代码之家 › 专栏 › 技术社区 › deschen

使用fromJSON创建JSON时有关意外符号的错误消息

jsonlite r

0

deschen · 技术社区 · 3 年前

这可能是件容易的事情,但我一直在努力用简单的文本输入创建一个简单的JSON文件。从错误信息来看,很明显我用引号写错了什么,但我不知道是什么。

library(jsonlite)

# Create an example
jsoncars <- toJSON(mtcars[1:2,], pretty=TRUE)
jsoncars

这使得:

[
  {
    "mpg": 21,
    "cyl": 6,
    "disp": 160,
    "hp": 110,
    "drat": 3.9,
    "wt": 2.62,
    "qsec": 16.46,
    "vs": 0,
    "am": 1,
    "gear": 4,
    "carb": 4,
    "_row": "Mazda RX4"
  },
  {
    "mpg": 21,
    "cyl": 6,
    "disp": 160,
    "hp": 110,
    "drat": 3.9,
    "wt": 2.875,
    "qsec": 17.02,
    "vs": 0,
    "am": 1,
    "gear": 4,
    "carb": 4,
    "_row": "Mazda RX4 Wag"
  }
]

现在,我将同样的文本复制到fromJSON中:

fromJSON("[
  {
    "mpg": 21,
    "cyl": 6,
    "disp": 160,
    "hp": 110,
    "drat": 3.9,
    "wt": 2.62,
    "qsec": 16.46,
    "vs": 0,
    "am": 1,
    "gear": 4,
    "carb": 4,
    "_row": "Mazda RX4"
  },
  {
    "mpg": 21,
    "cyl": 6,
    "disp": 160,
    "hp": 110,
    "drat": 3.9,
    "wt": 2.875,
    "qsec": 17.02,
    "vs": 0,
    "am": 1,
    "gear": 4,
    "carb": 4,
    "_row": "Mazda RX4 Wag"
  }
]")

我得到了以下错误:

Error: unexpected symbol in:
"      {
        "mpg"
Execution halted

顺便说一句,你在做什么 fromJSON(jsoncars) 行得通,但还是解决不了我的问题。

有什么想法吗?

1 回复 | 直到 3 年前

1

2

Waldi 3 年前

使用 ' 区别于 " 在里面 JSON 文本:

jsonlite::fromJSON('[
  {
    "mpg": 21,
    "cyl": 6,
    "disp": 160,
    "hp": 110,
    "drat": 3.9,
    "wt": 2.62,
    "qsec": 16.46,
    "vs": 0,
    "am": 1,
    "gear": 4,
    "carb": 4,
    "_row": "Mazda RX4"
  },
  {
    "mpg": 21,
    "cyl": 6,
    "disp": 160,
    "hp": 110,
    "drat": 3.9,
    "wt": 2.875,
    "qsec": 17.02,
    "vs": 0,
    "am": 1,
    "gear": 4,
    "carb": 4,
    "_row": "Mazda RX4 Wag"
  }
]')

              mpg cyl disp  hp drat    wt  qsec vs am gear carb
Mazda RX4      21   6  160 110  3.9 2.620 16.46  0  1    4    4
Mazda RX4 Wag  21   6  160 110  3.9 2.875 17.02  0  1    4    4

另一个选择是新的R>=4 raw character string 语法 r"(...)" :

jsonlite::fromJSON(r"([
  {
    "mpg": 21,
    "cyl": 6,
    "disp": 160,
    "hp": 110,
    "drat": 3.9,
    "wt": 2.62,
    "qsec": 16.46,
    "vs": 0,
    "am": 1,
    "gear": 4,
    "carb": 4,
    "_row": "Mazda RX4"
  },
  {
    "mpg": 21,
    "cyl": 6,
    "disp": 160,
    "hp": 110,
    "drat": 3.9,
    "wt": 2.875,
    "qsec": 17.02,
    "vs": 0,
    "am": 1,
    "gear": 4,
    "carb": 4,
    "_row": "Mazda RX4 Wag"
  }
])")