数据:sample_matrix, 包: xts

数据类型: 矩阵

头部数据:

|日期|开盘|最高|最低|收盘|

|---|---|---|---|---|n|2007-01-02|50.03978|50.11778|49.95041|50.11778|

|2007-01-03|50.23050|50.42188|50.23050|50.39767|

|2007-01-04|50.42096|50.26414|50.33236|

|2007-01-05|50.37347|50.22103|50.33459|

|2007-01-06|50.24433|50.11121|50.18112|

|2007-01-07|50.13211|50.21561|49.99185|

可变对象:x