R语言绘图abline函数 给图形增加参考线

 

1、

plot(1:10)
abline(h=5,col="red",lty=2,lwd = 3)

 

 

2、

plot(1:10)
abline(h=c(2,4,6),col="red",lwd=3)

 

 

3、

plot(1:10)
abline(v=c(2,4,8), col = "blue", lwd = 4)