能否给几行数据以及你的读入代码……总觉得你的代码可以优化的

以及……“直接读”是什么鬼……
R不支持这种格式吧

如果读入的是一个列表，可以直接用data.frame(a)转换成数据框
如果读入可以改……用a=data.frame(...)就能直接读取数据框的信息
> a=list("reviewerID"= "A2IBPI20UZIR0U", "asin"= "1384719342", "reviewerName"= "cassandra tu \"Yeah, well, that's just like, u...", "helpful"= "[0, 0]", "reviewText"= "Not much ...despite their pricing,", "overall"= 5.0, "summary"= "good", "unixReviewTime"= 1393545600, "reviewTime"= "02 28, 2014")
> data.frame(a)
      reviewerID       asin                                     reviewerName helpful                         reviewText overall summary
1 A2IBPI20UZIR0U 1384719342 cassandra tu "Yeah, well, that's just like, u...  [0, 0] Not much ...despite their pricing,       5    good
  unixReviewTime  reviewTime
1     1393545600 02 28, 2014

不过话说……我并不确定逐行rbind会不会死
a=data.frame(a)
b=data.frame(b)
rbind(a,b)
针对小规模数据是可行的，数据规模扩大的时候……不确定会不会死

不好意思，之前没有看到你的回复，是这样的，json文件原来的样子是


{"reviewerID": "A2IBPI20UZIR0U", "asin": "1384719342", "reviewerName": "cassandra tu \"Yeah, well, that's just like, u...", "helpful": [0, 0], "reviewText": "Not much ...despite their pricing,", "overall": 5.0, "summary": "good", "unixReviewTime": 1393545600, "reviewTime": "02 28, 2014"}
{"reviewerID": "A14VAT5EAX3D9S", "asin": "1384719342", "reviewerName": "Jake", "helpful": [13, 14], "reviewText": "The product ...this product! :]", "overall": 5.0, "summary": "Jake", "unixReviewTime": 1363392000, "reviewTime": "03 16, 2013"}
{"reviewerID": "A195EZSQDW3E21", "asin": "1384719342", "reviewerName": "Rick Bennette \"Rick Bennette\"", "helpful": [1, 1], "reviewText": "The primary... you put it.", "overall": 5.0, "summary": "It Does The Job Well", "unixReviewTime": 1377648000, "reviewTime": "08 28, 2013"}


这个东西，我是这样读的

library(rjson)
data = fromJSON(file = 'Musical_instruments_5.json')

但是结果只有最后一行，就是data的数据不全


我修改json文件之后，再这样读，就是列表嵌套的格式了

Reduce函数   Map函数  都很好

library(purrr)
scores %>% transpose() %>% map(unlist)

谢谢你的解决方案，很有启发！