json - R 格式化 JSON 输出的策略

Question

我正在尝试找出从 R 生成 JSON 文件的最佳方法。我有以下数据框 tmp在R .

> tmp
  gender age welcoming proud tidy unique
1      1  30         4     4    4      4
2      2  34         4     2    4      4
3      1  34         5     3    4      5
4      2  33         2     3    2      4
5      2  28         4     3    4      4
6      2  26         3     2    4      3

  

tmp <- data.frame(
  gender = c(1L, 2L, 1L, 2L, 2L, 2L),
  age = c(30, 34, 34, 33, 28, 26),
  welcoming = c(4L, 4L, 5L, 2L, 4L, 3L),
  proud = c(4L, 2L, 3L, 3L, 3L, 2L),
  tidy = c(4L, 4L, 4L, 2L, 4L, 4L),
  unique = c(4L, 4L, 5L, 4L, 4L, 3L)
)

使用rjson包，我运行 toJSON(tmp) 行它会生成以下 JSON 文件:

 {"gender":[1,2,1,2,2,2],
 "age":[30,34,34,33,28,26],
 "welcoming":[4,4,5,2,4,3],
 "proud":[4,2,3,3,3,2],
  "tidy":[4,4,4,2,4,4],
  "unique":[4,4,5,4,4,3]}

我还尝试了 RJSONIO包裹; toJSON()的输出是一样的。我想要生成的是以下结构:

  {"traits":["gender","age","welcoming","proud", "tidy", "unique"],
   "values":[   
            {"gender":1,"age":30,"welcoming":4,"proud":4,"tidy":4, "unique":4},
            {"gender":2,"age":34,"welcoming":4,"proud":2,"tidy":4, "unique":4},
            ....
            ]

我不知道如何最好地做到这一点。我意识到我可以使用 python 逐行解析它但我觉得可能有更好的方法来做到这一点。我还意识到我的数据结构在 R没有反射(reflect)我的 JSON 中所需的元信息文件(特别是 traits 行)，但我主要感兴趣的是生成类似于该行的格式的数据

{"gender":1,"age":30,"welcoming":4,"proud":4,"tidy":4, "unique":4}

因为我可以手动添加第一行。

<小时/>

编辑:我发现了一个有用的 blog作者在帖子中处理了类似的问题并提供了解决方案。此函数从数据帧生成格式化的 JSON 文件。

toJSONarray <- function(dtf){
clnms <- colnames(dtf)

name.value <- function(i){
quote <- '';
# if(class(dtf[, i])!='numeric'){
if(class(dtf[, i])!='numeric' && class(dtf[, i])!= 'integer'){ # I modified this line so integers are also not enclosed in quotes
quote <- '"';
}

paste('"', i, '" : ', quote, dtf[,i], quote, sep='')
}

objs <- apply(sapply(clnms, name.value), 1, function(x){paste(x, collapse=', ')})
objs <- paste('{', objs, '}')

# res <- paste('[', paste(objs, collapse=', '), ']')
res <- paste('[', paste(objs, collapse=',\n'), ']') # added newline for formatting output

return(res)
}

Answer 1

使用包jsonlite:

> jsonlite::toJSON(list(traits = names(tmp), values = tmp), pretty = TRUE)
{
  "traits": ["gender", "age", "welcoming", "proud", "tidy", "unique"],
  "values": [
    {
      "gender": 1,
      "age": 30,
      "welcoming": 4,
      "proud": 4,
      "tidy": 4,
      "unique": 4
    },
    {
      "gender": 2,
      "age": 34,
      "welcoming": 4,
      "proud": 2,
      "tidy": 4,
      "unique": 4
    },
    {
      "gender": 1,
      "age": 34,
      "welcoming": 5,
      "proud": 3,
      "tidy": 4,
      "unique": 5
    },
    {
      "gender": 2,
      "age": 33,
      "welcoming": 2,
      "proud": 3,
      "tidy": 2,
      "unique": 4
    },
    {
      "gender": 2,
      "age": 28,
      "welcoming": 4,
      "proud": 3,
      "tidy": 4,
      "unique": 4
    },
    {
      "gender": 2,
      "age": 26,
      "welcoming": 3,
      "proud": 2,
      "tidy": 4,
      "unique": 3
    }
  ]
}