panel.spacing解决了我许久的强迫症

一直以来画分面图都有一个小小的缺陷，如图1所示不能消除分面之间的间距，今天终于发现原来可以通过panel.spacing函数来调整间距，强迫症终于得到了满足

library(tidyverse)
ToothGrowth$dose <- as.factor(ToothGrowth$dose)
head(ToothGrowth)

p <- ggplot(ToothGrowth,aes(dose,len,fill=dose)) +
  geom_bar(stat="identity",width = 0.5)+
  ggtitle("Plot of length by dose")+
  theme(plot.title = element_text(hjust = 0.5))+
  xlab("supp")+ylab("len")+labs(fill = "lenge")

p + theme_test()+ 
  theme(plot.title = element_text(hjust = 0.5))+
  facet_grid(. ~ supp)

p + theme_test()+ 
  theme(plot.title = element_text(hjust = 0.5))+
  facet_grid(dose ~ supp)

p + theme_test()+ 
  theme(plot.title = element_text(hjust = 0.5))+
  facet_grid(. ~ supp)+
  theme(panel.spacing.x = unit(0, "cm"))+
  theme(panel.spacing.y = unit(0, "cm"))

p + theme_test()+ 
  theme(plot.title = element_text(hjust = 0.5))+
  facet_grid(dose ~ supp)+
  theme(panel.spacing.x = unit(0, "cm"))+
  theme(panel.spacing.y = unit(0, "cm"))