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rtime-seriesxts

R : Converting "Daily" time series to monthly

I am working with time series data (6000 observations, over 7000 days) that is said to be "daily". However, measurements do not necessarily happen everyday. Sometimes, several measurements can happen on the same day. This is why I think it would be better to analyze this data "monthly" instead of "daily".

I create some dummy data that represents my time series:

library(xts)

date_decision_made = seq(as.Date("2014/1/1"), as.Date("2016/1/1"),by="day")

date_decision_made <- format(as.Date(date_decision_made), "%Y/%m/%d")

property_damages_in_dollars <- rnorm(731,100,10)

final_data <- data.frame(date_decision_made, property_damages_in_dollars)

I am trying to follow the instructions here : Getting a monthly time series from weekly data

y.mon  <- aggregate(final_data, by = format(date_decision_made,format="%Y/%m/%d"), FUN=sum)

But this code gives me an error:

Error in aggregate.data.frame(final_data, by = format(date_decision_made,  : 
  'by' must be a list

Does someone know what I am doing wrong?

Thanks

Solution

  • The possible solution for OP issue can be based on:

    #Code
y.mon<-aggregate(property_damages_in_dollars~format(as.Date(date_decision_made),
format="%Y/%m"),data=final_data, FUN=sum)

    More variants can be explored around the format() options.