寻找在python中给出命令行参数的最佳方式，其中一些参数需要一些选项，一些参数需要其他选项

Question

嗨，我想第一次发送命令行参数。条件是一个选项和其他参数需要一个参数（寻求用户友好）。下面的代码看起来需要一些优化：

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() 

希望你从代码中得到我需要的参数为必需的选项。请让我知道要求的详细说明

Answer 1

脚本上的这种变化运行，并清理了几件事情。它使用choices来控制选项值。它在其他add_argument调用中省略了不必要的参数。它简化了逻辑后的parse_args。 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项。它贯穿始终，因为它不在action字典中。

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() 

该版本用子分析器代替options的选择。 config和jobid成为相应子分析器的必需参数。我使用parents来方便地定义所需的混合和匹配。现在​​做所有的检查。

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)