View Full Version : Probability of Flopping a Straight

08-03-2005, 02:12 PM
The probability of flopping a straight depends on the span of the cards (eg. K 8 has a 0% chance). So what I am looking for is a probabilty function based on the span of the cards. To complicate the matter A K has a single span but only Q J and 10 will result in a straight. So it might need to be based on the number of outs instead of just the span. Anybody have any thoughts on this?

08-03-2005, 02:31 PM
Obviously filtering out the impossible hands is elementary. If the difference of the ranks is 1, there are 4 distinct ways you can flop a straight. If the difference is 2, there are 3. If the difference is 3, there are two. If the difference is 4, there is only one. You're going to need to throw in some logic to determine if the cards have maximum reach or not.

08-03-2005, 02:51 PM
LetYouDown, I know you wouldn't so thanks once again. Yes, that's what I thought and have started work on it, it seems a bit sloppy at present but I'm sure I can clean it up a little. I will post the result for you approval as soon as I am finished.


08-03-2005, 03:00 PM
Just to clarify, you obviously need to factor in the suits...which I assume is obvious, but file it under "just in case". There's probably a solution out there that will turn this into a single formula, but in this case it really doesn't seem worth the effort. There was a truly elegant solution to ranking hands against each other with bit shifting that I found really impressive. I wouldn't be surprised if someone had done this with a more elegant method. It just seems like it would take more time to come up with that method than to write a full function. I'd imagine the performance hit would be almost negligible.

08-03-2005, 03:29 PM
I just noticed you hasve the BoSox emblen. I can't count the number of ALCS games I have gone to. My nephew's birthday is in October so it makes a nice present to take him. Except for last year and I'm still angry. I was pleased they won on the road so the scalpers would choke on the tickets.