On 3/12/21 2:49 PM, Ricky Teachey wrote:
On Fri, Mar 12, 2021 at 4:52 PM Ethan Furman wrote:
A question that comes up quite a bit on Stackoverflow is how to test
to see if a value will result in an Enum member, preferably without
having to go through the whole try/except machinery.
Could this be an instance where match-case might become the canonical
solution?
I'm probably getting the syntax wrong, but maybe it would be something like:
match value:
case MyEnum():
assert isinstance(value, MyEnum)
case _:
assert not isinstance(value, MyEnum)
The use case is when you have an unknown value that may or may not convert into
an Enum member. So a three-member Enum would look something like:
```python
match value:
case MyEnum():
pass
case 1|2|3:
value = MyEnum(value)
case _:
handle_error_or_use_default()
```
Seven lines of code. try/except would be something like:
```python
try:
value = MyEnum(value)
except ValueError:
handle_error_or_use_default()
```
vs what I'm envisioning:
```python
value = MyEnum.get(value, some_default)
```
or maybe
```python
value = MyEnum.get(value)
if value is None:
handle_error()
```
--
~Ethan~
_______________________________________________
Python-ideas mailing list -- python-ideas@python.org
To unsubscribe send an email to python-ideas-le...@python.org
https://mail.python.org/mailman3/lists/python-ideas.python.org/
Message archived at
https://mail.python.org/archives/list/python-ideas@python.org/message/Z7C36KHOFDDM6REA4PN6GPPYOJ22DPBY/
Code of Conduct: http://python.org/psf/codeofconduct/
