r - 使用 RJSONIO 解析一行 JSON 对象的文本文件

Question

我想要什么:我想解析一个格式为

的文本文件

{"business_id": "rncjoVoEFUJGCUoC1JgnUA", "full_address": "8466 W Peoria Ave\nSte 6\nPeoria, AZ 85345", "open": true, "categories": ["Accountants", "Professional Services", "Tax Services", "Financial Services"], "city": "Peoria", "review_count": 3, "name": "Peoria Income Tax Service", "neighborhoods": [], "longitude": -112.241596, "state": "AZ", "stars": 5.0, "latitude": 33.581867000000003, "type": "business"}
{"business_id": "0FNFSzCFP_rGUoJx8W7tJg", "full_address": "2149 W Wood Dr\nPhoenix, AZ 85029", "open": true, "categories": ["Sporting Goods", "Bikes", "Shopping"], "city": "Phoenix", "review_count": 5, "name": "Bike Doctor", "neighborhoods": [], "longitude": -112.10593299999999, "state": "AZ", "stars": 5.0, "latitude": 33.604053999999998, "type": "business"}

其中每一行都是一个单独的 json 对象。我希望解析后的形式是 RPart 可以作为参数的类型。

如果我循环遍历每一行，我可以使它工作，但根据这个 SO answer，R 更喜欢使用 apply 函数，而不是单独循环遍历每一行。

For each row in an R dataframe

问题:当我运行我的代码时出现此错误

Error in apply(yelp_df, 1, fromJSON) : dim(X) must have a positive length

我的代码

#!/usr/bin/Rscript

require(graphics)
require(RJSONIO)


con <- file("yelp_phoenix_academic_dataset/yelp_academic_dataset_business.json", "r")
yelp_df <- readLines(con) #rather then guessing what the optimal buffer size of the system is I'll just put everything into memeory

apply(yelp_df, 1, fromJSON)

Answer 1

readLines 正在返回一个字符向量。 apply 需要一个数组。使用 lapply 或类似的东西。

out <- lapply(readLines("test.txt"), fromJSON)

> head(out[[1]])
$business_id
[1] "rncjoVoEFUJGCUoC1JgnUA"

$full_address
[1] "8466 W Peoria Ave\nSte 6\nPeoria, AZ 85345"

$open
[1] TRUE

$categories
[1] "Accountants"           "Professional Services" "Tax Services"         
[4] "Financial Services"   

$city
[1] "Peoria"

$review_count
[1] 3