Pandas creating a column which counts the length of a previous column entries without getting a Set Copy Warning

Question

When I look at the answer to a similiar question as shown in this link: Pandas: adding column with the length of other column as value

I come across an issue where the solution its suggesting i.e

df['name_length'] = df['seller_name].str.len()

Throws the following warning

'''
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
'''

My question is: How could this be done inorder to prevent this warning from occuring? As in this command I would like to add a new column to the original dataframe not create some sort of copy of a slice.

Does the name_length column already exist? – Tarik Mar 08 '21 at 15:26 — Tarik, Mar 08 '21 at 15:26
No so this is a new column which I want to calculate – Curious Mar 08 '21 at 15:32 — Curious, Mar 08 '21 at 15:32
df['name_length'] = df.loc[:,'seller_name'].str.len() – Tarik Mar 08 '21 at 16:51 — Tarik, Mar 08 '21 at 16:51

score 0 · Answer 1 · answered Mar 08 '21 at 15:30

0

I took a sample data set to test this issue in Python 3.8

Sample data

here is the same code which you ran df['name_length'] = df['seller_name'].str.len()

there was no error

answered Mar 08 '21 at 15:30

Vivs

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OP is asking about the warning. – Tarik Mar 08 '21 at 16:48

Pandas creating a column which counts the length of a previous column entries without getting a Set Copy Warning

1 Answers1