使用Python比较两个CSV文件并基于比较结果更新一个CSV文件

Question

I'm new to Python and written this code to compare two CSV file. The idea is: my 1st CSV file has only one column:

1st CSV

    ColA
    ----

     A
     B
     C

My 2nd CSV file is like:

     Country    ColA  ColB
     -------------------------
      US          A
     Ind          B      
                  C     AU K-

What I wanted is, if any record of ColA of 1st CSV file matches with ColA of 2nd CSV file then, I want to parse ColB's "AU K-" value to get only "AU" and update in the country of the 2nd CSV file. and my output should look like this:

So, my 2nd CSV file/Output file will look like:

  Country    ColA  ColB
   ---------------------
   US           A
   Ind          B      
   AU           C     

The following code is written to find the match: However, I'm not getting the output in the console while testing. The console simply appears and disappears.

How to retain the console so that I can read the matches? Also, how to update the 2nd CSV if the values matched?

Below is my code sample how I' doing this:

import pandas
 with open('D:\Project\SourceFile.csv') as f:
r = pandas.read_csv(f)
with open('D:\Project\Searchfile.csv','r') as w:
x = pandas.read_csv(w)

col = w['ColA']
for line in w:
    for col in w:
        for row in r:
            if row in col:
                print(line)

Note: I'm using IronPython on VS 2015 with Win7 64Bit. Using IronPython as I would like to integrate few things with .Net code.However, I'm open for any normal/default Python tool.

It looks like IronPython or Python on Windows is somehow not reading CSV file: I referred this ( http://pythonhow.com/data-analysis-with-python-pandas/ ) just to test, however, nothing is showing up..Not sure why? Checked environment variables and Python folder, DLLs and Libs are added. What am I doing wrong? Hope I explained it correctly.

Please suggest. Thanks.

Answer 1

This is what it can look like with Pandas and Numpy (Pandas 0.15 Python 3)

import pandas as pd
import numpy as np

w["Country"] = np.where((w["ColA"].isin(r['ColA'].tolist())) & (~ pd.notnull(w["Country"])) ,w["ColB"], w["Country"]) 
# Np.where(condition, if true,if false)

It will affect the value of the ColB in w in Country only if the value of ColA in w is also in ColA of r and that there isn't a country entered yet.

Hope it helps