Suppose you have the following data set which contains (1) a list of items purchased by a given user and (2) a mapping that for item id's to the item name and price. Can you format the data into a matrix with users in rows and the items they purchased into columns with the frequency of the purchase for each type of item?
For example, if we have a user with the following row:
| user_id | ids |
|---|---|
| 12345 | 1, 4, 4, 3, 5, 5, 5 |
We would want the output to look like the following:
user_id 1 2 3 4 5
12345 1 0 2 2 3