如何查找grails中每個元素的出現次數？

Question

我想獲得所有數字及其發生次數。
樣1 = 4,2 = 3，等等

def list=[1,1,1,2,1,2,3,2,3,4,9,4,6,3,6] 

Answer 1

def list=[1,1,1,2,2,2,3,3,1,6,4,6,5,4] 
def countMap=[:] 
list.each{ 
    if(countMap[it]){ 
    countMap[it]=countMap[it]+1 
    }else{ 
    countMap[it]=1 
    } 
} 

Answer 2

assert list.countBy { it } == [1:4, 2:3, 3:3, 4:2, 9:1, 6:2]