Untested, but I expect that setting the levels to be the same across the
two factors
levels(tmp$R1) <- levels(tmp$R2) <- LETTERS[1:6]
and proceeding as before should be fine.
Best,
Ista
On Jul 6, 2017 6:54 PM, "Gang Chen" <gangch...@gmail.com> wrote:
Thanks a lot, Ista! I really appreciate it.
How about a slightly different case as the following:
set.seed(1)
(tmp <- data.frame(x = 1:10, R1 = sample(LETTERS[1:5], 10, replace =
TRUE), R2 = sample(LETTERS[2:6], 10, replace = TRUE)))
x R1 R2
1 C B
2 B B
3 C E
4 E C
5 E B
6 D E
7 E E
8 D F
9 C D
10 A E
Notice that the factor levels between the two factors, R1 and R2,
slide by one level; that is, factor R1 does not have level F while
factor R2 does not have level A. I want to swap the factor levels
based on the combined levels of the two factors as shown below:
tl <- unique(c(levels(tmp$R1), levels(tmp$R2)))
for(ii in 1:dim(tmp)[1]) {
kk <- which(tl %in% tmp[ii,'R2'], arr.ind = TRUE) - which(tl %in%
tmp[ii,'R1'], arr.ind = TRUE)
if(kk%%2!=0) { # swap the their levels between the two factors
qq <- tmp[ii,]$R1
tmp[ii,]$R1 <- tmp[ii,]$R2
tmp[ii,]$R2 <- qq
}
}
How to go about this case? Thanks!
On Thu, Jul 6, 2017 at 5:16 PM, Ista Zahn <istaz...@gmail.com> wrote:
> How about
>
> foo <- with(list(r1 = tmp$R1,
> r2 = tmp$R2,
> swapme = (as.numeric(tmp$R1) - as.numeric(tmp$R2)) %% 2
!= 0),
> {
> tmp[swapme, "R1"] <- r2[swapme]
> tmp[swapme, "R2"] <- r1[swapme]
> tmp
> })
>
> Best,
> Ista
>
> On Thu, Jul 6, 2017 at 4:06 PM, Gang Chen <gangch...@gmail.com> wrote:
>> Suppose that we have the following dataframe:
>>
>> set.seed(1)
>> (tmp <- data.frame(x = 1:10, R1 = sample(LETTERS[1:5], 10, replace =
>> TRUE), R2 = sample(LETTERS[1:5], 10, replace = TRUE)))
>>
>> x R1 R2
>> 1 1 B B
>> 2 2 B A
>> 3 3 C D
>> 4 4 E B
>> 5 5 B D
>> 6 6 E C
>> 7 7 E D
>> 8 8 D E
>> 9 9 D B
>> 10 10 A D
>>
>> I want to do the following: if the difference between the level index
>> of factor R1 and that of factor R2 is an odd number, the levels of the
>> two factors need to be switched between them, which can be performed
>> through the following code:
>>
>> for(ii in 1:dim(tmp)[1]) {
>> kk <- which(levels(tmp$R2) %in% tmp[ii,'R2'], arr.ind = TRUE) -
>> which(levels(tmp$R1) %in% tmp[ii,'R1'], arr.ind = TRUE)
>> if(kk%%2!=0) { # swap the their levels between the two factors
>> qq <- tmp[ii,]$R1
>> tmp[ii,]$R1 <- tmp[ii,]$R2
>> tmp[ii,]$R2 <- qq
>> }
>> }
>>
>> More concise and efficient way to do this?
>>
>> Thanks,
>> Gang
>>
>> ______________________________________________
>> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> 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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