[R] renaming factor-labels / add factors etc.

[David Winsemius]

On Dec 15, 2008, at 10:15 PM, Peter Alspach wrote:

> Jörg
>
> To add a level you could:
>
> x <- factor(c("xyz1", "abc1", "xyz2", "abc2"))
> x1 <- factor(x, levels=c(levels(x), 'fgh'))

Could also use:
levels(ff) <- c(levels(ff), "fgh")

>
> summary(x)
> abc1 abc2 xyz1 xyz2
>   1    1    1    1
> summary(x1)
> abc1 abc2 xyz1 xyz2  fgh
>   1    1    1    1    0
>
> For the others, I tend to convert to a character, make the changes  
> and convert back to a factor - but there is probably a better way.

 > levels(ff)[3] <- "zippy"
 > levels(ff)
[1] "abc1"  "abc2"  "zippy" "xyz2"  "fgh"

Just a note that these are not the names:
 > names(ff)
NULL

Although you could add names.


-- 
David Winsemius
>
>
> HTH ....
>
> Peter Alspach.
>
>> -----Original Message-----
>> From: r-help-bounces at r-project.org
>> [mailto:r-help-bounces at r-project.org] On Behalf Of Jörg Groß
>> Sent: Tuesday, 16 December 2008 3:26 p.m.
>> To: r-help at r-project.org
>> Subject: [R] renaming factor-labels / add factors etc.
>>
>> Hi,
>>
>> how can I change a defined factor-variable?
>> Like adding levels, renaming existing levels or merge several
>> levels of a factor to one level?
>>
>>
>>
>> For example; following factor-variable is given:
>>
>>  x <- factor(c("xyz1", "abc1", "xyz2", "abc2"))
>>
>>
>> How can I add the level fgh?
>> And how can I merge "xyz1" and "xyz2" to one level?
>> And how can I change the name?
>>
>>
>>
>>
>> Thanks for any help!
>>
>> ______________________________________________
>> R-help at r-project.org mailing list
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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.
>>
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