寻找在python中给出命令行参数的最佳方式，其中一些参数是某些选项的req，而一些参数是其他选项的req [英] looking for best way of giving command line arguments in python, where some params are req for some option and some params are req for other options

问题描述

我第一次尝试发送命令行参数.条件是一个选项需要一个参数，其他参数需要一个参数.(寻找用户友好).下面的代码看起来需要一些优化:

Hi i am trying to send command line arguments for first time. The condition is that one parameter is required for one option and for others other parameter.(looking for user friendly). The below code looks need some optimization:

import argparse
parser = argparse.ArgumentParser(description='Usage options.')
parser.add_argument('-o','--options',help='Options available: run,rerun,kill, resume,           suspend',required=True)
parser.add_argument('-c', '--config',help='config file input',type=file,required=False)
parser.add_argument('-j', '--id',help='id of the job',type=str,required=False)
args = parser.parse_args()
action_arg = list()
action_arg.append(args.options)
action = {'run': start_run,
          'rerun': start_rerun,
          'kill': kill_job,
          'resume': resume_job,
          'suspend': suspend_job,
          'get_run': get_run,
          'get_component': get_component,
          'help': print_help}.get('-'.join(action_arg))

if action:
    conf_file = str(args.config)
    jobid = str(args.jobid)
    if args.options == "run":
        if conf_file == "None":
            print "Job configuration is needed to start a run and job id is not needed"
            sys.exit(2)
    elif args.options == "rerun":
        if conf_file == "None" or jobid == "None":
            print "Job configuration and jobid is needed to start a rerun."
            sys.exit(2)
    else:
        if jobid == "None":
            print "Jobid is needed to perform %s action on job and configuration is not needed." %args.options
            sys.exit(2)
    action(conf_file, jobid)
else:
    print "Usage Error:"
    print_help()

希望你能从代码中得到我需要的参数.请让我知道有关要求的详细说明

Hope you get my required params for required options from code. Please let me know for detailed explanation on requirements

推荐答案

脚本上的这种变体运行，并清理了几件事情.它使用 choices 来控制选项值.它省略了其他 add_argument 调用中不必要的参数.它简化了后 parse_args 逻辑.help 并不是真的需要，因为总是有 -h 选项，但我把它作为一个选择.它落到最后，因为它不在 action 字典中.

This variation on your script runs, and cleans up several things. It uses choices to control the options values. It omits unnecessary parameters in the other add_argument calls. It simplifies the post parse_args logic. help isn't really needed since there is always the -h option, but I included it as a choice. It falls through to the end because it is not in the action dictionary.

import argparse
import sys
class Stub(object):
    def __init__(self,s):
        self.s = s
    def __call__(self,conf_file, jobid):
        print self.s, conf_file, jobid
parser = argparse.ArgumentParser(description='Usage options.')
parser.add_argument('-o','--options', choices=('run','rerun','kill', 'resume', 'suspend','help'),required=True)
parser.add_argument('-c', '--config',help='config file input')
# optionals normally not required; 'file' not valid type
# argparse.FileType will open the file
parser.add_argument('-j', '--jobid',help='id of the job')
# str is the default type
args = parser.parse_args()
# action_arg = [args.options]
action = {'run': Stub('start_run'),
          'rerun': Stub('start_rerun'),
          'kill': Stub('kill_job'),
          'resume': Stub('resume_job'),
          'suspend': Stub('suspend_job'),
          #'get_run': get_run, # not in choices
          #'get_component': get_component,
          #'help': print_help,
          }.get(args.options)  # what's with the '-'.join?

if action:
    if args.options == "run":
        if args.config is None: # proper test for None
            print "Job configuration is needed to start a run and job id is not needed"
            sys.exit(2)
    elif args.options == "rerun":
        if args.config is None or args.jobid is None:
            print "Job configuration and jobid is needed to start a rerun."
            sys.exit(2)
    else:
        if args.jobid is None:
            print "Jobid is needed to perform %s action on job and configuration is not needed." %args.options
            sys.exit(2)
    action(args.config, args.jobid)
else:
    print "Usage Error:"
    parser.print_help()

此版本用子解析器替换了 options 选项.config 和 jobid 成为相应子解析器的必需参数.我使用 parents 来方便地定义所需的混合和匹配.现在 argparse 完成所有检查.

This version replaces the options choices with subparsers. config and jobid become required arguments for the appropriate subparsers. I use parents to conveniently define the required mix and match. Now argparse does all the checking.

import argparse
class Stub(object):
    def __init__(self,s):
        self.s = s
    def __call__(self,conf_file, jobid):
        print self.s, conf_file, jobid

conf_parent = argparse.ArgumentParser(add_help=False)
conf_parent.add_argument('-c', '--config',help='config file input',required=True)
job_parent = argparse.ArgumentParser(add_help=False)
job_parent.add_argument('-j', '--jobid',help='id of the job',required=True)

parser = argparse.ArgumentParser(description='Usage options.')
parser.set_defaults(config=None, jobid=None) # put default value in namespace
sp = parser.add_subparsers(dest='options')
sp.add_parser('run',parents=[conf_parent])
sp.add_parser('rerun',parents=[conf_parent, job_parent])
sp.add_parser('kill',parents=[job_parent])
sp.add_parser('resume',parents=[job_parent])
sp.add_parser('suspend',parents=[job_parent])
args = parser.parse_args()

action = {'run': Stub('start_run'),
          'rerun': Stub('start_rerun'),
          'kill': Stub('kill_job'),
          'resume': Stub('resume_job'),
          'suspend': Stub('suspend_job'),
          }.get(args.options)
action(args.config, args.jobid)

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