R 培训之 Table

res = read.table("ttest_expression.tsv",sep=",",header = TRUE)
rownames(res)=res[,colnames(res)[1]]

res[rownames(res),colnames(res)[2:length(colnames(res))]]

res = read.table(exp_file, header=T, quote="",row.names=1, sep='\t',check.names=F,as.is=TRUE, encoding="utf-8")

rest = t(res)

ncols(res) nrows(res)

dim(rest)     dimnames(rest)  rownames(rest)  colnames(rest)

typeof class

同种数据类型： Array 数组 Matrix 二维数组

不同种数据类型 ：List 列表 data.frame 数据框  （命名元素）

v <- 1:20; w<-sapply(v,function(i){i^2})

>xxx<-matrix(1:20,ncol=4)

>apply(xxx,1,mean)

[1]  8.5  9.5 10.5 11.5 12.5

>apply(xxx,2,mean)

[1]  3  8 13 18

m <- factor(c("red","blue","green","green"))

l <- levels(m)