82 lines
2.1 KiB
Python
Executable File
82 lines
2.1 KiB
Python
Executable File
#!/usr/bin/env python
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from __future__ import print_function
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import sys, re, operator, string
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from functools import reduce
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try:
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xrange # Python 2
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except NameError:
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xrange = range # Python 3
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#
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# Functions for map reduce
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#
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def partition(data_str, nlines):
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"""
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Partitions the input data_str (a big string)
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into chunks of nlines.
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"""
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lines = data_str.split('\n')
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for i in xrange(0, len(lines), nlines):
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yield '\n'.join(lines[i:i+nlines])
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def split_words(data_str):
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"""
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Takes a string, returns a list of pairs (word, 1),
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one for each word in the input, so
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[(w1, 1), (w2, 1), ..., (wn, 1)]
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"""
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def _scan(str_data):
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pattern = re.compile('[\W_]+')
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return pattern.sub(' ', str_data).lower().split()
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def _remove_stop_words(word_list):
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with open('../stop_words.txt') as f:
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stop_words = f.read().split(',')
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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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result = []
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words = _remove_stop_words(_scan(data_str))
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for w in words:
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result.append((w, 1))
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return result
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def count_words(pairs_list_1, pairs_list_2):
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"""
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Takes two lists of pairs of the form
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[(w1, 1), ...]
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and returns a list of pairs [(w1, frequency), ...],
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where frequency is the sum of all the reported occurrences
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"""
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mapping = dict((k, v) for k, v in pairs_list_1)
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for p in pairs_list_2:
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if p[0] in mapping:
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mapping[p[0]] += p[1]
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else:
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mapping[p[0]] = 1
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return mapping.items()
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#
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# Auxiliary functions
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#
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def read_file(path_to_file):
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with open(path_to_file) as f:
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data = f.read()
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return data
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def sort(word_freq):
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return sorted(word_freq, key=operator.itemgetter(1), reverse=True)
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#
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# The main function
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#
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splits = map(split_words, partition(read_file(sys.argv[1]), 200))
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splits.insert(0, []) # Normalize input to reduce
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word_freqs = sort(reduce(count_words, splits))
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for (w, c) in word_freqs[0:25]:
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print(w, ' - ', c)
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