仅使用列表中的一个组件创建JSON文件列表

Question

我有4个json文件传播到文件夹：folder1和folder2。每个json文件都包含date,body和title。

folder1.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;"} 

folder2.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"} 

我会想创建所有这些JSON文件，但只有每一篇文章的身体公共列表。到目前为止，我正在尝试以下操作：

​​3210

但它不工作。有什么建议么？

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Azqueta

解决方案： 您需要derence的的fromJSON()，在sapply（）只检索body。

• fromJSON()$body

注：我假设文件格式从你previous问题

点是文件格式是须藤JSON，因此下面fromJSON()通话修改。

行，让通过一个例子步骤：

阶段1：串连JSON文件到1个

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. " 

阶段2：串联并提取body来自所有文件...

查找的参考代码行fromJSON()$body ...

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. "