Issue #13102 has been updated by jeremyevans0 (Jeremy Evans).


Eregon (Benoit Daloze) wrote:
> This is at least inconsistent with Array#delete, which could be used for the same case as above but doesn't end with a `?`.

This is not exactly true, as `Set#delete?` returns self and not the item if deleted:

```ruby
require 'set'
set = Set[true, false]
p(set.delete?(false) ? 1 : 0)
# => 1
p(set.delete?(false) ? 1 : 0)
# => 0

array = [true, false]
p(array.delete(false) ? 1 : 0)
# => 0
p(array.delete(false) ? 1 : 0)
# => 0
```

> I don't think there are many good examples for predicates with side effects, is it?

No, there aren't a lot of good examples.  I don't think there are any examples in core, and I'm not sure about the rest of stdlib.

> A good part of the Set API is quite inconsistent with the rest, unfortunately (e.g., Set#merge being inplace).
> Maybe we could slowly deprecate these inconsistent methods and align the API with Array and Hash?

We could definitely do that, but that is a feature request, not a bug report.


----------------------------------------
Bug #13102: Confusing method name: Set#delete?
https://bugs.ruby-lang.org/issues/13102#change-80973

* Author: kaikuchn (Kai Kuchenbecker)
* Status: Rejected
* Priority: Normal
* Assignee: 
* Target version: 
* ruby -v: 2.4.0
* Backport: 2.2: UNKNOWN, 2.3: UNKNOWN, 2.4: UNKNOWN
----------------------------------------
Greetings,

a colleague of mine who recently started to learn Ruby managed to greatly confuse me today when he used Set#delete? which he claimed would delete an item from a set.
Reading the documentation I suspect the method was meant to be named delete! as it behaves similiar to Array#uniq! and such methods.

If this is not a mistake, I'd still suggest to change the method name since I think it is very surprising for a method ending in a question mark to have a side effect.

Best regards,
Kai



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