#2-淘宝--指定url####
  tb <- 'https://s.taobao.com/search?q=折叠雨伞&commend=all&ssid=s5-e&search_type=item&sourceId=tb.index&spm=a21bo.2017.201856-taobao-item.1&ie=utf8&initiative_id=tbindexz_20170306'

#读取html代码 ####
  web <- read_html(tb,encoding = 'UTF-8')
  web

#获取标题
  title_all <- web %>%
    html_nodes( ' /html/body/div[1]/div[2]/div[3]/div[1]/div[21]/div/div/div[1]/div[1]/div[2] ') %>%
    html_text()

错误：
Error in tokenize(css) : Unexpected character '/' found at position 2