title: Build a data frame in R from a series of JSON files
body: <p>I'm trying to build a data frame from a series of API calls. Each call returns some JSON, like this:</p>
  
  <pre><code>{"ip":"83.108.241.206","country_code":"NO","country_name":"Norway","region_code":"15","region_name":"Sogn og Fjordane","city":"Ã˜vre Ã…rdal","zipcode":"6884","latitude":61.3167,"longitude":7.8,"metro_code":"","area_code":""}
  </code></pre>
  
  <p>I would like to compile a bunch of these calls into a data frame, with columns "ip", "country code", etc. But I'm having trouble efficiently getting each file into a form I can call rbind on.</p>
  
  <p>I'm using a vector of URLs to make the API calls, like this:</p>
  
  <pre><code>&gt; urls &lt;- c("http://freegeoip.net/json/83.108.241.206", "http://freegeoip.net/json/129.118.15.107","http://freegeoip.net/json/189.144.59.71", "http://freegeoip.net/json/24.106.181.190", "http://freegeoip.net/json/213.226.181.3", "http://freegeoip.net/json/84.1.204.89")
  
  &gt; urls
  [1] "http://freegeoip.net/json/83.108.241.206"
  [2] "http://freegeoip.net/json/129.118.15.107"
  [3] "http://freegeoip.net/json/189.144.59.71" 
  [4] "http://freegeoip.net/json/24.106.181.190"
  [5] "http://freegeoip.net/json/213.226.181.3" 
  [6] "http://freegeoip.net/json/84.1.204.89" 
  </code></pre>
  
  <p>What's the best way to get from URL to JSON to data frame?</p>