=================
Librería estándar
=================

.. Repasar los módulos de la librería y estándar y explicar el uso de los más
   comunes para poder usarlos para resolver problemas. Explicar como se
   empaquetan e instalan módulos propios para poder distribuirlos e instalarlos
   en producción. Duración 6 horas

Librería estándar
=================

Documentación
-------------

http://docs.python.org/3/library/index.html

Módulo sys
==========

Ejercicio: cat
--------------

.. code::

    $ ./cat.py file.txt
    This is the first line of the file
    ...
    This is the last one

Pistas: ``sys.stdout``

Ejercicio: grep
---------------

.. code::

    $ ./grep.py string file.txt
    ...string...

Pistas: ``sys.argv``, ``open()``

Opcional:

- Especificar número de línea. Pista: ``enumerate()``

  .. code::

      $ ./grep.py string file.txt
      Line 3: ...string...

Ejercicio: tee
--------------

.. code::

    $ cat.py file.txt | tee.py file2.txt
    This is the first line of the file
    ...
    This is the last one

Pistas: ``sys.stdin``

Módulo random
=============

Ejercicio: dice
---------------

.. code::

    $ ./dice.py
    5

Pistas: ``random.randint``

Módulos pathlib
===============

Ejercicio: find
---------------

.. code::

    $ ./find.py path pattern
    dir1/dir2/pattern.extension
    dira/xxxpattern.extension

Pista: ``pathlib.Path.iterdir()`` o ``pathlib.Path.glob()``

=========== =================================================== ======== ================ ============
Comodín     Resultado                                           Ejemplo  Encuentra        No encuentra
=========== =================================================== ======== ================ ============
``*``       Cualquier conjunto de caracteres incluido _ninguno_ ca*      ca, carro, casta caca
``?``       Cualquier carácter incluido                         ?oz      coz, hoz         oz, coza
``[abc]``   Alguno de los caracteres incluido en el conjunto    no[ae]   noa, noe         noi
``[a-z]``   Alguno de los caracteres incluido en el rango       199[2-6] 1993, 1995, 1996 1991, 1997
=========== =================================================== ======== ================ ============

Módulo argparse
===============

Ejercicio: -h/--help y --type
-----------------------------

.. code::

    $ ./find.py -h
    Usage: find.py [-h] [--type=EXT] pattern

    Buscar archivos.

    positional arguments:
      pattern

    optional arguments:
      -h, --help  show this help message and exit
      --type EXT  search EXT files


Pista: ``argparse``

Módulo re
=========

Ejercicio: *Semantic Versioning*
--------------------------------

.. code:: python

    >>> assert parse_semver('1.0.11') == (1, 0, 11, None, None)
    >>> assert parse_semver('1.7.1-rc.1') == (1, 7, 1, 'rc.1', None)
    >>> assert parse_semver('3.14.7-100+x86_64') == (1, 0, 11, '100', 'x86_64')

Pista:

.. code:: python

    import re

    REGEX = re.compile(
        '^(?P<major>(?:0|[1-9][0-9]*))'
        '\.(?P<minor>(?:0|[1-9][0-9]*))'
        '\.(?P<patch>(?:0|[1-9][0-9]*))'
        '(\-(?P<prerelease>[0-9A-Za-z-]+(\.[0-9A-Za-z-]+)*))?'
        '(\+(?P<build>[0-9A-Za-z-]+(\.[0-9A-Za-z-]+)*))?$'
    )

Módulo datetime
===============

Ejercicio: cumpleaños
---------------------

.. code::

    $ ./age.py
    Fecha de nacimiento> 01-01-1970
    Día de la semana: jueves
    Edad: 50 años, 0 meses y 1 días

Pistas: ``input()``, ``calendar.weekday()`` y ``datetime.date.today()``

Ejercicio: cumpleaños (2)
-------------------------

Opcional:

- Procesa esta tabla y calcula constelación

.. doctest::

    Aries       19 April – 13 May
    Taurus      14 May – 19 June
    Gemini      20 June – 20 July
    Cancer      21 July – 9 August
    Leo         10 August – 15 September
    Virgo       16 September – 30 October
    Libra       31 October – 22 November
    Scorpius    23 November – 29 November
    Ophiuchus   30 November – 17 December
    Sagittarius 18 December – 18 January
    Capricornus 19 January – 15 February
    Aquarius    16 February – 11 March
    Pisces      12 March – 18 April

Pistas: ``.split()``

Python Database API Specification (PEP249_): ejemplo módulo  sqlite3
====================================================================

.. _PEP249: http://www.python.org/dev/peps/pep-0249/

Demo: SQLite (1)
----------------

.. doctest:: python

    >>> import sqlite3
    >>> conn = sqlite3.connect(':memory:')
    >>> c = conn.cursor()

.. doctest:: python

    >>> # Create table
    >>> c.execute('''CREATE TABLE stocks
    ...              (date text, trans text, symbol text, qty real, price real)''')
    <sqlite3.Cursor object at 0x...>

.. doctest:: python

    >>> # Insert a row of data
    >>> c.execute("INSERT INTO stocks VALUES ('2006-01-05','BUY','RHAT',100,35.14)")
    <sqlite3.Cursor object at 0x...>

.. doctest:: python

    >>> # Save (commit) the changes
    >>> conn.commit()

Demo: SQLite (2)
----------------

.. doctest:: python

    >>> # Placeholder to avoid sql injection
    >>> t = ('RHAT',)
    >>> c.execute('SELECT * FROM stocks WHERE symbol=?', t)
    <sqlite3.Cursor object at 0x...>
    >>> print(c.fetchone())
    ('2006-01-05', 'BUY', 'RHAT', 100.0, 35.14)

.. doctest:: python

    >>> # Larger example that inserts many records at a time
    >>> purchases = [('2006-03-28', 'BUY', 'IBM', 1000, 45.00),
    ...              ('2006-04-05', 'BUY', 'MSFT', 1000, 72.00),
    ...              ('2006-04-06', 'SELL', 'IBM', 500, 53.00),
    ...             ]
    >>> c.executemany('INSERT INTO stocks VALUES (?,?,?,?,?)', purchases)
    <sqlite3.Cursor object at 0x...>

Demo: SQLite (3)
----------------

.. doctest:: python

    >>> # Iterator form
    >>> for row in c.execute('SELECT * FROM stocks ORDER BY price'):
    ...     print(row)
    ...
    ...
    ('2006-01-05', 'BUY', 'RHAT', 100.0, 35.14)
    ('2006-03-28', 'BUY', 'IBM', 1000.0, 45.0)
    ('2006-04-06', 'SELL', 'IBM', 500.0, 53.0)
    ('2006-04-05', 'BUY', 'MSFT', 1000.0, 72.0)

Módulo subprocess
=================

Demo: Ejecuta programas externos
--------------------------------

Ejecuta el comando `git pull` para actualizar el repositorio.

.. doctest:: python

    import sys
    import subprocess

    args = ['git', 'pull']

    with subprocess.Popen(args, stdout=subprocess.PIPE, stderr=subprocess.STDOUT) as process:
        for line in process.stdout:
            text = str(line, encoding=sys.stdout.encoding)
            sys.stdout.write(text)

    if not process.returncode == 0:
        print('ERROR')