Ah,
so that's how ifelse gets used...
Presumably if I had more than 2 non-missing values in the
control variable, I could use it several times.
Thank you very much, for a really useful answer, and thanks
for getting back so quickly!
All the best,
Anthony Staines
On 11/19/11 23:55, David Winsemius wrote:
On Nov 19, 2011, at 6:31 PM, Anthony Staines wrote:
This would seem to be an obvious task for ifelse()
SCQScore <- NA
d$SCQScore <- ifelse( SCQ1 == 1, d$SCQScore1, d$SCOScore2)
(And don't use 99 for missing. Use NA. It will protect you
better than "99".)
I suppose you could enforce the two level testing with:
d$SCQScore <- ifelse( SCQ1 == 1, d$SCQScore1,
ifelse(SCQ1 ==2, d$SCOScore2, NA))
d$SCQScore <- 99
##Distinct value for any other values I've missed
d$SCQScore[SCQ1 == 1] <- d$SCQScore1[SCQ1 == 1]
## Talks using phrases/sentences, so sum S2CQ:SCQ40
d$SCQScore[SCQ1 == 2] <- d$SCQScore2[SCQ1 == 2]
## Can't do this, so sum SCQ8:SCQ40
d$SCQScore[is.na(d$SCQ1)] <- d$SCQScore1 [is.na(d$SCQ1)]
## SCQ1 is missing
This fails on line 2
(d$SCQScore[SCQ1 == 1] <- d$SCQScore1[SCQ1 == 1])
with the error message
"NAs are not allowed in subscripted assignments",
presumably because SCQ1 does indeed contain missing values.
This can be fixed, got around, or otherwise bypassed, by
creating a new variable SCQ1, with no missing values, as
shown :-
SCQ1 <- d$SCQ1
SCQ1[is.na(SCQ1)] <- 3
d$SCQScore[SCQ1 == 1] <- d$SCQScore1[SCQ1 == 1]
## Talks using phrases/sentences so sum S2CQ:SCQ40
d$SCQScore[SCQ1 == 2] <- d$SCQScore2[SCQ1 == 2]
## Can't do this, so sum SCQ8:SCQ40
d$SCQScore[SCQ1 == 3] <- d$SCQScore1[SCQ1 == 3]
## We don't know if he/she can talk, so guess - sum S2:S40
This type of thing is a common problem in my little world.
Is there a better/less klutzy/smarter way of solving it
than creating a new variable each time? Please bear in
mind that it is critical, for later analysis, to keep the
missing values in SCQ1.
Best wishes,
Anthony Staines
--
Anthony Staines, Professor of Health Systems,
School of Nursing and Human Sciences, DCU, Dublin 9,Ireland.
Tel:- +353 1 700 7807. Mobile:- +353 86 606 9713
http://astaines.eu/
______________________________________________
R-help@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.
David Winsemius, MD
West Hartford, CT
--
Anthony Staines, Professor of Health Systems,
School of Nursing and Human Sciences, DCU, Dublin 9,Ireland.
Tel:- +353 1 700 7807. Mobile:- +353 86 606 9713
http://astaines.eu/
______________________________________________
R-help@r-project.org mailing list
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.
