Import PDF files embedded in an Excel file's cell

Question

I have a row in an excel file cell with an embedded PDF in it per cell. The PDF is embedded into Excel as an object. How can I load these PDF files into Mathematica?

Sorry, I do not know how to povide a sample Excel-file.

This is how it looks like in Excel:

Answer 1

XLSX file is nothing else than a simple ZIP archive. If PDFs were properly embedded in the Excel document, you will find them in the xl/embeddings folder, stored as oleObject###.bin files. These binary files are your embedded files, but they have some metadata prepended to them. I didn't go into the details of this metadata header, however, if you know what type of file you have embedded, you can simply look for the header of your file. All PDF files begin with a string %PDF-.

Long story short, you can simply use Import in Mathematica to extract files from the ZIP archive, find all oleObject###.bin files, look for the presence of PDF header string, and import the data as a PDF document.

importPDFsFromXLSX[xlsxFile_] := Module[{
   files = Import[xlsxFile, {"ZIP", "FileNames"}],
   binFiles, pdfHeader = Normal@StringToByteArray["%PDF-"]
   },
  binFiles = Import[xlsxFile, {"ZIP", 
   Select[files, StringEndsQ["oleObject" ~~ _ ~~ ".bin"]], "Byte"}];
  Table[ImportByteArray[
    ByteArray@binFile[[SequencePosition[binFile, pdfHeader][[1, 1]] ;;]], "PDF"], 
    {binFile, binFiles}]
  ]

Below, I've created a test Excel file with four embedded PDFs (VDELAJ is the Slovene translation of your EINBETTEN or English EMBED function).

Now we simply import the file using the function above.