r - 导出到 R 中列表的 JSON 列表

Question

我需要将一个列表列表导出到 json 以获得类似下一个的输出 JSON:

{
  "timestamp":"2018-02-01 10:20",
  "aux":[
    {"id":"x1","prog":['A','A','A']},
    {"id":"x2","prog":['A','A','A']},
    {"id":"x3","prog":['A','A','A']}
  ]
}

我怎样才能制作一个列表来获得这样的 JSON？提前致谢。

编辑:

这就是我正在尝试的:

l1 <- list(timestamp = "2018-02-01 10:20", 
           aux = list(id = c("x1","x2","x3"), 
           prog = rep('A',3)))

这是我得到的 JSON:

{"timestamp":"2018-02-01 10:20",
 "aux":{"id":["x1","x2","x3"],
        "prog":["A","A","A"]}
}

Answer 1

您可以通过附加级别的列表获得该结构:

l1 <- list(timestamp = "2018-02-01 10:20", 
           aux = list(list(id = "x1", prog = rep('A',3)),
                      list(id = "x2", prog = rep('A',3)),
                      list(id = "x3", prog = rep('A',3))))

jsonlite::toJSON(l1, pretty = TRUE, auto_unbox = TRUE)
#> {
#>   "timestamp": "2018-02-01 10:20",
#>   "aux": [
#>     {
#>       "id": "x1",
#>       "prog": ["A", "A", "A"]
#>     },
#>     {
#>       "id": "x2",
#>       "prog": ["A", "A", "A"]
#>     },
#>     {
#>       "id": "x3",
#>       "prog": ["A", "A", "A"]
#>     }
#>   ]
#> }