How to find strings from a list that didnt find exact matches from a file

Question

The question How to grep exact matches from a file of a list of strings asks how to find strings from one file (A) in another file (B), but only where the string makes up a complete field in file B. The awk command provided works perfectly. But how can I see which strings from file A didn't find a match in file B?

Answer 1

You can try this:

awk 'FNR==NR{b[$1];next} !($4 in b)' B A