[R] assign NA to rows by test on multiple columns of a data frame

[Bert Gunter]

Inline.

-- Bert


On Wed, Nov 22, 2017 at 11:52 PM, Massimo Bressan <
massimo.bressan at arpa.veneto.it> wrote:

> yes, it works, even if I do not really get how and why it's working the
> combination of logical results (could you provide some insights for that?)
>


Read the docs!

?"!"
?NA

explain

Then a more "compact" (but probably less efficient) solution just loops
over the indices:

##UNTESTED
choices <- ***column numbers of _flag columns***
chng <- ***column numbers of columns that will have values changed to NA***
for(i in seq_along choices) mydf[, ] <- is.na(mydf[, chng[i]) <- !mydf[,
choices[i]]




>
> moreover, and most of all, I was hoping for a compact solution because I
> need to deal with MANY columns (more than 40) in data frame with the same
> basic structure as the simplified example I posted
>
> thanks
>
> m
>
>
> ----- Messaggio originale -----
> Da: "Bert Gunter" <bgunter.4567 at gmail.com>
> A: "Massimo Bressan" <massimo.bressan at arpa.veneto.it>
> Cc: "r-help" <r-help at r-project.org>
> Inviato: Mercoledì, 22 novembre 2017 17:32:33
> Oggetto: Re: [R] assign NA to rows by test on multiple columns of a data
> frame
>
> Do you mean like this:
>
> mydf <- within(mydf, {
>       is.na(A)<- !A_flag
>       is.na(B)<- !B_flag
>       }
>    )
>
> > mydf
>    A A_flag  B B_flag
> 1  8     10  5     12
> 2 NA      0  6      9
> 3 10      1 NA      0
> 4 NA      0  1      5
> 5  5      2 NA      0
>
>
> Cheers,
> Bert
>
>
> Bert Gunter
>
> "The trouble with having an open mind is that people keep coming along and
> sticking things into it."
> -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )
>
> On Wed, Nov 22, 2017 at 2:34 AM, Massimo Bressan <
> massimo.bressan at arpa.veneto.it> wrote:
>
> >
> >
> > Given this data frame (a simplified, essential reproducible example)
> >
> >
> >
> >
> > A<-c(8,7,10,1,5)
> >
> > A_flag<-c(10,0,1,0,2)
> >
> > B<-c(5,6,2,1,0)
> >
> > B_flag<-c(12,9,0,5,0)
> >
> >
> >
> >
> > mydf<-data.frame(A, A_flag, B, B_flag)
> >
> >
> >
> >
> > # this is my initial df
> >
> > mydf
> >
> >
> >
> >
> > I want to get to this final situation
> >
> >
> >
> >
> > i<-which(mydf$A_flag==0)
> >
> > mydf$A[i]<-NA
> >
> >
> >
> >
> > ii<-which(mydf$B_flag==0)
> >
> > mydf$B[ii]<-NA
> >
> >
> >
> >
> > # this is my final df
> >
> > mydf
> >
> >
> >
> >
> > By considering that I have to perform this task in a data frame with many
> > columns I’m wondering if there is a compact and effective way to get the
> > final result with just one ‘sweep’ of the dataframe?
> >
> >
> >
> >
> > I was thinking to the function apply or lapply but I can not properly
> > conceive how to…
> >
> >
> >
> >
> > any hint for that?
> >
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> >
> > ______________________________________________
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> > PLEASE do read the posting guide http://www.R-project.org/
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> > and provide commented, minimal, self-contained, reproducible code.
> --
>

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