);
FCs = cell(nfiles,1);
intervals = cell(nfiles,1);
for K = 1 : nfiles
    
    filename = filenames{K};
    
    S = fileread(filename);
    parts = regexp(S, '(?<=Location ID\s*:\s*)(?<ID>\d+).*(?<=Field code\s*:\s*)(?<FC>\w+).*(?<=Sample interval\s*:\s*)(?<SI>\w+)', 'names');
    
    IDs{K} = str2double({parts.ID});
    FCs{K} = {parts.FC};
    intervals{K} = str2double({parts.SI});
end

Note: this code does not assume that there is only one occurance of the information per file. It will find all of the occurance in each file, provided that the parts are all in the same order and none of the parts are missing.

If there is only ever one occurance then the code could be simplified a little.

MATLAB: Load text file from subfolder

projectdir = 'fiber optics';
dinfo = dir(fullfile(projectdir, '**', '*.txt'));
filenames = fullfile({dinfo.folder}, {dinfo.name});
nfiles = length(filenames);
datum = cell(nfiles,1);
foldernames = cell(nfiles,1);
for K = 1 : nfiles
    thisfile = filenames{K};
    fullparent = fileparts(thisfile);
    [~, foldername] = fileparts(fullparent);
    datum{K} = load(thisfile);
    foldernames{K} = foldername;
end

Now you have a cell array, datum, and a cell array foldernames, and can plot as appropriate, using the foldernames as labels.

I doubt that you want 200k lines on one plot, so I will not try to guess how you want to do the plotting.

Best Answer

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MATLAB: Extract numbers or string after specific symbol from a text file

MATLAB: Load text file from subfolder

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