GroovyでのSetの使い方と積集合の求め方のサンプル Sample of Set on Groovy

set_sample.groovy

/**********************************
 * sample of Set
**********************************/
import groovy.transform.EqualsAndHashCode
@EqualsAndHashCode
class sample {
  def age
}

def list1 = [
	new sample(age:1),
	new sample(age:1),
	new sample(age:2),
]

def list2 = [
	new sample(age:2),
	new sample(age:3),
	new sample(age:4)
]

// ListからSetへの変換
// convert to Set from List
def set1 = list1 as Set
def set2 = list2 as Set

assert [new sample(age:1),new sample(age:2)] as Set == set1
assert [new sample(age:2),new sample(age:3),new sample(age:4)] as Set == set2

// Setへの値の追加（"set2.add(new sample(age:1))"は追加されません）
// add value to Set ("set2.add(new sample(age:1))" is not added)
set2.add(new sample(age:1))
set2.add(new sample(age:5))
set1.add(new sample(age:5))

// 積集合の取得（つまり両方のSetに存在するオブジェクト）
// get objects that exists in both Set
def both = set1.intersect(set2)	//or def both = set1.findAll{it in set2}
both.each{println it.age} // result is "1" and "2" and "5"

// 型はこんな感じ
// Type is so
assert "class java.util.ArrayList" == list1.getClass().toString()
assert "class java.util.LinkedHashSet" == set1.getClass().toString()
assert "class java.util.LinkedHashSet" == both.getClass().toString()