【问题标题】:Append existing excel sheet with new dataframe using python pandas使用 python pandas 将现有的 excel 表附加到新的数据框
【发布时间】:2016-10-30 16:34:26
【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('master_data.xlsx)

的底部
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。

【问题讨论】:

  • that 你在追求什么?
  • 不,不完全是,我不是要保存新工作表,只是想附加现有工作表。

标签: python excel for-loop pandas append


【解决方案1】:

更新 [2022-01-08]: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

对于

如果 Excel 文件不存在,则会创建它。


更新 [2021-09-12]:已针对 Pandas 1.3.0+ 修复

以下功能已经过测试:

  • 熊猫 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()

旧版本(使用 Pandas 1.2.3 和 Openpyxl 3.0.5 测试):

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()

用法示例:

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 如果您不想重复列名,您可能还想指定header=None...

更新:您可能还想查看this old solution

【讨论】:

  • 它只是覆盖指定索引中的文件,而不是附加到现有文件的末尾。
  • @shanlodh,很高兴它有帮助:) 谢谢你的建议!我认为以这种方式禁用它不是一个好主意,因为它不允许添加标题低于现有标题的 DF,或者如果您想保留现有标题行。但是用现有的功能可以很容易地实现:append_df_to_excel(filename, df, startrow=N, header=False);)
  • 从 pandas 1.2.0 开始,代码会产生问题(直到 1.1.5 都可以正常工作),引发 BadZipFile 异常,因为在您实例化 pd.ExcelWriter 时它会创建大小为 0 字节的空文件并覆盖现有文件。必须指定mode='a'。见stackoverflow.com/a/66585065/4046632stackoverflow.com/q/66471466/4046632
  • @Priya,很高兴它有帮助。 :) Pandas 1.2.0 发生了一些变化,导致 BadZipFile 使用我的函数的旧实现出现异常,所以我不得不将它调整到新的 Pandas 版本。
  • @Priya,参数 truncate_sheet=True 可能用于在将 DataFrame 写入该工作表之前清理工作表的旧内容。
【解决方案2】:

如果您不是严格查找 excel 文件,则将输出作为 csv 文件获取,然后将 csv 复制到新的 excel 文件中

df.to_csv('filepath', mode='a', index = False, header=None)

模式 = 'a'

a 表示追加

这是一种迂回的方式,但工作得很好!

【讨论】:

  • 这很好用!
【解决方案3】:

这个问题已经有一段时间了。答案还可以,但我相信这会解决大多数人的问题。

只需使用 glob 访问特定目录中的文件,遍历它们,为每个文件创建一个数据框,将其附加到最后一个,然后导出到文件夹。我还包含了注释掉的代码以使用 csvs 运行。

import os
import pandas as pd
import glob

# put in path to folder with files you want to append
# *.xlsx or *.csv will get all files of that type
path = "C:/Users/Name/Folder/*.xlsx"
#path = "C:/Users/Name/Folder/*.csv"

# initialize a empty df
appended_data = pd.DataFrame()

#loop through each file in the path
for file in glob.glob(path):
    print(file)

    # create a df of that file path
    df = pd.read_excel(file, sheet_name = 0)
    #df = pd.read_csv(file, sep=',')

    # appened it
    appended_data = appended_data.append(df)

appended_data

# export the appeneded data to a folder of your choice
exportPath = 'C:/My/EXPORT/PATH/appended_dataExport.csv'
appended_data.to_csv(os.path.join(exportPath),index=False)

【讨论】:

    【解决方案4】:

    作为@david 的补充,如果您不关心索引并且可以使用 .csv,此功能有助于将任何 df 附加到现有的 csv

    def append_df(self, path_file, df):
        with open(path_file, 'a+') as f:
            df.to_csv(f, header=f.tell() == 0, encoding='utf-8', index=False)
    

    注意事项:

    a+如果文件不存在则创建文件

    f.tell() == 0如果第一行添加标题

    【讨论】:

    • 您的方法需要读取所有现有的excel并在df中收集数据,然后在df中添加一个新行,然后写入excel。如果您使用大尺寸的 excel,这是一种非常不受欢迎的方法,可能是:(
    【解决方案5】:
    import pandas as pd
    import openpyxl
    
    workbook = openpyxl.load_workbook("test.xlsx")
    writer = pd.ExcelWriter('test.xlsx', engine='openpyxl')
    writer.book = workbook
    writer.sheets = dict((ws.title, ws) for ws in workbook.worksheets)
    data_df.to_excel(writer, 'Existing_sheetname')
    writer.save()
    writer.close()
    

    【讨论】:

    • 代码转储不能提供好的答案。你应该解释如何为什么这可以解决他们的问题。我推荐阅读,“How do I write a good answer?"。这可以帮助未来的用户学习并最终将这些知识应用到他们自己的代码中。当代码被解释时,你也可能会得到用户的积极反馈/赞成。
    • 同意,在这里做一些解释会很有帮助!
    • 这是一个误导性的答案。此代码仅更改 excel 文件中的第一行....在尝试确保您的代码之前不要共享。
    【解决方案6】:

    以 MaxU 和其他人的代码和 cmets 为基础,但进行了简化,仅修复了 pandas ExcelWriter 导致 to_excel 创建新工作表而不是在追加模式下追加到现有工作表的错误。

    正如其他人所指出的,to_excel 使用 ExcelWriter.sheets 属性,而 ExcelWriter 不会填充此属性。

    Fix 是单行代码,否则代码是标准的 pandas 方法,如 to_excel 中所述。

    
        # xl_path is destination xlsx spreadsheet
        with pd.ExcelWriter(xl_path, 'openpyxl', mode='a') as writer:
            # fix line
            writer.sheets = dict((ws.title, ws) for ws in writer.book.worksheets)
            df.to_excel(writer, sheet_name)
    
    

    【讨论】:

      【解决方案7】:

      如果您每次都在工作表上使用 ExcelWriter,它将覆盖前一个工作表,那么可见的只有您附加到工作簿的最后一个数据表。 相反,您可以维护一个最初为 1 的计数器,您需要为其初始化 excel 工作表并使用现有方法添加初始数据

      writer = pd.ExcelWriter(output_file, engine='openpyxl')
      
      df = pd.read_excel(output_file, sheet_name='TestSheet1')
      

      或者您可以使用我使用的以下方法。下次您想使用它时加载工作簿,否则如果您尝试在第一种情况下加载它,文件找不到异常。

      用法:

      from bs4 import BeautifulSoup
      import requests
      import pandas as pd
      from openpyxl import load_workbook
      
      urls = ["http://millenniumcricketleague.com/Home/ShowTeam.aspx?tid=22",
              "http://millenniumcricketleague.com/Home/ShowTeam.aspx?tid=40"]
      path = "F:\meta_1.xlsx"
      writer = pd.ExcelWriter(path,engine='openpyxl')
      counter = 1
      for url in urls:
          table_data = []
          final = []
          html_content = requests.get(url).text
          soup = BeautifulSoup(html_content, "lxml")
          x = soup.find_all('table')
          for table in x[1:]:
              for tr in table.find_all("tr"):
                  newrow = []
                  for td in tr.find_all("td"):
                      newrow.append(td.text.replace('\n', ' ').strip())
                  table_data.append(newrow)
          df = pd.DataFrame(table_data)
          sheetname = 'Sheet%s' % counter
          if(counter!=1):
              writer.book = load_workbook(path)
          df.to_excel(writer, sheet_name=sheetname)
          counter = counter + 1
          writer.save()
      
      

      无需关闭 excelwriter。它是一个自动功能。如果您明确定义它会向您显示警告

      【讨论】:

        【解决方案8】:

        这对我有用

        import os
        import openpyxl
        import pandas as pd
        from openpyxl.utils.dataframe import dataframe_to_rows
        
        file = r"myfile.xlsx"
        
        df = pd.DataFrame({'A': 1, 'B': 2})
        
        # create excel file
        if os.path.isfile(file):  # if file already exists append to existing file
            workbook = openpyxl.load_workbook(file)  # load workbook if already exists
            sheet = workbook['my_sheet_name']  # declare the active sheet 
        
            # append the dataframe results to the current excel file
            for row in dataframe_to_rows(df, header = False, index = False):
                sheet.append(row)
            workbook.save(file)  # save workbook
            workbook.close()  # close workbook
        else:  # create the excel file if doesn't already exist
            with pd.ExcelWriter(path = file, engine = 'openpyxl') as writer:
                df.to_excel(writer, index = False, sheet_name = 'my_sheet_name')
        

        【讨论】:

          【解决方案9】:
          from openpyxl import load_workbook
          wb = load_workbook(filepath)
          ws = wb["Sheet1"]
          df = dataframe.values.tolist()
          for i in range(len(df)):
              ws.append(df[i])
          wb.save(filepath)
          

          【讨论】:

          • 您好,如果您能帮助我们了解您的代码的作用以及它如何解决 OP 的问题,那就太好了!
          【解决方案10】:

          将 DataFrame 附加到现有的 excel 文件中

          使用ExcelWriter 将DataFrame 附加到现有的excel 文件中。这是一种简单的方法,并且使用了现有的库功能。

          with pd.ExcelWriter('existing_excel_file.xlsx',mode='a') as writer:  
              df.to_excel(writer, sheet_name='existing_sheet_name')
          

          详细示例请参考pandas read Excel File with Examples

          【讨论】:

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