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Better use of reflection

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This commit is contained in:
Crista Lopes
2013-12-29 07:59:22 -08:00
parent b0db7c03b5
commit ebd6f48c9d
1 changed files with 14 additions and 13 deletions
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27
16-reflective/tf-16.py
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@@ -1,9 +1,8 @@
#!/usr/bin/env python
import sys, re, operator, string
import sys, re, operator, string, os
#
# Two down-to-earth things that cannot be reflected on
# without serious performance penalties
# Two down-to-earth things
#
stops = set(open("../stop_words.txt").read().split(",") + list(string.ascii_lowercase))
@@ -19,18 +18,20 @@ def frequencies_imp(word_list):
#
# Let's write our functions as strings.
#
extract_words_func = "lambda name : [x.lower() for x in re.split('[^a-zA-Z]+', open(name).read()) if len(x) > 0 and x.lower() not in stops]"
frequencies_func = "lambda word_list : frequencies_imp(word_list)"
sort_func = "lambda word_freq: sorted(word_freq.iteritems(), key=operator.itemgetter(1), reverse=True)"
if len(sys.argv) > 1:
extract_words_func = "lambda name : [x.lower() for x in re.split('[^a-zA-Z]+', open(name).read()) if len(x) > 0 and x.lower() not in stops]"
frequencies_func = "lambda word_list : frequencies_imp(word_list)"
sort_func = "lambda word_freq: sorted(word_freq.iteritems(), key=operator.itemgetter(1), reverse=True)"
filename = sys.argv[1]
else:
extract_words_func = "lambda x: []"
frequencies_func = "lambda x: []"
sort_func = "lambda x: []"
filename = os.path.basename(__file__)
#
# So far, this program isn't much about term-frequency. It's about
# a bunch of strings that look like functions.
# Let's add our functions to the "base" program, dynamically.
# We're re-writing this program by adding more functions to it
# from "above".
#
exec('extract_words = ' + extract_words_func)
exec('frequencies = ' + frequencies_func)
@@ -38,11 +39,11 @@ exec('sort = ' + sort_func)
#
# The main function. This would work just fine:
# word_freqs = sort(frequencies(extract_words(sys.argv[1])))
# word_freqs = sort(frequencies(extract_words(filename)))
# But because we're being introspective, we'll call the
# functions also from "above"
#
word_freqs = locals()['sort'](locals()['frequencies'](locals()['extract_words'](sys.argv[1])))
word_freqs = locals()['sort'](locals()['frequencies'](locals()['extract_words'](filename)))
for (w, c) in word_freqs[0:25]:
print w, ' - ', c