Appending to an excel in matlab

问题

I am following up on my own question. By using:

excelWorkbook.SaveAs('figtest.xlsx'); 

I am overwriting the existing excel. I have created a function which uses the code to save two images to excel. Now I want to iterate over a number of images, process each image and then save the result alongside the original image to an excel. Obviously calling the function each iteration is a bad idea since, each iteration is deleting the results of former iterations.

How can I add the current data to the excel file without deleting any former data?

Is there a better way to do this?

Note that the data is images and not simple numeric data.

回答1:

Create a COM server once, iterate over the images and place them in the desired cells, quit the server and then delete the server object.

Building from my previous answer, here is a working example with 5 of many built-in images:

%Some sample images
im{1}=imread('peppers.png');
im{2}=imread('cameraman.tif');
im{3}=imread('pears.png');
im{4}=imread('greens.jpg');
im{5}=imread('bag.png');

excel = actxserver('Excel.Application'); % Create server object
excelWorkbook = excel.Workbooks.Add(1);  % Add a workbook
excelSheet = excel.ActiveSheet;          % Get the active sheet

f = figure('visible','off');             % To not show the images in MATLAB
dpi = get(groot, 'ScreenPixelsPerInch'); % Get screen dpi
for k=1:5
    imshow(im{k});
    print(gcf, sprintf('-r%d', dpi), ...     % Print the figure at the screen resolution
        '-clipboard', '-dbitmap');           %    to the clipboard as a bitmap
    %Adjust the cell names where you want to paste the images as desired
    excelSheet.Range(['B',num2str(k)]).PasteSpecial();
    %Unlocking aspect ratio to adjust height and width of the image according to the cell
    excelSheet.Shapes.Item(k).LockAspectRatio='msoFalse';
    excelSheet.Shapes.Item(k).Width=excelSheet.Range(['B',num2str(k)]).Width;
    excelSheet.Shapes.Item(k).Height=excelSheet.Range(['B',num2str(k)]).Height;     
end
excelWorkbook.SaveAs('figtest.xlsx');     % Save workbook to a file
excelWorkbook.Close();                    % Close workbook
excel.Quit();                             % Quit server
excel.delete();                           % Delete server object

which gives:

回答2:

One approach is to place each set of images in its own sheet, creating new sheets in the Excel file as needed. Here's some sample code, modified from my previous answer:

% Start COM server:
excel = actxserver('Excel.Application');
excelWorkbook = excel.Workbooks.Add(1);
excelWorksheets = excelWorkbook.Worksheets;

% Initializations:
dpi = get(groot, 'ScreenPixelsPerInch');

for iSheet = 1:nIterations  % Based on how many image sets you process

  % Get a blank sheet:
  if (iSheet == 1)
    excelSheet = excel.ActiveSheet;
  else
    excelSheet = excelWorksheets.Add([], excel.ActiveSheet, 1);
  end

  % Load, process, and plot your images here:
  ...

  % Paste image into sheet and adjust cell size:
  print(hFigure, sprintf('-r%d', dpi), '-clipboard', '-dbitmap');
  excelSheet.Range('B2').PasteSpecial();
  excelSheet.Range('B2').RowHeight = excelSheet.Shapes.Item(1).Height;
  widthScale = excelSheet.Range('B2').ColumnWidth./...
               excelSheet.Range('B2').Width;
  excelSheet.Range('B2').ColumnWidth = excelSheet.Shapes.Item(1).Width.*widthScale;

end

% Save and close workbook and stop COM server:
excelWorkbook.SaveAs('figtest.xlsx');
excelWorkbook.Close();
excel.Quit();
excel.delete();

回答3:

Adding data to an excel file is not well defined: creating new sheets or adding data to an existing one?

Therefore, you probably need the following methodology:

1. Open the existing excel file (to which you want to add data)
2. Add the new data to the opened excel file
3. Save this edited excel file

回答4:

Just found this here:

xlApp = actxserver('Excel.Application');
xlApp.visible = 1;
%Open the the spreadsheet
xlworkbook = xlApp.Workbooks.Open('figtest.xlsx');
xlsheet = xlworkbook.ActiveSheet;
mydata=randn(1,3);
data=xlsread('figtest.xlsx');
%Determine last row
last=size(data,1);
newRange=last+1;
xlCurrRange = xlsheet.Range(['A', num2str(newRange),':C', num2str(newRange)]);
xlCurrRange.Value2 = mydata;
%Save and Close the Excel File
invoke(xlworkbook,'Save');
invoke(excelApp,'Quit');
delete(excelApp);

Also, you may want to try this script from the File Exchange.

来源：https://stackoverflow.com/questions/45955681/appending-to-an-excel-in-matlab