How to read a text file and save it as different variables

Hi,

I have a text file in the following format:

String line

String line

.Sample 1 0 0 0

5441.45 5454.52 5425.85 742.95

512.12 9894.21 4511.45 78921.45

.Sample 2 0 0 0

45961.45 8562.45 859.24 9453.14

845.52 6896.25 1236.45 9856.23

I have 10 such sample numbers and each sample has around 100 rows of numeric data. I want to read and save the data listed under each sample number as different variables. For example, all the data under Sample 1 0 0 0 as A, all the data under Sample 2 0 0 0 as B and so on. May I know how can I do that and which will be the best function to use.

[Stephen23]

"For example, all the data under Sample 1 0 0 0 as A, all the data under Sample 2 0 0 0 as B and so on."

That makes accessing your data more complex, and forces you into writing slow, complex, inefficient code:

https://www.mathworks.com/matlabcentral/answers/304528-tutorial-why-variables-should-not-be-named-dynamically-eval

"May I know how can I do that and which will be the best function to use."

The neat, simple, and very efficient approach is to use indexing or fieldnames.

If you upload a sample file by clicking the paperclip button then someone can help you with this.

Answer 1

[Mathieu NOE]

hello

I saved you short text from the post in a file and started some coding

nota this code contains also an alternative to readlines if you have an older release

see the results below :

data is a 2 cell array containing your 2 data :

>> data{1}

2×1 cell array

{'5441.45 5454.52 5425.85 742.95' }

{'512.12 9894.21 4511.45 78921.45'}

>> data{2}

2×1 cell array

{'45961.45 8562.45 859.24 9453.14'}

{'845.52 6896.25 1236.45 9856.23' }

code

%%%%%%%% main code %%%%%%%%%
clc
clearvars

filename = 'test.txt';
str = "Sample ";

[data] = myfunction_read(filename,str);

%%%%%%% functions %%%%%%%%%
function lines = my_readlines(filename)
    % work around for earlier matlab releases (not having readlines)
    lines = regexp(fileread(filename), '\r?\n', 'split');
    if isempty(lines{end}); lines(end) = []; end  %end of file correction

end

%%%%%%%%%%%%%%%%%%%%%%%%%
function [data] = myfunction_read(filename,str)

lines = my_readlines(filename);
% init data
count = 0;
flag = 0;
k = 0;
line_index = 1;

for ci = 1:numel(lines)
     ll = lines(ci);        

    if contains(ll,str)  % 
        
        line_index = ci;
        flag = 1;
        k = 0;
        count = count+1;
    end        
  
    if flag == 1 && ci >= line_index+1
        k = k +1;
        data{count}(k,:) = ll;
    end
    
end

end