This question already has answers here:
How to use argv with Spyder
(4 answers)
Closed 4 years ago.
I don't know how to execute a program with optional arguments on Spyder. I know how to pass variables to it, but my program uses argparse, and I want to execute it with the "-h" or "--help" option, the code is the following one
import argparse
parser = argparse.ArgumentParser()
parser.parse_args()
For now, it only has the default optional argument of "-h"/"--help", I tried putting it on "Command line options" but it doesn't work.
You would have to define the arguments in order for them to be used. It looks like it is just using the default argparse method which only defines the help method in the constructor.
Check the docs here: https://docs.python.org/3/library/argparse.html
Here is an example method for parsing the args I have used before:
import argparse
def process_args(source=None):
parser = argparse.ArgumentParser(prog='my-awesome-program')
parser.add_argument('--value1', dest='value1', type=str)
parser.add_argument('--value2', dest='value2', type=str)
args = parser.parse_args(source)
return args
def main():
args = process_args()
args = vars(args)
my_value_1 = args['value1']
my_value_2 = args['value2']
print('%s, %s' % (my_value_1, my_value_2))
if __name__ == '__main__':
main()
Related
This question already has answers here:
How to insert newlines on argparse help text?
(14 answers)
Closed 3 years ago.
Python's argparse module allows explicit the specification of a version. Unfortunately, it doesn't seem to respect newlines in the output:
import argparse
parser = argparse.ArgumentParser(description="test")
parser.add_argument("--version", "-v", action="version", version="some\ntext")
parser.parse_args()
python3 a.py -v
some text
Any hints on how to work around this?
Try using the RawTextHelpFormatter:
parser = argparse.ArgumentParser(
description="test", formatter_class=argparse.RawTextHelpFormatter
)
You should know that this formatter will affect every argument and not just the version.
You could use a custom Action if you want to do something very specific with the version output:
#!/usr/bin/env python
import argparse
class VersionAction(argparse.Action):
def __init__(self, option_strings, version=None, **kwargs):
super(VersionAction, self).__init__(option_strings, nargs=0, help="show program's version number and exit", **kwargs)
self.version = version
def __call__(self, parser, namespace, values, option_string=None):
print('%s' % self.version)
exit(0)
if __name__ == '__main__':
parser = argparse.ArgumentParser(description="args")
parser.add_argument("--version", "-v", action=VersionAction, version="some\ntext")
parser.parse_args()
Also, this only changes you -v option and does not affect your other options.
Is there a way to use argparse with any list of strings, instead of only with sys.argv?
Here's my problem: I have a program which looks something like this:
# This file is program1.py
import argparse
def main(argv):
parser = argparse.ArgumentParser()
# Do some argument parsing
if __name__ == '__main__':
main(sys.argv)
This works fine when this program is called straight from the command line. However, I have another python script which runs batch versions of this script with different commandline arguments, which I'm using like this:
import program1
arguments = ['arg1', 'arg2', 'arg3']
program1.main(arguments)
I still want to be able to parse the arguments, but argparse automatically defaults to using sys.argv instead of the arguments that I give it. Is there a way to pass in the argument list instead of using sys.argv?
You can pass a list of strings to parse_args:
parser.parse_args(['--foo', 'FOO'])
Just change the script to default to sys.argv[1:] and parse arguments omitting the first one (which is the name of the invoked command)
import argparse,sys
def main(argv=sys.argv[1:]):
parser = argparse.ArgumentParser()
parser.add_argument("--level", type=int)
args = parser.parse_args(argv)
if __name__ == '__main__':
main()
Or, if you cannot omit the first argument:
import argparse,sys
def main(args=None):
# if None passed, uses sys.argv[1:], else use custom args
parser = argparse.ArgumentParser()
parser.add_argument("--level", type=int)
args = parser.parse_args(args)
# Do some argument parsing
if __name__ == '__main__':
main()
Last one: if you cannot change the called program, you can still do something
Let's suppose the program you cannot change is called argtest.py (I added a call to print arguments)
Then just change the local argv value of the argtest.sys module:
import argtest
argtest.sys.argv=["dummy","foo","bar"]
argtest.main()
output:
['dummy', 'foo', 'bar']
Python argparse now has a parameter nargs for add_argument (https://docs.python/3/library/argparse.html).
It allows us to have as many arguments as we want for a named parameter (here, alist)
import argparse
parser = argparse.ArgumentParser()
parser.add_argument("--alist", nargs="*")
args = parser.parse_args()
print(args.alist)
All command line values that follow --alist are added to a list.
Example:
$ python3 argparse-01.py --alist fred barney pebbles "bamm bamm"
['fred', 'barney', 'pebbles', 'bamm bamm']
As you see, it is allowed to quote the arguments, but not necessary unless you need to protect a space.
This question already has answers here:
How to modify the metavar for a positional argument in pythons argparse?
(2 answers)
Closed 7 years ago.
Just started using argparse for parsing commands.
I have a command arg that is -l. This argument takes 2 args from user.
-l ONE_ARG TWO_ARG
In the help file using argparse, I get the following:
-l L L Some message for this argument
How can I replace the 'L' to give a small temple of what the user needs to put into those arguments like so.
-l "First_Name" "Last_Name" Some message for this argument
Basically something more descriptive than 'L L' which means nothing to the user really.
The best options is to use metavars, https://docs.python.org/2/library/argparse.html#metavar which gives
import argparse
parser = argparse.ArgumentParser()
parser.add_argument('-l', nargs=2,
help = "Some message for this argument",
metavar=('"First Name"', '"Second Name"'))
args = vars(parser.parse_args())
A more flexible but less elegant answer may be to manually specify the exact help you want:
import argparse
def print_names():
outstr = "usage: scriptname -l 'First Name' 'Second Name' "
outstr += "Some message for this argument "
print(outstr)
parser = argparse.ArgumentParser()
parser.add_argument('-l', help=print_names(), nargs=2)
args = vars(parser.parse_args())
I'm new to python and currently playing with it.
I have a script which does some API Calls to an appliance. I would like to extend the functionality and call different functions based on the arguments given when calling the script.
Currently I have the following:
parser = argparse.ArgumentParser()
parser.add_argument("--showtop20", help="list top 20 by app",
action="store_true")
parser.add_argument("--listapps", help="list all available apps",
action="store_true")
args = parser.parse_args()
I also have a
def showtop20():
.....
and
def listapps():
....
How can I call the function (and only this) based on the argument given?
I don't want to run
if args.showtop20:
#code here
if args.listapps:
#code here
as I want to move the different functions to a module later on keeping the main executable file clean and tidy.
Since it seems like you want to run one, and only one, function depending on the arguments given, I would suggest you use a mandatory positional argument ./prog command, instead of optional arguments (./prog --command1 or ./prog --command2).
so, something like this should do it:
FUNCTION_MAP = {'top20' : my_top20_func,
'listapps' : my_listapps_func }
parser.add_argument('command', choices=FUNCTION_MAP.keys())
args = parser.parse_args()
func = FUNCTION_MAP[args.command]
func()
At least from what you have described, --showtop20 and --listapps sound more like sub-commands than options. Assuming this is the case, we can use subparsers to achieve your desired result. Here is a proof of concept:
import argparse
import sys
def showtop20():
print('running showtop20')
def listapps():
print('running listapps')
parser = argparse.ArgumentParser()
subparsers = parser.add_subparsers()
# Create a showtop20 subcommand
parser_showtop20 = subparsers.add_parser('showtop20', help='list top 20 by app')
parser_showtop20.set_defaults(func=showtop20)
# Create a listapps subcommand
parser_listapps = subparsers.add_parser('listapps', help='list all available apps')
parser_listapps.set_defaults(func=listapps)
# Print usage message if no args are supplied.
# NOTE: Python 2 will error 'too few arguments' if no subcommand is supplied.
# No such error occurs in Python 3, which makes it feasible to check
# whether a subcommand was provided (displaying a help message if not).
# argparse internals vary significantly over the major versions, so it's
# much easier to just override the args passed to it.
if len(sys.argv) <= 1:
sys.argv.append('--help')
options = parser.parse_args()
# Run the appropriate function (in this case showtop20 or listapps)
options.func()
# If you add command-line options, consider passing them to the function,
# e.g. `options.func(options)`
There are lots of ways of skinning this cat. Here's one using action='store_const' (inspired by the documented subparser example):
p=argparse.ArgumentParser()
p.add_argument('--cmd1', action='store_const', const=lambda:'cmd1', dest='cmd')
p.add_argument('--cmd2', action='store_const', const=lambda:'cmd2', dest='cmd')
args = p.parse_args(['--cmd1'])
# Out[21]: Namespace(cmd=<function <lambda> at 0x9abf994>)
p.parse_args(['--cmd2']).cmd()
# Out[19]: 'cmd2'
p.parse_args(['--cmd1']).cmd()
# Out[20]: 'cmd1'
With a shared dest, each action puts its function (const) in the same Namespace attribute. The function is invoked by args.cmd().
And as in the documented subparsers example, those functions could be written so as to use other values from Namespace.
args = parse_args()
args.cmd(args)
For sake of comparison, here's the equivalent subparsers case:
p = argparse.ArgumentParser()
sp = p.add_subparsers(dest='cmdstr')
sp1 = sp.add_parser('cmd1')
sp1.set_defaults(cmd=lambda:'cmd1')
sp2 = sp.add_parser('cmd2')
sp2.set_defaults(cmd=lambda:'cmd2')
p.parse_args(['cmd1']).cmd()
# Out[25]: 'cmd1'
As illustrated in the documentation, subparsers lets you define different parameter arguments for each of the commands.
And of course all of these add argument or parser statements could be created in a loop over some list or dictionary that pairs a key with a function.
Another important consideration - what kind of usage and help do you want? The different approaches generate very different help messages.
If your functions are "simple enough" take adventage of type parameter https://docs.python.org/2.7/library/argparse.html#type
type= can take any callable that takes a single string argument and
returns the converted value:
In your example (even if you don't need a converted value):
parser.add_argument("--listapps", help="list all available apps",
type=showtop20,
action="store")
This simple script:
import argparse
def showtop20(dummy):
print "{0}\n".format(dummy) * 5
parser = argparse.ArgumentParser()
parser.add_argument("--listapps", help="list all available apps",
type=showtop20,
action="store")
args = parser.parse_args()
Will give:
# ./test.py --listapps test
test
test
test
test
test
test
Instead of using your code as your_script --showtop20, make it into a sub-command your_script showtop20 and use the click library instead of argparse. You define functions that are the name of your subcommand and use decorators to specify the arguments:
import click
#click.group()
#click.option('--debug/--no-debug', default=False)
def cli(debug):
print(f'Debug mode is {"on" if debug else "off"}')
#cli.command() # #cli, not #click!
def showtop20():
# ...
#cli.command()
def listapps():
# ...
See https://click.palletsprojects.com/en/master/commands/
# based on parser input to invoke either regression/classification plus other params
import argparse
parser = argparse.ArgumentParser()
parser.add_argument("--path", type=str)
parser.add_argument("--target", type=str)
parser.add_argument("--type", type=str)
parser.add_argument("--deviceType", type=str)
args = parser.parse_args()
df = pd.read_csv(args.path)
df = df.loc[:, ~df.columns.str.contains('^Unnamed')]
if args.type == "classification":
classify = AutoML(df, args.target, args.type, args.deviceType)
classify.class_dist()
classify.classification()
elif args.type == "regression":
reg = AutoML(df, args.target, args.type, args.deviceType)
reg.regression()
else:
ValueError("Invalid argument passed")
# Values passed as : python app.py --path C:\Users\Abhishek\Downloads\adult.csv --target income --type classification --deviceType GPU
You can evaluate using evalwhether your argument value is callable:
import argparse
def list_showtop20():
print("Calling from showtop20")
def list_apps():
print("Calling from listapps")
my_funcs = [x for x in dir() if x.startswith('list_')]
parser = argparse.ArgumentParser()
parser.add_argument("-f", "--function", required=True,
choices=my_funcs,
help="function to call", metavar="")
args = parser.parse_args()
eval(args.function)()
I am using the argparse package of Python 2.7 to write some option-parsing logic for a command-line tool. The tool should accept one of the following arguments:
"ON": Turn a function on.
"OFF": Turn a function off.
[No arguments provided]: Echo the current state of the function.
Looking at the argparse documentation led me to believe that I wanted two--possibly three--subcommands to be defined, since these three states are mutually exclusive and represent different conceptual activities. This is my current attempt at the code:
parser = argparse.ArgumentParser()
subparsers = parser.add_subparsers()
parser.set_defaults(func=print_state) # I think this line is wrong.
parser_on = subparsers.add_parser('ON')
parser_on.set_defaults(func=set_state, newstate='ON')
parser_off = subparsers.add_parser('OFF')
parser_off.set_defaults(func=set_state, newstate='OFF')
args = parser.parse_args()
if(args.func == set_state):
set_state(args.newstate)
elif(args.func == print_state):
print_state()
else:
args.func() # Catchall in case I add more functions later
I was under the impression that if I provided 0 arguments, the main parser would set func=print_state, and if I provided 1 argument, the main parser would use the appropriate subcommand's defaults and call func=set_state. Instead, I get the following error with 0 arguments:
usage: cvsSecure.py [-h] {ON,OFF} ...
cvsSecure.py: error: too few arguments
And if I provide "OFF" or "ON", print_state gets called instead of set_state. If I comment out the parser.set_defaults line, set_state is called correctly.
I'm a journeyman-level programmer, but a rank beginner to Python. Any suggestions about how I can get this working?
Edit: Another reason I was looking at subcommands was a potential fourth function that I am considering for the future:
"FORCE txtval": Set the function's state to txtval.
The defaults of the top-level parser override the defaults on the sub-parsers, so setting the default value of func on the sub-parsers is ignored, but the value of newstate from the sub-parser defaults is correct.
I don't think you want to use subcommands. Subcommands are used when the available options and positional arguments change depending on which subcommand is chosen. However, you have no other options or positional arguments.
The following code seems to do what you require:
import argparse
def print_state():
print "Print state"
def set_state(s):
print "Setting state to " + s
parser = argparse.ArgumentParser()
parser.add_argument('state', choices = ['ON', 'OFF'], nargs='?')
args = parser.parse_args()
if args.state is None:
print_state()
elif args.state in ('ON', 'OFF'):
set_state(args.state)
Note the optional parameters to parser.add_argument. The "choices" parameter specifies the allowable options, while setting "nargs" to "?" specifies that 1 argument should be consumed if available, otherwise none should be consumed.
Edit: If you want to add a FORCE command with an argument and have separate help text for the ON and OFF command then you do need to use subcommands. Unfortunately there doesn't seem to be a way of specifying a default subcommand. However, you can work around the problem by checking for an empty argument list and supplying your own. Here's some sample code illustrating what I mean:
import argparse
import sys
def print_state(ignored):
print "Print state"
def set_state(s):
print "Setting state to " + s
parser = argparse.ArgumentParser()
subparsers = parser.add_subparsers()
on = subparsers.add_parser('ON', help = 'On help here.')
on.set_defaults(func = set_state, newstate = 'ON')
off = subparsers.add_parser('OFF', help = 'Off help here.')
off.set_defaults(func = set_state, newstate = 'OFF')
prt = subparsers.add_parser('PRINT')
prt.set_defaults(func = print_state, newstate = 'N/A')
force = subparsers.add_parser('FORCE' , help = 'Force help here.')
force.add_argument('newstate', choices = [ 'ON', 'OFF' ])
force.set_defaults(func = set_state)
if (len(sys.argv) < 2):
args = parser.parse_args(['PRINT'])
else:
args = parser.parse_args(sys.argv[1:])
args.func(args.newstate)
There are two problems with your approach.
First you probably already noticed that newstate is not some sub_value of the sub parser and needs to be addressed at the top level of args as args.newstate. That should explain that assigning a default to newstate twice will result in the first value being overwritten. Whether you call your programm with 'ON' or 'OFF' as a parameter, each time set_state() will be called with OFF. If you just want to be able to do python cvsSecure ON and
python cvsSecure OFF the following would work:
from __future__ import print_function
import sys
import argparse
def set_state(state):
print("set_state", state)
def do_on(args):
set_state('ON')
def do_off(args):
set_state('OFF')
parser = argparse.ArgumentParser()
subparsers = parser.add_subparsers()
parser_on = subparsers.add_parser('ON')
parser_on.set_defaults(func=do_on)
parser_on.add_argument('--fast', action='store_true')
parser_off = subparsers.add_parser('OFF')
parser_off.set_defaults(func=do_off)
args = parser.parse_args()
args.func(args)
The second problem is that argparse does handle subparsers as single value arguments, so you have to specify one before invoking parser.parse_args(). You can automate insertion of a lacking argument by adding a extra subparser 'PRINT' and automatically inserting
that using set_default_subparser added to argparse.ArgumentParser() (that code is part
of the package ruamel.std.argparse
from __future__ import print_function
import sys
import argparse
def set_default_subparser(self, name, args=None):
"""default subparser selection. Call after setup, just before parse_args()
name: is the name of the subparser to call by default
args: if set is the argument list handed to parse_args()
, tested with 2.7, 3.2, 3.3, 3.4
it works with 2.6 assuming argparse is installed
"""
subparser_found = False
for arg in sys.argv[1:]:
if arg in ['-h', '--help']: # global help if no subparser
break
else:
for x in self._subparsers._actions:
if not isinstance(x, argparse._SubParsersAction):
continue
for sp_name in x._name_parser_map.keys():
if sp_name in sys.argv[1:]:
subparser_found = True
if not subparser_found:
# insert default in first position, this implies no
# global options without a sub_parsers specified
if args is None:
sys.argv.insert(1, name)
else:
args.insert(0, name)
argparse.ArgumentParser.set_default_subparser = set_default_subparser
def print_state(args):
print("print_state")
def set_state(state):
print("set_state", state)
def do_on(args):
set_state('ON')
def do_off(args):
set_state('OFF')
parser = argparse.ArgumentParser()
subparsers = parser.add_subparsers()
parser_print = subparsers.add_parser('PRINT', help='default action')
parser_print.set_defaults(func=print_state)
parser_on = subparsers.add_parser('ON')
parser_on.set_defaults(func=do_on)
parser_on.add_argument('--fast', action='store_true')
parser_off = subparsers.add_parser('OFF')
parser_off.set_defaults(func=do_off)
parser.set_default_subparser('PRINT')
args = parser.parse_args()
args.func(args)
You don't need to handle in args to do_on(), etc., but it comes in handy if you start specifying options to the different subparsers.