删除带有csv文件某些关键字的行

Question

I have a large data file and I need to delete rows that have certain keywords.

Here is an example of the file I'm using:

User Name     DN
MB31212       CN=MB31212,CN=Users,DC=prod,DC=trovp,DC=net
MB23423       CN=MB23423 ,OU=Generic Mailbox,DC=prod,DC=trovp,DC=net
MB23424       CN=MB23424 ,CN=Users,DC=prod,DC=trovp,DC=net
MB23423       CN=MB23423,OU=DNA,DC=prod,DC=trovp,DC=net
MB23234       CN=MB23234 ,OU=DNA,DC=prod,DC=trovp,DC=net

This is how I import file:

import pandas as pd
df = pd.read_csv('sample.csv', sep=',', encoding='latin1')

How can I

1. Delete all rows that contain 'OU=DNA' in DN column for example?
2. How can I delete the first attribute 'CN= x' in the DN column without deleting the rest of the data in the column?

I would like to get something like what is posted below, with the 2 rows that contained 'OU=DNA' deleted and the 'CN=x' deleted from every row:

User Name     DN
MB31212       CN=Users,DC=prod,DC=trovp,DC=net
MB23423       OU=Generic Mailbox,DC=prod,DC=trovp,DC=net
MB23424       CN=Users,DC=prod,DC=trovp,DC=net

Answer 1

You can try this two-step filtering as your logic. Use the str.contains method to filter out rows with OU=DNA and use str.replace method with regular expression to trim the leading CN=x :

newDf = df.loc[~df.DN.str.contains("OU=DNA")]
newDf.DN = newDf.DN.str.replace("^CN=[^,]*,", "")
newDf

    UserName    DN
0   MB31212 CN=Users,DC=prod,DC=trovp,DC=net
1   MB23423 OU=Generic Mailbox,DC=prod,DC=trovp,DC=net
2   MB23424 CN=Users,DC=prod,DC=trovp,DC=net

A little break down of the regular expression: ^ stands for the beginning of the string which is followed by CN= and use [^,]*, to capture pattern until the first comma;

Answer 2

To read the file sample you gave I used:

df = pd.read_csv('sample.csv', sep='     ', encoding='latin1', engine="python")

and then:

df = df.drop(df[df.DN.str.contains("OU=DNA")].index)
df.DN = df.DN.str.replace('(CN=MB[0-9]{5}\s*,)', '')
df

gave the desired result:

    User Name   DN
0   MB31212     CN=Users,DC=prod,DC=trovp,DC=net
1   MB23423     OU=Generic Mailbox,DC=prod,DC=trovp,DC=net
2   MB23424     CN=Users,DC=prod,DC=trovp,DC=net