if key, value pair exist in a dictionary skip python
<p>I have two variables that I want to add to a dictionary using <code>collections.defaultdict(list)</code>
Here are the two variables:</p>

<pre><code>score = [0, 5, 7, 7, 8, 7]
match = ['turtle', 'cat', 'horse', 'horse', 'dog', 'bear']
</code></pre>

<p>What I would like to do is to remove the key/value pairs that are already in the dictionary. Right now I am creating my dictionary using this method:</p>

<pre><code>  scoring = collections.defaultdict(list)
  scoring[score].append(match)
</code></pre>

<p>However, this method gives me a dictionary like so:</p>

<pre><code>dictionary = {0: ['turtle'], 5: ['cat'], 7: ['horse', 'horse', 'bear'], 8: ['dog']}
</code></pre>

<p>However, I only want horse to appear in the dictionary once. Is there anyway to prevent the additional of an identical key/value pair in a dictionary this way?</p>