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I have a dataframe with 10 columns. I want to add a new column 'age_bmi' which should be a calculated column multiplying 'age' * 'bmi'. age is an INT, bmi is a FLOAT.
That then creates the new dataframe with 11 columns.
Something I am doing isn't quite right. I think it's a syntax issue. Any ideas?
Thanks
df2['age_bmi'] = df(['age'] * ['bmi']) print(df2) 
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To create a new column, use the [] brackets with the new column name at the left side of the assignment.
Pandas DataFrame sum() MethodThe sum() method adds all values in each column and returns the sum for each column. By specifying the column axis ( axis='columns' ), the sum() method searches column-wise and returns the sum of each row.
To add anew column with constant value, use the square bracket i.e. the index operator and set that value.
try df2['age_bmi'] = df.age * df.bmi.
You're trying to call the dataframe as a function, when you need to get the values of the columns, which you can access by key like a dictionary or by property if it's a lowercase name with no spaces that doesn't match a built-in DataFrame method.
Someone linked this in a comment the other day and it's pretty awesome. I recommend giving it a watch, even if you don't do the exercises: https://www.youtube.com/watch?v=5JnMutdy6Fw
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