argparse Basics

argparse 入门

≈ 20 min · python-cmdline · Open in WolfCode

Two add_argument calls — one positional, one flag. Free help text, error messages, and exit codes.

Python · runnable

import argparse

def parse_args(argv):
    parser = argparse.ArgumentParser(description="Greet someone by name.")
    parser.add_argument("name", help="The name of the person to greet")
    parser.add_argument("--shout", action="store_true", help="Print in UPPERCASE")
    return parser.parse_args(argv)

# Test it directly with a list — no subprocess needed.
a = parse_args(["Ada"])
print(a.name, a.shout)             # Ada False

a = parse_args(["Ada", "--shout"])
print(a.name, a.shout)             # Ada True

a = parse_args(["--shout", "Bob"]) # flags can come BEFORE positionals
print(a.name, a.shout)             # Bob True

Loading Python runtime (~5 MB, one-time)…

What you get for free

--help automatically generated
Missing-required-arg error with usage line
Order-independent flag/positional ordering
Exit code 2 on bad arguments