Question

我正在尝试将网络上的pdf导入R：

library(tm)

webpdf <- "https://www.lme.com/~/media/Files/Market%20data/COTR/2015/2015_01/Cotr%2019%20Jan%202015.pdf"
uri <- sprintf("file://%s", system.file(file.path("doc", webpdf), package = "tm"))
if(all(file.exists(Sys.which(c("pdfinfo", "pdftotext"))))) {
pdf <- readPDF(control = list(text = "-layout"))(elem = list(uri = uri),
                                                 language = "en",
                                                 id = "id1")
content(pdf)[1:13]
}
VCorpus(URISource(uri, mode = ""),
    readerControl = list(reader = readPDF(engine = "ghostscript")))

我无法执行此操作并收到错误消息：

Error in system2(gs_cmd, c("-dNODISPLAY -q", sprintf("-sFile=%s", shQuote(file)),  : 
  '""' not found

Answer 1

初始设置存在很多问题。这将为您提供PDF内容，但您应该针对您将要遇到的tm Corpus问题提出另一个问题。

library(tm)
library(httr) # this will make it easier to get to https conent

webpdf <- "https://www.lme.com/~/media/Files/Market%20data/COTR/2015/2015_01/Cotr%2019%20Jan%202015.pdf"

doc <- "cotr.pdf"

# save the file locally, write_disk() will act like a cache
stop_for_status(GET(webpdf, write_disk(doc)))

if(all(file.exists(Sys.which(c("pdfinfo", "pdftotext"))))) {

  pdf <- readPDF(control = list(text = "-layout"))(elem = list(uri = doc),
                                                   language = "en",
                                                   id = "id1")
  # httr also has a "content()" so make the call explicit
  NLP::content(pdf)[1:13]

}

print(str(pdf))

## List of 2
##  $ content: chr [1:113] "Commitment of Trader Report - Market Report as of 2015/01/21" "" "Metal" "AA" ...
##  $ meta   :List of 7
##   ..$ author       : NULL
##   ..$ datetimestamp: POSIXlt[1:1], format: "2015-01-21 08:59:10"
##   ..$ description  : NULL
##   ..$ heading      : NULL
##   ..$ id           : chr "cotr.pdf"
##   ..$ language     : chr "en"
##   ..$ origin       : NULL
##   ..- attr(*, "class")= chr "TextDocumentMeta"
##  - attr(*, "class")= chr [1:2] "PlainTextDocument" "TextDocument"
## NULL

将Web pdf导入R

1 个答案: