[R] help with median for each row

Jim Lemon jim at bitwrit.com.au
Sat Aug 22 12:03:11 CEST 2009


Jim Lemon wrote:
> Edward Chen wrote:
>> Hi,
>>
>> I tried looking through google search on whether there's a way to 
>> computer
>> the median for each row of a nxn matrix and return the medians for 
>> each row
>> for further computation.
>> And also if the number of columns in the matrix are even, how could I
>> specify which median to use? 
> Hi Edward,
> You can get the default row medians by transposing the matrix and 
> sending it to the "describe" function in the prettyR package:
>
> describe(t(my.matrix),num.desc="median")
>
> For choosing different methods of calculating the median, you can 
> write a wrapper for the "quantile" function:
>
> new.quantile<-function(x,na.rm=TRUE) 
> return(quantile(x,probs=0.5,type=n,na.rm=na.rm))
> describe(t(my.matrix),num.desc="my.median")
>
Oops, I meant:

describe(t(my.matrix,num.desc="new.quantile")

Jim




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