multi variable look up table in r

To create a multi-variable look-up table in R, you can use the data.frame() function to create a data frame with the variables you want to use as lookup keys, along with the corresponding values. Here's an example:

main.r
# create a data frame with lookup keys and values
df <- data.frame(x = c(1, 2, 3),
                 y = c(4, 5, 6),
                 z = c(7, 8, 9),
                 value = c("A", "B", "C"))

# define the lookup function
lookup <- function(x, y, z, df) {
  df[df$x == x & df$y == y & df$z == z, "value"]
}

# test the lookup function
lookup(2, 5, 8, df)
# returns "B"
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In this example, df is a data frame with three variables (x, y, and z) that are used as lookup keys, and a fourth variable (value) that contains the corresponding values. The lookup() function takes the three lookup keys as arguments and returns the corresponding value. The lookup is performed by filtering the data frame df based on the input keys using the == operator, and returning the corresponding value column.

You can modify this example to include as many lookup keys and corresponding values as you need.