title: Pandas: how to increment a column's cell value based on a list of ids
body: <p>I have a list of ids that correspond to the row of a data frame. From that list of ids, I want to increment a value of another column that intersects with that id's row.</p>
  
  <p>What I was thinking was something like this:</p>
  
  <pre><code>ids = [1,2,3,4]
  
  for id in ids:
      my_df.loc[my_df['id']] == id]['other_column'] += 1
  </code></pre>
  
  <p>But this doesn't work. How can I mutate the original df, <code>my_df</code>?</p>