[R] use of tapply?
tom wright
tom at maladmin.com
Thu Dec 29 16:43:27 CET 2005
I'm still learning how to program with R and I was hoping someone could
take the time to show me how I can rewrite this code?
Many thanks
Tom
data.intersects<-data.frame(
x=c(0.230,0.411,0.477,0.241,0.552,0.230),
y=c(0.119,0.515,0.261,0.431,0.304,0.389),
angle=vector(length=6),
length=vector(length=6),
row.names=c('tbr','trg','dbr','dbg','pbr','pbg'))
calcDist<-function(x,y){
#calcualates distance from origin (C)
origin<-data.frame(x=0.34,y=0.36)
dx<-origin$x-x
dy<-origin$y-y
length<-sqrt(dx^2+dy^2)
angle<-asin(dy/length)
return(list('length'=length,'angle'=angle))
}
for(iLoc in 1:length(data.intersects[,1])){
result<-calcDist(data.intersects[iLoc,]$x,data.intersects[iLoc,]$y)
data.intersects[iLoc,]$angle<-result$angle
data.intersects[iLoc,]$length<-result$length
}
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