[R] dataframe columns class

[Jeff Newmiller]

The apply function operates on arrays, so your data frame is being converted to an array (matrix) before doing its thing.  So use lapply or one of its variants. 
-- 
Sent from my phone. Please excuse my brevity.

On December 18, 2016 9:07:52 AM PST, "Cleber N.Borges via R-help" <r-help at r-project.org> wrote:
>Why columns classes are function dependents?
>Like this example:
>
> > for( i in 1:5 ) print( class( iris[,i] ) )
>[1] "numeric"
>[1] "numeric"
>[1] "numeric"
>[1] "numeric"
>[1] "factor"
> >
> > apply( iris, 2, class )
>Sepal.Length  Sepal.Width Petal.Length  Petal.Width Species
>  "character"  "character"  "character"  "character" "character"
> >
>
>
>
> > dat <- data.frame( v1=1:5, v2=letters[1:5] )
> > dat
>   v1 v2
>1  1  a
>2  2  b
>3  3  c
>4  4  d
>5  5  e
> >
> > summary( dat )
>        v1    v2
>  Min.   :1   a:1
>  1st Qu.:2   b:1
>  Median :3   c:1
>  Mean   :3   d:1
>  3rd Qu.:4   e:1
>  Max.   :5
> >
> > apply( dat, 2, class )
>          v1          v2
>"character" "character"
> >
>
>
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