title: How to find out for each product, how many were sold in Pandas DataFrame
body: <p>I have a pandas dataframe like this:</p>
  <pre><code>      Name Product  Amount
  0      Bob   Apple       1
  1      Bob  Banana       2
  2  Jessica  Orange       3
  3  Jessica  Banana       4
  4  Jessica  Tomato       3
  5     Mary  Banana       2
  6     John   Apple       3
  7     John   Grape       1
  </code></pre>
  <pre><code>import pandas as pd
  
  data = [('Bob','Apple',1), ('Bob','Banana',2), ('Jessica','Orange',3),
        ('Jessica','Banana',4),('Jessica','Tomato',3), ('Mary','Banana',2),
        ('John','Apple',3),('John','Grape',1)]
  
  df = pd.DataFrame(data,columns=['Name','Product','Amount'])
  
  </code></pre>
  <p>What I have done so far:</p>
  <pre><code>l = []
  count=0
  for i in range(0,8):
      row = df.iloc[i]
      
      if row.Product not in l:
          l.append(row.Product)
  
  </code></pre>
  <p>Now, <code>l</code> contains all the unique values in the Product column, but I need the total amount as well.</p>
  <p>How can I find out for each product how many items were sold (for example, 4 units of Apple were sold)?</p>