92 lines
2.9 KiB
Python
Executable File
92 lines
2.9 KiB
Python
Executable File
#!/usr/bin/env python
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import sys, re, string, sqlite3
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#
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# The relational database of this problem consists of 3 tables:
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# documents, words, characters
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#
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def create_db_schema(connection):
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c = connection.cursor()
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c.execute('''CREATE TABLE documents (id INTEGER PRIMARY KEY AUTOINCREMENT, name)''')
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c.execute('''CREATE TABLE words (id, doc_id, value)''')
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c.execute('''CREATE TABLE characters (id, word_id, value)''')
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connection.commit()
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c.close()
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def load_file_into_database(path_to_file, connection):
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""" Takes the path to a file and loads the contents into the database """
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def _read_file(path_to_file):
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"""
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Takes a path to a file and returns the entire contents of the
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file as a string
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"""
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f = open(path_to_file)
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data = f.read()
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f.close()
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return data
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def _filter_chars_and_normalize(str_data):
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"""
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Takes a string and returns a copy with all nonalphanumeric chars
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replaced by white space, and all characters lower-cased
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"""
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pattern = re.compile('[\W_]+')
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return pattern.sub(' ', str_data).lower()
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def _scan(str_data):
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""" Takes a string and scans for words, returning a list of words. """
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return str_data.split()
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def _remove_stop_words(word_list):
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f = open('../stop_words.txt')
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stop_words = f.read().split(',')
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f.close()
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# add single-letter words
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stop_words.extend(list(string.ascii_lowercase))
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return [w for w in word_list if not w in stop_words]
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# The actual work of splitting the input into words
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words = _remove_stop_words(_scan(_filter_chars_and_normalize(_read_file(path_to_file))))
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# Now let's add data to the database
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# Add the document itself to the database
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c = connection.cursor()
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c.execute("INSERT INTO documents (name) VALUES (?)", (path_to_file,))
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c.execute("SELECT id from documents WHERE name=?", (path_to_file,))
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doc_id = c.fetchone()[0]
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# Add the words to the database
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c.execute("SELECT MAX(id) FROM words")
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row = c.fetchone()
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word_id = row[0]
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if word_id == None:
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word_id = 0
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for w in words:
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c.execute("INSERT INTO words VALUES (?, ?, ?)", (word_id, doc_id, w))
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# Add the characters to the database
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char_id = 0
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for char in w:
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c.execute("INSERT INTO characters VALUES (?, ?, ?)", (char_id, word_id, char))
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char_id += 1
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word_id += 1
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connection.commit()
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c.close()
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#
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# The main function
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#
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connection = sqlite3.connect(':memory:')
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create_db_schema(connection)
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load_file_into_database(sys.argv[1], connection)
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# Now, let's query
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c = connection.cursor()
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c.execute("SELECT value, COUNT(*) as C FROM words GROUP BY value ORDER BY C DESC")
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for i in range(25):
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row = c.fetchone()
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if row != None:
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print row[0] + ' - ' + str(row[1])
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connection.close()
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