> x <- c(1,2,3) # a vector of numbers, such as snowfallsum
> (cx <- cumsum(x)) # a vector of cumulative sums.
1 3 6
> i <- 1 # The starting point.
> j <- 2 # The ending point.
> cx[j] - cx[i-1] # sum of x[i] + ... + x[j]
ERROR!
> cx <- c(0, cx) # Oops, we need this step.
> cx[j+1] - cx[i]
So usin
Hi Stefano,
Try using rollsum from the zoo package:
library(zoo)
rollsum_index<-function(x,window,val) return(which(rollsum(x,window) >= val))
rollsum_index(mydf$hn,2,80)
[1] 6 13 18 19
Jim
On Fri, Jul 30, 2021 at 5:24 PM Stefano Sofia
wrote:
>
> Dear R users,
> I have a data frame with daily
iginal Message-
> From: R-help On Behalf Of Stefano Sofia
> Sent: Friday, July 30, 2021 9:24 AM
> To: r-help mailing list
> Subject: [R] Cumulates of snowfall within a given interval
>
> Dear R users,
> I have a data frame with daily snow cumulates (these quantities are know
essage-
> From: R-help On Behalf Of Stefano Sofia
> Sent: Friday, July 30, 2021 9:24 AM
> To: r-help mailing list
> Subject: [R] Cumulates of snowfall within a given interval
>
> Dear R users,
> I have a data frame with daily snow cumulates (these quantities are known
> a
Dear R users,
I have a data frame with daily snow cumulates (these quantities are known as
"hn" and are expressed in cm), from the 1st of December to the 30th of April,
for more than twenty years.
I would need to find days when the sum of a given short interval (I might
choose two consecutive d
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