add Partition #1905

[RomanMIzulin]

I have added partition func to result module

Checklist

• I have double checked that there are no unrelated changes in this pull request (old patches, accidental config files, etc)
• I have created at least one test case for the changes I have made
• I have updated the documentation for the changes I have made
• I have added my changes to the CHANGELOG.md

Related issues

• Closes feat: add partition func for result ojbects #1905

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[RomanMIzulin]

maybe add more tests

[sobolevn]

I would expect to have a partition function that:

• Unwraps the values inside both Success and Failure objects

So, something like this:

vals = [Result.from_value(1), Result.from_failure('a')]
x: tuple[list[int], list[str]] = returns.methods.partition(vals)  # type is inferred automatically, of course
assert x[0] == [1]
assert x[1] == ['a']

the same for IOResult must be supported as:

vals = [IOResult.from_value(1), IOResult.from_failure('a')]
x: tuple[list[IO[int]], list[IO[str]]] = returns.methods.partition(vals)  # type is inferred automatically, of course
assert x[0] == [IO(1)]
assert x[1] == [IO('a')]

I guess that we can use ResultBased interface for that.

[RomanMIzulin]

additional func witch do partition and unwraping?

[sobolevn]

not additional, but the only one. there's no problem in writing a for loop to partinion based on is_succesful

[RomanMIzulin]

finally some working code

[RomanMIzulin]

can't understand why IOResult unwrapped to int instead of IO[int]

E   pytest_mypy_plugins.utils.TypecheckAssertionError: Invalid output:
E   Actual:
E     main:7: note: Revealed type is "Tuple[builtins.list[builtins.int], builtins.list[Any]]" (diff)
E   Expected:
E     main:7: note: Revealed type is "Tuple[builtins.list[IO[builtin.int]], builtins.list[IO[builtin.int]]" (diff)
E   Alignment of first line difference:
E     E: ... "Tuple[builtins.list[IO[builtin.int]], builtins.list[IO[builtin.int]...
E     A: ... "Tuple[builtins.list[builtins.int], builtins.list[Any]]"...

[sobolevn]

Because we used an incorrect interface 🤦
Sorry!

We need this one: https://github.com/dry-python/returns/blob/master/returns/interfaces/specific/result.py#L71

[RomanMIzulin]

Because we used an incorrect interface 🤦 Sorry!

We need this one: https://github.com/dry-python/returns/blob/master/returns/interfaces/specific/result.py#L71

used that, seems like working, got from unwrap_or_failure func
https://github.com/RomanMIzulin/returns/blob/7b37a0fd171bc6b4e8fb62daf97736cddc002617/returns/interfaces/unwrappable.py#L10

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 100.00%. Comparing base (82ef3ef) to head (edf92e1).
Report is 160 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff            @@
##            master     #1908   +/-   ##
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  Coverage   100.00%   100.00%           
=========================================
  Files           80        81    +1     
  Lines         2485      2540   +55     
  Branches       437       447   +10     
=========================================
+ Hits          2485      2540   +55     

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[sobolevn]

Thanks a lot! Great work!