help with simple function
I'm trying to build on Jim's approach to change the parameters in the
function, with new rules:
1. if (x[i]==0) NA
2. if (x[i]>0) log(x[i]/(number of consecutive zeros preceding it +1))
x<-c(1,0,1,0,0,1,0,0,0,1,0,0,0,0,1)
# i.e. output desired = c(0, NA, -0.69, NA, NA, -1.098, NA, NA, NA, -1.38,
NA, NA, NA, NA, -1.61)
y <- rle(x)
# attempting to modify Jim's function:
result <- lapply(seq_along(y$lengths), function(.indx){
if (y$values[.indx-1] == 0)
log(y$values[.indx]/seq(y$lengths[.indx-1]+1, by=-1,
length=y$lengths[.indx]))
else rep(log(y$values[.indx]), y$lengths[.indx])
})
# but I am clearly missing something!
Does it not work because I haven't addressed what to do with the zeros and
log(0)=-Inf?
I've tried adding another "ifelse" but I still get the same result.
Can someone find the error in my ways?
Tyler
T.D.Rudolph wrote:
I have a matrix of frequency counts from 0-160. x<-as.matrix(c(0,1,0,0,1,0,0,0,1,0,0,0,0,1)) I would like to apply a function creating a new column (x[,2])containing values equal to: a) log(x[m,1]) if x[m,1] > 0; and b) for all x[m,1]= 0, log(next x[m,1] > 0 / count of preceding zero values +1) for example, x[1,2] should equal log(x[2,1]/2) = log(1/2) = -0.6931472 whereas x[3,2] should equal log(x[5,1]/3) = log (1/3) = -1.098612 I will be applying this to nrow(x)=~70,000 so I would prefer to not do it by hand! Tyler
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