CODEWITHSUNDEEP
r
Bindini
Bindini

Reputation: 189

How to calculate 8-days accumulated rainfall on a daily time series, using R?

I am trying to calculate a 8-days accumulated rainfall, with this code, but it seems to not work well.

chuva$Precipitacao it is my vector of daily rainfall, of length 5601.

 rain<-chuva$Precipitacao 
j=1
rain8<-vector()
for (i in 1:800){
   rain8<-rbind(rain8, (rain[j]+rain[j+1]+rain[j+2]+rain[j+3]+
                     rain[j+4]+rain[j+5]+rain[j+6]+rain[j+7]));
  j=i+7
}

Upvotes: 1

Views: 1442

Answers (2)

ytk
ytk

Reputation: 2827

You can just do it like this:

## if you want to calculate moving sum of 8 days
rain <- chuva$Precipitacao
rain8 <- vector()
for (i in rain[1:5594]){
    rain8 <- c(rain8, sum(rain[i:i + 7]))
}

## if you want to calculate sum for each separate period of 8 days
rain <- chuva$Precipitacao
rain8 <- vector()
for (i in seq(1, length(rain), 7)){
    rain8 <- c(rain8, sum(rain[i:i + 7]))
}

Upvotes: 2

andrnev
andrnev

Reputation: 410

You could try the following one liner rollapply function from the zoo package. 

rain8<-rollapply(rain, 'your main vector
                 8,    'The number of consecutive data points
                 sum)  'The function you want to apply

Upvotes: 4

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