Created
August 13, 2018 13:45
-
-
Save pradeepkumargali/6caefbe8b88b65f40a55239e92acec5b to your computer and use it in GitHub Desktop.
HTML to Text in R
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
# Author: Tony Breyal | |
# Date: 2011-11-18 | |
# Modified: 2011-11-18 | |
# Description: Extracts all text from a webpage (aims to extract only the text you would see in a web browser) | |
# Packages Used: RCurl, XML | |
# Blog Reference: Not published | |
# Copyright (c) 2011, under the Creative Commons Attribution-NonCommercial 3.0 Unported (CC BY-NC 3.0) License | |
# For more information see: https://creativecommons.org/licenses/by-nc/3.0/ | |
# All rights reserved. | |
htmlToText <- function(input, ...) { | |
###---PACKAGES ---### | |
require(RCurl) | |
require(XML) | |
###--- LOCAL FUNCTIONS ---### | |
# Determine how to grab html for a single input element | |
evaluate_input <- function(input) { | |
# if input is a .html file | |
if(file.exists(input)) { | |
char.vec <- readLines(input, warn = FALSE) | |
return(paste(char.vec, collapse = "")) | |
} | |
# if input is html text | |
if(grepl("</html>", input, fixed = TRUE)) return(input) | |
# if input is a URL, probably should use a regex here instead? | |
if(!grepl(" ", input)) { | |
# downolad SSL certificate in case of https problem | |
if(!file.exists("cacert.perm")) download.file(url="http://curl.haxx.se/ca/cacert.pem", destfile="cacert.perm") | |
return(getURL(input, followlocation = TRUE, cainfo = "cacert.perm")) | |
} | |
# return NULL if none of the conditions above apply | |
return(NULL) | |
} | |
# convert HTML to plain text | |
convert_html_to_text <- function(html) { | |
doc <- htmlParse(html, asText = TRUE) | |
text <- xpathSApply(doc, "//text()[not(ancestor::script)][not(ancestor::style)][not(ancestor::noscript)][not(ancestor::form)]", xmlValue) | |
return(text) | |
} | |
# format text vector into one character string | |
collapse_text <- function(txt) { | |
return(paste(txt, collapse = " ")) | |
} | |
###--- MAIN ---### | |
# STEP 1: Evaluate input | |
html.list <- lapply(input, evaluate_input) | |
# STEP 2: Extract text from HTML | |
text.list <- lapply(html.list, convert_html_to_text) | |
# STEP 3: Return text | |
text.vector <- sapply(text.list, collapse_text) | |
return(text.vector) | |
} | |
# ###--- EXAMPLES ---### | |
# # Example 1: url input | |
# input <- "http://www.google.co.uk/search?gcx=c&sourceid=chrome&ie=UTF-8&q=r+project#pq=%22hello+%3C+world%22&hl=en&cp=5&gs_id=3r&xhr=t&q=phd+comics&pf=p&sclient=psy-ab&source=hp&pbx=1&oq=phd+c&aq=0&aqi=g4&aql=&gs_sm=&gs_upl=&bav=on.2,or.r_gc.r_pw.r_cp.,cf.osb&fp=27ff09b2758eb4df&biw=1599&bih=904" | |
# txt <- htmlToText(input) | |
# txt | |
# | |
# #r project - Google Search Web Images Videos Maps News Shopping Gmail More Translate Books Finance Scholar Blogs YouTube Calendar Photos Documents Sites Groups Reader Even more » Account Options Sign in Search settings Web History Advanced Search Results 1 - 10 of about 336,000,000 for r project . Everything More Search Options Show options... Web The R Project for Statistical Computing R , also called GNU S, is a strongly functional language and environment to statistically explore data sets, make many graphical displays of data from custom ... www. r - project .org/ - Cached - Similar [Trunc...] |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment