I have an argparse function:
def argParse():
# Possible Arguments
parser = argparse.ArgumentParser()
parser.add_argument("-s", "--search", dest="s", help="Seach parameters")
parser.add_argument("-d", "--directory", dest="d", help="Choose Directory to save data")
args = parser.parse_args()
params = str(args.s)
directory = str(args.d)
if params == "None":
print("Search parameters are null, exiting program.")
parser.print_help()
exit(1)
if directory == "None":
print("directory is null, storing to current working directory.")
But, it is adding a extra capitol S and D to the useage output? Any idea on how to clean this up?
usage: scan.py [-h] [-s S] [-d D]
optional arguments:
-h, --help show this help message and exit
-s S, --search S Seach parameters
-d D, --directory D Choose Directory to save data
I think you're looking for the metavar kwarg.
try this:
import argparse
def parse_args():
parser = argparse.ArgumentParser()
parser.add_argument('-s', '--search', dest='s', metavar='\b', help='Search parameters')
args = parser.parse_args()
parse_args()
\b is the backspace character, so it also removes the space between the two,
as opposed to using "" which I beleive would still leave a space after the initial variable name.
output of python argparse_test.py -h:
usage: argparse_test.py [-h] [-s]
optional arguments:
-h, --help show this help message and exit
-s, --search Search parameters
Related
I wanted to create an interface with argparse for my script with subcommands; so, if my script is script.py, I want to call it like python script.py command --foo bar, where command is one of the N possible custom commands.
The problem is, I already tried looking for a solution here on StackOverflow, but it seems like everything I tried is useless.
What I have currently is this:
parser = argparse.ArgumentParser()
parser.add_argument("-x", required=True)
parser.add_argument("-y", required=True)
parser.add_argument("-f", "--files", nargs="+", required=True)
# subparsers for commands
subparsers = parser.add_subparsers(title="Commands", dest="command")
subparsers.required = True
summary_parser = subparsers.add_parser("summary", help="help of summary command")
If I try to run it with:
args = parser.parse_args("-x 1 -y 2 -f a/path another/path".split())
I got this error, as it should be: script.py: error: the following arguments are required: command.
If, however, I run this command:
args = parser.parse_args("summary -x 1 -y 2 -f a/path another/path".split())
I got this error, that I shouldn't have: script.py: error: the following arguments are required: -x, -y, -f/--files.
If I put the command at the end, changing also the order of arguments because of -f, it works.
args = parser.parse_args("-x 1 -f a/path another/path -y 2 summary".split())
If I add the parents keyword in subparser, so substitute the summary_parser line with summary_parser = subparsers.add_parser("summary", help=HELP_CMD_SUMMARY, parents=[parser], add_help=False), then I got:
script.py summary: error: the following arguments are required: command when summary is in front of every other argument;
script.py summary: error: the following arguments are required: -x, -y, -f/--files, command when summary is at the end of the args.
My question is, how I have to setup the parsers to have the behaviour script.py <command> <args>? Every command shares the same args, because they are needed to create certain objects, but at the same time every command can needs other arguments too.
Creating another parser helped me getting what I wanted.
The root parser should add all the optional arguments - and also have add_help=False, to avoid an help message conflict -, then another parser - parser2, with a lot of fantasy - will be created.
The second parser will have subparsers, and they all needs to specify as parents the root parser.
parser = argparse.ArgumentParser(add_help=False)
parser.add_argument() ...
parser2 = argparse.ArgumentParser()
subparsers = parser2.add_subparsers(title="Commands", dest="command")
subparsers.required = True
summary_parser = subparsers.add_parser("summary", parents=[parser])
summary_parser.add_argument("v", "--verbose", action="store_true")
# parse args
args = parser2.parse_args()
Now the output will be this:
usage: script.py [-h] {summary} ...
optional arguments:
-h, --help show this help message and exit
Commands:
{summary}
summary For each report print its summary, then exit
usage: script.py summary [-h] -x X -y Y -f FILES [FILES ...] [-v]
optional arguments:
-h, --help show this help message and exit
-x X
-y Y
-f FILES [FILES ...], --files FILES [FILES ...]
-v, --verbose
I want the following structure with argparse :
usage: ms1.py [-h] [-c] [-u] [password] [DB_name]
optional arguments:
-h, --help show this help message and exit
-c, --c show available items
-u password DB_name, Update database
I wish to place -h -c -u all as optional.
but if -u was declared by user - password & DB_name must be positional to it.
What is the right code ? (I'm so confused by the documentation, many thanks)
Something like this should work for you:
from argparse import ArgumentParser
p = ArgumentParser()
p.add_argument('--c', required=False)
p.add_argument('--u', required=False)
p.add_argument('password')
p.add_argument('db_name')
args = p.parse_args()
print(args)
You don't need to have -h. argparse does it for you at no extra cost.
c and u are optional and password, db_name are required and the position matter.
import argparse
parser = argparse.ArgumentParser()
parser.add_argument('-c', action='store_true', help='show available items')
parser.add_argument('-u', nargs=2, metavar=('password', 'DB_name'), help='Update database')
args = parser.parse_args()
print(args)
samples:
1442:~/mypy$ python3 stack62967549.py -h
usage: stack62967549.py [-h] [-c] [-u password DB_name]
optional arguments:
-h, --help show this help message and exit
-c show available items
-u password DB_name Update database
1442:~/mypy$ python3 stack62967549.py -c
Namespace(c=True, u=None)
1443:~/mypy$ python3 stack62967549.py -u foobar FOO
Namespace(c=False, u=['foobar', 'FOO'])
I have the following code:
# Get parsed arguments
args = argparse.ArgumentParser(description=Messages().Get(112))
# Get the arguments for sinit
args.add_argument('init', help=Messages().Get(100), action="store_true")
args.add_argument('--url', default=None, help=Messages().Get(101))
# Get the arguments for schema import
args.add_argument('schema-import', help=Messages().Get(104), action="store_true")
args.add_argument('--file', default=None, help=Messages().Get(104))
The --url argument should only be used with init. For example: script.py schema-import --url should not be accepted but script.py schema-import --file should.
How to set arguments as child arguments?
As mentioned there might be a way to do this with argparse, I'm not sure, but in any event I find it more transparent to explicitly handle argument dependencies in application logic. This should achieve what I think you want:
import argparse
import sys
args = argparse.ArgumentParser(description="please only use the '--url' argument if you also use the 'init' argument")
# Going to use aliases here it's more conventional. So user can use, eg,
# -i or --init for the first argument.
args.add_argument('-i', '--init', help='init help', action="store_true")
args.add_argument('-u', '--url', default=None, help='init help')
args.add_argument('-s', '--schema-import', help='schema-import help', action="store_true")
args.add_argument('-f', '--file', help='file help')
def main():
arguments = args.parse_args()
if arguments.url and not arguments.init:
# You can log an output or raise an exception if you want
# But most likely a print statment is most appropriate
# Since you are interacting with the CLI.
print("You can only use the URL option with init. Exiting")
sys.exit(0)
print("gaurd clauses passed. Here is my code...")
...
if __name__ == "__main__":
main()
Test results (my file called temp.py):
$python temp.py -u https://www.google.com
You can only use the URL option with init. Exiting
$
$python temp.py -i -u https://www.google.com
Gaurd clauses passed. Here is my code...
Why bother with doing all the logic when you can let argparse do all the work for you?
Simply use Sub-commands to define different "branches" of execution:
args = argparse.ArgumentParser(description=Messages().Get(112))
subparsers = args.add_subparsers()
parser_init = subparsers.add_parser('init', help=Messages().Get(100))
parser_init.add_argument('--url', default=None, help=Messages().Get(101))
parser_schema = subparsers.add_parser('schema-import', help=Messages().Get(104))
parser_schema.add_argument('--file', default=None, help=Messages().Get(104))
And this will give you what you want without any logic added:
>>> print(args.parse_args(['schema-import', '--url', "some.url"]))
usage: args.py [-h] {init,schema-import} ...
args.py: error: unrecognized arguments: --url some.url
>>> print(args.parse_args(['schema-import', '--file', "some.file"]))
Namespace(file='some.file')
I have a Python program that takes as its (only) positional command-line argument one or more file path expressions. I'm using argparse for the CL parsing, and argparse.REMAINDER for the variable that contains the file path(s). See code below:
import argparse
import sys
# Create parser
parser = argparse.ArgumentParser(
description="My test program")
def parseCommandLine():
# Add arguments
parser.add_argument('filesIn',
action="store",
type=str,
nargs=argparse.REMAINDER,
help="input file(s)")
# Parse arguments
args = parser.parse_args()
return(args)
def main():
# Get input from command line
args = parseCommandLine()
# Input files
filesIn = args.filesIn
# Print help message and exit if filesIn is empty
if len(filesIn) == 0:
parser.print_help()
sys.exit()
# Do something
print(filesIn)
if __name__ == "__main__":
main()
Now, when a user runs the script without any arguments, this results in the following help message:
usage: test.py [-h] ...
Where ... represents the positional input. From a user's perspective it would be more informative if the name of the variable (filesIn) was displayed here instead. Especially because typing test.py -h results in this:
usage: test.py [-h] ...
My test program
positional arguments:
filesIn input file(s)
I.e. the usage line displays ... but then in the list of positional arguments filesIn is used.
So my question is whether there's some easy way to change this (i.e. always display filesIn)?
Don't use argparse.REMAINDER here. You are not gathering all remaining arguments, you are trying to take filenames.
Use '+' instead to capture all remaining arguments as filenames and you need at least one:
parser.add_argument('filesIn',
action="store",
type=str,
nargs='+',
help="input file(s)")
This produces better help output:
$ bin/python test.py
usage: test.py [-h] filesIn [filesIn ...]
test.py: error: too few arguments
$ bin/python test.py -h
usage: test.py [-h] filesIn [filesIn ...]
My test program
positional arguments:
filesIn input file(s)
optional arguments:
-h, --help show this help message and exit
I am trying to write usage/help for my python script using the argparse library.
This is my sample code:
import argparse
parser = argparse.ArgumentParser(
description='My description')
parser.add_argument(
"-r", "--remote",
help="help message")
parser.print_help()
Output:
usage: [-h] [-r REMOTE]
My description
optional arguments:
-h, --help show this help message and exit
-r REMOTE, --remote REMOTE
help message
I have no idea why it is printing REMOTE after the -r and --remote switches in the above output.
Can anyone tell me what am I doing wrong here or what should I do to get rid of it?
You are looking at the metavar; it is autogenerated from the option string to form a placeholder. It tells the user that it is there that they need to fill in a value.
You can set an explicit metavar value with the metavar keyword argument:
When ArgumentParser generates help messages, it needs some way to refer to each expected argument. By default, ArgumentParser objects use the dest value as the “name” of each object. By default, for positional argument actions, the dest value is used directly, and for optional argument actions, the dest value is uppercased.
You see it because your argument takes a value; if you expected it to be a toggle, use action='store_true'; in that case the option defaults to False unless the user specifies the switch.
Demo of the latter:
>>> import argparse
>>> parser = argparse.ArgumentParser(
... description='My description')
>>> parser.add_argument("-r", "--remote", action='store_true', help="help message")
_StoreTrueAction(option_strings=['-r', '--remote'], dest='remote', nargs=0, const=True, default=False, type=None, choices=None, help='help message', metavar=None)
>>> parser.print_help()
usage: [-h] [-r]
My description
optional arguments:
-h, --help show this help message and exit
-r, --remote help message
>>> opts = parser.parse_args([])
>>> opts.remote
False
>>> opts = parser.parse_args(['-r'])
>>> opts.remote
True
You are missing action.
import argparse
parser = argparse.ArgumentParser(
description='My description')
parser.add_argument(
"-r", "--remote", action="store_true", # add action
help="help message")
parser.print_help()
usage: -c [-h] [-r]
My description
optional arguments:
-h, --help show this help message and exit
-r, --remote help message