> str(u)
List of 36
$ X000005.SZ: num [1:21] 0 0 0 0 0 0 0 0 0 0 ...
$ X000584.SZ: num [1:21] 0 0 0 0 0 0 0 0 0 0 ...
$ X002119.SZ: num [1:21] 0 0 0 0 0 0 0 0 0 0 ...
$ X002131.SZ: num [1:21] 0 0 0 0 0 0 0 0 0 0 ...
$ X002169.SZ: num [1:21] 0 0 0 0 0 0 0 0 0 0 ...
$ X002171.SZ: num [1:21] 0 0 0 0 0 0 0 0 0 0 ...
$ X002361.SZ: num [1:21] 0 0 0 0 0 0 0 0 0 0 ...
$ X002491.SZ: num [1:21] 0 0 0 0 0 ...
$ X002548.SZ: num [1:21] 0 0 0 0 0 0 0 0 0 0 ...
$ X002698.SZ: num [1:21] -4.95 3.28 2.2 2.42 0 ...


比如上面的这个，是列表结构，想转成数据框格式，而且保留列名。用as.matrix虽然可以转成矩阵，但是列名都没有了。请教各位，谢谢