R aggregate data.frame with date column

Question

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           


        

Answer 1

Upgrade from base and use data.table instead to simplify (and speed up) your code/life:

library(data.table)

dt = as.data.table(dta)

dt[, lapply(.SD, sum), by = Date]