读取数据(txt文件,制表符分隔)
 E盘的Rdata是存放数据的目录

> mydf <- read.table("E:/Rdata/myfile.txt", header=TRUE, sep="\t")
> mydf

 显示如下:

 X  
1  AA   8  5  4 
2  AB   3  7  9 
3  AC   2  6  1 
4  AD   3  4  7  8
 ...

> mydf <- subset(mydf, select = -X )
 这样就删除了 X 这一列

> mydf

 显示如下:

  
1    8  5  4 
2    3  7  9 
3    2  6  1 
4    3  4  7  8
 ...

 其它命令:
> mydataframe <- data.frame(a=1:3, d=2:4, c=3:5, b=4:6)
 > mydataframe
  a d c b
 1 1 2 3 4
 2 2 3 4 5
 3 3 4 5 6 如果用以下命令读取myfile.txt (结果是没有了X,T1,T2,T3,T4,而且作为矩阵读入)
> df1 <- unname(as.matrix(read.table("E:/Rdata/myfile.txt", row.names=NULL,header=T, sep="\t")))
> df1
       [,1]    [,2] [,3] [,4] [,5]
    [1,] "AA"    "8"  "5"  "4"  "6"
    [2,] "AB"    "3"  "7"  "9"  "2"
    [3,] "AC"    "2"  "6"  "1"  "0"
    [4,] "AD"    "3"  "4"  "7"