[R] cumulate of snow cumulates from daily values of different automatic stations for some time intervals

[Jim Lemon]

Hi Stefano,
This was such a stinker of a problem that I just had to crack it:

# create some data the lazy man's way
year_dates<-c(paste(2000,rep("01",31),formatC(1:31,width=2,flag=0),sep="-"),
 paste(2000,rep("02",29),formatC(1:29,width=2,flag=0),sep="-"),
 paste(2000,rep("03",31),formatC(1:31,width=2,flag=0),sep="-"),
 paste(2000,rep("04",30),formatC(1:30,width=2,flag=0),sep="-"),
 paste(2000,rep("05",31),formatC(1:31,width=2,flag=0),sep="-"),
 paste(2000,rep("06",30),formatC(1:30,width=2,flag=0),sep="-"),
 paste(2000,rep("07",31),formatC(1:31,width=2,flag=0),sep="-"),
 paste(2000,rep("08",31),formatC(1:31,width=2,flag=0),sep="-"),
 paste(2000,rep("09",30),formatC(1:30,width=2,flag=0),sep="-"),
 paste(2000,rep("10",31),formatC(1:31,width=2,flag=0),sep="-"),
 paste(2000,rep("11",30),formatC(1:30,width=2,flag=0),sep="-"),
 paste(2000,rep("12",31),formatC(1:31,width=2,flag=0),sep="-"))

df1<-data.frame(station_code=rep(217,366),
 date_factor=year_dates,date_POSIX=year_dates,
 snow=c(sample(0:70,31),sample(0:50,29),sample(0:10,31,TRUE),rep(0,214),
 sample(0:20,30,TRUE),sample(0:60,31)))
df2<-data.frame(station_code=rep(218,366),
 date_factor=year_dates,date_POSIX=year_dates,
 snow=c(sample(0:70,31),sample(0:50,29),sample(0:10,31,TRUE),rep(0,214),
 sample(0:20,30,TRUE),sample(0:60,31)))
df3<-data.frame(station_code=rep(219,366),
 date_factor=year_dates,date_POSIX=year_dates,
 snow=c(sample(0:70,31),sample(0:50,29),sample(0:10,31,TRUE),rep(0,214),
 sample(0:20,30,TRUE),sample(0:60,31)))
df4<-data.frame(station_code=rep(220,366),
 date_factor=year_dates,date_POSIX=year_dates,
 snow=c(sample(0:70,31),sample(0:50,29),sample(0:10,31,TRUE),rep(0,214),
 sample(0:20,30,TRUE),sample(0:60,31)))
df5<-data.frame(station_code=rep(221,366),
 date_factor=year_dates,date_POSIX=year_dates,
 snow=c(sample(0:70,31),sample(0:50,29),sample(0:10,31,TRUE),rep(0,214),
 sample(0:20,30,TRUE),sample(0:60,31)))
df6<-data.frame(station_code=rep(222,366),
 date_factor=year_dates,date_POSIX=year_dates,
 snow=c(sample(0:70,31),sample(0:50,29),sample(0:10,31,TRUE),rep(0,214),
 sample(0:20,30,TRUE),sample(0:60,31)))
df7<-data.frame(station_code=rep(223,366),
 date_factor=year_dates,date_POSIX=year_dates,
 snow=c(sample(0:70,31),sample(0:50,29),sample(0:10,31,TRUE),rep(0,214),
 sample(0:20,30,TRUE),sample(0:60,31)))
df8<-data.frame(station_code=rep(224,366),
 date_factor=year_dates,date_POSIX=year_dates,
 snow=c(sample(0:70,31),sample(0:50,29),sample(0:10,31,TRUE),rep(0,214),
 sample(0:20,30,TRUE),sample(0:60,31)))
df9<-data.frame(station_code=rep(225,366),
 date_factor=year_dates,date_POSIX=year_dates,
 snow=c(sample(0:70,31),sample(0:50,29),sample(0:10,31,TRUE),rep(0,214),
 sample(0:20,30,TRUE),sample(0:60,31)))
df10<-data.frame(station_code=rep(226,366),
 date_factor=year_dates,date_POSIX=year_dates,
 snow=c(sample(0:70,31),sample(0:50,29),sample(0:10,31,TRUE),rep(0,214),
 sample(0:20,30,TRUE),sample(0:60,31)))

snow_list<-list(df1,df2,df3,df4,df5,df6,df7,df8,df9,df10)

for(station in 1:10)
 snow_list[[station]]$doy<-1:length(snow_list[[station]]$date_POSIX)

select_days<-c(1:12,83:88)

cum_snow<-function(x,which_days) {
 return(list(x$station_code[1],sum(x$snow[which_days])))
}

cum_list<-lapply(lapply(snow_list,cum_snow,select_days),unlist)

snow_totals<-data.frame(station_code=NULL,snow_cumulate=NULL)

for(station in 1:10) snow_totals<-rbind(snow_totals,cum_list[[station]])

names(snow_totals)<-c("station_code","snow_cumulate")

Jim


On Sat, Aug 11, 2018 at 2:48 AM, Stefano Sofia
<stefano.sofia using regione.marche.it> wrote:
> Dear R-list users,
> I have 10 data frames (called df1, df2, ... df10), where each of them contains snow data from an automatic meteorological station (obviously each station has a different station code).
> Here is an example of df1:
>
> station_code date_factor date_POSIX snow
> 217 1999-12-15 1999-12-15  0
> 217 1999-12-16 1999-12-16  0
> 217 1999-12-17 1999-12-17 38
> 217 1999-12-18 1999-12-18 31
> 217 1999-12-19 1999-12-19 21
> 217 1999-12-20 1999-12-20 12
> 217 1999-12-21 1999-12-21 42
> 217 1999-12-22 1999-12-22 61
> 217 1999-12-23 1999-12-23 57
> 217 1999-12-24 1999-12-24 48
> ...
>
> where
>> sapply(df1, class)
> $station_code
> [1] "numeric"
>
> $date_factor
> [1] "factor"
>
> $date_POSIX
> [1] "POSIXct" "POSIXt"
>
> $snow
> [1] "integer"
>
> Given a series of max three intervals (example with two intervals: from 1st to 12th of January 2000 and from 23rd to 28th of March 2000), I need to evaluate for each station the total snow cumulate for all the intervals selected, and finally create a data frame where for each line there is the station code and the snow cumulate. It should be like
>
> station_code total_snow_cumulate
> 217 125
> 218 80
> ...
>
> Could somebody show me a direction for an efficient solution?
>
> Thank you for your attention and your help
> Stefano
>
>
>          (oo)
> --oOO--( )--OOo----------------
> Stefano Sofia PhD
> Area Meteorologica e  Area nivologica - Centro Funzionale
> Servizio Protezione Civile - Regione Marche
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