acknowledgement:https://mp.weixin.qq.com/s?src=11&timestamp=1639817077&ver=3503&signature=W00Qqg2CbBY7cf0q99IMEE8gBVQ3UHOXDqWs2bC1R7ZGsKUN44yFz7NXkJ93tCpOiUFT00Nu09qHl4wnqv*jHEMHA86hjDEWXwC3p7KKL1-2Ns0fNpscC3hrnD9y&new=1

    1. library(tidyverse)
    2. library(ggsignif)
    3. library(ggforce)
    4. ggplot(iris,aes(Species,Sepal.Length,fill=Species)) + 
    5.   geom_violin()+
    6.   geom_sina(alpha=0.5)+
    7.   geom_signif(comparisons = list(c("versicolor", "virginica"),
    8.                                  c("versicolor","setosa"),
    9.                                  c("virginica","setosa")),
    10.               map_signif_level=T,
    11.               textsize=6,test=wilcox.test,step_increase=0.2)