x1 = read.csv("x.csv")
head(x1)

pdf("x.pdf")
plot(x1$len,col = factor(x1$dose))
title("Have a try")
dev.off()

write.table(x1,"x.txt")

getwd() #显示路径
# jimmy文件夹在biotrainee隔壁
x1 = read.csv("C:/Users/win10/Desktop/jimmy/x.csv")#绝对路径
x1 = read.csv("../jimmy/x.csv")#相对路径，..代表上一级
# jimmy文件夹在biotrainee下一级
x1 = read.csv("jimmy/x.csv")
head(x1)

class() #判断数据类型

#is族判断数据类型，返回TRUE/FALSE
is.numeric() 
is.logical()
is.character()
#as族实现可变换数据类型转换
as.numeric() 
as.logical()
as.character()