From: rringler@...
Date: 2018-03-08T04:42:04+00:00
Subject: [ruby-core:85992] [Ruby trunk Feature#14546] Hash#delete!

Issue #14546 has been updated by rringler (Ryan Ringler).


sawa (Tsuyoshi Sawada) wrote:
> What is wrong with using `fetch`?
> 
> ```ruby
> {a: "a"}.fetch(:b) # => KeyError: key not found: :b
> ```

Hash#fetch is not mutative. This proposal is for a whiny version of #delete.

```ruby
hsh = { a: 'a' }; hsh.delete!(:a); hsh # => {}
hsh = { a: 'a' }; hsh.delete!(:b); hsh # => KeyError (key not found: :b)
```

----------------------------------------
Feature #14546: Hash#delete!
https://bugs.ruby-lang.org/issues/14546#change-70856

* Author: rringler (Ryan Ringler)
* Status: Open
* Priority: Normal
* Assignee: matz (Yukihiro Matsumoto)
* Target version: 
----------------------------------------
Hash#delete currently returns nil if a given key is not found in the hash. It would be nice to have a way to check that the key was present in the hash. This can be accomplished with with a block, but it would be nice to have some sugar for this.

~~~ ruby
{ a: 'a' }.delete(:b)                                                  # => nil
{ a: 'a' }.delete(:b) { |key| raise KeyError, "key not found #{key}" } # => KeyError (key not found: b)
~~~

I'd like to propose a Hash#delete! method:

~~~ruby
{ a: 'a' }.delete!(:a) # => 'a'
{ a: 'a' }.delete!(:b) # => KeyError (key not found: :b)
~~~


---Files--------------------------------
hash_delete_bang.patch (2.37 KB)


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