On Wed, Jun 2, 2021 at 1:17 PM Julia Schmidt <accountearns...@gmail.com> wrote:
>
> From https://docs.python.org/3.10/whatsnew/3.10.html:
>
> def http_error(status):
> match status:
> case 400:
> return "Bad request"
> case 404:
> return "Not found"
> case 418:
> return "I'm a teapot"
> case _:
> return "Something's wrong with the Internet"
>
> The wildcard idea looks just wrong and confusing. What if I want to use it as
> a variable and match against it like _ = 504? This is how it should be done:
>
> def http_error(status):
> _ = 504
> match status:
> case 400:
> return "Bad request"
> case 404:
> return "Not found"
> case 418:
> return "I'm a teapot"
> case _:
> return "Gateway Timeout"
> else:
> return "Something's wrong with the Internet"
>
What you're suggesting wouldn't work anyway. The underscore is only
very minorly special in a match statement. *Any* simple name will
function as a catch-all; the only thing that's special about the
underscore is that it won't bind to that name.
match status:
case 400: ...
case 404: ...
case 418: ...
case other:
return "HTTP error %d" % other
The same is true inside any sort of nested match. You can "case [x,
y]:" and it'll take any two values and bind to x and y, or you can
"case [x, _]:" to take any two values, bind the first to x, and ignore
the second.
To match against non-constants, normally you'd want to use an
enumeration or somesuch. You can read more about pattern matching in
PEP 636:
https://www.python.org/dev/peps/pep-0636/
ChrisA
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