使用 python 实现 wc 命令程序的基本功能

#!/usr/bin/env python
#encoding: utf-8
# Author: liwei
# Function: wc program by python

from optparse import OptionParser
import sys,os

def opt():
parser = OptionParser()
parser.add_option('-c', '--char',
dest='chars',
action='store_true',
default=False,
help='only count chars')

parser.add_option('-w', '--word',
dest='words',
action='store_true',
default=False,
help='only count words')

parser.add_option('-l', '--line',
dest='lines',
action='store_true',
default=False,
help='only count lines')

parser.add_option('-n', '--nototal',
dest='nototal',
action='store_true',
default=False,
help='don\'t print total information')

options, args = parser.parse_args()
return options, args

#print options
def get_count(data):
chars = len(data)
words = len(data.split())
lines = data.count('\n')
return lines, words, chars

#if not options.chars and not options.words and not options

def print_wc(options, lines, words, chars, fn):
if options.lines:
print lines,
if options.words:
print words,
if options.chars:
print chars,
print fn

def main():
options, args = opt()

if not (options.lines or options.words or options.chars):
options.lines, options.words, options.chars = True, True, True

if args:
total_lines, total_words, total_chars = 0, 0, 0
for fn in args:
if os.path.isfile(fn):
with open(fn) as fd:
data = fd.read()
lines, words, chars = get_count(data)
print_wc(options, lines, words, chars, fn)
total_lines += lines
total_words += words
total_chars += chars
elif os.path.isdir(fn):
print >> sys.stderr, '%s is a directory' %fn
else:
sys.stderr.write('%s: No such file or directory\n' % fn)
# 只有多个文件的时候会计算出total字段
if len(args) > 1 and not options.nototal:
print_wc(options, total_lines, total_words, total_chars, 'total')
else:
fn = ''
data = sys.stdin.read()
lines, words, chars = get_count(data)
print_wc(options, lines, words, chars, fn)

if __name__ == '__main__':
main()