R: Check if value from dataframe is within range other dataframe

Question

I am looking for a way to look up infromation from 1 dataframe in another dataframe, get a value from that other dataframe and pass it back to the first frame..

exam

Answer 1

Here's a simple base method that uses the OP's logic:

f <- function(vec, id) {
  if(length(.x <- which(vec >= x$from & vec <= x$to & id == x$number))) .x else NA
}
y$name <- x$name[mapply(f, y$location, y$id_number)]
y
#  location id_number     name
#1      1.5        30 region 1
#2      2.8        30 region 2
#3     10.0        38     
#4      3.5        40     
#5      2.0        36 region 7