R rownames（foo [bar]）打印为null但可以成功更改 - 为什么？

I've written a script that works on a set gene-expression data. I'll try to separate my post in the short question and the rather lengthy explanation (sorry about that long text block). I hope the short question makes sense in itself. The long explanation is simply to clarify if I don't get the point along in the short question.I've written a script that works on a set gene-