pandas combine two columns with null values

Question

I have a df with two columns and I want to combine both columns ignoring the NaN values. The catch is that sometimes both columns have NaN values in which case I want the new co

Answer 1

you can use the combine method with a lambda:

df['foodstuff'].combine(df['type'], lambda a, b: ((a or "") + (b or "")) or None, None)

(a or "") returns "" if a is None then the same logic is applied on the concatenation (where the result would be None if the concatenation is an empty string).