使用 python pandas 将现有的 excel 表附加到新的数据框
问题描述
我目前有这个代码.效果很好.
它遍历文件夹中的 excel 文件，删除前 2 行，然后将它们保存为单独的 excel 文件，它还将循环中的文件保存为附加文件.
当前每次运行代码时，附加文件覆盖现有文件.
我需要将新数据追加到已经存在的excel表格('master_data.xlsx)
的底部dfList = []路径 = 'C:\Test\TestRawFile'newpath = 'C:\Path\To\New\Folder'对于 os.listdir(path) 中的 fn:# 绝对文件路径文件 = os.path.join(路径，fn)如果 os.path.isfile(file):# 导入excel文件并命名为xlsx_filexlsx_file = pd.ExcelFile(文件)# 查看excel文件工作表名称xlsx_file.sheet_names# 加载 xlsx 文件数据表作为数据框df = xlsx_file.parse('Sheet1',header= None)df_NoHeader = df[2:]数据 = df_NoHeader# 保存单个数据框data.to_excel(os.path.join(newpath, fn))dfList.append(数据)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，但我想不会.我想我需要将 master_data.xlsx 文件作为数据框引入，然后将索引与新的附加数据匹配，然后将其保存回来.或者也许有更简单的方法.任何帮助表示赞赏.
解决方案更新 [2022-01-08]:似乎从 1.4.0 版开始，Pandas 将支持开箱即用"附加到现有 Excel 工作表！
熊猫团队干得好！
根据
PS 如果您不想重复列名，您可能还需要指定 header=None...
更新:您可能还想查看这个旧解决方案
I currently have this code. It works perfectly.
It loops through excel files in a folder, removes the first 2 rows, then saves them as individual excel files, and it also saves the files in the loop as an appended file.
Currently the appended file overwrites the existing file each time I run the code.
I need to append the new data to the bottom of the already existing excel sheet ('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'))
I thought this would be a simple task, but I guess not. I think I need to bring in the master_data.xlsx file as a dataframe, then match the index up with the new appended data, and save it back out. Or maybe there is an easier way. Any Help is appreciated.
解决方案UPDATE [2022-01-08]: it seems starting from version 1.4.0 Pandas will support appending to existing Excel sheet "out of the box"!
Good job Pandas Team!
According to the DocString in pandas-dev github, ExcelWriter will support parameter if_sheet_exists='overlay'
if_sheet_exists : {'error', 'new', 'replace', 'overlay'}, default 'error' How to behave when trying to write to a sheet that already exists (append mode only). * error: raise a ValueError. * new: Create a new sheet, with a name determined by the engine. * replace: Delete the contents of the sheet before writing to it. * overlay: Write contents to the existing sheet without removing the old contents. .. versionadded:: 1.3.0 .. versionchanged:: 1.4.0 Added ``overlay`` option
For Pandas versions < 1.4.0 please find below a helper function for appending a Pandas DataFrame to an existing Excel file.
If an Excel file doesn't exist then it will be created.
UPDATE [2021-09-12]: fixed for Pandas 1.3.0+
The following functions have been tested with:
- Pandas 1.3.2
- OpenPyxl 3.0.7
from pathlib import Path
from copy import copy
from typing import Union, Optional
import numpy as np
import pandas as pd
import openpyxl
from openpyxl import load_workbook
from openpyxl.utils import get_column_letter
def copy_excel_cell_range(
src_ws: openpyxl.worksheet.worksheet.Worksheet,
min_row: int = None,
max_row: int = None,
min_col: int = None,
max_col: int = None,
tgt_ws: openpyxl.worksheet.worksheet.Worksheet = None,
tgt_min_row: int = 1,
tgt_min_col: int = 1,
with_style: bool = True
) -> openpyxl.worksheet.worksheet.Worksheet:
"""
copies all cells from the source worksheet [src_ws] starting from [min_row] row
and [min_col] column up to [max_row] row and [max_col] column
to target worksheet [tgt_ws] starting from [tgt_min_row] row
and [tgt_min_col] column.
@param src_ws: source worksheet
@param min_row: smallest row index in the source worksheet (1-based index)
@param max_row: largest row index in the source worksheet (1-based index)
@param min_col: smallest column index in the source worksheet (1-based index)
@param max_col: largest column index in the source worksheet (1-based index)
@param tgt_ws: target worksheet.
If None, then the copy will be done to the same (source) worksheet.
@param tgt_min_row: target row index (1-based index)
@param tgt_min_col: target column index (1-based index)
@param with_style: whether to copy cell style. Default: True
@return: target worksheet object
"""
if tgt_ws is None:
tgt_ws = src_ws
# https://stackoverflow.com/a/34838233/5741205
for row in src_ws.iter_rows(min_row=min_row, max_row=max_row,
min_col=min_col, max_col=max_col):
for cell in row:
tgt_cell = tgt_ws.cell(
row=cell.row + tgt_min_row - 1,
column=cell.col_idx + tgt_min_col - 1,
value=cell.value
)
if with_style and cell.has_style:
# tgt_cell._style = copy(cell._style)
tgt_cell.font = copy(cell.font)
tgt_cell.border = copy(cell.border)
tgt_cell.fill = copy(cell.fill)
tgt_cell.number_format = copy(cell.number_format)
tgt_cell.protection = copy(cell.protection)
tgt_cell.alignment = copy(cell.alignment)
return tgt_ws
def append_df_to_excel(
filename: Union[str, Path],
df: pd.DataFrame,
sheet_name: str = 'Sheet1',
startrow: Optional[int] = None,
max_col_width: int = 30,
autofilter: bool = False,
fmt_int: str = "#,##0",
fmt_float: str = "#,##0.00",
fmt_date: str = "yyyy-mm-dd",
fmt_datetime: str = "yyyy-mm-dd hh:mm",
truncate_sheet: bool = False,
storage_options: Optional[dict] = None,
**to_excel_kwargs
) -> None:
"""
Append a DataFrame [df] to existing Excel file [filename]
into [sheet_name] Sheet.
If [filename] doesn't exist, then this function will create it.
@param filename: File path or existing ExcelWriter
(Example: '/path/to/file.xlsx')
@param df: DataFrame to save to workbook
@param sheet_name: Name of sheet which will contain DataFrame.
(default: 'Sheet1')
@param 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...
@param max_col_width: maximum column width in Excel. Default: 40
@param autofilter: boolean - whether add Excel autofilter or not. Default: False
@param fmt_int: Excel format for integer numbers
@param fmt_float: Excel format for float numbers
@param fmt_date: Excel format for dates
@param fmt_datetime: Excel format for datetime's
@param truncate_sheet: truncate (remove and recreate) [sheet_name]
before writing DataFrame to Excel file
@param storage_options: dict, optional
Extra options that make sense for a particular storage connection, e.g. host, port,
username, password, etc., if using a URL that will be parsed by fsspec, e.g.,
starting "s3://", "gcs://".
@param to_excel_kwargs: arguments which will be passed to `DataFrame.to_excel()`
[can be a dictionary]
@return: None
Usage examples:
>>> append_df_to_excel('/tmp/test.xlsx', df, autofilter=True,
freeze_panes=(1,0))
>>> append_df_to_excel('/tmp/test.xlsx', df, header=None, index=False)
>>> append_df_to_excel('/tmp/test.xlsx', df, sheet_name='Sheet2',
index=False)
>>> append_df_to_excel('/tmp/test.xlsx', df, sheet_name='Sheet2',
index=False, startrow=25)
>>> append_df_to_excel('/tmp/test.xlsx', df, index=False,
fmt_datetime="dd.mm.yyyy hh:mm")
(c) [MaxU](https://stackoverflow.com/users/5741205/maxu?tab=profile)
"""
def set_column_format(ws, column_letter, fmt):
for cell in ws[column_letter]:
cell.number_format = fmt
filename = Path(filename)
file_exists = filename.is_file()
# process parameters
# calculate first column number
# if the DF will be written using `index=True`, then `first_col = 2`, else `first_col = 1`
first_col = int(to_excel_kwargs.get("index", True)) + 1
# ignore [engine] parameter if it was passed
if 'engine' in to_excel_kwargs:
to_excel_kwargs.pop('engine')
# save content of existing sheets
if file_exists:
wb = load_workbook(filename)
sheet_names = wb.sheetnames
sheet_exists = sheet_name in sheet_names
sheets = {ws.title: ws for ws in wb.worksheets}
with pd.ExcelWriter(
filename.with_suffix(".xlsx"),
engine="openpyxl",
mode="a" if file_exists else "w",
if_sheet_exists="new" if file_exists else None,
date_format=fmt_date,
datetime_format=fmt_datetime,
storage_options=storage_options
) as writer:
if file_exists:
# try to open an existing workbook
writer.book = wb
# 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 = sheets
else:
# file doesn't exist, we are creating a new one
startrow = 0
# write out the DataFrame to an ExcelWriter
df.to_excel(writer, sheet_name=sheet_name, **to_excel_kwargs)
worksheet = writer.sheets[sheet_name]
if autofilter:
worksheet.auto_filter.ref = worksheet.dimensions
for xl_col_no, dtyp in enumerate(df.dtypes, first_col):
col_no = xl_col_no - first_col
width = max(df.iloc[:, col_no].astype(str).str.len().max(),
len(df.columns[col_no]) + 6)
width = min(max_col_width, width)
column_letter = get_column_letter(xl_col_no)
worksheet.column_dimensions[column_letter].width = width
if np.issubdtype(dtyp, np.integer):
set_column_format(worksheet, column_letter, fmt_int)
if np.issubdtype(dtyp, np.floating):
set_column_format(worksheet, column_letter, fmt_float)
if file_exists and sheet_exists:
# move (append) rows from new worksheet to the `sheet_name` worksheet
wb = load_workbook(filename)
# retrieve generated worksheet name
new_sheet_name = set(wb.sheetnames) - set(sheet_names)
if new_sheet_name:
new_sheet_name = list(new_sheet_name)[0]
# copy rows written by `df.to_excel(...)` to
copy_excel_cell_range(
src_ws=wb[new_sheet_name],
tgt_ws=wb[sheet_name],
tgt_min_row=startrow + 1,
with_style=True
)
# remove new (generated by Pandas) worksheet
del wb[new_sheet_name]
wb.save(filename)
wb.close()
Old version (tested with Pandas 1.2.3 and Openpyxl 3.0.5):
import os
from openpyxl import load_workbook
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.
@param filename: File path or existing ExcelWriter
(Example: '/path/to/file.xlsx')
@param df: DataFrame to save to workbook
@param sheet_name: Name of sheet which will contain DataFrame.
(default: 'Sheet1')
@param 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...
@param truncate_sheet: truncate (remove and recreate) [sheet_name]
before writing DataFrame to Excel file
@param to_excel_kwargs: arguments which will be passed to `DataFrame.to_excel()`
[can be a dictionary]
@return: None
Usage examples:
>>> append_df_to_excel('d:/temp/test.xlsx', df)
>>> append_df_to_excel('d:/temp/test.xlsx', df, header=None, index=False)
>>> append_df_to_excel('d:/temp/test.xlsx', df, sheet_name='Sheet2',
index=False)
>>> append_df_to_excel('d:/temp/test.xlsx', df, sheet_name='Sheet2',
index=False, startrow=25)
(c) [MaxU](https://stackoverflow.com/users/5741205/maxu?tab=profile)
"""
# Excel file doesn't exist - saving and exiting
if not os.path.isfile(filename):
df.to_excel(
filename,
sheet_name=sheet_name,
startrow=startrow if startrow is not None else 0,
**to_excel_kwargs)
return
# ignore [engine] parameter if it was passed
if 'engine' in to_excel_kwargs:
to_excel_kwargs.pop('engine')
writer = pd.ExcelWriter(filename, engine='openpyxl', mode='a')
# 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}
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()
Usage examples:
filename = r'C:OCC.xlsx'
append_df_to_excel(filename, df)
append_df_to_excel(filename, df, header=None, index=False)
append_df_to_excel(filename, df, sheet_name='Sheet2', index=False)
append_df_to_excel(filename, df, sheet_name='Sheet2', index=False, startrow=25)
c:/temp/test.xlsx:
PS you may also want to specify header=None if you don't want to duplicate column names...
UPDATE: you may also want to check this old solution
相关文章