改善在R中从Google获取股票新闻数据的功能

 getNews <- function(symbol, number){

    # Warn about length
    if (number>300) {
        warning(\"May only get 300 stories from google\")
    }

    # load libraries
    require(XML); require(plyr); require(stringr); require(lubridate);
    require(xts); require(RDSTK)

    # construct url to news feed rss and encode it correctly
    url.b1 = \'http://www.google.com/finance/company_news?q=\'
    url    = paste(url.b1, symbol, \'&output=rss\', \"&start=\", 1,
               \"&num=\", number, sep = \'\')
    url    = URLencode(url)

    # parse xml tree, get item nodes, extract data and return data frame
    doc   = xmlTreeParse(url, useInternalNodes = TRUE)
    nodes = getNodeSet(doc, \"//item\")
    mydf  = ldply(nodes, as.data.frame(xmlToList))

    # clean up names of data frame
    names(mydf) = str_replace_all(names(mydf), \"value\\\\.\", \"\")

    # convert pubDate to date-time object and convert time zone
    pubDate = strptime(mydf$pubDate, 
                     format = \'%a, %d %b %Y %H:%M:%S\', tz = \'GMT\')
    pubDate = with_tz(pubDate, tz = \'America/New_york\')
    mydf$pubDate = NULL

    #Parse the description field
    mydf$description <- as.character(mydf$description)
    parseDescription <- function(x) {
        out <- html2text(x)$text
        out <- strsplit(out,\'\\n|--\')[[1]]

        #Find Lead
        TextLength <- sapply(out,nchar)
        Lead <- out[TextLength==max(TextLength)]

        #Find Site
        Site <- out[3]

        #Return cleaned fields
        out <- c(Site,Lead)
        names(out) <- c(\'Site\',\'Lead\')
        out
    }
    description <- lapply(mydf$description,parseDescription)
    description <- do.call(rbind,description)
    mydf <- cbind(mydf,description)

    #Format as XTS object
    mydf = xts(mydf,order.by=pubDate)

    # drop Extra attributes that we don\'t use yet
    mydf$guid.text = mydf$guid..attrs = mydf$description = mydf$link = NULL
    return(mydf) 

}