Python循环仅将数据帧的最后一个循环作为输出打印到Excel

Question

我一直在讨论这个问题（很可能很简单），但我的Excel输出只打印最后一个循环中的值。我相信这与缩进有关，并尝试将值从for循环中去掉，但没有成功。下面是一些帮助理解问题的伪代码：

#dummy code

#reads each file in folder, runs through a bunch of functions, and prints output in console
import os,glob
import csv
import pandas as pd
filename ='path to folder'
for filename in glob.glob(os.path.join(folder_path, '*.txt')):
    with open(filename, 'r') as f:
        text = f.read()
        data =function1(file= filename)
        data= function2(file= filename)
        data = function3(file= filename)
        final =pd.DataFrame(data)
        print(final)
        final.to_excel('output.xlsx')

控制台中的输出如下所示，这是正确的，我希望导出到csv：

0  some text here ...
1  more text...
2  clear text...
3  final data...
                                                   0
0  yes no...
1  does lots...
2  happy sunflower ...
3  ate food...

                                                  0
0  final data ...
1  apple strawberry...
2  different dataset...
3  dinne meals ...

如有任何建议，将不胜感激。多谢各位

Answer 1

在for循环的每次迭代中都覆盖output.csv。试着这样做

import pandas as pd
#use enumerate to have a counter variable at each index
for filename, n in enumerate(glob.glob(os.path.join(folder_path, '*.txt'))):
    with open(filename, 'r') as f:
        #your logic
        #this will be overwritten on next pass of for loop
        final = pd.DataFrame(data)
        #write to file with appended index- avoids file being overwritten on next pass
        final.to_csv("output_%d.csv" % n)

现在，您的数据帧将全部保存在output_x.csv格式中。即，如果找到三个文件，您将看到以下文件：output_1.csv、output_2.csv、output_3.csv