O means hes never bet or raised, and infinity means hes never called.

As far has this stat goes, its pretty useless in terms of pre flop. Youre better off at looking at what their PFR and 3 bet is, or better yet, what their "raise first in" is in each position, and then what their 3 bet is like from their position vs the position of the opener. Or even more generalized like say "3 bet from SB vs steal".

Post flop, combing AF for entire post flop is also not very good. You are much much better off having their AF by street, because play varies so much by street and when you combine it all into one stat it really muddies it out. It also provides you with way less information, cuz when trying to decide if you should bluff catch on the river, you wont know if you are playing a guy with a total AF of 4.1 who got it all because he was really aggressive on the flop but relatively passive on turn and river, or if you are playing the guy who has the same AF, but its 4.1 across all 3 streets.

Also I think AFQ (aggression frequency) is a much better stat to use than aggression factor, because it also takes into account checks. So what I would advice is dont use the stat at all for PF, then on your hud have AFQ given for each street.

ok, thanks very much for the advice. also, how can i customize the stats so that it only the opponent's stats for each specific position at the table? i haven't learned how to do that yet