title: Filtering by frequency of observations per ID, for each month and each day - Pandas
body: <p>I'm trying to filter my data frame [includes IDs, dates, time (these are the indexes) and other variables (no matter which)].</p>
  
  <p>I want to filter the data frame by the frequency of the observations per ID, for each month and each day.</p>
  
  <p>It means that, I want to stay with IDs that have at least 10 obs. <strong>every</strong> month, <strong>and</strong> at least 5 obs. <strong>every</strong> day, and to exclude those who don't meet the conditions.</p>
  
  <p>Data illustration:</p>
  
  <pre><code>ID  date        time x  y
  a   07/27/2019  ..  ..  ..
                  ..  ..  ..
                  ..  ..  ..
      08/27/2019  ..  ..  ..
                  ..  ..  ..
                  ..  ..  ..
                  ..  ..  ..
                  ..  ..  ..
                  ..  ..  ..
  b   06/28/2019  ..  ..  ..
                  ..  ..  ..
                  ..  ..  ..
                  ..  ..  ..
                  ..  ..  ..
                  ..  ..  ..
      07/30/2019  ..  ..  ..
                  ..  ..  ..
                  ..  ..  ..
                  ..  ..  ..
                  ..  ..  ..
                  ..  ..  ..
                  ..  ..  ..
                  ..  ..  ..
  </code></pre>