Replace a string from python df issue

Question

I am trying to separate few string from pandas dataframe :

x = pd.DataFrame()
x['y'] = ["Hernia|Infiltration","A|Hernia|Infiltration","Infiltration|Hernia"]
x

I am executing below code :

x['y'] = x['y'].replace({'|Hernia': ''},regex=True)
x['y'] = x['y'].str.replace('Hernia|', '',regex=True)
x

But output is wrong :

wrong output :

     y
0   |Infiltration
1   A||Infiltration
2   Infiltration|

Correct/ Expected output

     y
0   Infiltration
1   A|Infiltration
2   Infiltration

There can be any string in place of A and Infiltration , but pattern would be same.

Is there a reason you're using regex=True when you're trying to replace a literal string rather than a regular expression? — Barmar
– Barmar, Commented Jul 5, 2019 at 15:08

Chris · Accepted Answer · 2019-07-05 15:14:22Z

3

This can probably be more elegantly handled with split/join

x['y'].apply(lambda row: '|'.join(x for x in row.split('|') if 'Hernia'!= x))

Output:

0      Infiltration
1    A|Infiltration
2      Infiltration

answered Jul 5, 2019 at 15:11

Chris

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2 Comments

It should be if 'Hernia' != x Otherwise, you'll remove Herniated disk as well.

You can use a comprehension instead of apply... ['|'.join(filter('Hernia'.__ne__, s.split('|'))) for s in x.y]

Quang Hoang · Accepted Answer · 2019-07-05 15:19:56Z

3

You need to escape | in replace:

x['y'] = x['y'].replace({'\|Hernia': ''},regex=True)
x['y'] = x['y'].replace({'Hernia\|': ''},regex=True)

Taking from @user3483203 and @piRSquared's comments, you can join them with | acting as an or:

x['y'].replace({'\|Hernia|Hernia\|': '',
                '':''},regex=True, inplace=True)

answered Jul 5, 2019 at 15:07

Quang Hoang

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Since .replace() takes a dictionary, you can put both keys in the same dict.

But you can separate them with a '|'... x['y'].replace({'\|Hernia|Hernia\|': ''},regex=True)