[ruby-core:75370] [Ruby trunk Feature#12350] Introduce Array#find! that raises an error if element not found

Issue #12350 has been updated by Nobuyoshi Nakada.


Victor Shepelev wrote:
> > Could you elaborate what is bad in your example? Basically I don't see anything bad in your code except a little bit verbose like in mine solution.
> 
> I don't know! The most popular and widely accepted Ruby Style Guide just bans them: https://github.com/bbatsov/ruby-style-guide#no-and-or-or


I don't think it makes a sense, however, you can use `||` instead if you don't like `or` of course.

```ruby
prices.find { |p| p.key == size } || raise "Price for #{size} not found"
```

And it feels better to me because of the error message.

----------------------------------------
Feature #12350: Introduce Array#find! that raises an error if element not found
https://bugs.ruby-lang.org/issues/12350#change-58495

* Author: Andrey Koleshko
* Status: Open
* Priority: Normal
* Assignee: 
----------------------------------------
It would be great to have some function (like `Hash#fetch`) for `Array` that raises an exception if element not found by passed block in `find`.

For example:

~~~
[].find! { |el| el == 1 }
=> ElementError: element not found
~~~

I just noticed that there are many cases when it's needed to raise an exception (because this is exceptional situation) if an element not found.


Currently I just define methods like  this one:

~~~
def find_price!(size)
  found_price = prices.find { |p| p.key == size }
  fail "Price for #{size} not found" unless found_price
  found_price
end
~~~




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