Hi,
I'm trying to teach myself the Python language with the Google Python class (http://code.google.com/edu/languages/google-python-class/set-up.html).
With the exercise 'wordcount' I get a Traceback error (with the main function and sys.exit(1) function). Even with the solution script (as displayed here).
Does anyone recognize this problem and can some one tell me what I'm missing here?
wordcount gives the following output:
usage: ./wordcount.py {--count | --topcount} file
Traceback (most recent call last):
File "F:\Science\google-python-exercises\basic\solution\wordcount.py", line 114, in <module>
main()
File "F:\Science\google-python-exercises\basic\solution\wordcount.py", line 101, in main
sys.exit(1)
SystemExit: 1
The code:
import sys
def word_count_dict(filename):
"""Returns a word/count dict for this filename."""
# Utility used by count() and Topcount().
filename = 'f:\Science\google-python-exercises\basic\solution\small.txt'
word_count = {}
input_file = open(filename, 'r')
for line in input_file:
words = line.split()
for word in words:
word = word.lower()
# Special case if we're seeing this word for the first time.
if not word in word_count:
word_count[word] = 1
else:
word_count[word] = word_count[word] + 1
input_file.close() # Not strictly required, but good form.
return word_count
def print_words(filename):
"""Prints one per line '<word> <count>' sorted by word for the given file."""
word_count = word_count_dict(filename)
words = sorted(word_count.keys())
for word in words:
print word, word_count[word]
def get_count(word_count_tuple):
"""Returns the count from a dict word/count tuple -- used for custom sort."""
return word_count_tuple[1]
def print_top(filename):
"""Prints the top count listing for the given file."""
word_count = word_count_dict(filename)
# Each item is a (word, count) tuple.
# Sort them so the big counts are first using key=get_count() to extract count.
items = sorted(word_count.items(), key=get_count, reverse=True)
# Print the first 20
for item in items[:20]:
print item[0], item[1]
def main():
if len(sys.argv) != 3:
print 'usage: ./wordcount.py {--count | --topcount} file'
sys.exit(1)
option = sys.argv[1]
filename = sys.argv[2]
if option == '--count':
print_words(filename)
elif option == '--topcount':
print_top(filename)
else:
print 'unknown option: ' + option
sys.exit(1)
if __name__ == '__main__':
main()
