仅使用列表的一个组件创建 JSON 文件列表

Question

我有 4 个 json 文件分布到文件夹中：folder1 和 folder2。每个 json 文件包含 date、body 和 title。

文件夹1.json：

{"date": "December 31, 1989, Sunday, Late Edition - Final", "body": "Frigid temperatures across much of the United States this month sent demand for heating oil soaring, providing a final upward jolt to crude oil prices. That's assuming the economy performs as expected - about 1 percent growth in G.N.P. The other big uncertainty is the U.S.S.R. If their production drops more than 4 percent, prices could stengthen. ", "title": "Prospects;"}

{"date": "December 31, 1989, Sunday, Late Edition - Final", "body": "DATELINE: WASHINGTON, Dec. 30 For years, experts have dubbed Czechoslovakia's spy agency the ''two Czech'' service. Agents of the Office for the Protection of State Secrets got one check from Prague, the pun goes, and another from their real bosses at K.G.B. headquarters in Moscow. Roy Godson, head of the Washington-based National Strategy Information Center and a well-known intelligence scholar, called any democratic change ''a net loss'' for Soviet intelligence. But he cautioned against euphoria. ''The Soviets wouldn't have relied on just official cooperation,'' he said. ''It would be surprising if they haven't unilaterally penetrated friendly services with their own agents, too.'' ", "title": "Upheaval in the East: Espionage;"}

文件夹2.json：

{"date": "December 31, 1989, Sunday, Late Edition - Final", "body": "SURVIVING the decline in the economy will be the overriding issue for 1990, say leaders of the county's business community.  But facing business owners are numerous problems, from taxes and regulations at all levels of government to competition from other businesses in and out of Westchester. Successful Westchester business owners will face and overcome these risks and obstacles. Westchester is a land of opportunity for the business owner. ", "title": "Coping With the Economic Prospects of 1990"}

{"date": "December 29, 1989, Friday, Late Edition - Final", "body": "Eastern Airlines said yesterday that it was laying off 600 employees, mostly managers, and cutting wages by 10 percent or 20 percent for about half its work force. Thomas J. Matthews, Eastern's senior vice president of human resources, estimated that the measures would save the carrier about $100 million a year. Eastern plans to rebuild by making Atlanta its primary hub and expects to operate about 75 percent of its flights from there. ", "title": "Eastern Plans Wage Cuts, 600 Layoffs"}

我想为所有这些 json 文件创建一个通用列表，但仅限于每篇文章的正文。到目前为止，我正在尝试以下方法：

json1 <- lapply(readLines("folder1.json"), fromJSON)
json2 <- lapply(readLines("folder2.json"), fromJSON)

jsonl <- list(json1$body, json2$body)

但它不起作用。有什么建议吗？

Answer 1

require(RJSONIO)   
json_1<- fromJSON("~/folder1/1.json")
json_2<- fromJSON("~/folder2/2.json")

jsonl <- list(json1$body, json2$body)

Answer 2

安德烈斯·阿兹奎塔

解决方案： 您需要在 sapply() 中引用 fromJSON()，以仅检索 body。

• fromJSON()$body

注意：我假设您previous问题的文件格式

文件格式是 sudo JSON，因此修改后的 fromJSON() 调用如下。

好的，我们来看一个例子：

第 1 阶段：将 JSON 文件连接成 1

filelist <- c("./data/NYT_1989.json", "./data/NYT_1990.json")
newJSON <- sapply(filelist, function(x) fromJSON(sprintf("[%s]", paste(readLines(x), collapse = ",")), flatten = FALSE))
newJSON[2]# Extract bodies
newJSON[5]# Extract bodies

输出

filelist <- c("./data/NYT_1989.json", "./data/NYT_1990.json")
> newJSON <- sapply(filelist, function(x) fromJSON(sprintf("[%s]", paste(readLines(x), collapse = ",")), flatten = FALSE))
> newJSON[2]# Extract bodies
[[1]]
[1] "Frigid temperatures across much of the United States this month sent demand for heating oil soaring, providing a final upward jolt to crude oil prices. Some spot crude traded at prices up 40 percent or more from a year ago. Will these prices hold? Five experts on oil offer their views. That's assuming the economy performs as expected - about 1 percent growth in G.N.P. The other big uncertainty is the U.S.S.R. If their production drops more than 4 percent, prices could stengthen. "
[2] "DATELINE: WASHINGTON, Dec. 30 For years, experts have dubbed Czechoslovakia's spy agency the ''two Czech'' service. But he cautioned against euphoria. ''The Soviets wouldn't have relied on just official cooperation,'' he said. ''It would be surprising if they haven't unilaterally penetrated friendly services with their own agents, too.'' "                                                                                                                                                
[3] "SURVIVING the decline in the economy will be the overriding issue for 1990, say leaders of the county's business community. Successful Westchester business owners will face and overcome these risks and obstacles. Westchester is a land of opportunity for the business owner. "                                                                                                                                                                                                                  

> newJSON[5]# Extract bodies
[[1]]
[1] "Blue temperatures across much of the United States this month sent demand for heating oil soaring, providing a final upward jolt to crude oil prices. Some spot crude traded at prices up 40 percent or more from a year ago. Will these prices hold? Five experts on oil offer their views. That's assuming the economy performs as expected - about 1 percent growth in G.N.P. The other big uncertainty is the U.S.S.R. If their production drops more than 4 percent, prices could stengthen. "
[2] "BLUE1: WASHINGTON, Dec. 30 For years, experts have dubbed Czechoslovakia's spy agency the ''two Czech'' service. But he cautioned against euphoria. ''The Soviets wouldn't have relied on just official cooperation,'' he said. ''It would be surprising if they haven't unilaterally penetrated friendly services with their own agents, too.'' "                                                                                                                                                 
[3] "GREEN4 the decline in the economy will be the overriding issue for 1990, say leaders of the county's business community. Successful Westchester business owners will face and overcome these risks and obstacles. Westchester is a land of opportunity for the business owner. "   

第 2 阶段：连接并从所有文件中提取 body...

在代码行中查找对fromJSON()$body 的引用...

filelist <- c("./data/NYT_1989.json", "./data/NYT_1990.json")
newJSON <- sapply(filelist, function(x) fromJSON(sprintf("[%s]", paste(readLines(x), collapse = ",")), flatten = FALSE)$body)
newJSON

输出

> filelist <- c("./data/NYT_1989.json", "./data/NYT_1990.json")
> newJSON <- sapply(filelist, function(x) fromJSON(sprintf("[%s]", paste(readLines(x), collapse = ",")), flatten = FALSE)$body)
> newJSON
     ./data/NYT_1989.json                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  
[1,] "Frigid temperatures across much of the United States this month sent demand for heating oil soaring, providing a final upward jolt to crude oil prices. Some spot crude traded at prices up 40 percent or more from a year ago. Will these prices hold? Five experts on oil offer their views. That's assuming the economy performs as expected - about 1 percent growth in G.N.P. The other big uncertainty is the U.S.S.R. If their production drops more than 4 percent, prices could stengthen. "
[2,] "DATELINE: WASHINGTON, Dec. 30 For years, experts have dubbed Czechoslovakia's spy agency the ''two Czech'' service. But he cautioned against euphoria. ''The Soviets wouldn't have relied on just official cooperation,'' he said. ''It would be surprising if they haven't unilaterally penetrated friendly services with their own agents, too.'' "                                                                                                                                                
[3,] "SURVIVING the decline in the economy will be the overriding issue for 1990, say leaders of the county's business community. Successful Westchester business owners will face and overcome these risks and obstacles. Westchester is a land of opportunity for the business owner. "                                                                                                                                                                                                                  
     ./data/NYT_1990.json                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
[1,] "Blue temperatures across much of the United States this month sent demand for heating oil soaring, providing a final upward jolt to crude oil prices. Some spot crude traded at prices up 40 percent or more from a year ago. Will these prices hold? Five experts on oil offer their views. That's assuming the economy performs as expected - about 1 percent growth in G.N.P. The other big uncertainty is the U.S.S.R. If their production drops more than 4 percent, prices could stengthen. "
[2,] "BLUE1: WASHINGTON, Dec. 30 For years, experts have dubbed Czechoslovakia's spy agency the ''two Czech'' service. But he cautioned against euphoria. ''The Soviets wouldn't have relied on just official cooperation,'' he said. ''It would be surprising if they haven't unilaterally penetrated friendly services with their own agents, too.'' "                                                                                                                                                 
[3,] "GREEN4 the decline in the economy will be the overriding issue for 1990, say leaders of the county's business community. Successful Westchester business owners will face and overcome these risks and obstacles. Westchester is a land of opportunity for the business owner. "