Pandas: How to remove words in string which appear before a certain word from another column

user_18111004 0
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I have a large csv file with a column containing strings. At the beginning of these strings there are a set of id numbers which appear in another column as below.

0      Home /buy /York /Warehouse /P000166770Ou...             P000166770
1      Home /buy /York /Plot /P000165923A plot of la...        P000165923
2      Home /buy /London /Commercial /P000165504A str...       P000165504
                         ...                        
804    Brand new apartment on the first floor, situat...       P000185616

I want to remove all text which appears before the ID number so here we would get:

0      Ou...             
1      A plot of la...        
2      A str...       
                         ...                        
804    Brand new apartment on the first floor, situat...

I tried something like

df['column_one'].str.split(df['column_two'])

and

df['column_one'].str.replace(df['column_two'],'')
data-wrangling pandas data-cleaning dataframe python
4 Answers

You could replace the pattern using regex as follows:

>> my_pattern = "^(Alpha|Beta|QA|Prod)\s[A-Z0-9]{7}"
>> my_series = pd.Series(['Alpha P17089OText starts here'])
>> my_series.str.replace(my_pattern, '', regex=True)
0    Text starts here

There is a bit of work to be done to determine the nature of your pattern. I would suggest experimenting a bit with https://regex101.com/

user_105219590

To extend your split() idea:

df.apply(lambda x: x['column_one'].split(x['column_two'])[1], axis=1)

0    Text starts here
user_39687610

I managed to get it to work using:

df.apply(lambda x: x['column1'].split(x['column2'])[1] if x['column2'] in x['column1'] else x['column1'], axis=1)

This also works when the ID is not in the description. Thanks for the help!

user_181110040

Here is one way to do it, by applying regex to each of the row based on the code

import re
def ext(row):
    mch = re.findall(r"{0}(.*)".format(row['code']), row['txt'])
    if len(mch) >0:
        rtn = mch.pop()
    else:
        rtn = row['txt']
    return rtn

df['ext'] = df.apply(ext, axis=1) 
df

0                                               Ou...
1                                     A plot of la...
2                                            A str...
3    Brand new apartment on the first floor situat...



    x   txt                                                 code            ext
0   0   Home /buy /York /Warehouse / P000166770 Ou...        P000166770     Ou...
1   1   Home /buy /York /Plot /P000165923A plot of la...     P000165923     A plot of la...
2   2   Home /buy /London /Commercial /P000165504A str...    P000165504     A str...
3   804     Brand new apartment on the first floor situat... P000185616     Brand new apartment on the first floor situat...
user_34947540
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