title: groupby not grouping string together eventhough they are exactly same
body: <p>groupby has always worked for me, but in the Dataframe I am dealing with I have a column named &quot;ID&quot; which has the id and &quot;text&quot; which holds the text for each page of a fax:</p>
  <pre><code> ID                       text                  page
  
  210128_ABC8476583   |     text for page 1    |     1  
  210128_ABC8476583   |     text for page 2    |     2
  210128_ABC8476583   |     text for page 3    |     3
  210128_ABC8476583   |     text for page 4    |     4
  210324_ABC9476037   |     text for page 1    |     1
  .....
  </code></pre>
  <p>I am trying to do a simple <code>df.groupby(&quot;ID&quot;)</code> but it basically returns the exact same dataframe(no grouping of similar IDs). the ID and text are of type &quot;String&quot; and page is &quot;<code>numpy.int64</code>&quot;. I am not getting any errors and the result is a <code>pandas.core.groupby.generic.DataFrameGroupBy</code></p>
  <p>my code is something like this:</p>
  <pre><code>id_test = ids.groupby(&quot;ID&quot;)
  id_test[[&quot;ID&quot;, &quot;text&quot;, &quot;page&quot;]].head()
  </code></pre>
  <p>what am I doing wrong?</p>
  <p>*ids is the name of the dataframe I am working with</p>