Break down your problem into parts:
# compute two-day totals. I use filter here, but there are many ways
twoDayTotal <- function (x, init = 0)
{
# init lets you supply rainfall from day previous to first in x
filter(c(init, x), c(1, 1))[-length(x)]
}
# compute the first time a logical vector contains a TRUE
firstTime <-function (x, time. = as.vector(time(x)))
{
stopifnot(is.logical(x))
time.[!is.na(x) & x][1]
}
# combine them
f <- function(x, ...) firstTime(x>22 | twoDayTotal(x)>22, ...)
# test it
f(c(5, 20, 3, 4, 25))
# [1] 2
f(c(0, 25, 3, 4, 25), time=92:96)
# [1] 93
f(ts(c(0, 25, 3, 4, 25), start=92))
# [1] 93
Bill Dunlap
TIBCO Software
wdunlap tibco.com
On Wed, Oct 15, 2014 at 12:01 AM, Frederic Ntirenganya
<ntfr...@gmail.com> wrote:
> Dear All,
>
> i am solving the following problem in my work.
>
> The first day from April 01 that gets more than 20 mm on a single day, or
> totalled
> over 2 consecutive days. i.e April 01 = 92th day of the year.
>
> The column of interest is "Rain".
>> head(Samaru56)
> Year Day Rain
> 1 1928 1 0
> 2 1928 2 0
> 3 1928 3 0
> 4 1928 4 0
> 5 1928 5 0
> 6 1928 6 0
>
> I used the loop below but it is not printing anything.
>
> sow_day=c()
> for (i in 1928:1983){
> for (j in 92:366){
> k=j-1
> s_rain=Samaru56$Rain[k] + Samaru56$Rain[j]
> if (s_rain>=20)
> sow_day=j
> break
> }
> Samaru56$year=Samaru56$Year[sow_day]
> Samaru56$Day=Samaru56$Day[sow_day]
> Samaru56$Rain=Samaru56$Rain[sow_day]
> }
> sow_day
>
> Any idea is welcome on how I can solve this problem. Thanks
>
> --
> Frederic Ntirenganya
> Maseno University,
> Kenya.
> Mobile:(+254)718492836
> Email: fr...@aims.ac.za
> https://sites.google.com/a/aims.ac.za/fredo/
>
> [[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.
______________________________________________
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.
