Why does this piece of code:
letter = c("A","B","C","C","A")
product = c("Beef","Chicken","Beef","Beef","Beef")
value = c(10,20,40,10,5)
df <- data.frame(letter,product,value)
df1 = df %>% group_by(letter,product) %>% summarise(value = sum(value))
Results in this:
> df1
value
1 85
Rather than this?
> df
letter product value
1 A Beef 15
2 B Chicken 20
3 C Beef 50