CODEWITHSUNDEEP
python-3.xpandasdataframe
Chuck
Chuck

Reputation: 1293

getting error when trying to modify pandas dataframe values

I need to change '"Saint Louis" to "St. Louis" in this dataframe. These are just a few values, but there are many more: 

shoot[shoot['city'] == 'Saint Louis'].iloc[:5,0:3]

    Incident Date     state         city
119     24-Aug-17  Missouri  Saint Louis
139     13-May-19  Missouri  Saint Louis
217      1-Jun-17  Missouri  Saint Louis
220     18-Jun-17  Missouri  Saint Louis
228     25-Apr-18  Missouri  Saint Louis

I tried this way but I get an error: 

shoot.loc[shoot.city == 'Saint Louis', :]['city'] = 'St. Louis'

__main__:1: SettingWithCopyWarning: 
A value is trying to be set on a copy of a slice from a DataFrame.
Try using .loc[row_indexer,col_indexer] = value instead

That message is saying to do like this, but of course that's not practical with so many:

shoot.iloc[119,2] = 'St. Louis'

So, how to do it? I looked at some other solutions but they didn't work for me.

Upvotes: 0

Views: 64

Answers (1)

O.O
O.O

Reputation: 1298

Using apply method : 

    Incident    Date    state   city
0   119 24-Aug-17   Missouri    Saint Louis
1   139 13-May-19   Missouri    Saint Louis
2   139 13-May-19   Missouri    city1

Code :

df['city'] = df.apply(lambda x: ['St. Louis' if x == 'Saint Louis' else x for x in df['city']])

Result :

Incident    Date    state   city
0   119 24-Aug-17   Missouri    St. Louis
1   139 13-May-19   Missouri    St. Louis
2   139 13-May-19   Missouri    city1

Upvotes: 1

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