R aggregate data.frame with date column

aggregate, as.date, object, r

Solution

Indicate the variables you are trying to get the aggregate of in your aggregate statement, and this problem should be resolved:

dta.sum <- aggregate(x = dta[c("Expenditure","Indicator")],
                     FUN = sum,
                     by = list(Group.date = dta$Date))

EDITED TO ADD EXPLANATION: When you give the `aggregate` argument as just `dta`, aggregate attempts to apply the argument to every column. `sum` is not defined for date values in R, and therefore you are getting errors. You want to exclude the grouping column by using the code described above.

Problem

I have the data frame resambling the one in the below ``` Date Expenditure Indicator 29-01-2011 5455 212 25-01-2012 5452 111 11-02-2011 365 5 ``` I'm currently interested in summing up the Expenditure values, I'm trying to use the function below ``` dta.sum <- aggregate(x = dta, FUN = sum, by = list(Group.date = dta$date)) ``` but R returns the following error, Error in Summary.Date(c(15614L, 15614L, 15614L, 15614L, 15614L, 15614L, : sum not defined for "Date" objects. The Date column was previously defined as date with use of the as.Date function. Analogous function but with the mean works fine. ``` dta.sum <- aggregate(x = dta, FUN = mean by = list(Group.date = dta$date)) ``` I would like to keep date formatted as date.

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