Python中的optionParser模块

1、optionParser用于处理命令行参数

先看一个例子

#!/usr/bin/python
#coding:utf-8

import sys
import os
import logging

from optparse import OptionParser

DEFAULT_LOG = 'D:/var/log/tcollector.log'

def parse_cmdline(argv):

#获取默认程序路径
    default_cdir = os.path.join(os.path.dirname(os.path.realpath(sys.argv[0])),
                                'collectors')
    print default_cdir
#获取相关参数
    parser = OptionParser(description='Manages collectors which gather '
                                       'data and report back.')
    parser.add_option('-c', '--collector-dir', dest='cdir', metavar='DIR',
                      default=default_cdir,
                      help='Directory where the collectors are located.')
    parser.add_option('-d', '--dry-run', dest='dryrun', action='store_true',
                      default=False,
                      help='Don\'t actually send anything to the TSD, '
                           'just print the datapoints.')
    parser.add_option('-D', '--daemonize', dest='daemonize', action='store_true',
                      default=False, help='Run as a background daemon.')
    parser.add_option('--dedup-interval', dest='dedupinterval', type='int',
                      default=300, metavar='DEDUPINTERVAL',
                      help='Number of seconds in which successive duplicate '
                           'datapoints are suppressed before sending to the TSD. '
                           'default=%default')
    parser.add_option('--evict-interval', dest='evictinterval', type='int',
                      default=6000, metavar='EVICTINTERVAL',
                      help='Number of seconds after which to remove cached '
                           'values of old data points to save memory. '
                           'default=%default')
    parser.add_option('--backup-count', dest='backup_count', type='int',
                      default=0, help='Maximum number of logfiles to backup.')
    (options, args) = parser.parse_args(args=argv[1:])
    if options.dedupinterval < 2:
        parser.error('--dedup-interval must be at least 2 seconds')
    if options.evictinterval <= options.dedupinterval:
        parser.error('--evict-interval must be strictly greater than '
                     '--dedup-interval')
 
    if options.daemonize and not options.backup_count:
        options.backup_count = 1
    return (options, args)
        
def main(argv):

#分析参数和选项
    options, args = parse_cmdline(argv)
    print options
if __name__ == '__main__':
    sys.exit(main(sys.argv))

执行结果：

D:\>python ParTest.py --dry-run
D:\collectors
{'dryrun': True, 'evictinterval': 6000, 'daemonize': False, 'dedupinterval': 300
, 'backup_count': 0, 'cdir': 'D:\\collectors'}

2、解释：　

2.1

add_option用来加入选项，action是有store，store_true，store_false等，dest是存储的变量，default是缺省值，help是帮助提示

最后通过parse_args()函数的解析，获得选项

2.2

parse_args() 返回的两个值：

options，它是一个对象（optpars.Values），保存有命令行参数值。只要知道命令行参数名，就可以访问其对应的值 。

args，它是一个由 positional arguments 组成的列表。

3、optparse 另一个方便的功能是自动生成程序的帮助信息

D:\>python ParTest.py -h