Is it possible to get an Excel document's row count without loading the entire document into memory?

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暖寄归人
暖寄归人 2020-12-04 19:09

I\'m working on an application that processes huge Excel 2007 files, and I\'m using OpenPyXL to do it. OpenPyXL has two different methods of reading an Excel file - one \"no

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  •  有刺的猬
    2020-12-04 19:34

    The solution suggested in this answer has been deprecated, and might no longer work.


    Taking a look at the source code of OpenPyXL (IterableWorksheet) I've figured out how to get the column and row count from an iterator worksheet:

    wb = load_workbook(path, use_iterators=True)
    sheet = wb.worksheets[0]
    
    row_count = sheet.get_highest_row() - 1
    column_count = letter_to_index(sheet.get_highest_column()) + 1
    

    IterableWorksheet.get_highest_column returns a string with the column letter that you can see in Excel, e.g. "A", "B", "C" etc. Therefore I've also written a function to translate the column letter to a zero based index:

    def letter_to_index(letter):
        """Converts a column letter, e.g. "A", "B", "AA", "BC" etc. to a zero based
        column index.
    
        A becomes 0, B becomes 1, Z becomes 25, AA becomes 26 etc.
    
        Args:
            letter (str): The column index letter.
        Returns:
            The column index as an integer.
        """
        letter = letter.upper()
        result = 0
    
        for index, char in enumerate(reversed(letter)):
            # Get the ASCII number of the letter and subtract 64 so that A
            # corresponds to 1.
            num = ord(char) - 64
    
            # Multiply the number with 26 to the power of `index` to get the correct
            # value of the letter based on it's index in the string.
            final_num = (26 ** index) * num
    
            result += final_num
    
        # Subtract 1 from the result to make it zero-based before returning.
        return result - 1
    

    I still haven't figured out how to get the column sizes though, so I've decided to use a fixed-width font and automatically scaled columns in my application.

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