Check if data frame column is numeric

... 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)

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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Henrique Dallazuanna
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