Pandas: Replace column values to empty if not present in pre-defined list

Question

I have a list, X, that contains a set of legal values for a column. Say, I have column A. I want to replace (set to empty string) elements in df['A'] if their value is not in X. How can I do that efficiently in Pandas?

I know there is isin(), but that just checks if the values are present and returns a Series of True/False.

Answer 1

try this:

df.loc[~df.A.isin(X), 'A'] = ''