title: How to check if a value exists in a dictionary?
body: <p>I have the following dictionary in python: </p>
  
  <pre><code>d = {'1': 'one', '3': 'three', '2': 'two', '5': 'five', '4': 'four'}
  </code></pre>
  
  <p>I need a way to find if a value such as "one" or "two" exists in this dictionary.</p>
  
  <p>For example, if I wanted to know if the index "1" existed I would simply have to type: </p>
  
  <pre><code>"1" in d
  </code></pre>
  
  <p>And then python would tell me if that is true or false, however I need to do that same exact thing except to find if a value exists.</p>