[R] Check if data frame column is numeric

[Bert Gunter]

... and an addendum

Hadley Wickham's plyR package attempts to redress these (nevertheless
documented) apparent inconsistencies in the *apply family of functions by
handling everything in a more consistent intuitive manner. You may wish to
use those instead of the base R *apply functions.

-- Bert Gunter
Genentech



-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On
Behalf Of Henrique Dallazuanna
Sent: Tuesday, December 16, 2008 9:32 AM
To: Mark Heckmann
Cc: r-help at r-project.org
Subject: Re: [R] Check if data frame column is numeric

Try:

sapply(df, is.numeric)

On Tue, Dec 16, 2008 at 1:25 PM, Mark Heckmann <mark.heckmann at gmx.de> wrote:

> Hi R-users,
>
> I want to apply a function to each column of a data frame that is numeric.
> Thus I tried to check it for each column first:
>
> > apply(df, 2, function(x) is.numeric(x))
>
>     A60       A64      A66a       A67       A71      A75a       A80
> A85       A91       A95       A96       A97       A98       A99
>    FALSE     FALSE     FALSE     FALSE     FALSE     FALSE     FALSE
> FALSE     FALSE     FALSE     FALSE     FALSE     FALSE     FALSE
>
> I get only FALSE results although the variables are numeric. When I try
the
> following it works:
>
> > is.numeric(df$A60)
> [1] TRUE
>
> What am I doing wrong?
>
> TIA
> Mark
>
> ______________________________________________
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> PLEASE do read the posting guide
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> and provide commented, minimal, self-contained, reproducible code.
>



-- 
Henrique Dallazuanna
Curitiba-Parana-Brasil
250 25' 40" S 490 16' 22" O

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