21、map find collect

class GroovyTest {

    static void main(args) {
        def people = [
                1: [name:'Bob', age:32, gender:'M'],
                2: [name:'Johnny', age:36, gender:'M'],
                3: [name:'Claire', age:21, gender:'F'],
                4: [name:'Amy', age:54, gender:'F']
        ]

        def agesOfMales = people.findAll{
            id,person -> person.gender == 'M'
        }.collect{
            id, person -> person.age
        }
        println agesOfMales


        def females = people.findAll{it.value.gender == 'F'}
        def ageOfFemales = females.collect{it.value.age}
        println ageOfFemales

    }
}

输出：

[32, 36]
[21, 54]