title: How to determine whether a Pandas Column contains a particular value
body: <p>I am trying to determine whether there is an entry in a Pandas column that has a particular value. I tried to do this with <code>if x in df['id']</code>. I thought this was working, except when I fed it a value that I knew was not in the column <code>43 in df['id']</code> it still returned <code>True</code>. When I subset to a data frame only containing entries matching the missing id <code>df[df['id'] == 43]</code> there are, obviously, no entries in it. How to I determine if a column in a Pandas data frame contains a particular value and why doesn't my current method work? (FYI, I have the same problem when I use the implementation in this <a href="https://stackoverflow.com/a/19630449/2327821">answer</a> to a similar question).</p>