Alternative to loop ifelse() for vector data

Question

I have a price dataframe dat and a second dataframe with currencies cur. What i want to do is to transform every non-EUR price in dat into

Answer 1

I think this would be much easier as a merge/join operation. Using tidy verse you can do

library(tidyverse)
dat <- read_table("Nation   Price
AT       10
AT       12
BE       15
BG       30
BG       40
CZ       200")
cur <- read_table("Nation Rate
BG     0.51
CZ     0.03918")


dat %>% left_join(cur) %>% 
  mutate(Rate=coalesce(Rate, 1)) %>%
  mutate(EPrice = Price * Rate)

The only trick here is to change the Rate for those nations not in the cur table to 1.