.. DO NOT EDIT.
.. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY.
.. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE:
.. "auto_examples/basics/while_loops.py"
.. LINE NUMBERS ARE GIVEN BELOW.

.. only:: html

    .. note::
        :class: sphx-glr-download-link-note

        Click :ref:`here <sphx_glr_download_auto_examples_basics_while_loops.py>`
        to download the full example code or to run this example in your browser via Binder

.. rst-class:: sphx-glr-example-title

.. _sphx_glr_auto_examples_basics_while_loops.py:


=================
1.9 while loops
=================
.. important::
  This lesson is still under development.

.. GENERATED FROM PYTHON SOURCE LINES 10-13

Suppose we have a list of names of people who have ruled Pakistan with one name
in it who has not been the ruler and we want to find out at which position the
name of this person is located. One way to solve this problem is to use while loops.

.. GENERATED FROM PYTHON SOURCE LINES 15-27

.. code-block:: default


    looters = ['sikandar mirza', 'ayub khan', 'yahya khan', 'zulfiqar bhutto', 'shahid afridi',
               'zia-ul-haq', 'benazir', 'nawaz sharif', 'musharaf',   'zardari']

    acc_id = 0
    while acc_id<len(looters):   # this condition must become False at some point.
        if looters[acc_id] == 'shahid afridi':
            print('Found a normal person at position', acc_id)
        else:
            print(looters[acc_id], 'was a thug')
        acc_id += 1





.. rst-class:: sphx-glr-script-out

 .. code-block:: none

    sikandar mirza was a thug
    ayub khan was a thug
    yahya khan was a thug
    zulfiqar bhutto was a thug
    Found a normal person at position 4
    zia-ul-haq was a thug
    benazir was a thug
    nawaz sharif was a thug
    musharaf was a thug
    zardari was a thug




.. GENERATED FROM PYTHON SOURCE LINES 28-40

The basic syntax of while statement in python is:

.. code-block:: python

   while (condition):
       do something

The condition after ``while`` must become `False` after some time otherwise the
loop will continue indefinitely. Consider not increasing the value of `acc_id`
in upper example and the print statement will continue forever until we have
to stop it forcefully by terminating the program. (In case you do do this,
you can stop this by going to `Runtime` --> `Interrupt execution`.)

.. GENERATED FROM PYTHON SOURCE LINES 42-51

while with else

.. code-block:: python

 while condition:
   do something
 else:
   do something at last


.. GENERATED FROM PYTHON SOURCE LINES 53-67

.. code-block:: default


    looters = ['sikandar mirza', 'ayub khan', 'yahya khan', 'zulfiqar bhutto', 'shahid afridi',
               'zia-ul-haq', 'benazir', 'nawaz sharif', 'musharaf', 'zardari']

    acc_id = 0
    while acc_id<len(looters):
        if looters[acc_id] == 'shahid afridi':
            print('Found a normal person at position', acc_id)
        else:
            print(looters[acc_id], 'was a thug')
        acc_id += 1
    else:
        print("Search finished from the whole list of 'looters'")





.. rst-class:: sphx-glr-script-out

 .. code-block:: none

    sikandar mirza was a thug
    ayub khan was a thug
    yahya khan was a thug
    zulfiqar bhutto was a thug
    Found a normal person at position 4
    zia-ul-haq was a thug
    benazir was a thug
    nawaz sharif was a thug
    musharaf was a thug
    zardari was a thug
    Search finished from the whole list of 'looters'




.. GENERATED FROM PYTHON SOURCE LINES 68-82

.. code-block:: default


    looters = ['sikandar mirza', 'ayub khan', 'yahya khan', 'zulfiqar bhutto', 'shahid afridi',
               'zia-ul-haq', 'benazir', 'nawaz sharif', 'musharaf', 'zardari']

    acc_id = 0
    while acc_id<len(looters):
        if looters[acc_id] == 'shahid afridi':
            print('Found a normal person at position ', acc_id)
        else:
            print(looters[acc_id], 'was a thug')
        acc_id += 1

    print("Search finished from the whole list of 'looters'")





.. rst-class:: sphx-glr-script-out

 .. code-block:: none

    sikandar mirza was a thug
    ayub khan was a thug
    yahya khan was a thug
    zulfiqar bhutto was a thug
    Found a normal person at position  4
    zia-ul-haq was a thug
    benazir was a thug
    nawaz sharif was a thug
    musharaf was a thug
    zardari was a thug
    Search finished from the whole list of 'looters'




.. GENERATED FROM PYTHON SOURCE LINES 83-85

We may think `what is the use of else statement`? Of course we can achieve same
thing by just placing the code inside `else` statement, without making use of `else`.

.. GENERATED FROM PYTHON SOURCE LINES 87-89

Wouldn't it be better if we just stop the search after we found the thief.
Here comes the benefit of `break` statement along with `else` keyword.

.. GENERATED FROM PYTHON SOURCE LINES 91-106

.. code-block:: default


    looters = ['sikandar mirza', 'ayub khan', 'yahya khan', 'zulfiqar bhutto', 'shahid afridi',
               'zia-ul-haq', 'benazir', 'nawaz sharif', 'musharaf', 'zardari']

    acc_id = 0
    while acc_id<len(looters):
        if looters[acc_id] == 'shahid afridi':
            print('Found a normal person at position', acc_id, '. No need to continue searching anymore')
            break
        else:
            print(looters[acc_id], 'was a thug')
        acc_id += 1
    else:
        print("Search finished from the whole list of 'looters'")





.. rst-class:: sphx-glr-script-out

 .. code-block:: none

    sikandar mirza was a thug
    ayub khan was a thug
    yahya khan was a thug
    zulfiqar bhutto was a thug
    Found a normal person at position 4 . No need to continue searching anymore




.. GENERATED FROM PYTHON SOURCE LINES 107-116

**Question**
What is the output of the following code

.. code-block:: python

   x = 0
   y = 5
   while x+y<10:
       x += 1
       print(x)


.. rst-class:: sphx-glr-timing

   **Total running time of the script:** ( 0 minutes  0.003 seconds)


.. _sphx_glr_download_auto_examples_basics_while_loops.py:

.. only:: html

  .. container:: sphx-glr-footer sphx-glr-footer-example


    .. container:: binder-badge

      .. image:: images/binder_badge_logo.svg
        :target: https://mybinder.org/v2/gh/AtrCheema/python-seekho/master?urlpath=lab/tree/notebooks/auto_examples/basics/while_loops.ipynb
        :alt: Launch binder
        :width: 150 px

    .. container:: sphx-glr-download sphx-glr-download-python

      :download:`Download Python source code: while_loops.py <while_loops.py>`

    .. container:: sphx-glr-download sphx-glr-download-jupyter

      :download:`Download Jupyter notebook: while_loops.ipynb <while_loops.ipynb>`


.. only:: html

 .. rst-class:: sphx-glr-signature

    `Gallery generated by Sphinx-Gallery <https://sphinx-gallery.github.io>`_