Home Accessibility Courses Twitter The Mouth Facebook Resources Site Map About Us Contact
Method, Class, Module, Package - how to they relate in Python?

A file containing a number of python methods and classes is known as a module. In the simplest of cases, it mighy just contain one class.

A directory containing a number of python modules is known as a package. In the simplest of cases, it may just contain one module.

Here's a sample program that loads a class (or two) from within a module from within a package:

  import bundle.thing
  iHave = bundle.thing.matchbox("catapillar")
  print(iHave)


In Python 2, you are required to mark a package as being a package by having a file called __init__.py in the directory. This was described as being necessary to avoic confusion between module names if your package contained modules of the same name as standard modules. Failure to provide the file results in:

  WomanWithCat:flask grahamellis$ python bundemo
  Traceback (most recent call last):
    File "bundemo", line 2, in <module>
      import bundle.thing
  ImportError: No module named bundle.thing
  WomanWithCat:flask grahamellis$


In Python 3 there is no such requirement for a __init__.py file:

  WomanWithCat:flask grahamellis$ python3 bundemo
  A Matchbox containing catapillar
  WomanWithCat:flask grahamellis$


Although not needed in Python 3, both versions support the file whichc also allows the specificiation of code to be run on load, and allows you to define a __all__ variable which controls what you load when you import or from *.

Files in this demo:
Demo program using package
Python module to go within package

(written 2015-10-17)

 
Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articles
Y103 - Python - Conditionals and Loops
  [4723] Conditional operators in Python - (2016-11-05)
  [4713] Equality (in Python) - (2016-10-30)
  [4541] Setting up and tearing down with the Python with keyword - (2015-10-16)
  [4402] Finding sum, minimum, maximum and average in Python (and Ruby) - (2015-01-19)
  [4323] Learning to program - Loop statements such as while - (2014-11-22)
  [4322] Learning to Program - the conditional statement (if) - (2014-11-21)
  [4210] If elif elif elif - multiway selection in Python - (2013-11-16)
  [4092] Identity in Python - (2013-05-17)
  [3895] Flowchart to program - learning to program with Well House - (2012-10-14)
  [3762] Learning to program - the if statement. Python. - (2012-06-12)
  [3620] Finding the total, average, minimum and maximum in a program - (2012-02-22)
  [3558] Python or Lua - which should I use / learn? - (2011-12-21)
  [3439] Python for loops - applying a temporary second name to the same object - (2011-09-14)
  [3397] Does a for loop evaluate its end condition once, or on every iteration? - (2011-08-18)
  [3200] How a for loop works Java, Perl and other languages - (2011-03-12)
  [3083] Python - fresh examples from recent courses - (2010-12-11)
  [2899] Groupsave tickets - 3 or 4 train tickets for the price of 2 - (2010-08-02)
  [2778] Learning to program in Python 2 ... and / or in Python 3 - (2010-05-24)
  [1696] Saying NOT in Perl, PHP, Python, Lua ... - (2008-07-04)
  [1661] Equality, sameness and identity - Python - (2008-05-31)
  [1477] Decisions - small ones, or big ones? - (2007-12-18)
  [1201] No switch in Python - (2007-05-23)
  [909] Python is like a narrowboat - (2006-10-30)
  [835] Python - when to use the in operator - (2006-08-16)
  [788] New - Conditional expressions in Python 2.5 - (2006-07-01)
  [668] Python - block insets help with documentation - (2006-04-04)
  [657] The ternary operator in Python - (2006-03-25)
  [353] Wimbledon Neck - (2005-06-20)
  [299] What - no switch or case statement? - (2005-05-03)


Back to
RSpec - Ruby testing (stand alone example / no cucumber)
Previous and next
or
Horse's mouth home
Forward to
Is the RUH hopper a limited, duplicate service running unnecessarily and at high cost?
Some other Articles
Clarrissa-Marybelle - too long to really fit?
Melksham - two small townships, or one big one?
RUH Hopper - experience and thoughts forward
Is the RUH hopper a limited, duplicate service running unnecessarily and at high cost?
Method, Class, Module, Package - how to they relate in Python?
RSpec - Ruby testing (stand alone example / no cucumber)
Saturday morning at Well House Manor
The principle of mocking - and the Python Mock package
Unittest of a Flask application including forms
4738 posts, page by page
Link to page ... 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95 at 50 posts per page


This is a page archived from The Horse's Mouth at http://www.wellho.net/horse/ - the diary and writings of Graham Ellis. Every attempt was made to provide current information at the time the page was written, but things do move forward in our business - new software releases, price changes, new techniques. Please check back via our main site for current courses, prices, versions, etc - any mention of a price in "The Horse's Mouth" cannot be taken as an offer to supply at that price.

Link to Ezine home page (for reading).
Link to Blogging home page (to add comments).

You can Add a comment or ranking to this page

© WELL HOUSE CONSULTANTS LTD., 2017: 404 The Spa • Melksham, Wiltshire • United Kingdom • SN12 6QL
PH: 01144 1225 708225 • EMAIL: info@wellho.net • WEB: http://www.wellho.net • SKYPE: wellho

PAGE: http://www.wellho.net/mouth/4545_Met ... thon-.html • PAGE BUILT: Sat May 27 16:49:10 2017 • BUILD SYSTEM: WomanWithCat