say x is a holdem hand (board + hole cards) where J:A = 11:14 and A may = 1. Suit doesn't matter. You're just checking for a straight.
x <- c(2,5,6,7,8,9,14)
This is the straight1 function from the holdem package. I understand everything but the for loop at the end of the function. Could someone please explain how that portion is working. I'm lost.
function(x){
a1 = sort(unique(x))
if (length(a1)<4.5) return(0)
a3 = 0
n = length(a1)
if(a1[n] == 14) a1 = c(1,a1) ## count ace as both 1 and 14
a2 = length(a1)
for(j in c(5:a2)){ ## j will be the potential highest card of straight
if( sum(15^c(1:5) * a1[(j-4):j]) == sum(15^c(1:5) * ((a1[j]-4):a1[j]))) a3 = a1[j]
}
a3
} ## end of straight1
I think the question needs some clarification about what is needed:
Qstraight <-function(x){
a1 = sort(unique(x))
if (length(a1)<4.5) return(0)
a3 = 0
n = length(a1)
if(a1[n] == 14) a1 = c(1,a1) ## count ace as both 1 and 14
a2 = length(a1)
for(j in c(5:a2)){
## j will be the potential highest card of straight
if( sum(15^c(1:5) * a1[(j-4):j]) ==
sum(15^c(1:5) * ((a1[j]-4):a1[j]))) a3 = a1[j]
}
a3
} ## end
So the result with this is ...
Qstraight(x)
#[1] 9 # i.e a "nine-high straight
x2 <- c(2,5,6,7,8,10,14)
Qstraight(x2)
#[1] 0 # i.e not a straight at all.
I probably would have sorted the unique values and then taken the maximum of length of rle(diff(unique(sort(x))))$values == 1 .. or something less dependent on modular arithmetic.