友情提示：如果R代码无法正常显示，请点击原始链接查看正确代码：

http://stackoverflow.com/questions/23884991/how-to-add-break-in-axis-for-grouped-barplot

问题介绍：

用barplot可以制作分组柱状图，但是无法添加断轴。

用gap.barplot可以添加断轴，但是无法制作分组柱状图。

那么如何解决这个问题呢？

请看以下案例和解决方案：

案例

# set up data

x1=c(3,5,6,9,375,190);

x1

x2=c(2,2,3,30,46,60);

x2

data=rbind(x1,x2);

data

colnames(data)=c("Pig","Layer","Broiler","Dairy","Beef","Sheep")

rownames(data)=c("1980","2010")

data

# plot grouped bar by using barplot

barplot(data,

       beside=T,

       ylab="Number of animal",

       #cex.names=0.8,

       #las=2,

       col=c("darkblue","red")

)

# Since there are large differences in numbers,so I want to add a break between 200 to 340 as below:

data_T=t(data);

data_T

#install.packages("reshape")

library(reshape)

mdata <- melt(data_T, id=c("1980","2010"));

mdata

colnames(mdata)=c("Animal","Year",'value');

mdata

gap.barplot(mdata$value,

           gap=c(200,340),

           xlab="Animal",

           ytics=c(0,50,100,150,200,300,350,400),

           ylab="Number of animal",

           xaxlab=mdata$Animal,

           xaxt="n")

# xaxt="n" is esential to remove everything from x axis (e.g. a clean x axis)

# then define a axis using the following

axis(side = 1, at = seq_along(mdata$Animal),mdata$Animal,tick = FALSE)

abline(h=seq(200,205,.001), col="white")  # hiding vertical lines

axis.break(axis=2,breakpos=202.5,style="slash") # break the left Y axis

解决方案，见Jim Lemon给我的回信，如下：

Hi Wei, The gap.barplot function doesn't do grouped bars (yet). You can probably get what you want with this:

#install.packages("plotrix") # only need to install once

library(plotrix)

newdata<-data

newdata[newdata>200]<-newdata[newdata>200]-140

barpos<-barplot(newdata,names.arg=colnames(newdata),

ylim=c(0,250),beside=TRUE,col=c("darkblue","red"),axes=FALSE)

axis(2,at=c(0,50,100,150,200,235),

labels=c(0,50,100,150,200,375))

box()

axis.break(2,210,style="gap")

Jim

致谢：

Great thanks to Jim Lemon, the author of gap.barplot, for his kind help!

Wei