讀取兩個文件並根據第一個文件的列過濾第二個文件

Question

我有一個包含關鍵字的輸入文件，並且需要對這些關鍵字過濾csv文件。

這裏是我嘗試使用python自動化任務。

import csv 
with open('Input.txt', 'rb') as InputFile: 
    with open('28JUL2017.csv', 'rb') as CM_File: 
     read_Input=csv.reader(InputFile) 
     for row1 in csv.reader(InputFile): 
      #print row1 

      read_CM=csv.reader(CM_File) 
      next(read_CM, None) 
      for row2 in csv.reader(CM_File): 
       #print row2 
       if row1[0] == row2[0] : 

        Output= row2[0]+","+row2[1]+","+row2[5]+","+row2[6] 
        print Output 

我剛剛從要過濾的文件的第一行。嘗試了各種各樣的東西，但不明白我出錯的地方。請在這裏指出我的錯誤。

Answer 1

read_Input和read_CM本質上是迭代器。一旦你循環它們 - 你就完成了：你不能迭代兩次。如果您堅持按照自己的方式進行操作，那麼您每次需要開始一個新循環並「重新讀取」​​CSV文件時，都必須倒退到文件的開頭。這裏是一個修復：

import csv 
with open('file1.csv', 'rb') as InputFile: 
    with open('file2.csv', 'rb') as CM_File: 
     read_Input=csv.reader(InputFile) 
     for row1 in csv.reader(InputFile): 
      CM_File.seek(0) # rewind to the beginning of the file 
      read_CM=csv.reader(CM_File) 
      next(read_CM, None) 
      for row2 in csv.reader(CM_File): 
       if row1[0] == row2[0] : 
        Output= row2[0]+","+row2[1]+","+row2[5]+","+row2[6] 
        print Output 

取而代之的是，我會建議你循環已讀線，而不是重新閱讀文件。此外，而不必嵌套循環，打造「關鍵字」的列表，並簡單地檢查row2[0]是在該列表：

import csv 
with open('file1.csv', 'rb') as InputFile: 
    with open('file2.csv', 'rb') as CM_File: 
     read_Input = csv.reader(InputFile) # read file only once 
     keywords = [rec[0] for rec in read_Input] 
     read_CM = csv.reader(CM_File) # read file only once 
     next(read_CM, None) # not sure why you do this? to skip first line? 
     for row2 in read_CM: 
      if row2[0] in keywords: 
       Output = row2[0]+","+row2[1]+","+row2[5]+","+row2[6] 
       print("Output: {}".format(Output))