How to create the column in pandas based on values of another column

Question

I have created a new column, by adding values from one column, to the index of the column from which I have created this new column. However, my problem is the code works fine when I implement on sample column, but when I pass the already existing dataframe, it throws the error, "can only perform ops with scalar values". As per what I found is the code expects dist and that is why it is throwing error.

I tried converting the dataframe to dictionary or to a list, but no luck.

 df = pd.DataFrame({'Name': ['Sam', 'Andrea', 'Alex', 'Robin', 'Kia',    'Sia'], 'Age':[14,25,55,8,21,43], 'd_id_max':[2,1,1,2,0,0]})`

df['Expected_new_col'] = df.loc[df.index + df['d_id_max'].to_list, 'Age'].to_numpy()

print(df)

error: can only perform ops with scalar values.

This is the dataframe I want to implement this code:

      Weight   Name     Age     1     2   abs_max d_id_max
  0     45     Sam      14     11.0  41.0   41.0    2
  1     88     Andrea   25     30.0 -17.0   30.0    1
  2     56     Alex     55    -47.0 -34.0   47.0    1
  3     15     Robin    8      13.0  35.0   35.0    2
  4     71     Kia      21     22.0  24.0   24.0    2
  5     44     Sia      43     2.0   22.0   22.0    2
  6     54     Ryan     45     20.0  0.0    20.0    1

Explain what you want to do in a logical matter, instead of "why is my code not working". It's a good idea to also include your expected output based on the dataframe you provided — Erfan
– Erfan, Commented Nov 8, 2019 at 13:33

ignoring_gravity · Accepted Answer · 2019-11-11 09:39:46Z

1

Writing your new column like this will not return an error:

df.loc[df.index + df['d_id_max'], 'Age'].to_numpy()

EDIT: You should first format d_id_max as int (or float):

df['d_id_max'] = df['d_id_max'].astype(int)

edited Nov 11, 2019 at 9:39

answered Nov 8, 2019 at 14:04

ignoring_gravity

11.1k7 gold badges45 silver badges99 bronze badges

Sign up to request clarification or add additional context in comments.

7 Comments

ignoring_gravity Over a year ago

I've updated the answer with something that should work, @Saurabh

ignoring_gravity Over a year ago

@Saurabh I just tried it with the code you posted above, and it worked. Are you trying it out on different code?

Saurabh Over a year ago

Yeah, that's my problem. If you go through my 1st question post, I mentioned that my code does not work the same way when I am passing another existing dataframe.

ignoring_gravity Over a year ago

If you want us to help you, please post an example in which the error reproduces - else there's not much we can do

ignoring_gravity Over a year ago

Can you put something we can copy and paste rather than a screenshot?

|

Saurabh · Accepted Answer · 2019-11-09 04:31:23Z

0

The solution was very simple, I was getting the error because the data type of the column d_id_max was object type, which should be either float or integer, so i change the data type and it worked fine.

answered Nov 9, 2019 at 4:31

Saurabh

1211 silver badge13 bronze badges

Collectives™ on Stack Overflow

How to create the column in pandas based on values of another column

2 Answers 2

7 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

7 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related