title: Error with rvest - NAs introduced by coercion (xpath & css)
body: <p>I'm attempting to scrape a website and collect the daily prices for various articles of clothing over an extended period.  I've followed the tutorial on RStudio's blog but I am unable to replicate the idea on the test set despite using SelectorGadget.  I've tried the follow code still receive NAs:</p>
  
  <pre><code>url&lt;- "https://www.zara.com/us/en/authentic-jeans-p00840407.html?v1=9035594&amp;v2=1204074"
  
      jeans &lt;- url %&gt;%
        read_html() %&gt;%
        html_nodes(".description , .product-price span") %&gt;%
        html_text() %&gt;%
        as.numeric()
  </code></pre>
  
  <p>I've also attempting to use the xpath format and still no luck: </p>
  
  <pre><code>jeans &lt;- url %&gt;%
    read_html() %&gt;%
    html_nodes(xpath = '//*[contains(concat( " ", @class, " " ), concat( " ", "product-price", " " ))]') %&gt;%
    html_text() %&gt;%
    as.numeric()
  </code></pre>
  
  <p>I'd greatly appreciate any insight you might share - and would <strong>really</strong> appreciate it if you passed along any resources that details how to build a database over time from pulled data / or how to batch rvest webscrape requests!</p>
  
  <p>Thank you! </p>