NLTK & Python Day 8 LING Computational Linguistics Harry Howard Tulane University

11-Sept-2009LING , Prof. Howard, Tulane University2 Course organization  NLTK should be installed on the computers in this room!

NLPP §2 Accessing text corpora and lexical resources §2.2 Conditional frequency

11-Sept-2009LING , Prof. Howard, Tulane University4 Practice  Do "Your Turn" up to p. 55  Exercises , 2.8.8

NLPP §2 Accessing text corpora and lexical resources §2.3 More Python: Reusing code

11-Sept-2009LING , Prof. Howard, Tulane University6 Creating a program with a text editor  Create the monty.py program.

11-Sept-2009LING , Prof. Howard, Tulane University7 Other IDEs  Eclipse (Java Dev) + Pydev plugin   Mac users should use Cocoa version   Xcode Tools now supports Python  It is part of optional installation on DVD.  You have to register as a developer to download it from

11-Sept-2009LING , Prof. Howard, Tulane University8 Functions  What might you want to put in your program?  Why, a function, of course!  A function takes an input to produce an output or return value: >>> def my_function_name(my_inputs)... # calculate my_output... return my_output...

11-Sept-2009LING , Prof. Howard, Tulane University9 Modules and higher  As you accumulate functions, you will want to store them somewhere.  Save them all in the same text file with the.py suffix, i.e. my_mod.py, called a module and  import them as needed:  from my_mod import my_function_name  Hierarchy  function < module < package < library

NLPP §2 Accessing text corpora and lexical resources §2.4 Lexical resources

11-Sept-2009LING , Prof. Howard, Tulane University11 Lexical resources  What is a lexicon?  a collection of words and/or phrases, sometimes with additional information such as part of speech or meaning  What is a lexical entry?  A headword/lemma, along with that other info saw 1 [verb] past tense of see saw 2 [noun] cutting instrument

11-Sept-2009LING , Prof. Howard, Tulane University12 More corpora  Wordlist corpora  words  Names Corpus  Do ex  CMU Pronouncing Dictionary  Do ex  Comparative wordlists  Swadesh wordlist  Shoebox/Toolbox

NLPP §2 Accessing text corpora and lexical resources §2.5 WordNet

11-Sept-2009LING , Prof. Howard, Tulane University14 Semantic relations  Synonym  Synonyms are grouped into synsets in WordNet  look at code  Do Your turn

Next time Q/P2 Do two of Ex Start NLPP §3