如何在python中對命令行參數進行分組？

Question

import ArgumentParser 

parser = ArgumentParser(description="Tool to keep archiving tar files") 
parser.add_argument("-a", "--action", dest="action", choices=("start", "stop", "list"), help="start/stop/list the directories to be monitored", default="list", required=True) 
parser.add_argument("-t", "--type", dest="type", choices=("a", "b"), help="Type of spooler job", default=None) 
parser.add_argument("-p", "--path", dest="path", help="Absolute path of the directory to be monitored", default=None) 
parser.add_argument("-c", "--codeline", dest="codeline", choices=("x","y","z"), default=None, required=True) 
parser.add_argument("-r", "--release", dest="release", help="Directory path gets assigned automatically based on the release", default=None) 

args = parser.parse_args() 

在上面的代碼中，如果動作被指定爲start/stop，則type和path/release中的一個是必需的輸入。有沒有辦法在add_argument方法本身做到這一點？

附加信息：
如果該操作以「列表」形式給出，則不需要其他選項。例如，「script.py -a列表」應該工作。 只有當動作以開始/停止的形式給出時，其他選項纔是必需的。例如，「script.py -a start」應該拋出錯誤。 「script.py -a啓動-TA -p/tmp目錄-CX」或「script.py -a開始-tb -r RR -cy」應該工作

Answer 1

如果使用add_subparsers(dest='action')，創造list，start，stop subparsers，各有所需的參數（沒有爲list），根據需要以下輸入會工作。 （注意-a未使用）。

script.py list 
script.py start # fail with insufficient arguments 
script.py start -t a -p /tmp -c x 
script.py start -t b -r rr -c y 

---

，擴大了我的建議：

from argparse import ArgumentParser 

parser = ArgumentParser(description="Tool to keep archiving tar files") 
sub = parser.add_subparsers(dest='action') 
sp1 = sub.add_parser('start') 
sp2 = sub.add_parser('stop') 
sp3 = sub.add_parser('list') 
#parser.add_argument("-a", "--action", dest="action", choices=("start", "stop", "list"), help="start/stop/list the directories to be monitored", default="list", required=True) 
for sp in [sp1,sp2]: 
    sp.add_argument("-t", "--type", dest="type", choices=("a", "b"), help="Type of spooler job", default=None) 
    sp.add_argument("-p", "--path", dest="path", help="Absolute path of the directory to be monitored", default=None) 
    sp.add_argument("-c", "--codeline", dest="codeline", choices=("x","y","z"), default=None, required=True) 
    sp.add_argument("-r", "--release", dest="release", help="Directory path gets assigned automatically based on the release", default=None) 

for astr in [ 
    'list', 
    'start -t a -p /tmp -c x', 
    'start -t b -r rr -c y', 
    'start']: 
    print parser.parse_args(astr.split()) 

結果是：

Namespace(action='list') 
Namespace(action='start', codeline='x', path='/tmp', release=None, type='a') 
Namespace(action='start', codeline='y', path=None, release='rr', type='b') 
usage: stack19510774.py start [-h] [-t {a,b}] [-p PATH] -c {x,y,z} 
           [-r RELEASE] 
stack19510774.py start: error: argument -c/--codeline is required 

如果-c爲stop沒有意義，然後從它的參數設置忽略它。

有很多關於使用子分析器的SO問題。

Answer 2

只需創建一個argument group：

parser = ArgumentParser(description="Tool to keep archiving tar files") 

group = parser.add_argument_group('some group') 
group.add_argument("-a", "--action", dest="action", choices=("start", "stop", "list"), help="start/stop/list the directories to be monitored", default="list", required=True) 
group.add_argument("-t", "--type", dest="type", choices=("a", "b"), help="Type of spooler job", default=None) 
group.add_argument("-p", "--path", dest="path", help="Absolute path of the directory to be monitored", default=None) 
group.add_argument("-r", "--release", dest="release", help="Directory path gets assigned automatically based on the release", default=None) 

parser.add_argument("-c", "--codeline", dest="codeline", choices=("x","y","z"), default=None, required=True)