[R] round() a data frame containing 'character' variables?

[Dimitris Rizopoulos]

One approach is the following:

numVars <- sapply(iris, is.numeric)
iris[numVars] <- lapply(iris[numVars], round, digits = 2)
head(iris)

You can also put it in one lapply() call if you like.

I hope it helps.

Best,
Dimitris


On 8/10/2011 11:34 AM, Liviu Andronic wrote:
> Dear all
> It is difficult to use round(..., digits=2) on a data frame since one
> has to first take care to remove non-numeric variables such as
> 'character' or 'factor':
>> head(round(iris, 2))
> Error in Math.data.frame(list(Sepal.Length = c(5.1, 4.9, 4.7, 4.6, 5,  :
>    non-numeric variable in data frame: Species
>> head(round(iris[1:4], 2))
>    Sepal.Length Sepal.Width Petal.Length Petal.Width
> 1          5.1         3.5          1.4         0.2
> 2          4.9         3.0          1.4         0.2
> 3          4.7         3.2          1.3         0.2
> 4          4.6         3.1          1.5         0.2
> 5          5.0         3.6          1.4         0.2
> 6          5.4         3.9          1.7         0.4
>
> Is there an elegant way to use round() on a data frame containing
> 'character' variables without removing them? Thank you
> Liviu
>
>
>

-- 
Dimitris Rizopoulos
Assistant Professor
Department of Biostatistics
Erasmus University Medical Center

Address: PO Box 2040, 3000 CA Rotterdam, the Netherlands
Tel: +31/(0)10/7043478
Fax: +31/(0)10/7043014
Web: http://www.erasmusmc.nl/biostatistiek/