Files
exercises-in-programming-style/14-bulletin-board/tf-14.py

118 lines
3.6 KiB
Python
Executable File

#!/usr/bin/env python
import sys, re, operator, string
#
# The event management substrate
#
class EventManager:
def __init__(self):
self._subscriptions = {}
def subscribe(self, event_type, handler):
if event_type in self._subscriptions:
self._subscriptions[event_type].append(handler)
else:
self._subscriptions[event_type] = [handler]
def publish(self, event):
event_type = event[0]
if event_type in self._subscriptions:
for h in self._subscriptions[event_type]:
h(event)
#
# The "agents"
#
class DataStorage:
""" Models the contents of the file """
def __init__(self, event_manager):
self._event_manager = event_manager
self._event_manager.subscribe('load', self.load)
self._event_manager.subscribe('start', self.produce_words)
def load(self, event):
path_to_file = event[1]
f = open(path_to_file)
self._data = f.read()
f.close()
self.__filter_chars_normalize()
def __filter_chars_normalize(self):
"""
Takes a string and returns a copy with all nonalphanumeric chars
replaced by white space
"""
pattern = re.compile('[\W_]+')
self._data = pattern.sub(' ', self._data).lower()
def produce_words(self, event):
""" Yields the list words in storage, one word at a time """
data_str = ''.join(self._data)
for w in data_str.split():
self._event_manager.publish(('word', w))
self._event_manager.publish(('eof', None))
class StopWordFilter:
""" Models the stop word filter """
def __init__(self, event_manager):
self._stop_words = []
self._event_manager = event_manager
self._event_manager.subscribe('load', self.load)
self._event_manager.subscribe('word', self.is_stop_word)
def load(self, event):
f = open('../stop_words.txt')
self._stop_words = f.read().split(',')
f.close()
# add single-letter words
self._stop_words.extend(list(string.ascii_lowercase))
def is_stop_word(self, event):
word = event[1]
if word not in self._stop_words:
self._event_manager.publish(('valid_word', word))
class WordFrequencyCounter:
""" Keeps the word frequency data """
def __init__(self, event_manager):
self._word_freqs = {}
self._event_manager = event_manager
self._event_manager.subscribe('valid_word', self.increment_count)
self._event_manager.subscribe('print', self.print_freqs)
def increment_count(self, event):
word = event[1]
if word in self._word_freqs:
self._word_freqs[word] += 1
else:
self._word_freqs[word] = 1
def print_freqs(self, event):
word_freqs = sorted(self._word_freqs.iteritems(), key=operator.itemgetter(1), reverse=True)
for tf in word_freqs[0:25]:
print tf[0], ' - ', tf[1]
class WordFrequencyApplication:
def __init__(self, event_manager):
self._event_manager = event_manager
self._event_manager.subscribe('run', self.run)
self._event_manager.subscribe('eof', self.stop)
def run(self, event):
path_to_file = event[1]
self._event_manager.publish(('load', path_to_file))
self._event_manager.publish(('start', None))
def stop(self, event):
self._event_manager.publish(('print', None))
#
# The main function
#
em = EventManager()
DataStorage(em), StopWordFilter(em), WordFrequencyCounter(em), WordFrequencyApplication(em)
em.publish(('run', sys.argv[1]))