How to check a substring in dataframe included in a long string variable?

Question

My question is a different way as we usually check string by using str.contains(). I want to check if a substring in the dataframe is contained in a long string variable.

The dataframe looks like this:

Account	Substring	Category
1001	Cash Payment	Category #1
1002	Credit Card Payment	Category #2

The long string variable is long_str = “Cash Payment by Customer”.

So when using .loc to search/filter records in dataframe tha the substring that is contained in the long_str, is there any similar function like str.contains() but in the opposite way?

Below is the code I want to try to filter the dataframe, except str.contains() that won’t work. Thanks!

df.loc[df[‘Substring’].str.contains(long_str)]

Answer 1

You can simply use pandas.Series.apply method for that:

>>> long_str = "Cash Payment by Customer"
>>> df.loc[df.Substring.apply(lambda x: x in long_str)]
   Account     Substring     Category
0     1001  Cash Payment  Category #1