用 jsonlite 在 R 中构造 json - 括号太多

Question

不是 json 专家，但我需要我认为被称为“嵌套对象”的东西，而我得到的是我认为被称为“嵌套数组”的东西。换句话说，一些额外的括号。我正在尝试使用 R 中的 jsonlite 将数据帧转换为 json 数据。下面的可重现代码和结果。谁能指出我如何以正确的格式获取数据（作为嵌套对象的行）？

library(jsonlite)

testdat <- data.frame(locationColumn = c("US", "US"),
                      nameColumn = c("General Motors", "Walmart"), 
                      zipColumn = c(19890, 72712) )


jsl <- jsonlite::toJSON(
  list(
    config = list(
      item1 = list("country",
                   "city"),
      item2 = "true",
      item3 = "false",
      item4 = 3
    ),
    rows = split(testdat, 1:nrow(testdat))
  ), 
  auto_unbox = TRUE,
  pretty = TRUE,
  dataframe = "rows",
  simplifyDataFrame = TRUE
)

jsl

输出：

{
  "config": {
    "item1": [
      "country",
      "city"
    ],
    "item2": "true",
    "item3": "false",
    "item4": 3
  },
  "rows": {
    "1": [
      {
        "locationColumn": "US",
        "nameColumn": "General Motors",
        "zipColumn": 19890
      }
    ],
    "2": [
      {
        "locationColumn": "US",
        "nameColumn": "Walmart",
        "zipColumn": 72712
      }
    ]
  }
} 

我需要什么：（编辑：我给 json 增加了一些复杂性。我需要将括号保留在“config”中，但在“rows”中没有括号。

{
  "config": {
    "item1": [
      "country",
      "city"
    ],
    "item2": "true",
    "item3": "false",
    "item4": 3
  },
  "rows": {
    "1":
      {
        "locationColumn": "US",
        "nameColumn": "General Motors",
        "zipColumn": 19890
      },
    "2":
      {
        "locationColumn": "US",
        "nameColumn": "Walmart",
        "zipColumn": 72712
      }
  }
} 

Answer 1

这是一个可能的解决方案：

library(jsonlite)

testdat <- data.frame(locationColumn = c("US", "US"),
                      nameColumn = c("General Motors", "Walmart"), 
                      zipColumn = c(19890, 72712) )

jsl <- jsonlite::toJSON(
  list(
    rows = split(testdat, 1:nrow(testdat))
  ), 
  auto_unbox = TRUE,
  pretty = TRUE,
  dataframe = "columns",  #change from rows (moves brackets from row level to value level)
  simplifyDataFrame = TRUE
)

#removed the backets if desired
#jsl<-gsub("\\[|\\]", "", jsl)

all.equal(testcase, fromJSON(jsl))
testcase<-fromJSON('{
  "rows": {
    "1":{
         "locationColumn": "US",
         "nameColumn": "General Motors",
         "zipColumn": 19890
        },
    "2":{
         "locationColumn": "US",
         "nameColumn": "Walmart",
         "zipColumn": 72712
        }
  }
}')

all.equal(testcase, fromJSON(jsl))
#[1] TRUE

编辑这是一个批准的版本，它手动编辑列表列表以获得正确的格式。

#create a list of the data
top<-list(
  config = list(
    item1 = list("country",
                 "city"),
    item2 = "true",
    item3 = "false",
    item4 = 3
  ),
  rows = split(testdat, 1:nrow(testdat))
)

#edit the data frames store as part of rows
#lapply - lapply loops will parse each column in each row to create a new list
rows<-lapply(top$rows, function(x){
  tempdf<-x
  #collist<-lapply(names(tempdf), function(y){print(tempdf[ , y, drop=T])})
  collist<-lapply(names(tempdf), function(y){tempdf[, y, drop=T]})
  names(collist)<-names(tempdf)
  collist
})

#update the list with the list of list
top$rows<-rows

#make the JSON
jsl <- jsonlite::toJSON(
  top, 
  auto_unbox = TRUE,
  pretty = TRUE,
  dataframe = "columns",
  simplifyDataFrame = TRUE
)