Error in loop: missing value where TRUE/FALSE needed

Asked Oct 11 '16 at 07:14

Active Oct 11 '16 at 07:14

Viewed 27 times

sum_temp<-c()

for (i in 1:length(Station$Day)){
  if (Station$Day[i] == Station$Day[i+1]){
    sum_temp <- sum_temp + Station$h_temp[i]
  } else 
    mean_temp <- mean(sum_temp)
# put the value in a new table but not of importance here
    sum_temp <- 0
}

Hi, I have a data frame containing 9 columns with "Day" as POSIXlt and several meteorological parameters as numeric. What I am trying to do in the loop is to calculate the daily mean since temperature is recorded hourly, hence each day has 24 lines. For this I ask if Day in line i is the same as in line i+1. If yes, sum up the values as long as this statement is true. If the statement is false, calculate the mean and set the sum back to 0. However, I receive the error message "missing value where TRUE/FALSE needed". Btw there is no NA in it.

Can anybody see the mistake? Thanks a lot!

asked Oct 11 '16 at 07:14

David Hoffmann

2

Think about what is going on when you do `i +1`. If you have 10 rows/elements, it will, at one point, try to evaluate 11th row/element, which is not there. – Roman Luštrik Oct 11 '16 at 07:17
Start with 0 instead of 1 – Himanshu Moradiya Oct 11 '16 at 07:17
1

@HimanshuMoradiya R is not 0 index based. My advice would be to capture the last value and process it in a special way. There are other ways of going about this, of course, but a reproducible example would be a good start. – Roman Luštrik Oct 11 '16 at 07:19
thanks a lot. Now I simply start with 2 and do i-1. – David Hoffmann Oct 14 '16 at 12:13

Error in loop: missing value where TRUE/FALSE needed

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