ggplot一张图的诞生（1）

gzh：BBio

两个要求

#坐标轴截断
#添加标准误差线

制作过程

• 准备数据

  df<-data.frame(
    food=rep(c("番茄","红薯","鲫鱼"),each=9),
    filed=rep(c(LETTERS[1:3]),9),
    date=rep(c(rep(c("day1","day2","day3"),each=3)),3),
    price=c(
      round(c(runif(3,3.2,3.8),runif(3,7.3,8.0),runif(3,9.3,10)),2),
      round(c(runif(3,2.8,2.9),runif(3,2.9,3.5),runif(3,3.5,4.3)),2),
      round(c(runif(3,8,9),runif(3,17,18),runif(3,19,20)),2))
  )
  

• 计算标准差和标准误差

  library(Rmisc)
  summary.df<-summarySE(df,measurevar="price",groupvars=c("food","date"))
  

• 绘图

  library(ggplot2)
  p1<-ggplot(summary.df,aes(date,price,fill=food))+
    geom_col(position="dodge",alpha=0.8)+
    facet_grid(.~food)
  

image

• 调整1

  p1<-p1+labs(x=NULL,y="价格(元)/500g",fill="Food")+
    ggtitle("食品价格走势")+
    theme(plot.title=element_text(hjust=0.5))
  

image

• 调整2

  p1<-p1+scale_x_discrete(
    label=c("1月18日","2月2日","2月22日"))+
    theme(axis.text.x=element_text(angle=45,hjust=1))
  

image

• 调整3

  p1<-p1+theme(strip.background=element_rect(fill="grey50"),panel.grid=element_blank())
  

image

• 添加标准误差线

  p1<-p1+geom_errorbar(
    aes(ymin=price-se,ymax=price+se),width=.2,position=position_dodge(0.9))
  

image

• 截断坐标轴

  split1<-p1+coord_cartesian(ylim=c(0,11))+
    theme(strip.background = element_blank(),
          strip.text = element_blank(),
          legend.position="none")+
    labs(title=NULL,y=NULL)
  split2<-p1+coord_cartesian(ylim=c(16.5,20))+
    theme(axis.text.x=element_blank(),
          axis.ticks.x=element_blank(),
          legend.position="none")+
    labs(y=NULL)
  

• 拼接上下两部分

  library(grid)
  grid.newpage()
  pushViewport(viewport(layout=grid.layout(2,1)))
  vplayout = function(x, y){
    viewport(layout.pos.row=x, layout.pos.col=y)
  }
  print(split1, vp = vplayout(2, 1))
  print(split2, vp = vplayout(1, 1))
  

image