Filter dataframe rows containing a set of string in python

Question

I have a dataframe df like -

A      B
12     A cat
24     The dog
54     An elephant

I have to filter rows based on values on column B containing a list of string. I can do that for a string "cat" as follows:

df[df["B"].str.contains("cat", case=False, na=False)]

This will return me

A      B
12     A cat

But now I want to filter it for a list of string i.e. ['cat', 'dog',.....].

A      B
12     A cat
24     The dog

I can do that using a for loop but am searching for a pandas way of doing this. I am using python3 and pandas and have searched a lot of solutions on stack overflow since past 2 days

Answer 1

Use join with | for regex OR with \b for word boundary:

L = ['cat', 'dog']
pat = r'(\b{}\b)'.format('|'.join(L))
df[df["B"].str.contains(pat, case=False, na=False)]