========================
Data type: Lists & while
========================

.. _lists:

.. index:: list, lists, data type: list

.. |a| image:: /images/all/python-basics/square_brackets-100.png
   :width: 100px

Objectives
==========
   
.. tabularcolumns:: | c | l |
   :border: none

+-------+-------------------------------------------------------------------------+
|  |a|  | Introduction to the datatype *list*.                                    |
|       |                                                                         |
+-------+-------------------------------------------------------------------------+

Instructions
============
:Tasks:

1. Discover the methods a list supports. Use the command *dir([])* at the command line.
2. Create a list with things available in your environment.
3. Print some elements or all from your list.

Properties
==========

The essential properties of a list are: 

- Square brackets - the external indicator if parts of list are used. 
- A list can accommodate a wide variety of object types, for example, Strings, numbers ...
- She has a variety of methods to manage the list items. 

For more information about lists, have a look at: `Built-in Types <https://docs.python.org/3/library/stdtypes.html#list>`_

Repetition with while 
----------------------
With a while loop, you can reach the same results as with the for loop!
A termination condition leads to the end of the loop or to a premature demolition.

::

  L1 = []  # empty List
  L2 = ['The', 'brave', 'tailor', 'hit', 7, 'on', 'a', 'string'] 
  print(L2[0], L2[1], L2[2], L2[3], L2[4], L2[5], L2[6], L2[7])
  i = 0
  while i < len(L2):
      print(L2[i])
      i = i + 1           # The variable i must Modify the value,
                          # Otherwise it will loop indefinitely !!


  L2.reverse()
  print(L2)

With the slicing operator further sub output can be realized. 

See also:  :ref:`Slicing <slicing>`