divide.txt

=====================
$divide (aggregation)
=====================

.. default-domain:: mongodb

.. contents:: On this page
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   :class: singlecol

Definition
----------

.. expression:: $divide

   Divides one number by another and returns the result. Pass the
   arguments to :expression:`$divide` in an array.

   The :expression:`$divide` expression has the following syntax:

   .. code-block:: javascript

      { $divide: [ <expression1>, <expression2> ] }

   The first argument is the dividend, and the second argument is the
   divisor; i.e. the first argument is divided by the second argument.

   The arguments can be any valid :ref:`expression
   <aggregation-expressions>` as long as they resolve to numbers. For
   more information on expressions, see :ref:`aggregation-expressions`.

Examples
--------

Consider a ``conferencePlanning`` collection with the following documents:

.. code-block:: javascript

   db.conferencePlanning.insertMany( [
      { "_id" : 1, "city" : "New York", "hours" : 80, "tasks" : 7 },
      { "_id" : 2, "city" : "Singapore", "hours" : 40, "tasks" : 4 }
   ] )


The following aggregation uses the :expression:`$divide` expression to
divide the ``hours`` field by a literal ``8`` to compute the number of
work days:

.. code-block:: javascript

   db.planning.aggregate(
      [
        { $project: { city: 1, workdays: { $divide: [ "$hours", 8 ] } } }
      ]
   )

The operation returns the following results:

.. code-block:: javascript
   :copyable: false

   { "_id" : 1, "city" : "New York", "workdays" : 10 }
   { "_id" : 2, "city" : "Singapore", "workdays" : 5 }