Loops and vector operations
Look at ?ifelse. You'll need to nest them however. If you are feeling a little more ambitious this can be done with ?switch, but for clarity, I'd rather see pre-allocation followed by assignments Something along this pattern: out <- numeric(50) x <- sample(3, 50, TRUE) out[x==3] <- "A" out[x==2] <- "B" out[x==1] <- "C" Not the fastest, but quite clear HTH, Michael
On Dec 28, 2011, at 10:55 AM, Mago84 <davidquiasmo at gmail.com> wrote:
Dear all,
this is my first post and I?m very new at R, I don?t know if somebody can
help with an issue.
I?m doing some exercices and I don?t know if for example I can convert this
for in an operation with vectors:
for (i in 2:n){
if (ES[i-1]==0 && sprd[i-1]>mediaSDP[i-1] && sprd[i]<=mediaSDP[i]) {ES[i]
<- -1} else
if((ES[i-1]==-1 || ES[i-1]==-15) && sprd[i]>media[i]) {ES[i] <- -15} else
if((ES[i-1]==-1 || ES[i-1]==-15) && sprd[i]<=media[i]) {ES[i] <- -17} else
if(ES[i-1]==0 && sprd[i-1]<mediaSDN[i-1] && sprd[i]>=mediaSDN[i])
{ES[i] <- 1} else
if((ES[i-1]==1 || ES[i-1]==15)&& sprd[i]<media[i]) {ES[i] <- 15} else
if((ES[i-1]==1 || ES[i-1]==15)&& sprd[i]>=media[i]) {ES[i] <- 17}
else {ES[i] <-0}
}
Thanks a lot!!
--
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