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I found part of the answer from this post and it was very useful https://stackoverflow.com/a/42375263/13765378

However, every time I ran this code with new data, a new sheet gets added to the end of a workbook. After a while, it is quite an effort to get to that new sheet that was just added. Is there a way to specify adding to the beginning of the workbook, so it will be the default sheet when we open the workbook?

Dershan
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  • The way the example you provided works, there is no easy way to re-order the sheets without rebuilding the whole workbook with the sheet you want first first. However, you can set the active sheet which will be opened by default. see https://stackoverflow.com/questions/41556378/openpyxl-set-active-sheet/50117733 – NickSlash Jun 17 '20 at 22:29

2 Answers2

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This will help you.use the second line.this uses openpyxl module help link https://openpyxl.readthedocs.io/en/stable/tutorial.html

ws1 = wb.create_sheet("Mysheet") # insert at the end (default)

ws2 = wb.create_sheet("Mysheet", 0) # insert at first position
Vignesh
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Thanks to Vignesh's answer, and Thanks to and modifying the code from writing pandas data frame to existing workbook I got the following code to work: [Every time the program is run, a new sheet will be created at the beginning of the workbook and contains (new) data. Rest of the code just testing out the function append_df_to_excel()] The function append_df_to_excel() seems over-kill for what I need to do, but for now I could not find a better and cleaner way to do it.

I also do not understand why saving the workbook at the end will not save the data.

import os
from openpyxl import load_workbook
import xlsxwriter
import pandas as pd
from datetime import datetime

filename = r'C:\test\test.xlsx'
if not os.path.exists(filename):
    wb = xlsxwriter.Workbook(filename)
    wb.close()   

def append_df_to_excel(filename, df, sheet_name='Sheet1', startrow=None,
                       truncate_sheet=False, 
                       **to_excel_kwargs):
    """
    Append a DataFrame [df] to existing Excel file [filename]
    into [sheet_name] Sheet.
    If [filename] doesn't exist, then this function will create it.

    Parameters:
      filename : File path or existing ExcelWriter
                 (Example: '/path/to/file.xlsx')
      df : dataframe to save to workbook
      sheet_name : Name of sheet which will contain DataFrame.
                   (default: 'Sheet1')
      startrow : upper left cell row to dump data frame.
                 Per default (startrow=None) calculate the last row
                 in the existing DF and write to the next row...
      truncate_sheet : truncate (remove and recreate) [sheet_name]
                       before writing DataFrame to Excel file
      to_excel_kwargs : arguments which will be passed to `DataFrame.to_excel()`
                        [can be dictionary]

    Returns: None
    """


    # ignore [engine] parameter if it was passed
    if 'engine' in to_excel_kwargs:
        to_excel_kwargs.pop('engine')

    writer = pd.ExcelWriter(filename, engine='openpyxl')

    if not os.path.exists(filename):
        wb = xlsxwriter.Workbook(filename)
        wb.close()     
    try:
        # try to open an existing workbook
        writer.book = load_workbook(filename)

        # get the last row in the existing Excel sheet
        # if it was not specified explicitly
        if startrow is None and sheet_name in writer.book.sheetnames:
            startrow = writer.book[sheet_name].max_row
        # truncate sheet
        if truncate_sheet and sheet_name in writer.book.sheetnames:
            # index of [sheet_name] sheet
            idx = writer.book.sheetnames.index(sheet_name)
            # remove [sheet_name]
            writer.book.remove(writer.book.worksheets[idx])
            # create an empty sheet [sheet_name] using old index
            writer.book.create_sheet(sheet_name, idx)
            # writer.book.create_sheet(sheet_name, 0) #not working

        # copy existing sheets
        writer.sheets = {ws.title:ws for ws in writer.book.worksheets}
    except FileNotFoundError:
        # file does not exist yet, we will create it
        pass

    if startrow is None:
        startrow = 0

    # write out the new sheet
    df.to_excel(writer, sheet_name, startrow=startrow, **to_excel_kwargs)

    # save the workbook
    writer.save()

A = [[0,1,2],[3,4,5],[6,7,8],[9,10,11]]
df = pd.DataFrame(A, columns=list('XYZ'))

newSheet = "New_" + datetime.now().strftime('%Y-%m-%d_%H%M%S')
wb = load_workbook(filename)
ws = wb.create_sheet(newSheet, 0)
wb.save(filename)

append_df_to_excel(filename, df, sheet_name="Old2", startrow=1, startcol=1)
append_df_to_excel(filename, df, sheet_name="Old3", index=False)
append_df_to_excel(filename, df, sheet_name="Old1", startcol=2, index=False) 
append_df_to_excel(filename, df, sheet_name=newSheet, columns=df.columns.values, startrow=0, startcol=0, index=False)

# wb.save(filename) # Do not do this, will get nothing written to workbook
Dershan
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