[R] ifelse() question

F Z
Fri, 29 Oct 2004 17:03:55 -0000

Thanks for you reply Peter.  I tried using as.character and then converting
to factors but it did not work since it generates missing values for all the
dat[,4]=="POR".  See:

>dat[1:5,4]
[1] BOV POR BOV POR BOV
Levels: BOV CAP CER OVI POR

test<-dat

>test[,4]<-as.character(test[,4])
>test[,5]<-as.character(test[,5])
>test[test[,4]=="POR",4]<-test[test[,4]=="POR",5]
Error in "[<-.data.frame"(`*tmp*`, test[, 4] == "POR", 4,
value = c(NA,  :
        missing values are not allowed in subscripted assignments of data
frames
>test[,4]<-as.factor(test[,4])
>test[,5]<-as.factor(test[,5])

>test[1:5,4]
[1] BOV  <NA> BOV  <NA> BOV
Levels: BOV CAP CER OVI


Any suggestions?

Thanks again!

Francisco


>From: "Peter Alspach" <PAlspach at hortresearch.co.nz>
>To: <gerifalte28 at hotmail.com>,<R-help at stat.math.ethz.ch>
>Subject: Re: [R] ifelse() question
>Date: Fri, 29 Oct 2004 13:33:54 +1300
>
>
>Francisco
>
>Did you try changing the factors to character, with as.character?
>
>Also you don't really need ifelse() for this.  Something like the
>following (untested) should do it:
>
>dat[,4] <- as.character(dat[,4])
>dat[,5] <- as.character(dat[,5])
>dat[dat[,4]=='POR',4] <- dat[dat[,4]=='POR',5]
>dat[,4] <- as.factor(dat[,4])
>dat[,5] <- as.factor(dat[,5])
>
>
>Peter Alspach
>
> >>> "F Z" <gerifalte28 at hotmail.com> 29/10/04
12:48:54 >>>
>Hi
>
>I have a data.frame with dim = 18638 (rows)     6 (cols)
>
>names(dat)
>[1] "id"      "long"    "lat"
"species" "type"    "size"
>
>Variable "species" and "type" are factors.  Species has
5 levels "BOV"
>"CAP"
>"CER" "OVI" "POR"
>Variable "type" has 11 levels "BRD" "CL" ...
"OTHER"
>
>I would like to replace the values on species by the values on types
>only if
>species is == "POR"
>I tried:
>
>x<-ifelse(dat$species %in% "POR",dat$type,dat$species)
>dat[,4]<-x
>but levels(x)
>[1] "1"  "2"  "3"  "4"
"5"  "6"  "8"  "9"  "10"
"11" "12"
>
>So x changes the factor names by numbers.  I can not use factor() to
>recover
>the names since the resulting factors in x are a mixture of factors
>from
>species and type.
>
>I also tried
>
>x<-gsub(pattern = "POR",replacement=
factor(dat$type),dat$species)
>with
>same behavior.
>
>Apparently I did not have my granola bar today so I can't find a
>solution!
>Any help is greatly appreciated
>
>Thanks!
>
>Francisco
>
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