XML轉換為JSON R

Question

R中的軟件包在將XML轉換為JSON時似乎無法正常工作。 我已經嘗試過“ XML”包的RJSONIO，rjson和jsonlite。 我首先解析XML，然后使用XML :: xmlToList（）將其轉換為列表，然后使用這3個包中的toJSON（）將其轉換為JSON。

我的XML文件：

<?xml version="1.0" encoding="utf-8"?>
<votes>
  <row Id="1" PostId="1" VoteTypeId="2" CreationDate="2014-05-13T00:00:00.000" />
  <row Id="2" PostId="1" VoteTypeId="2" CreationDate="2014-05-13T00:00:00.000" />
  <row Id="3" PostId="3" VoteTypeId="2" CreationDate="2014-05-13T00:00:00.000" />
</votes>

我的源代碼：

library(XML)
library(RJSONIO)
library(rjson)
library(jsonlite)

xml_parse <- xmlTreeParse("~/Downloads/test.xml", useInternalNodes=TRUE)
xml_root <- xmlRoot(xml_parse)
xml_list <- xmlToList(xml_root, simplify = TRUE)

#jsonlite package
xml_jsonlite <- jsonlite::toJSON(xml_list)
write(xml_jsonlite, "test_jsonlite.json")

#RJSONIO package
xml_rjsonio <- RJSONIO::toJSON(xml_list)
write(xml_rjsonio, "test_rjsonio.json")

#rjson package
xml_rjson <- RJSONIO::toJSON(xml_list)
write(xml_rjson, "test_rjson.json")

從RJSONIO轉換的JSON文件：

{
"row": {
    "Id": "98",
    "PostId": "10",
    "VoteTypeId": "2",
    "CreationDate": "2014-05-14T00:00:00.000" 
 },
"row": {
    "Id": "99",
    "PostId": "7",
    "VoteTypeId": "5",
    "UserId": "111",
    "CreationDate": "2014-05-14T00:00:00.000" 
 }
}

由於字段名重復，這顯然是錯誤的。

從jsonlite轉換的JSON文件：

{"row":["1","1","2","2014-05-13T00:00:00.000"],
 "row.1":["2","1","2","2014-05-13T00:00:00.000"],
 "row.2":["3","3","2","2014-05-13T00:00:00.000"]}

這很奇怪，因為應該只有一個字段名稱“ row”帶有子文檔數組，而不是遞增“ rows”數組。 它甚至沒有字段名。

從rjson轉換的JSON文件：

{
 "row": {
 "Id": "1",
"PostId": "1",
"VoteTypeId": "2",
"CreationDate": "2014-05-13T00:00:00.000" 
},
"row": {
 "Id": "2",
"PostId": "1",
"VoteTypeId": "2",
"CreationDate": "2014-05-13T00:00:00.000" 
}
}

理想的JSON文件將是這樣的：

{"votes" : {
    "row" : [
        {
            "Id" : "1",
            "PostId" : "1",
            "VoteTypeId" : "2",
            "CreationDate" : "2014-05-13T00:00:00.000"
        },
        {
            "Id" : "2",
            "PostId" : "1",
            "VoteTypeId" : "2",
            "CreationDate" : "2014-05-13T00:00:00.000"
        }
       ]
      }
}

尋找解決方案。 任何幫助表示贊賞。

Answer 1

xml2和jsonlite能為您提供大部分幫助，但是您甚至還沒有向我們展示，您知道R代碼確實為此嘗試了解決方案，所以這里發布了部分解決方案，它可以幫助其他人：

library(xml2)
library(jsonlite)

read_xml('<?xml version="1.0" encoding="utf-8"?>
<votes>
  <row Id="1" PostId="1" VoteTypeId="2" CreationDate="2014-05-13T00:00:00.000" />
  <row Id="2" PostId="1" VoteTypeId="2" CreationDate="2014-05-13T00:00:00.000" />
  <row Id="3" PostId="3" VoteTypeId="2" CreationDate="2014-05-13T00:00:00.000" />
</votes>') -> doc

x <- xml2::as_list(doc) 

xl <- lapply(x, attributes)

toJSON(xl, pretty = TRUE, auto_unbox = TRUE)
## {
##   "row": {
##     "Id": "1",
##     "PostId": "1",
##     "VoteTypeId": "2",
##     "CreationDate": "2014-05-13T00:00:00.000"
##   },
##   "row.1": {
##     "Id": "2",
##     "PostId": "1",
##     "VoteTypeId": "2",
##     "CreationDate": "2014-05-13T00:00:00.000"
##   },
##   "row.2": {
##     "Id": "3",
##     "PostId": "3",
##     "VoteTypeId": "2",
##     "CreationDate": "2014-05-13T00:00:00.000"
##   }
## } 

根據您的評論

您想要的不是數據的結構方式。 這意味着，如果您想要某些東西，則不能使用罐頭香草實用程序。

xml_find_all(doc, "//votes/row") %>% 
  map_chr(~{
    toJSON(as.list(xml_attrs(.x)), auto_unbox = TRUE, pretty = TRUE)
  }) %>% 
  paste0(collapse=",\n") %>% 
  gsub("[\n]", "\n    ", .) %>% 
  sprintf('{ "votes" : {\n  row" : [\n    %s]\n  }\n}', .) %>% 
  cat()

## { "votes" : {
##   row" : [
##     {
##       "Id": "1",
##       "PostId": "1",
##       "VoteTypeId": "2",
##       "CreationDate": "2014-05-13T00:00:00.000"
##     },
##     {
##       "Id": "2",
##       "PostId": "1",
##       "VoteTypeId": "2",
##       "CreationDate": "2014-05-13T00:00:00.000"
##     },
##     {
##       "Id": "3",
##       "PostId": "3",
##       "VoteTypeId": "2",
##       "CreationDate": "2014-05-13T00:00:00.000"
##     }]
##   }
## }