[R] ODP: unexpected behavior in apply

[Grzegorz Smoliński]

Hi,
but why is there a space before 6? Isn't it the source of the problem?

Best regards,
Grzegorz


pt., 8 paź 2021 o 20:14 Andrew Simmons <akwsimmo using gmail.com> napisał(a):
>
> Hello,
>
>
> The issue comes that 'apply' tries to coerce its argument to a matrix. This
> means that all your columns will become character class, and the result
> will not be what you wanted. I would suggest something more like:
>
>
> sapply(d, function(x) all(x[!is.na(x)] <= 3))
>
> or
>
> vapply(d, function(x) all(x[!is.na(x)] <= 3), NA)
>
>
> Also, here is a different method that might look cleaner:
>
>
> sapply(d, function(x) all(x <= 3, na.rm = TRUE))
>
> vapply(d, function(x) all(x <= 3, na.rm = TRUE), NA)
>
>
> It's up to you which you choose. I hope this helps!
>
> On Fri, Oct 8, 2021 at 1:50 PM Derickson, Ryan, VHA NCOD via R-help <
> r-help using r-project.org> wrote:
>
> > Hello,
> >
> > I'm seeing unexpected behavior when using apply() compared to a for loop
> > when a character vector is part of the data subjected to the apply
> > statement. Below, I check whether all non-missing values are <= 3. If I
> > include a character column, apply incorrectly returns TRUE for d3. If I
> > only pass the numeric columns to apply, it is correct for d3. If I use a
> > for loop, it is correct.
> >
> > > d<-data.frame(d1 = letters[1:3],
> > +               d2 = c(1,2,3),
> > +               d3 = c(NA,NA,6))
> > >
> > > d
> >   d1 d2 d3
> > 1  a  1 NA
> > 2  b  2 NA
> > 3  c  3  6
> > >
> > > # results are incorrect
> > > apply(d, 2, FUN=function(x)all(x[!is.na(x)] <= 3))
> >    d1    d2    d3
> > FALSE  TRUE  TRUE
> > >
> > > # results are correct
> > > apply(d[,2:3], 2, FUN=function(x)all(x[!is.na(x)] <= 3))
> >    d2    d3
> >  TRUE FALSE
> > >
> > > # results are correct
> > > for(i in names(d)){
> > +   print(all(d[!is.na(d[,i]),i] <= 3))
> > + }
> > [1] FALSE
> > [1] TRUE
> > [1] FALSE
> >
> >
> > Finally, if I remove the NA values from d3 and include the character
> > column in apply, it is correct.
> >
> > > d<-data.frame(d1 = letters[1:3],
> > +               d2 = c(1,2,3),
> > +               d3 = c(4,5,6))
> > >
> > > d
> >   d1 d2 d3
> > 1  a  1  4
> > 2  b  2  5
> > 3  c  3  6
> > >
> > > # results are correct
> > > apply(d, 2, FUN=function(x)all(x[!is.na(x)] <= 3))
> >    d1    d2    d3
> > FALSE  TRUE FALSE
> >
> >
> > Can someone help me understand what's happening?
> >
> > ______________________________________________
> > R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
> > https://stat.ethz.ch/mailman/listinfo/r-help
> > PLEASE do read the posting guide
> > http://www.R-project.org/posting-guide.html
> > and provide commented, minimal, self-contained, reproducible code.
> >
>
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>
> ______________________________________________
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> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.