i want to convert a csv file, having data in this form:
customer merchant transaction
john walmart 23
jack walmart 21
mary carrefour 34
mary tesco 12
abbey carrefour 12
john tesco 34
abby tesco 12
into a n*n matrix in this form:
[customer walmart carrefour tesco]
[john 23 0 34]
[jack 21 0 0]
[mary 0 34 0]...