[R] Operating on each row of data frame

[Pete B]

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)



Abhishek Pratap wrote:
> 
> 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]]
> 
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> 
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