groovy之使用List方法

使用列表方法：

 

删除list中为null和重复的元素

 

def myList = [1, 2, 2, 3, 3, null, 4, null]
def lst = new HashSet(myList).toList()
assert lst.size() == 5

assert lst.grep{it} == [1, 2, 3, 4]
assert List.'package'.name == java.util

 

常用list方法

assert [1, [2, 3]].flatten() == [1, 2, 3]

assert [1, 2, 3].intersect([4, 3, 1]) == [3, 1]
assert [1, 2, 3].disjoint([4, 5, 6])

//Treating a list like stack
def lst = [1, 2, 3]
assert lst.pop() == 3
assert lst == [1, 2]

assert [3, 1, 2].sort() == [1, 2, 3]
assert [1, 2, 3].reverse == [3, 2, 1]

def doubled = [1, 2, 3].collect{elem ->
  elem*2
}
assert doubled == [2, 4, 6]

def odd = [1, 2, 3].findAll{elem ->
  elem % 2 == 1
}
assert odd == [1, 3]

def lst = [3,1,4]
lst.sort{a, b->
    return a.compareTo(b)
}

lst.sort{a,b ->
    return -a.compareTo(b)
}