读写json中的jsonlite

Question

其任务是加载一个json，操作一些数据并进行回写。第一步是用相同的输出和输入读写json文件，但事实并非如此。这里有一个旨在解决问题的测试文件：

{
  "hourly": [
      {
        "Temperatur": {
          "Datum": ["2021-09-24 21:00:00", "2021-09-24 22:00:00"],
          "Vorhersage": [14.82, 14.83],
          "Referenz": [16.6, 16.2],
          "DWD_Name": ["Elpersbüttel", "Elpersbüttel"],
          "Export": [17.2, 16.71],
          "color": ["rgb(0,128,0)", "rgb(0,128,0)"],
          "Status": ["ok", "ok"],
          "min": [13.05, 12.81],
          "max": [17, 17]
        }},
      {
        "Temperatur2": {
          "Datum": ["2021-09-24 21:00:00", "2021-09-24 22:00:00"],
          "Vorhersage": [13.82, 14.83],
          "Referenz": [16.6, 16.2],
          "DWD_Name": ["Elpersbüttel", "Elpersbüttel"],
          "Export": [17.2, 16.71],
          "color": ["rgb(0,128,0)", "rgb(0,128,0)"],
          "Status": ["ok", "ok"],
          "min": [13.05, 12.81],
          "max": [17, 18]
        }
      }
    ]
}

然而，jsonlite改变了数据结构：

library(jsonlite)
id = "test3" # my testfile
setwd("/path/")
myjs = fromJSON(paste0(id,".json"),simplifyVector = T) 
write_json(myjs, paste0(id,"_.json"), pretty = T) # output file 'test3_.json'

这是我得到的结果：

{
  "hourly": [
    {
      "Temperatur": {
        "Datum": ["2021-09-24 21:00:00", "2021-09-24 22:00:00"],
        "Vorhersage": [14.82, 14.83],
        "Referenz": [16.6, 16.2],
        "DWD_Name": ["Elpersbüttel", "Elpersbüttel"],
        "Export": [17.2, 16.71],
        "color": ["rgb(0,128,0)", "rgb(0,128,0)"],
        "Status": ["ok", "ok"],
        "min": [13.05, 12.81],
        "max": [17, 17]
      },
      "Temperatur2": {
        "Datum": {},
        "Vorhersage": {},
        "Referenz": {},
        "DWD_Name": {},
        "Export": {},
        "color": {},
        "Status": {},
        "min": {},
        "max": {}
      }
    },
    {
      "Temperatur": {
        "Datum": {},
        "Vorhersage": {},
        "Referenz": {},
        "DWD_Name": {},
        "Export": {},
        "color": {},
        "Status": {},
        "min": {},
        "max": {}
      },
      "Temperatur2": {
        "Datum": ["2021-09-24 21:00:00", "2021-09-24 22:00:00"],
        "Vorhersage": [13.82, 14.83],
        "Referenz": [16.6, 16.2],
        "DWD_Name": ["Elpersbüttel", "Elpersbüttel"],
        "Export": [17.2, 16.71],
        "color": ["rgb(0,128,0)", "rgb(0,128,0)"],
        "Status": ["ok", "ok"],
        "min": [13.05, 12.81],
        "max": [17, 18]
      }
    }
  ]
}

如果simplifyVector = F，则会产生嵌套数组。

{
  "hourly": [
    {
      "Temperatur": {
        "Datum": [
          ["2021-09-24 21:00:00"],
          ["2021-09-24 22:00:00"]
        ],
        "Vorhersage": [
          [14.82],
          [14.83]
        ],
        "Referenz": [
          [16.6],
          [16.2]
        ],
        "DWD_Name": [
          ["Elpersbüttel"],
          ["Elpersbüttel"]
        ],
        "Export": [
          [17.2],
          [16.71]
        ],
        "color": [
          ["rgb(0,128,0)"],
          ["rgb(0,128,0)"]
        ],
        "Status": [
          ["ok"],
          ["ok"]
        ],
        "min": [
          [13.05],
          [12.81]
        ],
        "max": [
          [17],
          [17]
        ]
      }
    },
    {
      "Temperatur2": {
        "Datum": [
          ["2021-09-24 21:00:00"],
          ["2021-09-24 22:00:00"]
        ],
        "Vorhersage": [
          [13.82],
          [14.83]
        ],
        "Referenz": [
          [16.6],
          [16.2]
        ],
        "DWD_Name": [
          ["Elpersbüttel"],
          ["Elpersbüttel"]
        ],
        "Export": [
          [17.2],
          [16.71]
        ],
        "color": [
          ["rgb(0,128,0)"],
          ["rgb(0,128,0)"]
        ],
        "Status": [
          ["ok"],
          ["ok"]
        ],
        "min": [
          [13.05],
          [12.81]
        ],
        "max": [
          [17],
          [18]
        ]
      }
    }
  ]
}

在这两种情况下，下面的问题是fromJSON生成一个list对象，它不能正确地表示输入的数据结构.或者write_json (tojson)用错误的方式解释它。解决办法可以是使用simplifyVector = F，然后重新加载并修复数组。

Answer 1

选项simplifyDataFrame = F解决了这个问题。