Calculate daily means from 5-minute interval data

Hello,

You have date and hour in two separate columns, so to compute daily 
stats part of the work is already done. (Were they in the same column 
you would have to extract the date only.)

# convert to class "Date"
df1$date <- as.Date(df1$date)

# function to compute the stats required
# it's important to note that all the stats
# are returned in a vector, see below
fun <- function(x, na.rm = FALSE){
   c(mean_cfs = mean(x, na.rm = na.rm),
     sd_cfs = sd(x, na.rm = na.rm))
}

# now this will put a *matrix* under cfs
# each row has the  statistics computed
# by the function
agg <- aggregate(cfs ~ date, df1, fun)
str(agg)
#'data.frame':	1 obs. of  2 variables:
# $ date: Date, format: "2020-08-26"
# $ cfs : num [1, 1:2] 110400 16143
#  ..- attr(*, "dimnames")=List of 2
#  .. ..$ : NULL
#  .. ..$ : chr [1:2] "mean_cfs" "sd_cfs"

# so now put everything in separate columns
agg <- cbind(agg[-ncol(agg)], agg[[ncol(agg)]])
str(agg)
#'data.frame':	1 obs. of  3 variables:
# $ date    : Date, format: "2020-08-26"
# $ mean_cfs: num 110400
# $ sd_cfs  : num 16143

Hope this helps,

Rui Barradas

?s 17:49 de 29/08/21, Rich Shepard escreveu:

Calculate daily means from 5-minute interval data

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