[R] how to apply two or more functions to each columns in a time?

[David L Carlson]

Combine the functions with rbind(). If there are more than two, it will
probably be easier to define the function outside sapply.

> dta <- sapply(iris[,-5],function(x) rbind(mean(x,na.rm=T), sd(x,na.rm=T)))
> rownames(dta) <- c("mean", "SD")
> dta
     Sepal.Length Sepal.Width Petal.Length Petal.Width
mean    5.8433333   3.0573333     3.758000   1.1993333
SD      0.8280661   0.4358663     1.765298   0.7622377

----------------------------------------------
David L Carlson
Associate Professor of Anthropology
Texas A&M University
College Station, TX 77843-4352



> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of Yao He
> Sent: Wednesday, December 26, 2012 6:54 PM
> To: r-help at r-project.org
> Subject: [R] how to apply two or more functions to each columns in a
> time?
> 
> Dear All:
> 
> I want to calculate the mean and sd for each column in a data.frame.
> 
> Taking data(iris) for example:
> I tried sapply(iris[,-5],mean,na.rm=T) or sapply(iris[,-5],sd,na.rm=T)
> to calculate the mean and sd .But sapply() transfer a function per
> time. How to transfer two functions in a time to generate a data.frame
> like this:
> 
>            Sepal.Length Sepal.Width Petal.Length Petal.Width
> mean    5.84333        3.05733        3.758000      1.199333
> SD        0.82806        0.43586        1.765298       0.762237
> 
> 
> Thanks a lot
> 
> Yao He
> 
> --
> -------------------------
> Master candidate in 2rd year
> Department of Animal genetics & breeding
> Room 436,College of Animial Science&Technology,
> China Agriculture University,Beijing,100193
> E-mail: yao.h.1988 at gmail.com
> --------------------------
> 
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