将R数据表列从JSON转换为数据表 [英] Convert R data table column from JSON to data table

问题描述

我有一个包含JSON数据的列，如以下示例所示，

I have a column that contains JSON data as in the following example,

library(data.table)
test <- data.table(a = list(1,2,3), 
           info = list("{'duration': '10', 'country': 'US'}", 
                       "{'duration': '20', 'country': 'US'}",
                       "{'duration': '30', 'country': 'GB', 'width': '20'}"))

我想将最后一列转换为等效的R存储，这看起来类似于，

I want to convert the last column to equivalent R storage, which would look similar to,

res <- data.table(a = list(1, 2, 3),
                  duration = list(10, 20, 30),
                  country = list('US', 'US', 'GB'),
                  width = list(NA, NA, 20))

由于我有50万行具有不同内容的行，所以我会寻找一种快速的方法来实现这一点.

Since I have 500K rows with different contents I would look for a quick way to do this.

推荐答案

无需分离JSON字符串的变体

A variation without the need to separate out the JSON string

library(data.table)
library(jsonlite)

test[, info := gsub("'", "\"", info)]
test[, rbindlist(lapply(info, fromJSON), use.names = TRUE, fill = TRUE)]

#    duration country width
# 1:       10      US    NA
# 2:       20      US    NA
# 3:       30      GB    20

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