How to cost minimize among markets

Question

Hello there and thanks in advance. I have the current problem. I have a dataset that looks like this

data <- data.frame (id = 1:3, A = 1:3, B = 1:3)

Where:

• id are products
• A and B represent the price of every id product on markets A and B, although i might have in future n times markets C,D, etc

My objective is to arrange a solution that shows up where is better to buy every id product.

Something like a data frame showing the best place to buy from every id item.

I have read some optimization packages info, so far i have no clue on how i can get this done. I think those packages might be for more complex tasks.

Answer 1

Your example isn't great, since A and B have the same value in each row; therefore neither A nor B is 'better' (i.e. lower). A more useful example is:

data <- data.frame(id = 1:3, A = c(2, 4, 3), B = c(3, 5, 2))

In which case you can do:

library(dplyr)

data %>%
  rowwise() %>%
  mutate(best = names(.)[which.min(c(A, B)) + 1])
#> # A tibble: 3 x 4
#> # Rowwise: 
#>      id     A     B best 
#>   <int> <dbl> <dbl> <chr>
#> 1     1     2     3 A    
#> 2     2     4     5 A    
#> 3     3     3     2 B