.. _exercise_dict_lab:

**********************
Dictionary and Set Lab
**********************

Learning about dictionaries and sets
====================================

Goal:
-----

Learn the basic ins and outs of Python dictionaries and sets.

Procedure
---------

In your student dir in the IntroPython2015 repo, create a ``session04`` dir and put in a new ``dict_lab.py`` file.

The file should be an executable python script. That is to say that one
should be able to run the script directly like so:

.. code-block:: bash

    $ ./dict_lab.py

(At least on OS-X and Linux)

-- you do that with this command:

.. code-block:: bash

  $ chmod +x dict_lab.py

(The +x means make this executable)

.. nextslide::

Add the file to your clone of the repository and commit changes frequently
while working on the following tasks. When you are done, push your changes to
GitHub and issue a pull request.

(if you are struggling with git -- just write the code for now)

When the script is run, it should accomplish the following four series of
actions:

.. nextslide:: Dictionaries 1

* Create a dictionary containing "name", "city", and "cake" for "Chris" from "Seattle" who likes "Chocolate".

* Display the dictionary.

* Delete the entry for "cake".

* Display the dictionary.

* Add an entry for "fruit" with "Mango" and display the dictionary.

  - Display the dictionary keys.
  - Display the dictionary values.
  - Display whether or not "cake" is a key in the dictionary (i.e. False) (now).
  - Display whether or not "Mango" is a value in the dictionary (i.e. True).


.. nextslide:: Dictionaries 2


* Using the dictionary from item 1: Make a dictionary using the same keys but
  with the number of 't's in each value.

.. nextslide:: Sets

* Create sets s2, s3 and s4 that contain numbers from zero through twenty,
  divisible 2, 3 and 4.

* Display the sets.

* Display if s3 is a subset of s2 (False)

* and if s4 is a subset of s2 (True).

.. nextslide:: Sets 2

* Create a set with the letters in 'Python' and add 'i' to the set.

* Create a frozenset with the letters in 'marathon'

* display the union and intersection of the two sets.