Count all categories in pandas data frame and add their values
<p>I've got a data frame that looks something along these lines:</p>

<pre><code>           Dog_breed       Dog_name             Points 
      ============================================================
Monday        Pug            George               12
Tuesday       Poodle         Fido                -15
Wednesday     Pug            Buddy                 8
Thursday      Dachshund      Lyla                -10
Friday        Poodle         Remi                  9
Saturday      Pug            Kermit               -5
Sunday        Beagle         Sara                  3
</code></pre>

<p>For every breed of dog (i.e., category), I need to get the sum of the points — for some rows, it's positive, and for some, it's negative — and the number of dogs of that breed. </p>

<p>The goal is to add up all the points for each breed, count the number of times each breed occurs in the original data set, and end up with a data frame that looks like this:</p>

<pre><code>             Quantity     Overall_point_change
          ============================================
Pug             3                  15
Poodle          2                  -6
Dachshund       1                 -10
Beagle          1                   3
</code></pre>

<p>Can pandas do this, or does it require a loop? Really struggling to wrap my head around this — can anyone recommend a way to set this up?</p>