Python - pandas 中的錯誤（在循環處理文件期間）

Question

嗨，我在處理時遇到了奇怪的錯誤（從 CSV 文件中提取數據）我無法理解。 我是初學者，我編寫了一些代碼來提取 mri 生成的發作時間和持續時間。 我的代碼（如下）貫穿所有（144）個 csv 文件作為輸入文件，提取我需要的信息並將其保存為 output 目錄中的 csv 。 問題是處理 10 個文件后出現錯誤。 我真的不明白發生了什么，因為所有 csv 輸入文件的格式都相同。 你能幫我理解錯誤以及如何解決它嗎？ 代碼在單個文件上正常工作，提取行的唯一問題是循環遍歷多個文件時。 任何幫助，將不勝感激！

import csv
import os
import pandas as pd
import math
import numpy as np  
import csv
import glob
IN="/Users/*****/Documents/LMG_Env/RSA/RSA_mri/events/behavioral_stimuli_computer/CSVlog/" # points to csv files
OUT= "/Users/*****/Documents/LMG_Env/RSA/RSA_mri/events/onsets/" # outputted.
file_list = os.path.join(IN, '*.csv')

for infile in glob.glob(file_list):

    # open log file and load it into table from 3rd row.
    in_txt = pd.read_csv(infile, names=['Subject','Trial','Event Type','Code','Time','TTime','Uncertainty','Duration','Uncertainty_1','ReqTime','ReqDur','Stim Type','Pair Index'], skiprows=3, delimiter=',')
    df = pd.DataFrame(in_txt,columns=['Subject','Trial','Event Type','Code','Time','TTime','Uncertainty','Duration','Uncertainty_1','ReqTime','ReqDur','Stim Type','Pair Index'])

    # for each row in table extract only columns: Trial, Event type, Code, Time, Duration
    columns = df.columns
    extract_column = df[['Trial','Event Type', 'Code', 'Time','Duration']]
    extract_column = extract_column.set_index('Event Type') #changing index to Event Type

    # extract only rows with Event Type: Picture.
    extract_rows = extract_column.loc['Picture']

    #recalculare time & duration into seconds.
    extract_rows.loc[:,'Time'] = extract_rows['Time'].div(10000) #to seconds
    extract_rows.loc[:,'Duration'] = extract_rows['Duration'].div(10000) #to seconds

    # save file in OUT as tsv (tab separated vectors)
    filename = 'sub-' + os.path.splitext( os.path.basename(infile))[0] + '_events' + '.csv'
    filename = os.path.join(OUT, filename)
    extract_rows.to_csv(filename, index=False)
    print(filename)

和錯誤：

    ---------------------------------------------------------------------------
KeyError                                  Traceback (most recent call last)
//anaconda3/lib/python3.7/site-packages/pandas/core/indexes/base.py in get_loc(self, key, method, tolerance)
   2656             try:
-> 2657                 return self._engine.get_loc(key)
   2658             except KeyError:

pandas/_libs/index.pyx in pandas._libs.index.IndexEngine.get_loc()

pandas/_libs/index.pyx in pandas._libs.index.IndexEngine.get_loc()

pandas/_libs/hashtable_class_helper.pxi in pandas._libs.hashtable.PyObjectHashTable.get_item()

pandas/_libs/hashtable_class_helper.pxi in pandas._libs.hashtable.PyObjectHashTable.get_item()

KeyError: 'Picture'

During handling of the above exception, another exception occurred:

KeyError                                  Traceback (most recent call last)
<ipython-input-15-640c70c49427> in <module>
     11 
     12 # extract only rows with Event Type: Picture.
---> 13     extract_rows = extract_column.loc['Picture']
     14 
     15 #recalculare time & duration into seconds.

//anaconda3/lib/python3.7/site-packages/pandas/core/indexing.py in __getitem__(self, key)
   1498 
   1499             maybe_callable = com.apply_if_callable(key, self.obj)
-> 1500             return self._getitem_axis(maybe_callable, axis=axis)
   1501 
   1502     def _is_scalar_access(self, key):

//anaconda3/lib/python3.7/site-packages/pandas/core/indexing.py in _getitem_axis(self, key, axis)
   1911         # fall thru to straight lookup
   1912         self._validate_key(key, axis)
-> 1913         return self._get_label(key, axis=axis)
   1914 
   1915 

//anaconda3/lib/python3.7/site-packages/pandas/core/indexing.py in _get_label(self, label, axis)
    139             raise IndexingError('no slices here, handle elsewhere')
    140 
--> 141         return self.obj._xs(label, axis=axis)
    142 
    143     def _get_loc(self, key, axis=None):

//anaconda3/lib/python3.7/site-packages/pandas/core/generic.py in xs(self, key, axis, level, drop_level)
   3583                                                       drop_level=drop_level)
   3584         else:
-> 3585             loc = self.index.get_loc(key)
   3586 
   3587             if isinstance(loc, np.ndarray):

//anaconda3/lib/python3.7/site-packages/pandas/core/indexes/base.py in get_loc(self, key, method, tolerance)
   2657                 return self._engine.get_loc(key)
   2658             except KeyError:
-> 2659                 return self._engine.get_loc(self._maybe_cast_indexer(key))
   2660         indexer = self.get_indexer([key], method=method, tolerance=tolerance)
   2661         if indexer.ndim > 1 or indexer.size > 1:

pandas/_libs/index.pyx in pandas._libs.index.IndexEngine.get_loc()

pandas/_libs/index.pyx in pandas._libs.index.IndexEngine.get_loc()

pandas/_libs/hashtable_class_helper.pxi in pandas._libs.hashtable.PyObjectHashTable.get_item()

pandas/_libs/hashtable_class_helper.pxi in pandas._libs.hashtable.PyObjectHashTable.get_item()

KeyError: 'Picture'

Answer 1

df = pd.DataFrame(in_txt,columns=['Subject','Trial','Event Type','Code','Time','TTime','Uncertainty','Duration','Uncertainty_1','ReqTime','ReqDur','Stim Type','Pair Index'])

dataframe 沒有名為Picture的列。