在 R 中导入 JSON 文件并将其进一步处理为表

Question

我对 R 很陌生。一整天都在尝试解决一个问题。不幸的是，我无法解决它。

我想在 R 中导入 JSON 文件，然后有机会以与导入 CSV 文件时相同的方式进一步处理它。

我的 JSON 文件必须具有以下结构：

{ "reviewerID": "A2SUAM1J3GNN3B",
  "asin": "0000013714",
  "reviewerName": "J. McDonald",
  "helpful": [2, 3],
  "reviewText": "I bought this for my husband who plays the piano.
  He is having a wonderful time playing these old hymns. The music is at
  times hard to read because we think the book was published for singing
  from more than playing from. Great purchase though!",
  "overall": 5.0,
  "summary": "Heavenly Highway Hymns",
  "unixReviewTime": 1252800000,
  "reviewTime": "09 13, 2009"
}

我想导入 JSON 文件，然后创建一个包含 9 列（reviewerID、asin、reviewerName 等）的表。

我尝试使用 R 包 jsonlite，但如果这样做，我会收到以下错误消息：

 data <- fromJSON('reviews_Office_Products.json.gz2')
 Error in feed_push_parser(buf) : parse error: trailing garbage
      "reviewTime": "07 19, 2013"} {"reviewerID": "A3BBNK2R5TUYGV"
                 (right here) ------^

你知道我可以完成我的任务吗？

非常感谢您。

最好的问候 保罗

Answer 1

最后我做到了：

library(rjson)
url <- "reviews_Office_Products.json.gz2"
con = file(url, "r")
input <- readLines(con, -1L)
my_results <- lapply(X=input,fromJSON)

close(con)
tr.review <- ldply(lapply(input, function(x) t(unlist(fromJSON(x)))))
save(tr.review, file= 'tr.review.rdata')

出于我的目的，这是可行的，我可以使用 tm-package 进一步处理数据。

非常感谢您的帮助。 保罗

Answer 2

这行得通。您可能需要使用正则表达式以使其适合。请注意，R 正则表达式中需要双反斜杠而不是单反斜杠。

library(rjson)
library(magrittr)
library(dplyr)
library(lubridate)
library(stringi)

options(stringsAsFactors = FALSE)

'{ "reviews": [ { "reviewerID": "A2SUAM1J3GNN3B",
  "asin": "0000013714",
  "reviewerName": "J. McDonald",
  "helpful": [2, 3],
  "reviewText": "I bought this for my husband who plays the piano.
  He is having a wonderful time playing these old hymns. The music is at
  times hard to read because we think the book was published for singing
  from more than playing from. Great purchase though!",
  "overall": 5.0,
  "summary": "Heavenly Highway Hymns",
  "unixReviewTime": 1252800000,
  "reviewTime": "09 13, 2009"
} { "reviewerID": "A2SUAM1J3GNN3B",
  "asin": "0000013714",
  "reviewerName": "J. McDonald",
  "helpful": [2, 3],
  "reviewText": "I bought this for my husband who plays the piano.
  He is having a wonderful time playing these old hymns. The music is at
  times hard to read because we think the book was published for singing
  from more than playing from. Great purchase though!",
  "overall": 5.0,
  "summary": "Heavenly Highway Hymns",
  "unixReviewTime": 1252800000,
  "reviewTime": "09 13, 2009"
} ] }' %>%
  writeLines("reviews_Office_Products.json.gz2")

data = 
  "reviews_Office_Products.json.gz2" %>%
  readLines %>%
  stri_replace_all_regex("\\}[ \\n]*\\{", "},{") %>%
  paste(collapse = "\n") %>%
  fromJSON %>%
  .[[1]] %>%
  lapply(as.data.frame) %>%
  bind_rows %>%
  select(-unixReviewTime) %>%
  mutate(asin = as.numeric(asin),
         reviewTime = mdy(reviewTime) )

review = 
  data %>%
  select(-helpful) %>%
  distinct

review__helpful =
  data %>%
  select(reviewerID, helpful) %>%
  distinct