reject和reject!reject返回不满足代码块的元素数组reject!删除数组中满足代码块的元素
a=[1,2,3,5]a.reject! {|x| x<4}p a #[5]b = [1,2,3,4,5]c = b.reject {|x| x>4}p cp b
[1, 2, 3, 4][1, 2, 3, 4, 5]