Binding in R without a loop

Question

I can answer this question using a loop, I would like to do it without (preferably in dplyr or plyr).

I have a dataframe and a list of countries

Data <- data.frame(
  Date = c(2012:2014,2014,2013:2014),
  Value = rnorm(6),
)

Countries <- c("AUS","USA","UK")

The data frame looks like this

 Date       Value
1 2012  0.20200445
2 2013  1.75576426
3 2014 -0.67385232
4 2014  2.36476344
5 2013 -2.00068346
6 2014 -0.01290928

I need to allocate the country list to the data. The rule for application is -- keep applying the same country until the difference between two adjacent dates in the data frame is <= 0. The finished product should look like this

  Date       Value Countries
1 2012  0.64706706       AUS
2 2013  0.26878534       AUS
3 2014 -0.07091867       AUS
4 2014  0.49546373       USA
5 2013 -0.18158935        UK
6 2014 -0.43114076        UK

Answer 1

No need to use dplyr here.

Data$Countries <- Countries[c(1, cumsum(diff(Data$Date) <= 0) + 1)]