Extracting text from pdf and other files
download.file("http://arxiv.org/pdf/1403.2805.pdf", "data/1403.2805.pdf", mode = "wb")
txt <- pdf_text("data/1403.2805.pdf")
# all 29 pages
length(txt)
#> [1] 29
cat(txt[[1]])
#> The jsonlite Package: A Practical and Consistent Mapping
#> Between JSON Data and R Objects
#> Jeroen Ooms
#> arXiv:1403.2805v1 [stat.CO] 12 Mar 2014
#> UCLA Department of Statistics
#> Abstract
#> A naive realization of JSON data in R maps JSON arrays to an unnamed list, and JSON objects to a
#> named list. However, in practice a list is an awkward, inefficient type to store and manipulate data.
#> Most statistical applications work with (homogeneous) vectors, matrices or data frames. Therefore JSON
#> packages in R typically define certain special cases of JSON structures which map to simpler R types.
#> Currently there exist no formal guidelines, or even consensus between implementations on how R data
#> should be represented in JSON. Furthermore, upon closer inspection, even the most basic data structures
#> in R actually do not perfectly map to their JSON counterparts and leave some ambiguity for edge cases.
#> These problems have resulted in different behavior between implementations and can lead to unexpected
#> output. This paper explicitly describes a mapping between R classes and JSON data, highlights potential
#> problems, and proposes conventions that generalize the mapping to cover all common structures. We
#> emphasize the importance of type consistency when using JSON to exchange dynamic data, and illustrate
#> using examples and anecdotes. The jsonlite R package is used throughout the paper as a reference
#> implementation.
#> 1 Introduction
#> JavaScript Object Notation (JSON) is a text format for the serialization of structured data (Crockford, 2006a).
#> It is derived from the object literals of JavaScript, as defined in the ECMAScript Programming Language
#> Standard, Third Edition (ECMA, 1999). Design of JSON is simple and concise in comparison with other
#> text based formats, and it was originally proposed by Douglas Crockford as a “fat-free alternative to XML”
#> (Crockford, 2006b). The syntax is easy for humans to read and write, easy for machines to parse and generate
#> and completely described in a single page at http://www.json.org. The character encoding of JSON text
#> is always Unicode, using UTF-8 by default (Crockford, 2006a), making it naturally compatible with non-
#> latin alphabets. Over the past years, JSON has become hugely popular on the internet as a general purpose
#> data interchange format. High quality parsing libraries are available for almost any programming language,
#> making it easy to implement systems and applications that exchange data over the network using JSON. For
#> R (R Core Team, 2013), several packages that assist the user in generating, parsing and validating JSON
#> are available through CRAN, including rjson (Couture-Beil, 2013), RJSONIO (Lang, 2013), and jsonlite
#> (Ooms et al., 2014).
#> The emphasis of this paper is not on discussing the JSON format or any particular implementation for using
#> 1
enframe(txt) %>%
rename(page = name) %>%
nest_paragraphs(input = value, width = 100) %>%
head()
#> text
#> 1 The jsonlite Package: A Practical and Consistent Mapping Between JSON Data and R Objects Jeroen Ooms
#> 2 arXiv:1403.2805v1 [stat.CO] 12 Mar 2014 UCLA Department of Statistics Abstract A naive realization
#> 3 of JSON data in R maps JSON arrays to an unnamed list, and JSON objects to a named list. However,
#> 4 in practice a list is an awkward, inefficient type to store and manipulate data. Most statistical
#> 5 applications work with (homogeneous) vectors, matrices or data frames. Therefore JSON packages in
#> 6 R typically define certain special cases of JSON structures which map to simpler R types. Currently
#> page
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#> 5 1
#> 6 1
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