el-menu-itemindex="2-2">选项2</el-menu-item><el-menu-itemindex="2-3">选项3</el-menu-item><el-submenuindex="<em>2-</em>
0,9,2,2,3,2,7,5,9,5]pa.chunk_while{|i,j|i<=j}.to_a#=>[[0,9],[2,2,3],[2,7],[5,9],[5]] 相邻的evens和odds可以如下分块:(可枚举