1.线图示例
plot()为高水平作图命令，axis()、lines()、legend()都为低水平作图命令
> rain<-read.csv("cityrain.csv")
> plot(rain$Tokyo,type="b",lwd=2, #type ="b"表示即画散点也画直线，lwd设置线宽
+ xaxt="n",ylim=c(0,300),col="black", #xaxt="n"表示不显示X轴刻度
+ xlab="Month",ylab="Rainfall (mm)",
+ main="Monthly Rainfall in major cities")
> axis(1,at=1:length(rain$Month),labels=rain$Month) #画坐标轴，1表示方向
> lines(rain$Berlin,col="red",type="b",lwd=2)
> lines(rain$NewYork,col="orange",type="b",lwd=2)
> lines(rain$London,col="purple",type="b",lwd=2)
> legend("topright",legend=c("Tokyo","Berlin","New York","London"), #增加图例
+ lty=1,lwd=2,pch=21,col=c("black","red","orange","purple"), #lty设置线形，pch设置线上点的形状
+ ncol=2,bty="n",cex=0.8, #ncol=2表示图例为两列，bty="n"表示图例没有边框
+ text.col=c("black","red","orange","purple"), #图例中字体颜色
+ inset=0.01) #图例与边缘的距离
2.用线图描画时间序列
> gdp<-read.table("gdp_long.txt",header=T)
> library(RColorBrewer)
> pal<-brewer.pal(5,"Set1") #用调色板包生成5种颜色
> par(mar=par()$mar+c(0,0,0,2),bty="l") #mar留白边
> plot(Canada~Year,data=gdp,type="l",lwd=2,lty=1,ylim=c(30,60),
+ col=pal[1],main="Percentage change in GDP",ylab="")
> mtext(side=4,at=gdp$Canada[length(gdp$Canada)],text="Canada", #标识文本，side设置方向，at设置位置
+ col=pal[1],line=0.3,las=2) #line设置粗细，las设置方向
> lines(gdp$France~gdp$Year,col=pal[2],lwd=2)
> mtext(side=4,at=gdp$France[length(gdp$France)],text="France",
+ col=pal[2],line=0.3,las=2)
> lines(gdp$Germany~gdp$Year,col=pal[3],lwd=2)
> mtext(side=4,at=gdp$Germany[length(gdp$Germany)],text="Germany",
+ col=pal[3],line=0.3,las=2)
> lines(gdp$Britain~gdp$Year,col=pal[4],lwd=2)
> mtext(side=4,at=gdp$Britain[length(gdp$Britain)],text="Britain",
+ col=pal[4],line=0.3,las=2)
> lines(gdp$USA~gdp$Year,col=pal[5],lwd=2)
> mtext(side=4,at=gdp$USA[length(gdp$USA)]-2, #位置下调2刻度
+ text="USA",col=pal[5],line=0.3,las=2)
