pdfsearch (version 0.4.1)

keyword_search: Search a pdf file for keywords

Description

This uses the pdf_text from the pdftools package to perform keyword searches. Keyword locations indicating the line of the text as well as the page number that the keyword is found are returned.

Usage

keyword_search(
  x,
  keyword,
  path = FALSE,
  surround_lines = FALSE,
  ignore_case = FALSE,
  token_results = TRUE,
  heading_search = FALSE,
  heading_args = NULL,
  split_pdf = FALSE,
  blank_lines = TRUE,
  remove_hyphen = TRUE,
  convert_sentence = TRUE,
  remove_equations = FALSE,
  split_pattern = "\\p{WHITE_SPACE}{3,}",
  ...
)

Value

A tibble data frame that contains the keyword, location of match, the line of text match, and optionally the tokens associated with the line of text match.

Arguments

x

Either the text of the pdf read in with the pdftools package or a path for the location of the pdf file.

keyword

The keyword(s) to be used to search in the text. Multiple keywords can be specified with a character vector.

path

An optional path designation for the location of the pdf to be converted to text. The pdftools package is used for this conversion.

surround_lines

numeric/FALSE indicating whether the output should extract the surrounding lines of text in addition to the matching line. Default is FALSE, if not false, include a numeric number that indicates the additional number of surrounding lines that will be extracted.

ignore_case

TRUE/FALSE/vector of TRUE/FALSE, indicating whether the case of the keyword matters. Default is FALSE meaning that case of the keyword is literal. If a vector, must be same length as the keyword vector.

token_results

TRUE/FALSE indicating whether the results text returned should be split into tokens. See the tokenizers package and convert_tokens for more details. Defaults to TRUE.

heading_search

TRUE/FALSE indicating whether to search for headings in the pdf.

heading_args

A list of arguments to pass on to the heading_search function. See heading_search for more details on arguments needed.

split_pdf

TRUE/FALSE indicating whether to split the pdf using white space. This would be most useful with multicolumn pdf files. The split_pdf function attempts to recreate the column layout of the text into a single column starting with the left column and proceeding to the right.

blank_lines

TRUE/FALSE indicating whether blank text lines should be removed. Default is TRUE.

remove_hyphen

TRUE/FALSE indicating whether hyphenated words should be adjusted to combine onto a single line. Default is TRUE.

convert_sentence

TRUE/FALSE indicating if individual lines of PDF file should be collapsed into a single large paragraph to perform keyword searching. Default is TRUE

remove_equations

TRUE/FALSE indicating if equations should be removed. Default behavior is to search for a literal parenthesis, followed by at least one number followed by another parenthesis at the end of the text line. This will not detect other patterns or detect the entire equation if it is a multi-row equation.

split_pattern

Regular expression pattern used to split multicolumn PDF files using stringi::stri_split_regex. Default pattern is to split based on three or more consecutive white space characters.

...

token_function to pass to convert_tokens function.

Examples

file <- system.file('pdf', '1501.00450.pdf', package = 'pdfsearch')

keyword_search(file, keyword = c('repeated measures', 'mixed effects'),
  path = TRUE)
  
# Add surrounding text
keyword_search(file, keyword = c('variance', 'mixed effects'),
  path = TRUE, surround_lines = 1)
  
# split pdf
keyword_search(file, keyword = c('repeated measures', 'mixed effects'),
  path = TRUE, split_pdf = TRUE, remove_hyphen = FALSE)