Does this help?

B1, copied down:

=IF(ISNUMBER(FIND(" AB "," "&SUBSTITUTE(A1,"_"," ")&" ")),"AB","NA")

In article ,
Nir wrote:

Hi,
I need to find and return a string in another string only if the searched
string is straight A to Z chars in a row.
saying A1:A3 is the string to find in B1:B3 is the formula.
need to find string "AB"
A1: ABDF_ABD
A2: ABDF_AB
A3: ABDF AB

result should be B1 - NA, B2-AB , B3-AB