R无法打开连接`

Question

我正在从NBA.com API上搜索一些镜头数据。我正在使用的网址是

url = "stats.nba.com/stats/shotchartdetail?CFID=33&CFPARAMS=2017-18&ContextFilter=&ContextMeasure=FGA&DateFrom=&DateTo=&GameID=&GameSegment=&LastNGames=0&LeagueID=00&Location=&MeasureType=Base&Month=0&OpponentTeamID=0&Outcome=&PaceAdjust=N&PerMode=PerGame&Period=0&PlayerID=101107&PlusMinus=N&PlayerPosition=&Rank=N&RookieYear=&Season=2017-18&SeasonSegment=&SeasonType=Regular%20Season&TeamID=0&VsConference=&VsDivision="

通过复制和粘贴到您的浏览器，可以轻松验证此网站是否存在。但是，当我进入行

data = rjson::fromJSON(file = url)

我收到错误：文件错误（con，＆＃34; r＆＃34;）：无法打开连接... HTTP状态为＆＃39; 403禁止＆＃39;。

我尝试过将http和https添加到网址但无济于事。为什么R不读这个明显存在的网址？

Answer 1

概述

您需要将数据下载到r，然后导入fromJSON()内的.json文件。我已经展示了如何提取列表对象marvin.williams.shot.data中包含的两个数据框：

1. Marvin William个人2017-2018拍摄数据;和
2. NBA联盟2017-2018赛季的平均投篮数据。

可重复的示例

# load necessary packages
library( jsonlite )

# load necessary data
download.file( url = "http://stats.nba.com/stats/shotchartdetail?CFID=33&CFPARAMS=2017-18&ContextFilter=&ContextMeasure=FGA&DateFrom=&DateTo=&GameID=&GameSegment=&LastNGames=0&LeagueID=00&Location=&MeasureType=Base&Month=0&OpponentTeamID=0&Outcome=&PaceAdjust=N&PerMode=PerGame&Period=0&PlayerID=101107&PlusMinus=N&PlayerPosition=&Rank=N&RookieYear=&Season=2017-18&SeasonSegment=&SeasonType=Regular%20Season&TeamID=0&VsConference=&VsDivision="
               , destfile = "stats_nba.json" )

# transfrom into data frame
marvin.williams.shot.data <- 
  fromJSON( txt = "stats_nba.json" )

# view results
lapply( X = marvin.williams.shot.data, FUN = class)
# $resource
# [1] "character"
# 
# $parameters
# [1] "list"
# 
# $resultSets
# [1] "data.frame"

# transfrom the matrix into a data frame
player.shotchart.df <-
  as.data.frame( marvin.williams.shot.data$resultSets$rowSet[[1]]
                 , stringsAsFactors = FALSE )

# assign colnames
colnames( player.shotchart.df ) <-
  marvin.williams.shot.data$resultSets$headers[[1]]

# view results
dim( player.shotchart.df ) # [1] 563  24

# transfrom the matrix into a data frame
league.average.df <-
  as.data.frame( marvin.williams.shot.data$resultSets$rowSet[[2]]
                 , stringsAsFactors = FALSE )

# assign colnames
colnames( league.average.df ) <-
  marvin.williams.shot.data$resultSets$headers[[2]]

# view results
dim( league.average.df ) # [1] 20  7

# end of script #