Argparse 错误：python2.x 上的参数太少

Question

我正在尝试将 argparse 库与 python2 一起使用，但它总是报错：

代码：

parent_parser = argparse.ArgumentParser()
sub_parsers = parent_parser.add_subparsers(title = "actions")

parser_create = sub_parsers.add_parser("create", parents = [parent_parser], add_help = False, description = "Create new Customer account.", help = "create")
parser_create.add_argument('-p', '--password', help = 'User Password', required = True)
parser_create.add_argument('-n', '--fullname', nargs = 2, help = 'User Full Name', required = True)
parser_create.add_argument('-e', '--email', required = True, help = "User Email address")

parser_deactivate = sub_parsers.add_parser("deactivate", parents = [parent_parser], add_help = False, description = "Deactivate existing customer account.", help = "deactivate.")
parser_deactivate.add_argument('-e','--email', required = True, help = "User Email address")
args = parent_parser.parse_args()

输出：

[root@localhost ~]# python2 create-user.py deactivate -e o@x.com

usage: create-user.py deactivate [-h] -e EMAIL {create,deactivate} ...
create-user.py deactivate: error: too few arguments

使用create 而不是deactivate 时出现同样的错误。

它在 python3.x 中也能正常工作。

Answer 1

parents 用于“继承”来自一个或多个解析器的参数，而无需在多个解析器之间重复它们的定义。

您的子解析器不需要这样做。您实际上是在说使用子命令deactivate 后，您需要再次指定create 或deactivate，从而导致无限循环。

只需省略子解析器的 parents 参数即可。

import argparse


parser = argparse.ArgumentParser()
sub_parsers = parser.add_subparsers(title="actions")

parser_create = sub_parsers.add_parser("create", 
                                       description="Create new Customer account.")
parser_create.add_argument('-p', '--password',
                           help='User Password', required=True)
parser_create.add_argument('-n', '--fullname', nargs=2,
                           help='User Full Name', required=True)
parser_create.add_argument('-e', '--email', required=True,
                           help="User Email address")

parser_deactivate = sub_parsers.add_parser("deactivate",
                                           description="Deactivate existing customer account.")
parser_deactivate.add_argument('-e','--email', required=True,
                               help="User Email address")

args = parser.parse_args()

示例运行：

$ python2 create-user.py deactivate -e o@x.com
Namespace(email='o@x.com')

---

您可能使用父解析器的一种方法是从单个解析器继承--email。

parser = argparse.ArgumentParser()

email_parser = argparse.ArgumentParser(add_help=False)
email_parser.add_argument("-e", "--email", required=True,
                          help="User Email address")

sub_parsers = parser.add_subparsers(title="actions")

parser_create = sub_parsers.add_parser("create",
                                       description="Create new Customer account.",
                                       parents=[email_parser])
parser_create.add_argument('-p', '--password',
                           help='User Password', required=True)
parser_create.add_argument('-n', '--fullname', nargs=2,
                           help='User Full Name', required=True)

parser_deactivate = sub_parsers.add_parser("deactivate",
                                           description="Deactivate existing customer account.",
                                           parents=[email_parser])

args = parser.parse_args()