R dunn测试不适用于关于协同的错误

我试图让dunn测试起作用，但我发现了一个关于协同的错误：

   dt = data.frame(c = 1:50 , group = rep(  c("a","b") ,each=25)  )

        dunn.test(dt$c   ~   dt$group )

Error in dunn.test(dt$c ~ dt$group) : 
  'pairlist' object cannot be coerced to type 'double'
In addition: Warning message:
In is.na(unlist(x)) :
  is.na() applied to non-(list or vector) of type 'language'

---

我也有同样的错误-因为dunn.test（）希望变量之间使用逗号，而不是a~

所以这是可行的：

dt = data.frame(c = 1:50 , group = rep(  c("a","b") ,each=25)  )

dunn.test(dt$c , dt$group )