Extract rows from a text file and create array

Question

Syed Rizvi 2022-3-29

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1683384-extract-rows-from-a-text-file-and-create-array

回答： Omega 2023-9-25

I have a text file called horizon as shown below. I want to extract the data into cells but am not sure where to start. this is the code so far

function data = loaddata(filename)
disp(filename)
filename = strcat(filename,'.txt');
fid = fopen(filename,'rt');
if fid ~= -1
    line = '';
    while ~feof(fid) && ~strcmp(line,'$$SOE')
        line = fgetl(fid);
    end
    data = cell(1000,3); % Preallocate
    num = 0;
    while ~feof(fid)
        line = fgetl(fid);
        if strcmp(line,'$$EOE') % Sentinel
            break % while
        end
        num = num+1;
        if size(data,1) < num
            disp(size(data,1))
            data{2*end,1} = []; % Allocate
        end
        data(num,:) = str2cell(line);
    end
    data = data(1:num,:); % Truncate
    fclose(fid);
    disp(num)
else
    data = {}; % File open failure
end
end
function cellrow = str2cell(fid)
numdate = textscan(fid, '%*s', 'HeaderLines', 1);

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Jan 2022-3-29

Which data do you want to import in which format? Why cells?

Please post an example file. A screen shot is less useful, exspecially, if it is hard to read.

Mathieu NOE 2022-3-29

hello

if you want us to help you , maybe it would be great to share the txt file and the code + some explanations about what you want to retrieve.

all the best

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Answer 1

Omega 2023-9-25

0
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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1683384-extract-rows-from-a-text-file-and-create-array#answer_1317222

在 MATLAB Online 中打开

Hi Syed,

I understand that you would like to extract the variables JDTDB, Calendar Data (TDB), X, Y and Z into a cell array. This can be achieved through the utilization of MATLAB's strtrim and strsplit functions.

Below is an illustrative code snippet that accomplishes the intended task:

data = loaddata(‘horizon_results’); 
function data = loaddata(filename) 
    disp(filename) 
    filename = strcat(filename, '.txt'); 
    fid = fopen(filename, 'rt'); 
    if fid ~= -1 
        line = ''; 
        while ~feof(fid) && ~strcmp(line, '$$SOE') 
            line = fgetl(fid); 
        end 
        data = cell(1000, 5); % Preallocate 
        num = 0; 
        while ~feof(fid) 
            line = fgetl(fid); 
            if strcmp(line, '$$EOE') % Sentinel 
                break; % Exit the loop 
            end 
            num = num + 1; 
            if size(data, 1) < num 
                disp(size(data, 1)) 
                data{2 * end, 1} = []; % Allocate more space 
            end 
            data(num, :) = str2cell(line);  
        end 
        data = data(1:num, :); % Truncate 
        fclose(fid); 
        disp(num) 
    else 
        data = {}; % File open failure 
    end 
end 
function cellrow = str2cell(line) 
    % Remove any extra whitespaces 
    line = strtrim(line); 
    % Split the input line by commas 
    parts = strsplit(line, ','); 
    % Take the first 5 cells 
    cellrow = parts(1:5); 
end 