Pandas: df.assign in for loop

[mirco69]

Code Sample, a copy-pastable example if possible

list_of_columns = ["name", "weight"]

for column in list_of_columns:
    if column in other_df.columns:
        df = df.assign(column = other_df[column])

Problem description

df.assign creates a new column called "column" and then overwrites it with another new column called "column" instead of adding the collumns "name" and "weight". i think its because of the use of an equal sign instead of colon or comma.

i would like to have an "assign" function, that i can use in a for loop.

im sorry if im wrong or if this is not the right place for this issue. im quite new to programming.

regards
Florian

[mroeschke]

The Github Issues board is for bugs and enhancement requests for the library. For usage questions, we recommend using Stack Overflow.

[hwalinga]

Assign uses keyword arguments. Keywords arguments are basically just dictionaries being passed. Using dictionaries and using argument unpacking, you can use the value of the string instead. Like this:

df.assign(**{column: other_df[column]})

You can even go more advanced in with this by instead of using for loops, using a dictionary comprehension.

df.assign(**{column: other_df[column] for column in list_of_columns if column in other_df.columns})