The document describes a Python Object Oriented Programming session that covers using the Eclipse IDE and PyDev plugin to create Python projects, packages, and modules. It provides instructions for setting up a project structure with the CLTL group's packages and assigning a task to create specific modules and functions within that structure.

1. CLTL Python Course
Object Oriented Programming in Python
3rd session
May 15th 2013

2. Reminders
● Session I
– What is Object Oriented Programming
– Classes, objects, methods, properties...
– How to define classes, with methods and attributes
– How to create objects
● Session II
– Create modules
– Create packages
– Reuse and import

3. Session 3
● Eclipse and PyDev
– Use python within eclipse
– Create projects
– Create packages
– Create modules
– ...

4. Eclipse and PyDev
1)Create a PyDev project
Will contain all the structure, folders and information of the project
2)Create a source folder in the project
Required for creating modules and packages
3)Create packages
You already know python packages
4)Create modules
You also know python modules

5. Creating a PyDev project
● File > new > project > PyDev > PyDev Project
● Project name: the name of the project
● Project contents: the folder to locate the project
● Project type: usually Python
● Grammar version: the python grammar version (not
important)
● Interpreter: which python you want use to run the project
● Create default 'src' folder
● Referenced projects: their source folders are added to the
PYTHONPATH for the new project

6. Creating a source folder
● Required in PyDev for creating packages and modules
– For every new package/module, an existing source folder
must be selected
● Two ways of creating (if you didn't create it with the PyDev
project)
– File -> new -> source folder Browse and select the
project (the name will be always 'src')
– Right click on the project -> new -> Source folder (you
can select the name of the folder)

7. Creating a Python package
● Python package:
– A special folder where group python modules
– There is a special module __init__.py
– It will be seen as a whole package
● How to create packages:
– File -> new -> python package. Select source folder and
name
– Right click on the project / source folder -> new python
package
● How to nest packages:
– Drag/drop on the pydev package explorer
– By the “dotted” name --> root.nested

8. Creating a Python module
● Python module: a python file that can contain functions, classes...
● In PyDev a python module can be associated to:
– A source folder
– A python package
● How to create modules:
– File -> new -> python module. Select source folder (leave
package empty) or package, module name and template
– Right click on source folder/package on explorer -> new python
module
● Pydev modules templates:
– Empty: just an empty file
– Class: contains the basic definition for a class
– Main: contains the basic definition of a main python script (you
can run it)

9. How to run a module in PyDev
● Option 1
– Select the module and make it active
– Run --> Run As --> Python run
● Option 2
– Right click on the module on the explorer
– Run --> Run as --> python run
● Advanced:
– Breakpoints, debugging...

10. Assignment
We want to develop some python packages for different
projects of the CLTL group, so we should create a nice
structure of packages and modules.
● We have only a main group (CLTL)
● There are several projects going on: newsreader, opener,
semantics_of_history, each one could be a package
● In each project we will developed different tools...
● Each tool will process different data, different files...
● ....

11. Assignment
● Define a project called my_cltl_project with a source folder
● This package structure
● Cltl (pkg)
– Newsreader (pkg)
– Opener (pkg)
– semantics_of_history (pkg)
● coreference_tool (pkg)
– metrics: B3.py, MUC.py (mods)
– data: coref_set.py (mods)
– io: coref_set_reader.py, coref_set_writer.py,
csv_reader.py (mods)
– Common (pkg)
● time_functions (mod)

12. Assignment
● In time_functions.py implement a function called get_time()
that returns a string with the current time (check python
module time)
● In csv_reader.py implement a function read_csv(path) that
takes as input the path of a file, which is CSV comma
separated, and prints each line reversed
a,b,c,d,e --> e,d,c,b,a
1,ruben,2,canito --> canito,2,ruben,1
(check split and list slicing and indexing)
● Created another project
– with a main python module at least
– Import the required stuff from the project cltl and call
to the functions get_time() and read_csv(path)