ENH: write to existing sheet of excel file

[fdzuJ]

Is your feature request related to a problem?

Prior to GH40230 it was possible to write to existing sheet using code like below. I would like to be able to do it again.
I use it to create excel files with overly compicated and/or regularly changing header requirements.

def write_to_excel(df: pd.DataFrame, mode: str = 'a', form: Path, sheetname: Union[int, str] = 0, **kwargs)
    with pd.ExcelWriter(path, mode=mode) as writer:
        if mode == 'a':
            for sheet, sheet_name in zip(writer.book.worksheets, writer.book.sheetnames)
                writer.sheets.setdefault(sheet_name, sheet)
            if isinstance(sheetname, int):
                sheetname = writer.book.sheetnames[sheetname]
        else:
            sheetname = sheetname if isinstance(sheetname, str) else 'Sheet1'

        df.to_excel(writer, sheet_name=sheetname, engine='openpyxl', **kwargs)

Describe the solution you'd like

Add append option for if_sheet_exists parameter

API breaking implications

New option for parameter shouldn't break API.

Describe alternatives you've considered

This was possible prior to previously mentioned enhancement. Only solution I can think of now is to initiate ExcelWriter with if_sheet_exists='new' and to copy everything from previously existing sheet before writing dataframe and to rename and delete sheets accordingly later.

[pavel-hushcha]

Strongly agree with that.

[simonjayhawkins]

@fdzuJ duplicate of #42221?

[fdzuJ]

Yes, it's a duplicate. Closing.