Fail on command line, e:\Works\Python>py infix2postfix.py "-4^2+5.3*abs(-2-1)/2" usage: infix2postfix.py [-h] [infix] infix2postfix.py: error: unrecognized arguments: -4^2+5.3*abs(-2-1)/2
Also fail in REPL, e:\Works\Python>py Python 3.8.8 (tags/v3.8.8:024d805, Feb 19 2021, 13:08:11) [MSC v.1928 32 bit (Intel)] on win32 Type "help", "copyright", "credits" or "license" for more information. >>> import argparse >>> parser = argparse.ArgumentParser(description='Convert infix notation to >>> postfix') >>> parser.parse_args("-4^2+5.3*abs(-2-1)/2") usage: [-h] : error: unrecognized arguments: - 4 ^ 2 + 5 . 3 * a b s ( - 2 - 1 ) / 2 Just can't figure out where is wrong!? --Jach -- https://mail.python.org/mailman/listinfo/python-list