Grouped totals with a Dict

orders = [
    (customer = "alice", cents = 1200),
    (customer = "bob", cents = 800),
    (customer = "alice", cents = 300),
]

totals = Dict{String,Int}()
for order in orders
    totals[order.customer] = get(totals, order.customer, 0) + order.cents
end

for (customer, cents) in sort(collect(totals))
    println("$customer: $cents")
end