title: Define a column type as 'list' in Pandas
body: <p>I have a pandas data frame df. I want df to be composed of 3 columns : the first one is a brand name (a string), the second is a list of integers, and the third one is a list of floats. So for each brand, I have two lists, and I want to put them all in a data frame to access different lists easily based on the brand name.</p>
  
  <p>I have :</p>
  
  <pre><code>count = [1,5,198,0,0,35]
  brand = 'Nike'
  </code></pre>
  
  <p>and to put the count list into the 'count' column corresponding to 'Nike' line I tried the following :</p>
  
  <pre><code>df[df['brand']==brand].loc[0,'count'] = count
  df[df['brand']==brand]['count'] == count
  df[df['brand']==brand]['count'].loc[0] == count
  </code></pre>
  
  <p>None of these would work and I get <code>ValueError: Must have equal len keys and value when setting with an iterable</code> or <code>A value is trying to be set on a copy of a slice from a DataFrame</code> and nothing changes in df.</p>
  
  <p>How can I write a list into a pandas data frame cell ?</p>