R help - Jan 2006 - function for rowMedian?

Hi
is anybody aware of a function to calculate a the median for specified
columns in a dataframe or matrix - so analogous to rowMeans?
Thanks
Max

--

Max Kauer wrote:
> Hi
> is anybody aware of a function to calculate a the median for specified
> columns in a dataframe or matrix - so analogous to rowMeans?
> Thanks
> Max
> 
> --
> 
No equivalent in base R, but you could always use ?apply:

apply(x, 1, median)

assuming "x" is an array or is coercible to a array.

I have a C-function that does this as part of my personal R package (not 
available from CRAN). It has the same time savings as "rowMeans" has 
over apply(x, 1, mean). Contact me offline if you would like a copy.

HTH,

--sundar

apply(x, 1, median) should do it.  If not, you need to explain why.

Andy

-----Original Message-----
From: Max Kauer
Sent: Friday, January 20, 2006 10:24 AM
To: r-help at stat.math.ethz.ch
Subject: [R] function for rowMedian?


Hi
is anybody aware of a function to calculate a the median for specified
columns in a dataframe or matrix - so analogous to rowMeans?
Thanks
Max

--

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Note that there is a confusion here: 1st dimension is row, 2nd dimension 
is column for matrix & data.frame.
So, if the question is about "rowMedian", you have:

 > rowMedian <- function(x, na.rm = FALSE)
 >     apply(x, 2, median, na.rm = na.rm)

Now, you ask for the "median for specified columns", which should be
as
Andy proposes you, or, if you really want a colMedian function:

 > colMedian <- function(x, na.rm = FALSE)
 >     apply(x, 1, median, na.rm = na.rm)

Best,

Philippe Grosjean

Liaw, Andy wrote:
> apply(x, 1, median) should do it.  If not, you need to explain why.
> 
> Andy
> 
> -----Original Message-----
> From: Max Kauer
> Sent: Friday, January 20, 2006 10:24 AM
> To: r-help at stat.math.ethz.ch
> Subject: [R] function for rowMedian?
> 
> 
> Hi
> is anybody aware of a function to calculate a the median for specified
> columns in a dataframe or matrix - so analogous to rowMeans?
> Thanks
> Max
> 
> --
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide!
> http://www.R-project.org/posting-guide.html
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide!
http://www.R-project.org/posting-guide.html
> 
>