I'm looking to provide flexible input into my parser. My use case is I have a python script to run some queries that are date range based. How I want the arg parser to operate is if only one date is supplied, use that date as both the start and end dates, but if two dates are used, use those.
So at least one date needs to be supplied, but no more than two dates. Is that possible?
def main(args):
parser = argparse.ArgumentParser(description="Run ETL for script")
parser.add_argument('-j', '--job_name', action='store', default=os.path.basename(__file__), type=str, help="Job name that gets used as part of the metadata for the job run.")
parser.add_argument("-d", "--date-range", nargs=2, metavar=('start_date', 'end_date'), default=['2021-01-01', '2021-01-01'], action='store', help="Operating range for script and data sources (as applicable)")
parser.add_argument('-e', '--env', action='store', choices=['dev', 'stage', 'prod'], default='dev', help="Environment to execute.")
parser.add_argument('-c', '--config', action='store', choices=['small', 'medium', 'large'], default='small', help="Resource request. See configs for each.")
args = parser.parse_args()
if args.date_range[0] <= args.date_range[1]:
job_meta = {
"script" : args.job_name,
"start_date" : args.date_range[0],
"end_date" : args.date_range[1],
"environment" : args.env,
"resource" : args.config
}
run_job(job_meta)
else:
print('Invalid date range. Start date as inputted may be following the end date.')
sys.exit(0)
if __name__ == "__main__":
main(sys.argv[1:])
In order to achieve that you can create a new action that check the number of argument given to the nargs.
import argparse
class LimitedAppend(argparse._AppendAction):
def __call__(self, parser, namespace, values, option_string=None):
if not (1 <= len(values) <= 2):
raise argparse.ArgumentError(self, "%s takes 1 or 2 values, %d given" % (option_string, len(values)))
super().__call__(parser, namespace, values, option_string)
parser.add_argument("-d", "--date-range", ..., nargs='+', action=LimitedAppend)
Then you can check the length of this argument and do what you wanted to do
I've got not words to thank you all of you for such great advice. Now everything started to make sense. I apologize for for my bad variable naming. It was just because I wanted to quickly learn and I wont carry out such practices when I write the final script with my own enhancements which will be posted here.
I want to go an another step further by passing the values we've isolated (ip,port,and name) to a template. I tried but couldn't get it right even though I feel close. The text I want to construct looks like this. (
Host Address:<IP>:PORT:<1>
mode tcp
bind <IP>:<PORT> name <NAME>
I have tried this within the working script provided by rahul.(I've edited my original code abiding stackexchange's regulations. Please help out just this once as well. Many thanks in advance.
#!/usr/bin/python
import argparse
import re
import string
p = argparse.ArgumentParser()
p.add_argument("input", help="input the data in format ip:port:name", nargs='*')
args = p.parse_args()
kkk_list = args.input
def func_three(help):
for i in help:
print(i)
for kkk in kkk_list:
bb = re.split(":|,", kkk)
XXX=func_three(bb)
for n in XXX:
ip, port, name = n
template ="""HOST Address:{0}:PORT:{1}
mode tcp
bind {0}:{1} name {2}"""
sh = template.format(ip,port,name)
print sh
orignial post:--
Beginner here. I wrote the below code and it doesn't get me anywhere.
#!/usr/bin/python
import argparse
import re
import string
p = argparse.ArgumentParser()
p.add_argument("INPUT")
args = p.parse_args()
KKK= args.INPUT
bb=re.split(":|,", KKK)
def func_three(help):
for i in help:
#print help
return help
#func_three(bb[0:3])
YY = var1, var2, var3 = func_three(bb[0:3])
print YY
The way to run this script should be "script.py :". i.e: script.py 192.168.1.10:80:string 172.25.16.2:100:string
As you can see if one argument is passed I have no problems. But when there are more arguments I cant determine how to workout the regexes and get this done via a loop.
So to recap, this is how i want the output to look like to proceed further.
192.168.1.10
80
name1
172.25.16.2
100
name2
If there are better other ways to achieve this please feel free to suggest.
I would say what you are doing could be done more simply. If you want to split the input whenever a colon appears you could use:
#!/usr/bin/python
import sys
# sys.argv is the list of arguments you pass when you run the program
# but sys.argv[0] is the actual program name
# so you want to start at sys.argv[1]
for arg in sys.argv[1:]:
listVar = arg.split(':')
for i in listVar:
print i
# Optionally print a new line
print
Please name your variable with respect to context. You will need to use nargs=* for accepting multiple arguments. I have added the updated code below which prints as you wanted.
#!/usr/bin/python
import argparse
import re
import string
p = argparse.ArgumentParser()
p.add_argument("input", help="input the data in format ip:port:name", nargs='*')
args = p.parse_args()
kkk_list = args.input # ['192.168.1.10:80:name1', '172.25.16.2:100:name3']
def func_three(help):
for i in help:
print(i)
for kkk in kkk_list:
bb = re.split(":|,", kkk)
func_three(bb)
print('\n')
# This prints
# 192.168.1.10
# 80
# name1
# 172.25.16.2
# 100
# name3
Updated Code for new requirement
#!/usr/bin/python
import argparse
import re
import string
p = argparse.ArgumentParser()
p.add_argument("input", help="input the data in format ip:port:name", nargs='*')
args = p.parse_args()
kkk_list = args.input # ['192.168.1.10:80:name1', '172.25.16.2:100:name3']
def printInFormat(ip, port, name):
formattedText = '''HOST Address:{ip}:PORT:{port}
mode tcp
bind {ip}:{port} name {name}'''.format(ip=ip,
port=port,
name=name)
textWithoutExtraWhitespaces = '\n'.join([line.strip() for line in formattedText.splitlines()])
# you can break above thing
# text = ""
# for line in formattedText.splitlines():
# text += line.strip()
# text += "\n"
print(formattedText)
for kkk in kkk_list:
ip, port, name = re.split(":|,", kkk)
printInFormat(ip, port, name)
# HOST Address:192.168.1.10:PORT:80
# mode tcp
# bind 192.168.1.10:80 name name1
# HOST Address:172.25.16.2:PORT:100
# mode tcp
# bind 172.25.16.2:100 name name3
Bad variable names aside, if you want to use argparse (which I think is a good habit, even if it is somewhat more complex initially) you should use the nargs='+' option:
#!/usr/bin/env python
import argparse
import re
import string
p = argparse.ArgumentParser()
p.add_argument("INPUT", nargs='+')
args = p.parse_args()
KKK= args.INPUT
def func_three(help):
for i in help:
#print help
return help
for kkk in KKK:
bb=re.split(":|,", kkk)
#func_three(bb[0:3])
YY = var1, var2, var3 = func_three(bb[0:3])
print YY
If you look at the documentation for argparse, you'll notice that there's an nargs argument you can pass to add_argument, which allows you to group more than one input.
For example:
p.add_argument('INPUT', nargs='+')
Would make it so that there is a minimum of one argument, but all arguments will be gathered into a list.
Then you can go through each of your inputs like this:
args = p.parse_args()
for address in args.INPUT:
ip, port = address.split(':')
I am fairly new to python and need a little guidance. I'm trying to pass some variables from the console and get and error message:
AuctionStrategy_2.0.py: error: argument -s/--sectorStocks: invalid int value: 'tep3'
when I run the console command:
run AuctionStrategy_2.0.py -in10 -out5 -rolls15 -step3 -t.001 -s5 -m100 -v50 -e'01/01/2016'
Could someone let me how to fix this please? My code at the moment does nothing except try and pass the variables from the console. Please see below for my code:
import argparse
import os
import fnmatch
import pandas as pd
from pandas.tseries.offsets import BDay
import lzma
import numpy as np
import math
import datetime
def main():
print('Processing args....')
insampleLength,outsampleLength,rolls,step,threshold,minStocksPerSector,minMarketCap,minVolume,endDate = get_args()
print(insampleLength,outsampleLength,rolls,step,threshold,minStocksPerSector,minMarketCap,minVolume,endDate)
rawDataPath = 'C:/Users/simon/Documents/data/close_unadjusted/close_unadjusted/'
def get_args():
'''This function parses and return arguments passed in'''
insampleLength = 0
outsampleLength = 0
rolls = 0
step = 0
endDate =''
minStocksPerSector = 0
threshold = 0
parser = argparse.ArgumentParser(
description='Args to run VWAP Auction simulation')
''' Command line arguments'''
parser.add_argument('-in', '--inSampleDataLength', type=int, help='Number of historic epochs insample', required=True)
parser.add_argument('-out', '--outSampleDataLength', type=int, help='Number of historic epochs outsample', required=True)
parser.add_argument('-rolls', '--numberRolls', type=int, help='Number of rolls', required=True)
parser.add_argument('-step', '--rollStep', type=int, help='Number of historic epochs', required=True)
parser.add_argument('-t','--threshold', type=float, help='starting value', required=True)
parser.add_argument('-s','--sectorStocks', type=int, help='minimum number', required=True)
parser.add_argument('-m','--marketCapCutOff', type=int,help='market capitalisation', required=True)
parser.add_argument('-v','--volumeCutOff', type=int, help='daily volume', required = True)
parser.add_argument('-e', '--endDate', type=str,help='last day of testing',required = True)
args = parser.parse_args()
''' Assign args to variables'''
insampleLength = args.inSampleDataLength
outsampleLength = args.outSampleDataLength
rolls = args.numberRolls
step = args.rollStep
threshold = args.threshold
minStocksPerSector = args.sectorStocks
minMarketCap = args.marketCapCutOff
minVolume = args.volumeCutOff
endDate = datetime.datetime.strptime(args.endDate, "%d-%b-%Y")
return insampleLength,outsampleLength,rolls,step,threshold,minStocksPerSector,minMarketCap,minVolume,endDate
if __name__ == "__main__":
print ("AuctionStategy_1.0...25/03/16")
try:
main()
except KeyboardInterrupt:
print ("Ctrl+C pressed. Stopping...")
A single dash always identifies a single-character argument. But you are trying to define -step; this is interpreted as -s, which is redefined later by the actual -s argument.
You should either pick a different identifier for "step", or always use the double-dash version --rollStep.
The argument -s expects an integer, you gave a string, this causes the error you get.
BTW, I think it's better to add spaces between the names of the arguments and it's values, e.g.:
run AuctionStrategy_2.0.py -in 10 -out 5 -rolls 15 -step 3 -t .001 -s 5 -m 100 -v 50 -e '01/01/2016'
Hope this helps
I am implementing a command line program which has interface like this:
cmd [GLOBAL_OPTIONS] {command [COMMAND_OPTS]} [{command [COMMAND_OPTS]} ...]
I have gone through the argparse documentation. I can implement GLOBAL_OPTIONS as optional argument using add_argument in argparse. And the {command [COMMAND_OPTS]} using Sub-commands.
From the documentation it seems I can have only one sub-command. But as you can see I have to implement one or more sub-commands. What is the best way to parse such command line arguments useing argparse?
I came up with the same qustion, and it seems i have got a better answer.
The solution is we shall not simply nest subparser with another subparser, but we can add subparser following with a parser following another subparser.
Code tell you how:
parent_parser = argparse.ArgumentParser(add_help=False)
parent_parser.add_argument('--user', '-u',
default=getpass.getuser(),
help='username')
parent_parser.add_argument('--debug', default=False, required=False,
action='store_true', dest="debug", help='debug flag')
main_parser = argparse.ArgumentParser()
service_subparsers = main_parser.add_subparsers(title="service",
dest="service_command")
service_parser = service_subparsers.add_parser("first", help="first",
parents=[parent_parser])
action_subparser = service_parser.add_subparsers(title="action",
dest="action_command")
action_parser = action_subparser.add_parser("second", help="second",
parents=[parent_parser])
args = main_parser.parse_args()
#mgilson has a nice answer to this question. But problem with splitting sys.argv myself is that i lose all the nice help message Argparse generates for the user. So i ended up doing this:
import argparse
## This function takes the 'extra' attribute from global namespace and re-parses it to create separate namespaces for all other chained commands.
def parse_extra (parser, namespace):
namespaces = []
extra = namespace.extra
while extra:
n = parser.parse_args(extra)
extra = n.extra
namespaces.append(n)
return namespaces
argparser=argparse.ArgumentParser()
subparsers = argparser.add_subparsers(help='sub-command help', dest='subparser_name')
parser_a = subparsers.add_parser('command_a', help = "command_a help")
## Setup options for parser_a
## Add nargs="*" for zero or more other commands
argparser.add_argument('extra', nargs = "*", help = 'Other commands')
## Do similar stuff for other sub-parsers
Now after first parse all chained commands are stored in extra. I reparse it while it is not empty to get all the chained commands and create separate namespaces for them. And i get nicer usage string that argparse generates.
parse_known_args returns a Namespace and a list of unknown strings. This is similar to the extra in the checked answer.
import argparse
parser = argparse.ArgumentParser()
parser.add_argument('--foo')
sub = parser.add_subparsers()
for i in range(1,4):
sp = sub.add_parser('cmd%i'%i)
sp.add_argument('--foo%i'%i) # optionals have to be distinct
rest = '--foo 0 cmd2 --foo2 2 cmd3 --foo3 3 cmd1 --foo1 1'.split() # or sys.argv
args = argparse.Namespace()
while rest:
args,rest = parser.parse_known_args(rest,namespace=args)
print args, rest
produces:
Namespace(foo='0', foo2='2') ['cmd3', '--foo3', '3', 'cmd1', '--foo1', '1']
Namespace(foo='0', foo2='2', foo3='3') ['cmd1', '--foo1', '1']
Namespace(foo='0', foo1='1', foo2='2', foo3='3') []
An alternative loop would give each subparser its own namespace. This allows overlap in positionals names.
argslist = []
while rest:
args,rest = parser.parse_known_args(rest)
argslist.append(args)
The solution provide by #Vikas fails for subcommand-specific optional arguments, but the approach is valid. Here is an improved version:
import argparse
# create the top-level parser
parser = argparse.ArgumentParser(prog='PROG')
parser.add_argument('--foo', action='store_true', help='foo help')
subparsers = parser.add_subparsers(help='sub-command help', dest='subparser_name')
# create the parser for the "command_a" command
parser_a = subparsers.add_parser('command_a', help='command_a help')
parser_a.add_argument('bar', type=int, help='bar help')
# create the parser for the "command_b" command
parser_b = subparsers.add_parser('command_b', help='command_b help')
parser_b.add_argument('--baz', choices='XYZ', help='baz help')
# parse some argument lists
argv = ['--foo', 'command_a', '12', 'command_b', '--baz', 'Z']
while argv:
print(argv)
options, argv = parser.parse_known_args(argv)
print(options)
if not options.subparser_name:
break
This uses parse_known_args instead of parse_args. parse_args aborts as soon as a argument unknown to the current subparser is encountered, parse_known_args returns them as a second value in the returned tuple. In this approach, the remaining arguments are fed again to the parser. So for each command, a new Namespace is created.
Note that in this basic example, all global options are added to the first options Namespace only, not to the subsequent Namespaces.
This approach works fine for most situations, but has three important limitations:
It is not possible to use the same optional argument for different subcommands, like myprog.py command_a --foo=bar command_b --foo=bar.
It is not possible to use any variable length positional arguments with subcommands (nargs='?' or nargs='+' or nargs='*').
Any known argument is parsed, without 'breaking' at the new command. E.g. in PROG --foo command_b command_a --baz Z 12 with the above code, --baz Z will be consumed by command_b, not by command_a.
These limitations are a direct limitation of argparse. Here is a simple example that shows the limitations of argparse -even when using a single subcommand-:
import argparse
parser = argparse.ArgumentParser()
parser.add_argument('spam', nargs='?')
subparsers = parser.add_subparsers(help='sub-command help', dest='subparser_name')
# create the parser for the "command_a" command
parser_a = subparsers.add_parser('command_a', help='command_a help')
parser_a.add_argument('bar', type=int, help='bar help')
# create the parser for the "command_b" command
parser_b = subparsers.add_parser('command_b', help='command_b help')
options = parser.parse_args('command_a 42'.split())
print(options)
This will raise the error: argument subparser_name: invalid choice: '42' (choose from 'command_a', 'command_b').
The cause is that the internal method argparse.ArgParser._parse_known_args() it is too greedy and assumes that command_a is the value of the optional spam argument. In particular, when 'splitting' up optional and positional arguments, _parse_known_args() does not look at the names of the arugments (like command_a or command_b), but merely where they occur in the argument list. It also assumes that any subcommand will consume all remaining arguments.
This limitation of argparse also prevents a proper implementation of multi-command subparsers. This unfortunately means that a proper implementation requires a full rewrite of the argparse.ArgParser._parse_known_args() method, which is 200+ lines of code.
Given these limitation, it may be an options to simply revert to a single multiple-choice argument instead of subcommands:
import argparse
parser = argparse.ArgumentParser()
parser.add_argument('--bar', type=int, help='bar help')
parser.add_argument('commands', nargs='*', metavar='COMMAND',
choices=['command_a', 'command_b'])
options = parser.parse_args('--bar 2 command_a command_b'.split())
print(options)
#options = parser.parse_args(['--help'])
It is even possible to list the different commands in the usage information, see my answer https://stackoverflow.com/a/49999185/428542
You can always split up the command-line yourself (split sys.argv on your command names), and then only pass the portion corresponding to the particular command to parse_args -- You can even use the same Namespace using the namespace keyword if you want.
Grouping the commandline is easy with itertools.groupby:
import sys
import itertools
import argparse
mycommands=['cmd1','cmd2','cmd3']
def groupargs(arg,currentarg=[None]):
if(arg in mycommands):currentarg[0]=arg
return currentarg[0]
commandlines=[list(args) for cmd,args in intertools.groupby(sys.argv,groupargs)]
#setup parser here...
parser=argparse.ArgumentParser()
#...
namespace=argparse.Namespace()
for cmdline in commandlines:
parser.parse_args(cmdline,namespace=namespace)
#Now do something with namespace...
untested
Improving on the answer by #mgilson, I wrote a small parsing method which splits argv into parts and puts values of arguments of commands into hierarchy of namespaces:
import sys
import argparse
def parse_args(parser, commands):
# Divide argv by commands
split_argv = [[]]
for c in sys.argv[1:]:
if c in commands.choices:
split_argv.append([c])
else:
split_argv[-1].append(c)
# Initialize namespace
args = argparse.Namespace()
for c in commands.choices:
setattr(args, c, None)
# Parse each command
parser.parse_args(split_argv[0], namespace=args) # Without command
for argv in split_argv[1:]: # Commands
n = argparse.Namespace()
setattr(args, argv[0], n)
parser.parse_args(argv, namespace=n)
return args
parser = argparse.ArgumentParser()
commands = parser.add_subparsers(title='sub-commands')
cmd1_parser = commands.add_parser('cmd1')
cmd1_parser.add_argument('--foo')
cmd2_parser = commands.add_parser('cmd2')
cmd2_parser.add_argument('--foo')
cmd2_parser = commands.add_parser('cmd3')
cmd2_parser.add_argument('--foo')
args = parse_args(parser, commands)
print(args)
It behaves properly, providing nice argparse help:
For ./test.py --help:
usage: test.py [-h] {cmd1,cmd2,cmd3} ...
optional arguments:
-h, --help show this help message and exit
sub-commands:
{cmd1,cmd2,cmd3}
For ./test.py cmd1 --help:
usage: test.py cmd1 [-h] [--foo FOO]
optional arguments:
-h, --help show this help message and exit
--foo FOO
And creates a hierarchy of namespaces containing the argument values:
./test.py cmd1 --foo 3 cmd3 --foo 4
Namespace(cmd1=Namespace(foo='3'), cmd2=None, cmd3=Namespace(foo='4'))
You could try arghandler. This is an extension to argparse with explicit support for subcommands.
Built a full Python 2/3 example with subparsers, parse_known_args and parse_args (running on IDEone):
from __future__ import print_function
from argparse import ArgumentParser
from random import randint
def main():
parser = get_parser()
input_sum_cmd = ['sum_cmd', '--sum']
input_min_cmd = ['min_cmd', '--min']
args, rest = parser.parse_known_args(
# `sum`
input_sum_cmd +
['-a', str(randint(21, 30)),
'-b', str(randint(51, 80))] +
# `min`
input_min_cmd +
['-y', str(float(randint(64, 79))),
'-z', str(float(randint(91, 120)) + .5)]
)
print('args:\t ', args,
'\nrest:\t ', rest, '\n', sep='')
sum_cmd_result = args.sm((args.a, args.b))
print(
'a:\t\t {:02d}\n'.format(args.a),
'b:\t\t {:02d}\n'.format(args.b),
'sum_cmd: {:02d}\n'.format(sum_cmd_result), sep='')
assert rest[0] == 'min_cmd'
args = parser.parse_args(rest)
min_cmd_result = args.mn((args.y, args.z))
print(
'y:\t\t {:05.2f}\n'.format(args.y),
'z:\t\t {:05.2f}\n'.format(args.z),
'min_cmd: {:05.2f}'.format(min_cmd_result), sep='')
def get_parser():
# create the top-level parser
parser = ArgumentParser(prog='PROG')
subparsers = parser.add_subparsers(help='sub-command help')
# create the parser for the "sum" command
parser_a = subparsers.add_parser('sum_cmd', help='sum some integers')
parser_a.add_argument('-a', type=int,
help='an integer for the accumulator')
parser_a.add_argument('-b', type=int,
help='an integer for the accumulator')
parser_a.add_argument('--sum', dest='sm', action='store_const',
const=sum, default=max,
help='sum the integers (default: find the max)')
# create the parser for the "min" command
parser_b = subparsers.add_parser('min_cmd', help='min some integers')
parser_b.add_argument('-y', type=float,
help='an float for the accumulator')
parser_b.add_argument('-z', type=float,
help='an float for the accumulator')
parser_b.add_argument('--min', dest='mn', action='store_const',
const=min, default=0,
help='smallest integer (default: 0)')
return parser
if __name__ == '__main__':
main()
I had more or less the same requirements: Being able to set global arguments and being able to chain commands and execute them in order of command line.
I ended up with the following code. I did use some parts of the code from this and other threads.
# argtest.py
import sys
import argparse
def init_args():
def parse_args_into_namespaces(parser, commands):
'''
Split all command arguments (without prefix, like --) in
own namespaces. Each command accepts extra options for
configuration.
Example: `add 2 mul 5 --repeat 3` could be used to a sequencial
addition of 2, then multiply with 5 repeated 3 times.
'''
class OrderNamespace(argparse.Namespace):
'''
Add `command_order` attribute - a list of command
in order on the command line. This allows sequencial
processing of arguments.
'''
globals = None
def __init__(self, **kwargs):
self.command_order = []
super(OrderNamespace, self).__init__(**kwargs)
def __setattr__(self, attr, value):
attr = attr.replace('-', '_')
if value and attr not in self.command_order:
self.command_order.append(attr)
super(OrderNamespace, self).__setattr__(attr, value)
# Divide argv by commands
split_argv = [[]]
for c in sys.argv[1:]:
if c in commands.choices:
split_argv.append([c])
else:
split_argv[-1].append(c)
# Globals arguments without commands
args = OrderNamespace()
cmd, args_raw = 'globals', split_argv.pop(0)
args_parsed = parser.parse_args(args_raw, namespace=OrderNamespace())
setattr(args, cmd, args_parsed)
# Split all commands to separate namespace
pos = 0
while len(split_argv):
pos += 1
cmd, *args_raw = split_argv.pop(0)
assert cmd[0].isalpha(), 'Command must start with a letter.'
args_parsed = commands.choices[cmd].parse_args(args_raw, namespace=OrderNamespace())
setattr(args, f'{cmd}~{pos}', args_parsed)
return args
#
# Supported commands and options
#
parser = argparse.ArgumentParser(formatter_class=argparse.ArgumentDefaultsHelpFormatter)
parser.add_argument('--print', action='store_true')
commands = parser.add_subparsers(title='Operation chain')
cmd1_parser = commands.add_parser('add', formatter_class=argparse.ArgumentDefaultsHelpFormatter)
cmd1_parser.add_argument('add', help='Add this number.', type=float)
cmd1_parser.add_argument('-r', '--repeat', help='Repeat this operation N times.',
default=1, type=int)
cmd2_parser = commands.add_parser('mult', formatter_class=argparse.ArgumentDefaultsHelpFormatter)
cmd2_parser.add_argument('mult', help='Multiply with this number.', type=float)
cmd2_parser.add_argument('-r', '--repeat', help='Repeat this operation N times.',
default=1, type=int)
args = parse_args_into_namespaces(parser, commands)
return args
#
# DEMO
#
args = init_args()
# print('Parsed arguments:')
# for cmd in args.command_order:
# namespace = getattr(args, cmd)
# for option_name in namespace.command_order:
# option_value = getattr(namespace, option_name)
# print((cmd, option_name, option_value))
print('Execution:')
result = 0
for cmd in args.command_order:
namespace = getattr(args, cmd)
cmd_name, cmd_position = cmd.split('~') if cmd.find('~') > -1 else (cmd, 0)
if cmd_name == 'globals':
pass
elif cmd_name == 'add':
for r in range(namespace.repeat):
if args.globals.print:
print(f'+ {namespace.add}')
result = result + namespace.add
elif cmd_name == 'mult':
for r in range(namespace.repeat):
if args.globals.print:
print(f'* {namespace.mult}')
result = result * namespace.mult
else:
raise NotImplementedError(f'Namespace `{cmd}` is not implemented.')
print(10*'-')
print(result)
Below an example:
$ python argstest.py --print add 1 -r 2 mult 5 add 3 mult -r 5 5
Execution:
+ 1.0
+ 1.0
* 5.0
+ 3.0
* 5.0
* 5.0
* 5.0
* 5.0
* 5.0
----------
40625.0
Another package which supports parallel parsers is "declarative_parser".
import argparse
from declarative_parser import Parser, Argument
supported_formats = ['png', 'jpeg', 'gif']
class InputParser(Parser):
path = Argument(type=argparse.FileType('rb'), optional=False)
format = Argument(default='png', choices=supported_formats)
class OutputParser(Parser):
format = Argument(default='jpeg', choices=supported_formats)
class ImageConverter(Parser):
description = 'This app converts images'
verbose = Argument(action='store_true')
input = InputParser()
output = OutputParser()
parser = ImageConverter()
commands = '--verbose input image.jpeg --format jpeg output --format gif'.split()
namespace = parser.parse_args(commands)
and namespace becomes:
Namespace(
input=Namespace(format='jpeg', path=<_io.BufferedReader name='image.jpeg'>),
output=Namespace(format='gif'),
verbose=True
)
Disclaimer: I am the author. Requires Python 3.6. To install use:
pip3 install declarative_parser
Here is the documentation and here is the repo on GitHub.
In order to parse the sub commands, I used the following (referred from argparse.py code). It parses the sub parser arguments and retains the help for both. Nothing additional passed there.
args, _ = parser.parse_known_args()
you can use the package optparse
import optparse
parser = optparse.OptionParser()
parser.add_option("-f", dest="filename", help="corpus filename")
parser.add_option("--alpha", dest="alpha", type="float", help="parameter alpha", default=0.5)
(options, args) = parser.parse_args()
fname = options.filename
alpha = options.alpha