Merge and Aggregate data in Groovy - groovy

Question

I was wondering what the best way to aggregate this data would be in Groovy?
Lets say I have the following data:
[
[id: 1, name: bob, age:20, numberOfPackages: 10, numberOfPurchases:20 ],
[id: 1, name: bob, age:20, numberOfPackages: 5, numberOfPurchases:6 ],
[id: 2, name: Rob, age:22, numberOfPackages: 3, numberOfPurchases:5 ],
]
and I want to transform it to the following (merge id/name/age but sum price/number of purchases per id):
[
[id: 1, name: bob, age:20, numberOfPackages: 15, numberOfPurchases:26 ],
[id: 2, name: Rob, age:22, numberOfPackages: 3, numberOfPurchases:5 ],
]

Answer 1

Summing the prices, and the number of purchases separately makes little sense, do you mean:
def data = [
[id: 1, name: 'bob', age:20, price: 10, numberOfPurchases:20],
[id: 1, name: 'bob', age:20, price: 5, numberOfPurchases:6],
[id: 2, name: 'rob', age:22, price: 3, numberOfPurchases:5]
]
data.groupBy { [id:it.id, name:it.name, age:it.age] }.collect { k, v ->
[id:k.id,
name:k.name,
age:k.age,
spend:v.collect { it.price * it.numberOfPurchases }.sum()]
}
Which gives:
[
[id:1, name:'bob', age:20, spend:230],
[id:2, name:'rob', age:22, spend:15]
]

Answer 2

It may be e.g.:
def data = [
[id: 1, name: 'bob', age:20, price: 10, numberOfPurchases:20 ],
[id: 1, name: 'bob', age:20, price: 5, numberOfPurchases:6 ],
[id: 2, name: 'rob', age:22, price: 3, numberOfPurchases:5 ],
]
data.groupBy { it.id }.collectEntries {
[
(it.key): [
name: it.value.name.first(),
age: it.value.first(),
price: it.value.sum { it.price },
numberOfPurchases: it.value.sum { it.numberOfPurchases },
]
]
}