Summary totals and running totals

A common need in reports is to provide totals. This can be done using Python expressions to compute those totals.

After the closing tag of the <t t-foreach>,we will add a final row with the totals:

<!-- Totals --> 
<div class="row"> 
  <div class="col-xs-3"> 
    Count: <t t-esc="len(docs)" /> 
  </div> 
  <div class="col-xs-2" /> 
  <div class="col-xs-1"> 
    Total:  
   <t t-esc="sum([o.amount_cost for o in docs])" /> 
  </div> 
  <div class="col-xs-3" /> 
  <div class="col-xs-3" /> 
</div> 

The len() Python statement is used to count the number of elements in a collection. Totals can be computed using sum() value over a list of values. In the example preceding, we use a list comprehension to produce a list of values out of the docs recordset. You can think of list comprehensions like an embedded for loop.

Sometimes...