[R] Subset and sumerize

[Ashta]

Hi all,

I am trying to summarize  big data set  by   selecting a row
conditionally. and tried  to do it in a loop

Here is  the sample of my data and my attempt

dat<-read.table(text=" ID,x1,x2,y
1,a,b,15
1,x,z,21
1,x,b,16
1,x,k,25
2,d,z,31
2,x,z,28
2,g,t,41
3,h,e,32
3,x,z,38
3,x,g,45
",sep=",",header=TRUE)

For  each unique ID,  I want to select  a data when x1= "x" and x2="z"
Here is the selected data (newdat)
ID,x1,x2,y
1,x,z,21
2,x,z,28
3,x,z,38

Then I want summarize  Y values and out put as follows
Summerize
summary(newdat[i])
######################################################
ID   Min. 1st Qu.  Median    Mean 3rd Qu.    Max.
1
2
3
.
.
.
28
####################################################

Here is my attempt but did not work,

trt=c(1:28)
for(i  in 1:length (trt))
{
  day[i]= newdat[which(newdat$ID== trt[i] &  newdat$x1 =="x" &
newdat$x2 =="z"),]
NR[i]=dim(day[i])[1]
print(paste("Number of Records      :", NR[i]))
sm[i]=summary(day[i])
}

Thank you in advance