如何以优雅的功能将 pandas DataFrames 导出到 Excel 文件？

Question

我正在尝试编写一个接受数据和文件名作为参数的函数，前者是以后者的名称保存的数据。我想将它保存在一个函数中，而不是像我通过test3 使OutWriter3 工作那样诉诸列表理解。

import numpy as np
import pandas as pd

data_a = np.random.randint(100, size=21)
data_b = np.random.randint(200, size=21)

def OutWriter1(data, filename):
    for d, f in zip(data, filename):
        out = pd.DataFrame(d)
        return out.to_excel(f, header=False, index=False)

def OutWriter2(data, filename):
    out = []
    for d, f in zip(data, filename):
        df = pd.DataFrame(d)
        out.append(df)
        out = pd.DataFrame(out)
        return out.to_excel(f, header=False, index=False)

def OutWriter3(data, filename):
    out = pd.DataFrame(data)
    return out.to_excel(filename, header=False, index=False)

test1 = OutWriter1([data_a, data_b], ['data_a_1.xlsx', 'data_b_1.xlsx'])
test2 = OutWriter2([data_a, data_b], ['data_a_2.xlsx', 'data_b_2.xlsx'])
test3 = [OutWriter3(i, j) for i, j in zip([data_a, data_b], ['data_a_3.xlsx', 'data_b_3.xlsx'])]

来自OutWriter1 的data_a_1.xlsx 是正确的，但data_b_1.xlsx 不存在，data_a_2.xlsx 完全错误，data_b_2.xlsx 也不存在。但是，data_a_3.xlsx 和 data_b_3.xlsx 是正确的。

受another question 的启发，我还尝试将data_a 和data_b 保存为单个Excel 文件中的工作表，但运气不佳(AttributeError: 'list' object has no attribute 'write')。

def OutWriter4(data, filename):
    data = pd.DataFrame(data)
    with pd.ExcelWriter(filename) as writer:
        for n, df in enumerate(data):
            df.to_excel(writer, 'sheet%s' % n)
        writer.save()

test4 = OutWriter4([data_a, data_b], ['data_a_4.xlsx', 'data_b_3.xlsx'])

• 是否有一种优雅的方法来创建一个函数，该函数在提供数据和文件名的情况下创建 Excel 文件？
• 是否还有一种优雅的方法可以创建一个函数，将不同的数据写入单个 Excel 文件中的指定工作表？

Answer 1

解决方案

您可以使用以下代码将多个数据帧写入单个 excel 文件，或将每个数据帧写入单个 excel 文件。

target = 'single_file.xlsx'
targets = ['mult_1.xlsx', 'mult_2.xlsx', 'mult_3.xlsx']
# df1 = pd.DataFrame(data_a)
# df2 = pd.DataFrame(data_b)
# df3 = pd.DataFrame(data_c)
# dfs = [pd.DataFrame(x) for x in [data_a, data_b]] # >> in your case
dfs = [df1, df2, df3]

# to write to a single file
write_to_excel(targets = target, dfs = dfs, verbose=1)

# to write to multiple files
write_to_excel(targets = targets, dfs = dfs, verbose=1)

自定义函数

def write_to_excel(targets, dfs: list, verbose=1):
    """Writes single of multiple dataframes to either a single or multiple excel files.

    targets: str or list of str --> path(s) excel files
    dfs: list of dataframes
    Example
    -------
    target = 'single_file.xlsx'
    targets = ['mult_1.xlsx', 'mult_2.xlsx', 'mult_3.xlsx']
    dfs = [df1, df2, df3]

    # to write to a single file
    write_to_excel(targets = target, dfs = dfs, verbose=1)

    # to write to a multiple files
    write_to_excel(targets = targets, dfs = dfs, verbose=1)
    """
    if not isinstance(targets, list):
        targets = [targets]
    writer_scheme = 'single' if len(target)==1 else 'multi'
    if verbose>=1:
        print(f'excel-writer-scheme: {writer_scheme}-file(s)')
    if writer_scheme == 'single':
        with pd.ExcelWriter(targets[0]) as writer:
            for i, df in enumerate(dfs):  
                df.to_excel(writer, sheet_name=f'Sheet_{i+1}')
    else:
        for df, target in zip(dfs, targets):
            df.to_excel(target, sheet_name='data')

参考文献

1. https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.DataFrame.to_excel.html