[R] Subset and sumerize
Mark Sharp
msharp at txbiomed.org
Fri Oct 14 21:04:26 CEST 2016
Ashta,
## I may have misunderstood your question and if so I apologize.
## I had to remove the extra line after "45" before
## the ",sep=" to use your code.
## You could have used dput(dat) to send a more reliable (robust) version.
dat <- structure(list(ID = c(1L, 1L, 1L, 1L, 2L, 2L, 2L, 3L, 3L, 3L),
x1 = structure(c(1L, 5L, 5L, 5L, 2L, 5L, 3L, 4L, 5L, 5L), .Label = c("a",
"d", "g", "h", "x"), class = "factor"), x2 = structure(c(1L,
6L, 1L, 4L, 6L, 6L, 5L, 2L, 6L, 3L), .Label = c("b", "e",
"g", "k", "t", "z"), class = "factor"), y = c(15L, 21L, 16L,
25L, 31L, 28L, 41L, 32L, 38L, 45L)), .Names = c("ID", "x1",
"x2", "y"), class = "data.frame", row.names = c(NA, -10L))
# In your proposed solution "newdat" is never defined yet you are using it as if it were.
## It is my understanding that your goal is to define newdat as a
## subset of dat where x1 == "x" and x2 == "z".
## This can be done with one line.
newdat <- dat[dat$x1 == "x" & dat$x2 == "z", ]
newdat
> On Oct 14, 2016, at 1:26 PM, Ashta <sewashm at gmail.com> wrote:
>
> 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
>
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