Hello Everybody,

The code:

dfmed<-lapply(unique(colnames(df)), function(x)
rowMedians(as.matrix(df[,colnames(df) == x]),na.rm=TRUE))

takes really long time to execute ( in hours). Is there a faster way to do
this?

Thanks!

On Tue, May 22, 2012 at 3:46 PM, Preeti <preeti@sci.utah.edu> wrote:

> Thanks Henrik! Here is the one-liner that I wrote:
>
> dfmed<-lapply(unique(colnames(df)), function(x)
> rowMedians(as.matrix(df[,colnames(df) == x]),na.rm=TRUE))
>
> Thanks again!
>
>
> On Tue, May 22, 2012 at 3:23 PM, Henrik Bengtsson <hb@biostat.ucsf.edu>wrote:
>
>> See rowMedians() of the matrixStats package for replacing apply(x,
>> MARGIN=1, FUN=median). /Henrik
>>
>> On Tue, May 22, 2012 at 12:34 PM, Preeti <preeti@sci.utah.edu> wrote:
>> > Hi,
>> >
>> > I have a 250,000 by 300 matrix. I am trying to calculate the median of
>> > those columns (by row) with column names that are identical. I would
>> like
>> > this to be efficient since apply(x,1,median) where x is created by
>> choosing
>> > only those columns with same column name and looping on this is taking a
>> > really long time. Is there an efficient way to do this?
>> >
>> > Thanks!
>> >
>> >        [[alternative HTML version deleted]]
>> >
>> > ______________________________________________
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>>
>
>

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