R语言学习笔记（四）

R语言支持很多图形，并且有些图形是非常少见的，可能也因为自己不是专业弄数据分析的所以就孤陋寡闻了，总结下目前学习到的图形。

条形图

这个图比较常见，很多数据统计软件都支持这种图形，这种图形可以很好的展示数据的汇总结果，可以简洁明了的方式表达数据背后的含义

> library(vcd)

> counts<-table(Arthritis$Improved)
> counts


  None   Some Marked 
    42     14     28 
> barplot(counts,main="Simple Bar Plot",xlab="Improvement",ylab=""Frequency)
Error: unexpected symbol in "barplot(counts,main="Simple Bar Plot",xlab="Improvement",ylab=""Frequency"
> barplot(counts,main="Simple Bar Plot",xlab="Improvement",ylab="Freqency")
> 
> barplot(counts,main="Horizontal Bar Plot",xlab="Frequency",ylab="Improvement",horiz=TRUE)

堆砌图

这个图是条形图的进化版本，它可以表达出更加丰富的含义，如果说条形图只能表达两个维度的结果，那么堆砌图则能表达三个维度的数据分析结果

 library(vcd)
> counts<-table(Arthritis$Improved,Arthritis$Treatment)
> counts
        
         Placebo Treated
  None        29      13
  Some         7       7
  Marked       7      21
> barplot(counts,main="Stacked Bar Plot",xlab="Treatment",ylab="Frequency",col=c("red","yellow","green"),legend=rownames(counts))
> 

分组条形图

和上面的堆砌图一样的效果，只是数据的展现方式不一样。

> barplot(counts,main="Stacked Bar Plot",xlab="Treatment",ylab="Frequency",col=c("red","yellow","green"),legend=rownames(counts),beside=TRUE)

均值图

个人觉得和条形图类型，就图形而言，没有显著的差别。

 states<-data.frame(state.region,state.x77)

 means<-aggregate(states$Illiteracy,by=list(state.region),FUN=mean)
> means
        Group.1        x
1     Northeast 1.000000
2         South 1.737500
3 North Central 0.700000
4          West 1.023077

> means<-means[order(means$x),]
> means
        Group.1        x
3 North Central 0.700000
1     Northeast 1.000000
4          West 1.023077
2         South 1.737500
> barplot(means$x,names.arg = means$Group.1)
> title("Mean Illiteracy Rate")
> 
> 
> par(mar=c(5,8,4,2))
> par(las=2)
> counts<-table(Arthritis$Improved)
> barplot(counts,main="Treatment Outcome", horiz=TRUE, cex.name=0.8, names.arg = c("No Improvement","Some Improvement", "Marked Improvement"))
> 

荆状图

和堆砌图类似，但是所有分组的高度都是一样的，唯一不同的则是分组中的色块面积大小，用来分析数据在某种情况下所占比例比较合适。

> library(vcd)
> counts<-table(Treatment,Improved)
Error in table(Treatment, Improved) : object 'Treatment' not found
> attach(Arthritis)
> counts<-table(Treatment,Improved)
> spine(counts,main="Spinogram Example")
> counts
         Improved
Treatment None Some Marked
  Placebo   29    7      7
  Treated   13    7     21

饼图

最常见的图，不多说了

 library(plotrix)

> par(mfrow=c(2,2))
> slices<-c(10,12,4,16,8)
> lbls<-c("US","UK","Australia","Germany","France")
> pie(slices,labels=lbls,main="Simple Pie Chart")
> 
> pct<-round(slices/sum(slices)*100)
> lbls2<-paste(lbls," ",pct,"%",sep="")
> lbls2
[1] "US 20%"       "UK 24%"       "Australia 8%" "Germany 32%"  "France 16%"  

> pie(slices,labels=lbls,explode=0.1,main="3D Pie Chart ")

> pie(slices,labels=lbls2,col=rainbow(length(lbls2)),main="Pie Chart wit Precentage")

> pie3D(slices,labels=lbls,explode=0.1,main="3D Pie Chart ")

> mytable<-table(state.region)

> pie(mytable,labels=lbls3,main="Pie Chart from a Table\n (with sample sizes)")

扇形图

和饼图类型，不过这个图形还是比较少见的

> library(plotrix)
> slices<-c(10,12,4,16,8)
> lbls<-c("US","UK","Australia","Germany","France")
> fan.plot(slices,labels=lbls,main="Fan Plot")

直方图

柱图，最常见的图，和之前提到的条形图类似。

> par(mfrow=c(2,2))

> hist(mtcars$mpg)
> 
> hist(mtcars$mpg,breaks=12,col="red",xlab="Miles Per Gallon",main="Colored histogram with 12 bins")
> 
> 
> hist(mtcars$mpg,freq=FALSE,col="red",xlab="Miles Per Gallon",main="Histogram, rug plot, density curve")

> rug(jitter(mycars$mpg))       #轴须图

> lines(density(mtcars$mpg),col="blue",lwd=2)  #密度曲线

> x<-mtcars$mpg
> h<-hist(x,breaks=12,col="red",xlab="Miles Per Gallon",main="Histogram with normal curve and box")
> xfit<-seq(min(x),max(x),length=40)
> yfit<-dnorm(xfit,mean=mean(x),sd=sd(x))
> yfit<-yfit*diff(h$mids[1:2])*length(x)
> lines(xfit,yfit,col="blue",lwd=2)
> box()
> mtcars$mpg
 [1] 21.0 21.0 22.8 21.4 18.7 18.1 14.3 24.4 22.8 19.2 17.8 16.4 17.3 15.2 10.4 10.4
[17] 14.7 32.4 30.4 33.9 21.5 15.5 15.2 13.3 19.2 27.3 26.0 30.4 15.8 19.7 15.0 21.4

核密度图

这个图形比较少见，有点像原始版本的热点图，用来显示变量的密度关系。

> library(sm)

>par(mfrow=c(2,1))

> d<-density(mtcars$mpg)
> plot(d)

> d<-density(mtcars$mpg)
> plot(d,main="Kernel Density of Miles Per Gallon")
> polygon(d,col="red",border="blue")

> attach(mtcars)
> cyl.f<-factor(cyl,levels=c(4,6,8),labels=c("4 cylinder","6 cylinder","8 cylinder"))
> sm.density.compare(mpg,cyl,xlab="Miles Per Gallon")

> title(main="MPG Distribution by Car Cylinders")
> 
> colfill<-c(2:(1+length(levels(cyl.f))))    #这行代码没效果
> legend(locator(1),levels(cyl.f),fill=colfill)

箱线图

这个图也比较有意思，它主要关注一组观察变量的5个指标：Min，1/4，mean，4/3，Max。第一次发现这么有意思的分析方式，不过在日常的统计中，这5ge指标应该是经常被使用的，所以箱线图也是非常实用的一种图形。

boxplot(mtcars$mpg,main="Box plot",ylab="Miles per Gallon")
> 

> boxplot(mpg~cyl,data=mtcars,main="Car Mileage Data", xlab="Number of Cylinders",ylab="Miles Per Gallon")

boxplot(mpg~cyl,data=mtcars,notch=TRUE,varwidth=TRUE,col="red",main="Car Mileage Data",xlab="Number of Cylinders",ylab="Miles Per Gallon")  #有对称效果的箱线图，该图形包含了变量密度信息

#分组箱线图

 mtcars$cyl.f<-factor(mtcars$cyl,levels=c(4,6,8),labels=c("4","6","8"))
> mtcars$cyl.f

 mtcars$am.f<-factor(mtcars$am,levels=c(0,1),labels=c("auto","standard"))
> mtcars$am.f
 [1] standard standard standard auto     auto     auto     auto     auto     auto    
[10] auto     auto     auto     auto     auto     auto     auto     auto     standard
[19] standard standard auto     auto     auto     auto     auto     standard standard
[28] standard standard standard standard standard
Levels: auto standard
> boxplot(mpg~am.f*cyl.f,data=mtcars,varwidth=TRUE,col=c("gold","darkgreen"),main="MPG Distribution by Auto Type",xlab="Auto Type",ylab="Miles Per Gallon")
> 

小提琴图

和箱线图的分析套路类似，但是提供更加明确的变量密度分布信息。

> library(vioplot)

 x1<-mtcars$mpg[mtcars$cyl==4]
> x2<-mtcars$mpg[mtcars$cyl==6]
> x3<-mtcars$mpg[mtcars$cyl==8]
> vioplot(x1,x2,x3,names=c("4 cyl","6 cyl","8 cyl"),col="gold")
> title("Violin Plots of Miles Per Gallon",ylab="Miles Per Gallon",xlab="Number of Cylinders")

点图

也是一种比较常见的图，它的进化版本应该是散点图

> dotchart(mtcars$mpg, labels=row.names(mtcars),cex=.7,main="Gas Mileage for Car Models",xlab="Miles Per Gallon")
> 

#分组散点图
> x<-mtcars[order(mtcars$mpg),]
> x$cyl<-factor(x$cyl)
> x$color[x$cyl==4] <- "red"
> x$color[x$cyl==6] <- "blue"
> x$color[x$cyl==8]<- "darkgreen"
> dotchart(x$mpg,labels=row.names(x),cex=.7,groups=x$cyl,gcolor="black",color=x$color,pch=19,main="Gas Mileage for Car Models\ngrouped by cylinder", xlab="Miles Per Gallon")