# bentley_knuth.py
# Author: Vasudev Ram - http://www.dancingbison.com
# Version: 0.1
# The problem this program tries to solve is from the page:
# http://www.leancrew.com/all-this/2011/12/more-shell-less-egg/
# Description: The program Bentley asked Knuth to write:
# Read a file of text, determine the n most frequently
# used words, and print out a sorted list of those words
# along with their frequencies.
import sys
import os
import string
sys_argv = sys.argv
def usage():
sys.stderr.write("Usage: %s n file\n" % sys_argv[0])
sys.stderr.write("where n is the number of most frequently\n")
sys.stderr.write("used words you want to find, and \n")
sys.stderr.write("file is the name of the file in which to look.\n")
if len(sys_argv) < 3:
usage()
sys.exit(1)
try:
n = int(sys_argv[1])
except ValueError:
sys.stderr.write("%s: Error: %s is not a decimal numeric value" % (sys_argv[0],
sys_argv[1]))
sys.exit(1)
print "n =", n
if n < 1:
sys.stderr.write("%s: Error: %s is not a positive value" %
(sys_argv[0], sys_argv[1]))
in_filename = sys.argv[2]
print "%s: Finding %d most frequent words in file %s" % \
(sys_argv[0], n, in_filename)
try:
fil_in = open(in_filename)
except IOError:
sys.stderr.write("%s: ERROR: Could not open in_filename %s\n" % \
(sys_argv[0], in_filename))
sys.exit(1)
word_freq_dict = {}
for lin in fil_in:
words_in_line = lin.split()
for word in words_in_line:
if word_freq_dict.has_key(word):
word_freq_dict[word] += 1
else:
word_freq_dict[word] = 1
word_freq_list = []
for item in word_freq_dict.items():
word_freq_list.append(item)
wfl = sorted(word_freq_list,
key=lambda word_freq_list: word_freq_list[1], reverse=True)
#wfl.reverse()
print "The %d most frequent words sorted by decreasing frequency:" % n
len_wfl = len(wfl)
if n > len_wfl:
print "n = %d, file has only %d unique words," % (n, len_wfl)
print "so printing %d words" % len_wfl
print "Word: Frequency"
m = min(n, len_wfl)
for i in range(m):
print wfl[i][0], ": ", wfl[i][1]
fil_in.close()
