On Jun 18, 2010, at 10:52 AM, clips10 wrote:
Hi,
I have a vector of time in days t<-1:48.
I have observations and the day they were recorded. I also have a
vector, S
which takes different values depending on which day the observation
was
recorded. For example if on day 1 all in vector S get a value of
46/48, on
day 2 get 42/48, day 3 38/48, decreasing by 4/48 each time until day
12 gets
the value 2/48. Then for any day greater than 12 the vector S has
value 0.
I want to create a vector which gives the values of S in terms of
days, t.
I have tried:
t<-1:48
for(i in 1:t){
S<-rep(0,48)
if(t<12){
S[i]<-(48-3*t)/48}
else{
S[i]<-0}
}
> t<- 1:48; x <- ifelse( (50-t*4)> 0 , (50-t*4)/48, 0) ; x
[1] 0.95833333 0.87500000 0.79166667 0.70833333 0.62500000 0.54166667
[7] 0.45833333 0.37500000 0.29166667 0.20833333 0.12500000 0.04166667
[13] 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000
[19] 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000
[25] 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000
[31] 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000
[37] 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000
[43] 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000
but this doesn't work. I'm fairly new to R and don't have much skill
in
manipulating things. I'm trying to plot time against this vector so
need it
in terms of t. Sorry that this isn't even very clear in what I want
and I'm
aware that the (48-3*t)/48 won't even give me the
46/48,42/48,38/48....2/48,0....0 pattern I'm after but no idea what
to do!
Close, just not quite there. Try:
(50-4*t)/48
Any help would be great.
Thanks
David Winsemius, MD
West Hartford, CT
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