pandas dataframe aggregate adding index in some cases

Question

i have a pandas dataframe with an id column and relatively large text in other column. i want to group by id column and concatenate all the large texts into one single text whenever id repeats. it works great in simple toy example but when i run it on my real data it adds index of rows added in final concatenated text. here is my example code

data = {"A":[1,2,2,3],"B":['asdsa','manish','shukla','wfs']}
testdf = pd.DataFrame(data)
testdf = testdf.groupby(['A'],as_index=False).agg({'B':" ".join})

as you can see this code works great but when i run it on my real data it adds indexes in begnning of column B like it will say something like "1 manish \n 2 shukla" for A=2. it obviously is working here but no idea why its misbehaving when i have larger text with real data. any pointers? i tried to search but apparently noone else has run into this issue.

Answer 1

ok i figured out the answer. if any rows in the dataframe as na or nulls, it does that. once i removed the na and nulls it worked.