title: How do I extract all the values of a specific key from a list of dictionaries?
body: <p>I have a list of dictionaries that all have the same structure within the list.  For example:</p>
  
  <pre><code>test_data = [{'id':1, 'value':'one'}, {'id':2, 'value':'two'}, {'id':3, 'value':'three'}]
  </code></pre>
  
  <p>I want to get each of the <code>value</code> items from each dictionary in the list:</p>
  
  <pre><code>['one', 'two', 'three']
  </code></pre>
  
  <p>I can of course iterate through the list and extract each value using a for loop:</p>
  
  <pre><code>results = []
  for item in test_data:
      results.append(item['value'])
  </code></pre>
  
  <p>however my data set is quite large.  I'm wondering if there's a faster way to this.</p>