Reusable codes

NLTK

O'Reilly's textbook in Chapter 2.3:

Can write down source codes from IDLE by menu: File -> New window

Screen Shot 2013-05-03 at 10.40.57 AM

This can be saved as a file with extension ".py".
Then execute via menu: Run -> Run Module

Screen Shot 2013-05-03 at 10.41.18 AM

Defining Functions: Already experienced in previous sections more or less.

>>> def plural(word):
...     if word.endswith('y'):
...             return word[:-1] + 'ies'
...     elif word[-1] in 'sx' or word[-2:] in ['sh', 'ch']:
...             return word + 'es'
...     else:
...             return word + 's'
... 
>>> plural('fairy')
'fairies'
>>> plural('woman')
'women'

How about this?

>>> plural('tooth')
'tooths'

I got a result as same as I expected... No logic is included in the code for foot/feet or tooth/teeth patterns.

Moving forward. Copy the code and save as textproc.py under /Documents/workspace/NLTK Learning. But I felt the place could be slightly uncomfortable. Then I created a new folder scripts under NLTK learning.

Try to import, but ....

>>> from textproc import *
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: No module named textproc

That could be PATH is not set to the current location (scripts). Let's check the sys.path.

>>> import sys
>>> print sys.path
['/Users/xxx/Documents/workspace/NLTK Learning', '/Users/xxx/Documents', '/Library/Python/2.7/site-packages/setuptools-0.6c11-py2.7.egg', '/Library/Python/2.7/site-packages/pip-1.3.1-py2.7.egg', '/Library/Python/2.7/site-packages/ipython-0.13.2-py2.7.egg', '/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python', '/Library/Frameworks/Python.framework/Versions/2.7/lib/python27.zip', '/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7', '/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/plat-darwin', '/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/plat-mac', '/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/plat-mac/lib-scriptpackages', '/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-tk', '/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-old', '/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-dynload', '/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages', '/Library/Python/2.7/site-packages']
>>>

It seems the original location (NLTK learning) is set to the PATH. However, I have moved the file one level lower by Finder. After I thought for a second. I opened the file (textproc.py) from IDLE side then show sys.path again.

>>> import sys
>>> print sys.path
['/Users/xxx/Documents/workspace/NLTK Learning/scripts', '/Users/xxx/Documents', '/Library/Python/2.7/site-packages/setuptools-0.6c11-py2.7.egg', '/Library/Python/2.7/site-packages/pip-1.3.1-py2.7.egg', '/Library/Python/2.7/site-packages/ipython-0.13.2-py2.7.egg', '/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python', '/Library/Frameworks/Python.framework/Versions/2.7/lib/python27.zip', '/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7', '/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/plat-darwin', '/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/plat-mac', '/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/plat-mac/lib-scriptpackages', '/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-tk', '/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-old', '/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-dynload', '/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages', '/Library/Python/2.7/site-packages']
>>>

Yes, the PATH has been updated. Now the system should be able to recognise the new location. 

>>> from textproc import plural
>>> 
>>> plural('wish')
'wishes'
>>> plural('fan')
'fans'
>>>