🔒 More pythonic way of handling output of function that can return 1 or 2 arguments? | Python | Page 1

lone fern Jul 17, 2024, 5:31 AM

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maybe something with unpacking?

maybe2 = foo() # foo can return 1 or 2 arguments
try:
  a, b = maybe2
except ValueError:
  a = maybe2
try:
  foo2(a, b)
except (SomeError, NameError):
  foo3(a)

haughty thicketBOT Jul 17, 2024, 5:31 AM

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lone fern maybe something with unpacking? ```python maybe2 = foo() # foo can return 1 or 2...

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@lone fern

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buoyant coral Jul 17, 2024, 5:37 AM

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lone fern maybe something with unpacking? ```python maybe2 = foo() # foo can return 1 or 2...

Why does the function return different shapes sometimes?

lone fern Jul 17, 2024, 5:38 AM

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because foo() can be multiple different functions

buoyant coral Jul 17, 2024, 5:38 AM

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what do you mean?

lone fern Jul 17, 2024, 5:39 AM

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def outer(foo: Callable)
  maybe2 = foo() # foo can return 1 or 2 arguments
  try:
    a, b = maybe2
  except ValueError:
    a = maybe2
  try:
    foo2(a, b)
  except (SomeError, NameError):
    foo3(a)

outer(someFunc)
outer(someFunc2)

buoyant coral Jul 17, 2024, 5:40 AM

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lone fern ```python def outer(foo: Callable) maybe2 = foo() # foo can return 1 or 2 argu...

Do you have some examples of functions you'd pass here?

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What kind of objects do they return?

lone fern Jul 17, 2024, 5:40 AM

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a is a discord embed

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b is a filepath string

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it's a path to an icon for the embed

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foo is a function that creates an embed that may or may not have a thumbnail

buoyant coral Jul 17, 2024, 5:42 AM

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lone fern `a` is a discord embed

Sounds like you want to always return embed, filepath. If there's no thumbnail, return None as the second element of the tuple

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def outer(foo):
    embed, filepath = foo()
    if filepath is None:
        return foo3(embed)
    else:
        return foo2(embed, filepath)

lone fern Jul 17, 2024, 5:43 AM

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you forgot about the SomeError

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if foo2 returns SomeError I want the same behavior as if there was no b

buoyant coral Jul 17, 2024, 5:44 AM

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def outer(foo):
    embed, filepath = foo()
    if filepath is None:
        return foo3(embed)
    else:
        try:
            return foo2(embed, filepath)
        except SomeError:
            return foo3(embed)

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what is SomeError?

lone fern Jul 17, 2024, 5:44 AM

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FileNotFound

buoyant coral Jul 17, 2024, 5:45 AM

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Maybe that try-except belongs inside foo2?

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If the file is missing, log some warning message and return an embed as if there was no thumbnail

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actually I'm not sure why you'd need this outer function

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If you know you have an embed with thumbnail, call foo2. If you know that you don't have a thumbnail, call foo3

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Maybe you could have a single foo1 function that accepts an optional thumbnail_path parameter

lone fern Jul 17, 2024, 5:48 AM

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https://paste.pythondiscord.com/L4KQ

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if you really want more context

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i can't put the try except inside foo2

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since that is interaction.response.edit_message

buoyant coral Jul 17, 2024, 5:49 AM

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lone fern https://paste.pythondiscord.com/L4KQ

what are outer, foo, foo2 and foo3 here?

lone fern Jul 17, 2024, 5:50 AM

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foo is embedAndIconPath

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which is the output of self.matchFunc(**self.kwargs)

buoyant coral Jul 17, 2024, 5:50 AM

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Wait. you are always returning embed, fullIconPath from match_and_create_embed

lone fern Jul 17, 2024, 5:50 AM

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there's another function besides match_and_create_embed

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that will not be returning fullIconPath

buoyant coral Jul 17, 2024, 5:51 AM

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return embed, None from it then

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If you're parameterizing something with a function, it's better if it has a uniform interface. It is a big pain to figure out what the function intended to return if it's very diverse

lone fern Jul 17, 2024, 5:54 AM

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hmm i don't like that foo3 needs to be repeated

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is this really the best way?

buoyant coral Jul 17, 2024, 5:56 AM

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If the icon file doesn't exist, do you really want it to pass silently?

lone fern Jul 17, 2024, 5:56 AM

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it's not silent

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i have a print statement

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that specifies when it gets returned without an icon

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oh you mean separately from intentionally returning without icon?

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i mean i'll see it

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and it's expected in most casese

buoyant coral Jul 17, 2024, 5:58 AM

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I'd do something like this:

            embed, fullIconPath = embedAndIconPath
            if fullIconPath is None:
                await interaction.response.edit_message(content=None, embed=embed, view=None)
                print('Successfully returned request without icon after editing.')
                return
            image = discord.File(fullIconPath, filename='icon.png')
            embed.set_thumbnail(url="attachment://icon.png")
            try:
                await interaction.response.edit_message(content=None, embed=embed, attachments=[image], view=None)
                print('Successfully returned request after editing.')
            except FileNotFoundError:
                await interaction.response.edit_message(content=None, embed=embed, view=None)
                print(f'Icon {fullIconPath!r} was not found. Sending embed without icon')

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Catching an error for an undefined variable is a pretty non-obvious move (what variable are you catching?), and it's definitely not the idiomatic way.

wet cairn Jul 17, 2024, 5:59 AM

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pattern matching would be cleaner

buoyant coral Jul 17, 2024, 5:59 AM

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that is also possible

lone fern Jul 17, 2024, 6:00 AM

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what's that

buoyant coral Jul 17, 2024, 6:01 AM

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buoyant coral Catching an error for an undefined variable is a pretty non-obvious move (what v...

Also, NameError is the kind of error that mostly indicates a programming mistake, and you should avoid catching them. You might have a typo in a variable name (like photo instead of image), and you'll have a hard time debugging that

wet cairn Jul 17, 2024, 6:01 AM

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lone fern what's that

https://peps.python.org/pep-0636/

Python Enhancement Proposals (PEPs)

PEP 636 – Structural Pattern Matching: Tutorial | peps.python.org

This PEP is a tutorial for the pattern matching introduced by PEP 634.

lone fern Jul 17, 2024, 6:05 AM

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this seems like a very neat feature

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im trying to build a query command for my bot with stuff like AND and NOT and OR

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could be useful for that

haughty thicketBOT Jul 17, 2024, 7:06 AM

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#🔒 More pythonic way of handling output of function that can return 1 or 2 arguments?