On 1/23/2023 9:12 PM, Chris Angelico wrote:
On Tue, 24 Jan 2023 at 13:09, Jach Feng <jf...@ms4.hinet.net> wrote:
Chris Angelico 在 2023年1月24日 星期二清晨5:00:27 [UTC+8] 的信中寫道：
On Tue, 24 Jan 2023 at 07:47, Cameron Simpson <c...@cskk.id.au> wrote:
But for Jach Feng: the "--" is really expected as something the user
does when they invoke your programme, _explicitly_ saying that what
follows from here is not an argument. So the user is expected to type:
your_script -x -y -- "-4^2+5.3*abs(-2-1)/2"
where there are -x and -y options, then end of options, then an
argument, which would look like an option if there wasn't the "--"
argument.
And if you DON'T expect the user to enter the "--", then why use
argparse? You can just check argv directly to get your arguments.
This entire thread is a massive "how can I use X to do Y?" problem.
ChrisA
The '--' requirement makes its usage less instinctive, and handling argv
directly makes me loss the benefit of using '-h':-)
if "-h" in sys.argv: usage()
else: do_stuff_with(sys.argv[1:])
What is argparse really doing for you?
I second this. "if '-h' in sys.argv:" is usually what I do.
Alternatively, you could use "--arg=" syntax and place your string
"-4^2+5.3*abs(-2-1)/2" its right-hand side":
infix2postfix [options] "--infix=-4^2+5.3*abs(-2-1)/2"
This shouldn't be too hard for a user to work with. You could scan the
argument list for the presence of "--infix=" and display the help
message if it isn't there.
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