僅使用列表中的一個組件創建JSON文件列表

Question

我有4個json文件傳播到文件夾：folder1和folder2。每個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"} 

我會想創建所有這些JSON文件，但只有每一篇文章的身體公共列表。到目前爲止，我正在嘗試以下操作：

​​3210

但它不工作。有什麼建議麼？

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

解決方案： 您需要derence的的fromJSON()，在sapply（）只檢索body。

• fromJSON()$body

注：我假設文件格式從你previous問題

點是文件格式是須藤JSON，因此下面fromJSON()通話修改。

行，讓通過一個例子步驟：

階段1：串連JSON文件到1個

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 

輸出

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. " 

階段2：串聯並提取body來自所有文件...

查找的參考代碼行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 

輸出

> 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. "