[R] find max value in different columns

arun smartpink111 at yahoo.com
Thu Feb 27 08:16:23 CET 2014


Hi,
Try:
dat <- read.table(text="ID    ONE  TWO  THREE
1    2      5        7
2    6      NA      NA
3    5      7        NA
4    1      NA      NA",sep="",header=TRUE)
dat1 <- dat

#Either:
dat$MAX <- apply(dat[,-1],1,max,na.rm=TRUE)


#or
 dat1$MAX <- do.call('pmax',c(dat1[,2:4],list(na.rm=TRUE)))
 identical(dat,dat1)
#[1] TRUE
A.K.




On Thursday, February 27, 2014 2:08 AM, Mat <matthias.weber at fnt.de> wrote:
Hello together,

i have a data.frame like this one:

ID    ONE   TWO   THREE
1     2       5        7
2     6       NA      NA
3     5       7        NA
4     1       NA      NA

Now i want a new column with the max-Value of "ONE", "TWO" and THREE. The
result look like this one:

ID    ONE   TWO   THREE    MAX
1     2       5        7           7
2     6       NA      NA         6
3     5       7        NA         7
4     1       NA      NA         1

how can i do this?

thank you. Mat



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