这个方法借助闭包，统计符合闭包条件元素的个数，返回值为Integer

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']
        ]

        int count = people.count {it.value.age >35}
        print count

    }
}

输出：

2