groovy removeAll闭包不删除列表中的元素

Question

I'm not sure how removeAll in groovy works, but I expected this to return [40289454470ea94601470ea977d00018]

def list = ['40289454470ea94601470ea977b20014', '40289454470ea94601470ea977d00018']
def list2 = ['40289454470ea94601470ea977b20014']

list.removeAll {
   list2
}

println list

but instead it returns []

please enlighten :(

Answer 1

removeAll with a Closure removes every element that the closure returns true for

list2 coerces to true under groovy truth as it isn't empty so your code removes everything

Try

list1 -= list2

Answer 2

Instead of using removeAll closure, you should simply use the removeAll method.

list.removeAll {
   list2
}

The way with closure to go :

list.removeAll {
   list2.contains(it)
}

If list2 contains this element, then it's removed from list