Jerry Licun Pages

Week 1 Tutor -- R语言入门（3）-- 作图

Some of the key base plotting functions
• plot(): plots based on the object type of the imput
• lines(): add lines to the plot (just connect dots)
• points(): add points
• text(): add text labels to a plot using x,y coordinates
• title(): add titles
• mtext():add arbitrary text to the margin
• axis(): adding axis ticks/labels
Some important parameters
• pch: the plotting symbol (plotting character)
• lty: the line type; solid, dashed, …
• lwd: the line width; lwd=2
• col: color; col=“red”
• xlab: x-axis label; xlab=“units”
• ylab: y-axix label; ylab=“price”

x <- seq(-2*pi,2*pi,0.1)
plot(x, sin(x),							plot()意味着它是一系列函数的占位符。
    main="my Sine function",								图名
    xlab="the values", 									X坐标名
    ylab="the sine values",								Y坐标名
    type="s",  备注:“p”-points(defult);“l”-lines;“b”-both points and lines
    col="blue")										颜色
	legend("topleft",								图注
      	c("sin(x)","cos(x)"),
      	fill=c("blue","red")
		  )
	abline(lm(mtcars$mpg~mtcars$wt), col="red", lwd=3)  参考线
只是初步了解,其他的具体R语言作图方法在后续的课或其他课程中再学

在图像上加辅助线
	x <- c(0,2,3)
	y <- c(1,3,8)
	plot(x,y) 		 # same as before
	fit <- lm(y ~ x) 	 # a regression line
				 #The call to abline() then adds a line to the current graph. 
				 #abline(c(2,1)) adds y = x + 2
	abline(fit) 		 #adds a line to a plot.
	abline(h=1, col="red")
	abline(v=2, col="blue")
	abline(3,4, col="green") # y=3x+4
	curve((x^2+1)^0.5,0,5,add=T, col="yellow")


导出保存图
	jpeg(file="plot1.jpeg") 保存到当前文件夹
	png(file="plot2.png",width=600, height=350)
	pdf(file="saving_plot4.pdf")

	hist(Temperature, col="gold")
	dev.off()