R列表以序列化json

Question

如何使用R-list获取json字符串？ 我有ntext代码

library(jsonlite)
x<-list(
  "a" = "test",
  "b" = 1,
  "c" = 2

)
serial_data<-toJSON( x )

但它的回归

{"a":["test"],"b":[1],"c":[2]} 

我需要下一个字符串

{"a":"test","b":1,"c":2}