标签：python pandas for-loop excel append
我目前有这个代码.它完美地运作.
它循环遍历文件夹中的excel文件,
删除前两行,然后将它们保存为单独的excel文件,
它还将文件保存在循环中作为附加文件.
目前,每次运行代码时附加的文件都会覆盖现有文件.
我需要将新数据附加到已经存在的Excel工作表的底部(‘master_data.xlsx)
dfList = []
path = 'C:\\Test\\TestRawFile'
newpath = 'C:\\Path\\To\\New\\Folder'
for fn in os.listdir(path):
# Absolute file path
file = os.path.join(path, fn)
if os.path.isfile(file):
# Import the excel file and call it xlsx_file
xlsx_file = pd.ExcelFile(file)
# View the excel files sheet names
xlsx_file.sheet_names
# Load the xlsx files Data sheet as a dataframe
df = xlsx_file.parse('Sheet1',header= None)
df_NoHeader = df[2:]
data = df_NoHeader
# Save individual dataframe
data.to_excel(os.path.join(newpath, fn))
dfList.append(data)
appended_data = pd.concat(dfList)
appended_data.to_excel(os.path.join(newpath, 'master_data.xlsx'))
我认为这将是一项简单的任务,但我猜不是.
我想我需要将master_data.xlsx文件作为数据帧引入,然后将索引与新的附加数据匹配,并将其保存回来.或者也许有一种更简单的方法.任何帮助表示赞赏.
解决方法:
用于将DataFrame附加到现有Excel文件的辅助函数：
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
"""
from openpyxl import load_workbook
import pandas as pd
# ignore [engine] parameter if it was passed
if 'engine' in to_excel_kwargs:
to_excel_kwargs.pop('engine')
writer = pd.ExcelWriter(filename, engine='openpyxl')
# Python 2.x: define [FileNotFoundError] exception if it doesn't exist
try:
FileNotFoundError
except NameError:
FileNotFoundError = IOError
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)
# 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()
旧答案：它允许您将多个DataFrame写入新的Excel文件.
您可以将openpyxl引擎与startrow参数结合使用：
In [48]: writer = pd.ExcelWriter('c:/temp/test.xlsx', engine='openpyxl')
In [49]: df.to_excel(writer, index=False)
In [50]: df.to_excel(writer, startrow=len(df)+2, index=False)
In [51]: writer.save()
C：/temp/test.xlsx：
如果你不想复制列名,你可能还想指定header = None …
更新：您可能还想查看this solution
标签：python,pandas,for-loop,excel,append 来源： https://codeday.me/bug/20190916/1807350.html
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