[R] correction to the previously asked question (about merging factors)

[Sundar Dorai-Raj]

How about simply

F1 <- factor(c("b", "a"))
F2 <- factor(c("c", "b"))
F3 <- factor(c(levels(F1)[F1], levels(F2)[F2]))

-sundar

Spencer Graves wrote:

>      What about the following:
>  > F1 <- factor(c("b", "a"))
>  > F2 <- factor(c("c", "b"))
>  > k1 <- length(F1)
>  > k2 <- length(F2)
>  > F12.lvls <- unique(c(levels(F1), levels(F2)))
>  > F. <- factor(rep(F12.lvls[1], k1+k1), levels=F12.lvls)
>  > F.[1:k1] <- F1
>  > F.[-(1:k1)] <- F2
>  > F.
> [1] b a c b
> Levels: a b c
> 
>      This saves converting the factors to characters, which might save 
> computer time at the expense of your time.      hope this helps.      
> spencer graves
> 
> Svetlana Eden wrote:
> 
>> I have two factors l1, l2, and I'd like to merge them.
>>
>> (Remark:       The factors can not be converted to charaters)
>>
>> Function c() does not give me the result I want:
>>
>>
>>  
>>
>>> l1 = factor(c('aaaa', 'bbbb'))
>>> l2 = factor(c('ccc', 'dd'))
>>> lMerge = factor(c(l1, l2))
>>> lMerge
>>>   
>>
>> [1] 1 2 1 2
>> Levels: 1 2
>>  
>>
>> I'd like to merge l1 and l2 and to get lMerge 
>> ----------------------------------------------
>>
>> [1] aaaa bbbb ccc dd
>> Levels: aaaa bbbb ccc dd
>>
>> instead of ----------
>>
>> [1] 1 2 1 2
>> Levels: 1 2
>>  
>>
>>
>> How should I do that without converting the factors back to strings.
>> -------------------------------------------------------------------
>>
>>  
>>
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://www.stat.math.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide! 
> http://www.R-project.org/posting-guide.html