Pandas DataFrame.assign arguments

Question

QUESTION

How can assign be used to return a copy of the original DataFrame with multiple new columns added?

DESIRED RES

Answer 1

You can create multiple column by supplying each new column as a keyword argument:

df = df.assign(C=df['A']**2, D=df.B*2)

I got your example dictionary to work by unpacking the dictionary as keyword arguments using **:

df = df.assign(**{'C': df.A.apply(lambda x: x ** 2), 'D': df.B * 2})

It seems like assign should be able to take a dictionary, but it doesn't look to be currently supported based on the source code you posted.

The resulting output:

   A   B   C   D
0  1  11   1  22
1  2  12   4  24
2  3  13   9  26
3  4  14  16  28