[R] about adding a column for water year

[Jim Lemon]

Hi lily,
It might be easier doing it like this:

DF<-data.frame(year=rep(1972:1985,each=12),
 month=rep(1:12,14),day=rep(1,168))
DF$time<-paste(DF$year,DF$month,DF$day,sep="-")
DF$flow<-runif(168,4,7)
DF$wyear<-DF$year + (DF$month > 9)

Jim

On Wed, Jul 5, 2017 at 4:31 AM, lily li <chocold12 at gmail.com> wrote:
> Hi R users,
> I have a question about adding a column for water year. The dataframe has
> the structure below. But the wyear column just shows one year. Could anyone
> help me with this problem? Thanks.
>
> DF
> year   month   day      time            flow
> 1972      1         1    1972-01-01       5
> 1972      1         2    1972-01-02       5.5
> 1972      1         3    1972-01-03       6
> ...
> 1985     12       31   1985-12-31       6
>
>
> for(i in 1972:1985){
>     if(DF$year==i & DF$month %in% 1:9){
>       DF$wyear <- i {
>     }else{
>       DF$wyear < i-1
>     }
>   }
> }
>
>         [[alternative HTML version deleted]]
>
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