數(shù)據(jù)結(jié)構(gòu)
1.1向量與標(biāo)量
> x<-c(1,2,3)
> x<-1:10
> x
[1] 1 2 3 4 5 6 7 8 9 10
> x<-seq(1,10,by=0.5)
> x
[1] 1.0 1.5 2.0 2.5 3.0 3.5
[7] 4.0 4.5 5.0 5.5 6.0 6.5
[13] 7.0 7.5 8.0 8.5 9.0 9.5
[19] 10.0
> x<-rep(1:3,times=2)
> x
[1] 1 2 3 1 2 3
1.2從向量中提取元素
> x[4]
[1] 1
> x[-4]
[1] 1 2 3 2 3
> x[2:4]
[1] 2 3 1
> x[-(2:4)]
[1] 1 2 3
x[x=3]
[1] 3
1.3數(shù)據(jù)框
將示例數(shù)據(jù)放在你的工作目錄下
> X<-read.csv('doudou.txt')
微信圖片_20210423224729.png
1.4讀取本地數(shù)據(jù)
> read.table(file="huahua.txt",sep="\t",header=T)
X1 X2
1 A 1
2 B NA
3 C NA
4 D 3
5 E NA
> a<-read.table(file="huahua.txt",sep="\t",header=T)
> View(X)
> View(a)
> View(X)
1.5設(shè)置行名與列名
> X<-read.csv('doudou.txt')
> colnames(X)
[1] "X1" "X2"
> rownames(X)
[1] "1" "2" "3" "4" "5"
> colnames(X)[1]<-"bioplanet"
> X<-read.csv(file = "huahua.txt",sep = " ",header =T,row.names=1)
1.6 數(shù)據(jù)框的導(dǎo)出
> write.table(X,file = "yu.txt",sep = ",",quote=F)
1.7變量的保存與重新加載
save.image(file="bioinfoplanet.RData")#保存當(dāng)前所有變量
save(X,file="test.RData")#保存其中一個變量
load("test.RData")#再次使用RData時的加載命令
1.8提取元素
- X[x,y]#第x行第y列
- X[x,]#第x行
- X[,y]#第y列
- X[y] #也是第y列
- X[a:b]#第a列到第b列
- X[c(a,b)]#第a列和第b列
