Data Prep query - How to achieve a Case statement in Data Preparation

[RachelT]

1. How can I manipulate a column in data preparation to satisfy a case condition like this
CASE
when column 1 like '%F%' then 'Yes'
else ''
END
I can use a 'search and replace' in string to look at the values in Column1, if it contains F then set it to Yes . But the other part , if it doesn't contain F then should be blank , how do I achieve this.

How to achieve equivalent of 'not contains'

Thanks