利用数据进行统计分析前，需要对数据进行收集整理，这是R中的基本命令(The function data.frame() creates data frames, tightly coupled collections of variables which share many of the properties of matrices and of lists, used as the fundamental data structure by most of R's modeling soft

一些简单硬件资料合集 已经用vb编辑出来了,请尊重版权,(Some simple hardware collections have been edited in vb. Please respect the copyright.)