Question

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#!/usr/bin/env python

import argparse
import sys
import itertools as IT
from snemail import *

parser = argparse.ArgumentParser(
        prog='snemail',
        usage='%(prog)s [-h] [--usage] action target [input]',
        epilog="refer to '%(prog)s usage' for examples of how to run snemail"
        )
parser.add_argument('action', metavar='action', nargs='?', type=str, choices=('list', 'add', 'remove'), help="list | remove | add")
parser.add_argument('target', metavar='target', nargs='?', type=str, choices=('domain', 'forwarding', 'transport', 'user', 'all'), help="domain | forwarding | transport | user")
parser.add_argument('input', nargs='?', type=str, default=None, help="required input to go with the 'remove' and 'add' flags. 'list' requires no input field")
parser.add_argument('--usage', action='store_true', help="show usage examples for snemail")
args = parser.parse_args()

if args.usage:
        usage()
        sys.exit(0)
if args.action is None or args.target is None:
        parser.print_help()
        sys.exit(0)
if args.target == 'all':
        all_list()
        sys.exit(0)
if len(sys.argv) >= 3:
        input = args.input
        input = input.split(',')
else:
        input = None

def usage():
        print 'usage info here'

targets = 'domain forwarding transport user'.split()
actions = 'list add remove'.split()

dispatch = {key:globals()['%s_%s' % key] for key in IT.product(targets, actions)}

if input is not None:
        dispatch.get((args.target, args.action), usage)(input)
elif args.action is not None and args.target is not None:
        parser.print_help()
        sys.exit(0)

这段代码可能会让专业python-coder的皮肤爬行，但它适用于我，在Python 2.7（我用于我的开发机器），但当我尝试在机器上执行此代码时将在生产中运行此代码，它没有执行代码，因为

dispatch = {key:globals()['%s_%s' % key] for key in IT.product(targets, actions)}

在2.7中不起作用。

亲爱的互联网大师，如何在Python 2.6上完成这项工作？（因为升级到2.7不是一个选项，但更重要的是我想编写适当的Python）

Answer 1

将dict()与生成器表达式一起使用：

dispatch = dict((key, globals()['%s_%s' % key]) for key in IT.product(targets, actions))

生成器表达式创建(key, value) 2值元组;这适用于2.6和2.7（或python 3，就此而言）。

使代码python 2.6兼容

1 个答案: