Well, I think that's kind of overkill.
Assuming "oldvar" is a factor in the data frame mydata, then the
following shows how to do it:
> set.seed(27)
> d <- data.frame(a = sample(c(letters[1:3],NA),15,replace = TRUE))
> d
a
1 <NA>
2 a
3 <NA>
4 b
5 a
6 b
7 a
8 a
9 a
10 a
11 c
12 <NA>
13 c
14 c
15 <NA>
> d$b <- factor(d$a,labels = LETTERS[3:1])
> d
a b
1 <NA> <NA>
2 a C
3 <NA> <NA>
4 b B
5 a C
6 b B
7 a C
8 a C
9 a C
10 a C
11 c A
12 <NA> <NA>
13 c A
14 c A
15 <NA> <NA>
See ?factor for details.
Incidentally note that in the OP's post,
mydata$newvar[oldvar = "topic1"] <- "parenttopic"
is completely incorrect; it should probably be:
mydata$newvar[mydata$oldvar == "topic1"] <- "parenttopic";
This suggests to me that the OP would probably find it useful to spend
some time with one or more of the many good R tutorials on the web.
Cheers,
Bert
Bert Gunter
"The trouble with having an open mind is that people keep coming along
and sticking things into it."
-- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )
On Mon, Oct 10, 2016 at 9:08 AM, S Ellison <s.elli...@lgcgroup.com> wrote:
>> Is there a convenient way to edit this code to allow me to recode a list of
>> categories 'topic 1', 'topic 9' and 'topic 14', say, of the the old variable
>> 'oldvar'
>> as 'parenttopic' by means of the new variable 'newvar', while also mapping
>> system missing values to system missing values?
>
> You could look at 'recode()' in the car package.
>
> There's a fair description of other options at
> http://www.uni-kiel.de/psychologie/rexrepos/posts/recode.html
>
> S Ellison
>
>
>
>
> *******************************************************************
> This email and any attachments are confidential. Any u...{{dropped:8}}
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