Operating on each row of data frame

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Look at the apply function
?apply

x = data.frame(x1=c(1,2,3,4,5),x2=c(2,4,6,8,10),x3=c(1,3,5,7,9))
x$x5=apply(x,1,mean)
x$x6=apply(x,1,sd)

print(x)
Hi All

I have a data frame in which there are 4 columns .

Column 1 : name

Column 2-4 : values

I would like to calculate mean/Standard error  of values in column 2-4 and
store them in column 5,6 respectively.

I have done the following but doesn't seem to work

mean_N_SE <-function(x)
{

name <- x[1]
vals <- c(x[2:4])
temp_mean <- mean(vals)
SE <-  sqrt(var(x)/length(x))

}

apply(d,1,mean_N_SE) where d = data frame.

Can someone help me with this.

Thanks!
-Abhi

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Hi,

does this do what you want?

d <- cbind(d,apply(d[,c(2,3,4)],1,mean),apply(d[,c(2,3,4)],1,sd))

HTH,
Stephan

Abhishek Pratap schrieb:
Hi All

I have a data frame in which there are 4 columns .

Column 1 : name

Column 2-4 : values

I would like to calculate mean/Standard error  of values in column 2-4 and
store them in column 5,6 respectively.

I have done the following but doesn't seem to work

mean_N_SE <-function(x)
{

name <- x[1]
vals <- c(x[2:4])
temp_mean <- mean(vals)
SE <-  sqrt(var(x)/length(x))

}

apply(d,1,mean_N_SE) where d = data frame.

Can someone help me with this.

Thanks!
-Abhi

	[[alternative HTML version deleted]]

______________________________________________
R-help at r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

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