如何将新工作表保存到现有 excel 工作簿的开头？

Question

我从这篇文章中找到了部分答案，它非常有用https://stackoverflow.com/a/42375263/13765378

但是，每次我使用新数据运行此代码时，都会在工作簿的末尾添加一个新工作表。 过了一会儿，要找到刚刚添加的新工作表是相当困难的。 有没有办法指定添加到工作簿的开头，所以当我们打开工作簿时它将是默认工作表？

Answer 1

这将对你有所帮助。使用第二行。这使用 openpyxl 模块帮助链接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

Answer 2

感谢 Vignesh 的回答，感谢并修改将pandas 数据框写入现有工作簿的代码，我得到了以下代码工作：[每次运行程序时，都会在工作簿的开头创建一个新工作表并包含（新数据。 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.

我也不明白为什么最后保存工作簿不会保存数据。

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