使用jsonlite包解析JSON文件时出错 [英] Error parsing JSON file with the jsonlite package
问题描述
我正在尝试将JSON文件读入R，但出现此错误:
I'm trying to read a JSON file into R but I got this error:
Error in parseJSON(txt) : parse error: trailing garbage
[ 33.816101, -117.979401 ] } { "a": "Mozilla\/4.0 (compatibl
(right here) ------^
我从 http://1usagov.measuredvoice.com/下载了文件并使用7zip解压缩，然后在R中使用以下代码:
I downloaded the file from http://1usagov.measuredvoice.com/ and unzipped it using 7zip, then I used the following code in R:
library(jsonlite)
jsonData <- fromJSON("usagov_bitly_data2013-05-17-1368832207")
我不确定为什么会发生此错误，我在Google中进行了查询，但没有信息，有人可以帮助我吗?这是文件问题还是我的代码?
I'm not sure why this error happens, I looked up in Google but there's no information, someone that could help me? Is this a file problem or my code?
推荐答案
另一个更新
您可以使用ndjson包来处理ndjson/流JSON数据.它比jsonlite::stream_in()更快，并且始终会产生一个完全平坦"的数据帧:
You can use the ndjson package to process this ndjson/streaming JSON data. It's faster than jsonlite::stream_in() and always produces a completely "flat" data frame:
system.time(bitly01 <- ndjson::stream_in("usagov_bitly_data2013-05-17-1368832207.gz"))
## user system elapsed
## 0.146 0.004 0.154
system.time(bitly02 <- jsonlite::stream_in(file("usagov_bitly_data2013-05-17-1368832207.gz"), verbose=FALSE, pagesize=10000))
## user system elapsed
## 0.419 0.008 0.427
如果我们检查结果数据帧2，您会看到ndjson将ll扩展为ll.0和ll.1，在其中您会在jsonlite中获得一个list列，以后需要处理.
If we examine the resultant data frame2, you'll see ndjson expands ll into ll.0 and ll.1 where you get a list column in jsonlite that you have to deal with later.
ndjson:
dplyr::glimpse(bitly01)
## Observations: 3,959
## Variables: 19
## $ a <chr> "Mozilla/5.0 (Linux; U; Android 4.1.2; en-us; HTC_PN071 Build/JZO54K) AppleWebKit/534.30 ...
## $ al <chr> "en-US", "en-us", "en-US,en;q=0.5", "en-US", "en", "en-US", "en-US,en;q=0.5", "en-us", "e...
## $ c <chr> "US", NA, "US", "US", NA, "US", "US", NA, "AU", NA, "US", "US", "US", "US", "US", "US", "...
## $ cy <chr> "Anaheim", NA, "Fort Huachuca", "Houston", NA, "Mishawaka", "Hammond", NA, "Sydney", NA, ...
## $ g <chr> "15r91", "ifIpBW", "10DaxOu", "TysVFU", "10IGW7m", "13GrCeP", "YmtpnZ", "13oM0hV", "15r91...
## $ gr <chr> "CA", NA, "AZ", "TX", NA, "IN", "WI", NA, "02", NA, "OH", "MD", "KY", "OR", "IL", "TX", "...
## $ h <chr> "10OBm3W", "ifIpBW", "10DaxOt", "TChsoQ", "10IGW7l", "13GrCeP", "YmtpnZ", "15PUeH0", "10O...
## $ hc <dbl> 1365701422, 1302189369, 1368814585, 1354719206, 1368738258, 1368130510, 1363711958, 13687...
## $ hh <chr> "j.mp", "1.usa.gov", "1.usa.gov", "1.usa.gov", "1.usa.gov", "1.usa.gov", "1.usa.gov", "go...
## $ l <chr> "pontifier", "bitly", "jaxstrong", "o_5004fs3lvd", "peacecorps", "bitly", "bitly", "nasat...
## $ ll.0 <dbl> 33.8161, NA, 31.5273, 29.7633, NA, 41.6123, 45.0070, NA, -33.8615, NA, 39.5151, 39.1317, ...
## $ ll.1 <dbl> -117.9794, NA, -110.3607, -95.3633, NA, -86.1381, -92.4591, NA, 151.2055, NA, -84.3983, -...
## $ nk <dbl> 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 1, 0, 1, 1, 0, 0, 0, 1, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0,...
## $ r <chr> "direct", "http://www.usa.gov/", "http://www.facebook.com/l.php?u=http%3A%2F%2F1.usa.gov%...
## $ t <dbl> 1368832205, 1368832207, 1368832209, 1368832209, 1368832208, 1368832209, 1368832210, 13688...
## $ tz <chr> "America/Los_Angeles", "", "America/Phoenix", "America/Chicago", "", "America/Indianapoli...
## $ u <chr> "http://www.nsa.gov/", "http://answers.usa.gov/system/selfservice.controller?CONFIGURATIO...
## $ _heartbeat_ <dbl> NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, N...
## $ kw <chr> NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, N...
jsonlite:
dplyr::glimpse(bitly02)
## Observations: 3,959
## Variables: 18
## $ a <chr> "Mozilla/5.0 (Linux; U; Android 4.1.2; en-us; HTC_PN071 Build/JZO54K) AppleWebKit/534.30 ...
## $ c <chr> "US", NA, "US", "US", NA, "US", "US", NA, "AU", NA, "US", "US", "US", "US", "US", "US", "...
## $ nk <int> 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 1, 0, 1, 1, 0, 0, 0, 1, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0,...
## $ tz <chr> "America/Los_Angeles", "", "America/Phoenix", "America/Chicago", "", "America/Indianapoli...
## $ gr <chr> "CA", NA, "AZ", "TX", NA, "IN", "WI", NA, "02", NA, "OH", "MD", "KY", "OR", "IL", "TX", "...
## $ g <chr> "15r91", "ifIpBW", "10DaxOu", "TysVFU", "10IGW7m", "13GrCeP", "YmtpnZ", "13oM0hV", "15r91...
## $ h <chr> "10OBm3W", "ifIpBW", "10DaxOt", "TChsoQ", "10IGW7l", "13GrCeP", "YmtpnZ", "15PUeH0", "10O...
## $ l <chr> "pontifier", "bitly", "jaxstrong", "o_5004fs3lvd", "peacecorps", "bitly", "bitly", "nasat...
## ## $ al <chr> "en-US", "en-us", "en-US,en;q=0.5", "en-US", "en", "en-US", "en-US,en;q=0.5", "en-us", "e...
## $ hh <chr> "j.mp", "1.usa.gov", "1.usa.gov", "1.usa.gov", "1.usa.gov", "1.usa.gov", "1.usa.gov", "go...
## $ r <chr> "direct", "http://www.usa.gov/", "http://www.facebook.com/l.php?u=http%3A%2F%2F1.usa.gov%...
## $ u <chr> "http://www.nsa.gov/", "http://answers.usa.gov/system/selfservice.controller?CONFIGURATIO...
## $ t <int> 1368832205, 1368832207, 1368832209, 1368832209, 1368832208, 1368832209, 1368832210, 13688...
## $ hc <int> 1365701422, 1302189369, 1368814585, 1354719206, 1368738258, 1368130510, 1363711958, 13687...
## $ cy <chr> "Anaheim", NA, "Fort Huachuca", "Houston", NA, "Mishawaka", "Hammond", NA, "Sydney", NA, ...
## $ ll <list> [<33.8161, -117.9794>, NULL, <31.5273, -110.3607>, <29.7633, -95.3633>, NULL, <41.6123, ...
## $ _heartbeat_ <int> NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, N...
## $ kw <chr> NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, N...
更新
jsonlite软件包的最新版本支持流JSON(这实际上是).您现在可以像这样用一行来阅读它:
The latest version of the jsonlite package supports streaming JSON (which is what this actually is). You can now read it with one line like so:
json_file <- stream_in(file("usagov_bitly_data2013-05-17-1368832207"))
有关直接通过http进行流解析的信息，另请参见下面的Jeroen答案.
See also Jeroen's answer below for stream-parsing it directly over http.
旧答案
事实证明这是一个伪JSON"文件.我在工作的许多朴素的API系统中遇到了这些问题.每一行都是有效的JSON，但是各个对象不在JSON数组中.您需要使用readLines，然后从中构建自己的有效JSON数组，并将其传递到fromJSON:
It turns out this is a "pseudo-JSON" file. I come across these in many naive API systems I work in. Each line is valid JSON, but the individual objects aren't in a JSON array. You need to use readLines and then build your own, valid JSON array from it and pass that into fromJSON:
library(jsonlite)
# read in individual JSON lines
json_file <- "usagov_bitly_data2013-05-17-1368832207"
# turn it into a proper array by separating each object with a "," and
# wrapping that up in an array with "[]"'s.
dat <- fromJSON(sprintf("[%s]", paste(readLines(json_file), collapse=",")))
dim(dat)
## [1] 3959 18
str(dat)
## 'data.frame': 3959 obs. of 18 variables:
## $ a : chr "Mozilla/5.0 (Linux; U; Android 4.1.2; en-us; HTC_PN071 Build/JZO54K) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile "| __truncated__ "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; .NET CLR 1.1.4322; .NET CLR 2.0.50727; .NET CLR 3.0.04506.30; .NET CLR 3.0.4"| __truncated__ "Mozilla/5.0 (Windows NT 6.1; rv:21.0) Gecko/20100101 Firefox/21.0" "Mozilla/5.0 (Linux; U; Android 4.1.2; en-us; SGH-T889 Build/JZO54K) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile S"| __truncated__ ...
## $ c : chr "US" NA "US" "US" ...
## $ nk : int 0 0 1 1 0 0 1 0 0 0 ...
## $ tz : chr "America/Los_Angeles" "" "America/Phoenix" "America/Chicago" ...
## $ gr : chr "CA" NA "AZ" "TX" ...
## $ g : chr "15r91" "ifIpBW" "10DaxOu" "TysVFU" ...
## $ h : chr "10OBm3W" "ifIpBW" "10DaxOt" "TChsoQ" ...
## $ l : chr "pontifier" "bitly" "jaxstrong" "o_5004fs3lvd" ...
## $ al : chr "en-US" "en-us" "en-US,en;q=0.5" "en-US" ...
## $ hh : chr "j.mp" "1.usa.gov" "1.usa.gov" "1.usa.gov" ...
## ... (goes on for a while, many columns)
我将readLines与paste/sprintf调用结合在一起，因为结果(临时)对象的object.size是2,025,656个字节(〜2MB)，并且感觉不像执行rm在一个单独的临时变量上.
I combined the readLines in with the paste/sprintf call since the object.size of the resultant (temporary) object is 2,025,656 bytes (~2MB) and didn't feel like doing an rm on a separate temporary variable.
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