将Pandas DataFrame附加到现有Excel文档

Question

根据https://github.com/pandas-dev/pandas/pull/21251/files/09e5b456e1af5cde55f18f903ab90c761643b05a，我们应该能够将DataFrames附加到新的XLSX表。

根据文档，我尝试了以下内容：

>>> import pandas as pd
>>>                
... d1 = pd.DataFrame({"A":['Bob','Joe', 'Mark'], 
...                "B":['5', '10', '20']})
>>> d2 = pd.DataFrame({"A":['Jeffrey','Ann', 'Sue'], 
...                "B":['1', '2', '3']})
>>> 
>>> # Create XLSX document for ticker
... writer = pd.ExcelWriter('test.xlsx',engine='openpyxl')
>>> d1.to_excel(writer,sheet_name='d1')
>>> writer.save()
>>> 
>>> writer = pd.ExcelWriter('test.xlsx',engine='openpyxl', mode='a')
>>> d2.to_excel(writer,sheet_name='d2')
>>> writer.save()
>>> 
>>> pd.__version__
'0.23.4'     # Just updated this per a comment
>>> 
>>> 

结果是一个名为“test.xlsx”的工作簿，其中包含一个标签“d2”。

如何防止覆盖工作簿/表单？

Answer 1

你可以使用with：

with pd.ExcelWriter('test.xlsx', engine='openpyxl', mode='a') as writer:
    d1.to_excel(writer,sheet_name='d1')
    d2.to_excel(writer,sheet_name='d2')
    writer.save()

writer.close()

update

这应该只需要注意一个空白文件需要事先创建。如果需要，您可以使用python创建一个空白文件。我创建了一个简单的循环，在某些方面，模仿了你想要完成的事情的本质：

import pandas as pd
from openpyxl import load_workbook

d1 = pd.DataFrame({"A":['Bob','Joe', 'Mark'], 
               "B":['5', '10', '20']})
d2 = pd.DataFrame({"A":['Jeffrey','Ann', 'Sue'], 
                "B":['1', '2', '3']})

dfs = [d1,d2]

for i in range(len(dfs)):
    sheet = 'd'+str(i+1)
    data = dfs[i]
    writer = pd.ExcelWriter('atest.xlsx',engine='openpyxl', mode='a')
    writer.book = load_workbook('atest.xlsx') # here is the difference
    data.to_excel(writer,sheet_name=sheet)
    writer.save()
    writer.close()

或者这是修改后的第一个例子：

d1 = pd.DataFrame({"A":['Bob','Joe', 'Mark'], 
               "B":['5', '10', '20']})
d2 = pd.DataFrame({"A":['Jeffrey','Ann', 'Sue'], 
                "B":['1', '2', '3']})

writer = pd.ExcelWriter('atest.xlsx', engine='openpyxl', mode='w')
d1.to_excel(writer,sheet_name='d1')
writer.save()
writer.close()

writer = pd.ExcelWriter('atest.xlsx', engine='openpyxl', mode='a')
writer.book = load_workbook('atest.xlsx')
d2.to_excel(writer,sheet_name='d2')
writer.save()
writer.close()

Answer 2

我在GitHub上提交了一篇帖子，并收到了贡献者的回复（见下面突出显示的部分）。事实证明，直到0.24才会发布此功能，因此它在0.23.1中不可用。仅供参考 - 我下载了RC并成功试用了mode='a'option。但是，可能存在不存在的工作簿的错误;我收到FileNotFoundError: [Errno 2] No such file or directory: 'test.xlsx'。

“这个功能是作为0.24的一部分发布的，我们刚刚发布了过去几天的候选版本。你可以尝试使用RC或者这里的主人，如果两个工作都没有根据贡献指南打开一个问题，但这不会'预期可以使用早于那个版本的版本“

Answer 3

将pandas导入为pd

writer = pd.ExcelWriter(wk_path + save_file)
# ....
# build sc_files DataFrame and save. sc_files includes
# a column called OS.

sc_file.to_excel(writer, sheet_name='test')

# build data frame of OS counts out of sc_file
counts_os = sc_file.OS.value_counts() 

# To append to 'test' sheet, use startcol=x1, startrow=y
# To append counts_OS to the end of the current 'test' sheet
y = len(sc_file)
y += 1
counts_os.to_excel(writer, sheet_name='test', 
    startcol=1, startrow=y)

# write counts_os to sheet test2 
counts_os.to_excel(writer, sheet_name='test2')
writer.save()
writer.close()