How can I build a utility matrix in R?

Question

   | Store_id  | Product  |  Count   |
   | --------------------------------|
   |        6  |  Soda    |  10      | 
   |        8  |  Chips   |  24      | 
   |        9  |  Candy   |  5       | 

I basically have an above table. I want to make Store_id the rows and product the columns and have count as the values of the table. This is basically a user-interactions matrix/utility matrix.

How can i convert this DF to another DF of the aforementioned form?

output:

  store_id soda chips candy
     6      10   0     0
     8      0    24    0
     9      0    0     5

Answer 1

Maybe something like this

library(tidyverse)

df_example <- tibble::tribble(
  ~Store_id, ~Product, ~Count,
  6, "Soda", 10,
  8, "Chips", 24,
  9, "Candy", 5
)


df_example %>%
  pivot_wider(names_from = Product, values_from = Count,values_fill = 0)
#> # A tibble: 3 x 4
#>   Store_id  Soda Chips Candy
#>      <dbl> <dbl> <dbl> <dbl>
#> 1        6    10     0     0
#> 2        8     0    24     0
#> 3        9     0     0     5

^{Created on 2020-06-10 by the reprex package (v0.3.0)}

Answer 2

An option with base R using xtabs

xtabs(Count ~ Store_id + Product, df_example)
#     Product
#Store_id Candy Chips Soda
#       6     0     0   10
#       8     0    24    0
#       9     5     0    0