




Hello.
Thanks for the help and your reasonable explanation. I'll definitely start using 'dput' next time. 
Apologies for the trouble to all who helped me.
Suhaila.

> On 05/08/2012 06:35 PM, Suhaila Haji Mohd Hussin wrote:
> >
> > Hello.
> > Sorry if that's considered laziness as I've just learnt R and didn't know how important it is to do dput for all problems.
> > If I was truly lazy then I wouldn't even bother to sign up here and ask questions.
> > Please be nicer next time.
> 
> Hi Suhaila,
> It looks like you are confused about indexing your data frame. You want 
> to replace the NA value in the fourth row and first column of your data 
> frame with a median. Say that your median value really is 78. What you 
> want to do is one of these:
> 
> median_a.AC<-median(unlist(a.AC),na.rm=TRUE)
> x[4,1]<-median_a.AC
> x$a[4]<-median_a.AC
> x[4,"a"]<-median_a.AC
> 
> which are all pretty much equivalent. The operation of selecting one or 
> more values from a data frame is known as "extraction" in R. The way you 
> have defined a.AC results in a "list" object. If you "unlist" it, it 
> becomes a vector with two elements, 78 and NA. If you want the median, 
> you will have to use the na.rm=TRUE argument or you will get NA. Now 
> that you have the median, you can change the value of the NA element to 
> that median using one of the above commands.
> 
> The reason that everyone was cross about sending pictures of data is 
> that it forces anyone who wants to help you to type in the data 
> manually. The "dput" function makes it easy on the helpers.
> 
> Jim
 		 	   		  
 		 	   		  
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