I am making a terminal game using Python's wonderful Cmd library. But i was curious if i could somehow put argparse code into it. Like use argparse to handle the 'args' from my cmd.Cmd() class. To do this, i was really hoping that argparse had a way to manually pass args into it. I skimmed over the docs, but didn't notice anything like that.
2 Answers
parse_args() takes an optional argument args with a list (or tuple) of to parse. parse_args() (without arguments) is equivalent to parse_args(sys.argv[1:]):
In a script,
parse_args()will typically be called with no arguments, and theArgumentParserwill automatically determine the command-line arguments fromsys.argv.
If you do not have a tuple, but a single string, shell-like argument splitting can be accomplished using shlex.split()
>>> shlex.split('"A" B C\\ D')
['A', 'B', 'C D']
Note that argparse will print usage and help messages as well as exit() on fatal errors. You can override .error() to handle errors yourself:
class ArgumentParserNoExit(argparse.ArgumentParser):
def error(self, message):
raise ValueError(message) # or whatever you like
3 Comments
Kieee
Side note for anyone else taking this as an answer: if you imput an invalid command (like 'help' instead of '--help') argparse will give you an error(visually) and THEN raise an error. So if you
except the error the user will still see the error, but the script wont crash.
dhke
@Cyanite
argparse will also exit() on fatal errors. Override .error() on the parser to fix that.Kieee
I do not understand the part about overriding the
.error() can i not just except SystemExit: pass? It's a game - I don't want it to crash everytime players typo a command in Cmd()You could also try namedtuple to manually provide the input arguments,
from collections import namedtuple
ManualInput = namedtuple("ManualInput", ["arg1", "arg2"])
args = ManualInput(1, 4)
you will get
In [1]: print(args.arg2)
Out[1]: 4
parse_args(args)?sys.argv.parse_args()is equal toparse_args(sys.argv). If you want to pass a single shell-like string (with quoting), you might want to useshlex.split(), first.shlex?