...well, I don't think this is exactly the expected result (see my post)
to be noted that the columns affected should be "A" and "B"
thanks for the help
max
----- Messaggio originale -----
Da: "Rui Barradas" <ruipbarra...@sapo.pt>
A: "Massimo Bressan" <massimo.bres...@arpa.veneto.it>, "r-help"
<r-help@r-project.org>
Inviato: Mercoledì, 22 novembre 2017 11:49:08
Oggetto: Re: [R] assign NA to rows by test on multiple columns of a data frame
Hello,
Try the following.
icol <- which(grepl("flag", names(mydf)))
mydf[icol] <- lapply(mydf[icol], function(x){
is.na(x) <- x == 0
x
})
mydf
# A A_flag B B_flag
#1 8 10 5 12
#2 7 NA 6 9
#3 10 1 2 NA
#4 1 NA 1 5
#5 5 2 0 NA
Hope this helps,
Rui Barradas
On 11/22/2017 10:34 AM, Massimo Bressan 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?
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
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>
--
------------------------------------------------------------
Massimo Bressan
ARPAV
Agenzia Regionale per la Prevenzione e
Protezione Ambientale del Veneto
Dipartimento Provinciale di Treviso
Via Santa Barbara, 5/a
31100 Treviso, Italy
tel: +39 0422 558545
fax: +39 0422 558516
e-mail: massimo.bres...@arpa.veneto.it
______________________________________________
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