extract certain Columns from table in which the value varies

Question

Hussam Saddour 2022-10-9

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1820500-extract-certain-columns-from-table-in-which-the-value-varies

回答： Image Analyst 2022-10-9

automesssung1.xlsx

i have a 4 column table, i need to extract certain arrays based on the number of the 3rd column and plot x=column2 ,y=column4

note that the number of elements in each iteration is not constant (in this example 76) it may be more or less, and the Values in the 3rd column are also not fix

3 个评论
显示 1更早的评论隐藏 1更早的评论

Hussam Saddour 2022-10-9

Microsoft Excel-Arbeitsblatt (neu).xlsx

i have attached a new table actually x,y refers to each element of the same value on the third column, so i have to create and plot arrays seperatly that have a common Value on 3rd column, hope that explained what i mean

dpb 2022-10-9

We know what you meant; @Davide Masiello was suggesting using the very good MATLAB documentation that includes <read-a-sequence-of-spreadsheet-files> to give it a shot on your own first; "learning by doing" is typically much more effective than just having somebody hand off a complete solution.

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Image Analyst 2022-10-9

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1820500-extract-certain-columns-from-table-in-which-the-value-varies#answer_1069860

在 MATLAB Online 中打开

Try this, modifying the file pattern as needed:

% Get a list of files
filePattern = fullfile(pwd, 'Microsoft Excel-Arbeitsblatt*.xlsx');
fileList = dir(filePattern);
numFiles = numel(fileList)
for fileNumber = 1 : numFiles
    % Read in this particular file.
    fullFileName = fullfile(fileList(fileNumber).folder, fileList(fileNumber).name);
    fprintf('Reading in file #%d of %d.\n', fileNumber, numFiles);
    data = readtable(fullFileName);
    [rows, columns] = size(data);
    % Initialize x and y for this file.
    x = [];
    y = [];
    % Extract the third column and determine if it's x or y
    for row = 1 : rows
        if strcmpi(data{row, 3}, 'x')
            x = [x; data{row, 2}];
        elseif strcmpi(data{row, 3}, 'y')
            y = [y; data{row, 2}];
        end
    end
    % Plot it.
    if ~isempty(x)
        figure;
        plot(x, y, 'b-', 'LineWidth', 2);
        grid on;
        xlabel('x');
        ylabel('y')
        title(fileList(fileNumber).name)
    end
end
message = sprintf('Done processing %d files.', numFiles);
fprintf('%s\n', message);
uiwait(helpdlg(message))