Find string function, right-to-left

[David Fishman]

I'm looking for a function to identify the last appearance of a string within a text, i.e. right-to-left. Especially interested in finding last space character in a text.

[#2]

David, position of the last space is

=LOOKUP(2^30,FIND(" ",A1,ROW(INDIRECT("1:"&LEN(A1)))))

What do you mean under last appearance of a string within a text?