Home: http://manmustbecool.github.io/MyWiki/

Entropy

X <- c("no", "no", "yes", "yes", "yes", "no", "yes", "no", "yes", "yes", "yes", "yes", "yes", "no")
myEntropy <- function(X){
  freqs <- table(X)/length(X)
  -sum(freqs * log2(freqs))
}
myEntropy(X)

## [1] 0.940286

Y <-  c("yes", "yes", "no", "yes", "no", "yes", "yes", "no", "yes", "yes", "yes", "yes", "yes", "no")
U<-data.frame(Y,X)
U <- U[U[,1]=="yes",][, 2]

Hyx<-myEntropy(U) 
Hx<-myEntropy(X)
Hy<-myEntropy(Y)
Hx+Hy-Hyx

## [1] 0.9221156

.

^Home Page^