Hi Peter!
The 'if' function operate on a single logical expression, while you provided
a vector. What your code does at present is subtract 5 from all values in
rr.dia.2m if the first value in med.hyper is 1 and otherwise simply returns
all values as is. Since you have no reproducible data, it's harder to
provide a fix, but you may want to check ?for or (preferably) ?apply. Or
simply try :
rr.dia.2m.corr<-rr.dia.2m
rr.dia.2m.corr[med.hyper==1]<-rr.dia.2m.corr[med.hyper==1]-5
#NOTE: untested
hth/ Rafael
2010/6/8 Peter Lercher <peter.lerc...@i-med.ac.at>
> Dear colleagues,
>
> What did I not understand ?
>
> ->my intention
> I want to create a new variable:
> In plain language:
> If someone is taking anithypertensive treatment (med.hyper==1)
> table(med.hyper)
> med.hyper
> 0 1
> 472 97
> I want to subtract 5 mmHg (rr.dia.2m-5) from the measured diastolic blood
> pressure (rr.dia.2m)
> if not treated - the value of the measured diastolic blood pressure should
> remain the same
>
> ->my code (data frame is attached !)
> rr.dia2.corr<-if(med.hyper==1)
> {
> rr.dia.2m-5
> } else
> {
> rr.dia2.corr==rr.dia.2m
> }
>
> R warning
> Warnmeldung:
> In if (med.hyper == 1) { :
> Bedingung hat Länge > 1 und nur das erste Element wird benutzt
> "Only first condition is use"
> which you can see from the result (simply 5 mm was subtracted and the
> second condition was taken into account)
>
> > describe(rr.dia.2m)
> rr.dia.2m
> n missing unique Mean .05 .10 .25 .50 .75
> .90 .95
> 546 26 110 85.32 67.00 71.50 77.62 84.50 92.00
> 99.25 105.00
>
> lowest : 45.0 57.0 60.0 61.0 62.0, highest: 127.5 128.5 129.5 142.5
> 146.5
> > describe(rr.dia2.corr)
> rr.dia2.corr
> n missing unique Mean .05 .10 .25 .50 .75
> .90 .95
> 546 26 110 80.32 62.00 66.50 72.62 79.50 87.00
> 94.25 100.00
>
> lowest : 40.0 52.0 55.0 56.0 57.0, highest: 122.5 123.5 124.5 137.5
> 141.5
> --------------------
> OS windows
> R version 2.10.1 (2009-12-14)
> attached R modules: design+hmisc
> ------------------
> Thank you so much
>
> Peter
>
>
> ______________________________________________
> 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.
>
>
[[alternative HTML version deleted]]
______________________________________________
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.
