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

Or use dplyr:

library(dplyr)

dta %>%
  group_by(Date) %>%
  summarise(Tot.Expenditure = sum(Expenditure))