导出到 R 中列表的 JSON 列表

Question

我需要将列表列表导出到 json 以获得类似于下一个的输出 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']}
]
}

如何制作列表来获取这样的 JSON？提前谢谢。

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

您可以使用其他级别的列表来获取该结构：

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"]
#>     }
#>   ]
#> }