Feature #16287

Updated by nobu (Nobuyoshi Nakada) over 2 years ago

I meant to suggest this earlier, but then I think I did not; if I actually did, then please excuse my forgetfulness and 
 close the issue request here. I am very unorganized (also in reallife). 

 Anyway - I will be as short as possible here. 

 I would like to propose that we add `.second` .second and `.third`, .third, in particular for `Array`s. Arrays. I don't care that much for other  
 data structures, so I will limit my initial suggestion here to the "minimum" case. 

 I will next explain as to why I suggest it (as many ruby core members said before, to demonstrate the use case,  
 needs, trade-offs etc...). 

 Consider the following `Array`, Array, aptly called array: 


     array = ['cat','dog','horse','fox','snake'] 

 So five elements, five animals. 

 The archetypical "default" (main) way to query the "slot" at a specific position, in ruby, is via the 
 index number, and []. So for example: 


     array[2] # => "horse" 

 So in this case we asked the array object for its third element (array index starts at 0). 

 This is all fine; we ruby users use this a lot. 

 We also have this available in ruby: 


     array.first # => "cat" 
     array.last    # => "snake" 

 This is often useful too, and I personally like this because it reads "naturally". But 
 I think most of us may agree that the index specifier via [] is the main way for ruby 
 to query elements at a certain position. We can also custom-define [] on our classes 
 to allow for the [] to work (as syntactic sugar) on our own custom classes. 

 Now consider the following situation - we wish to return the first element, the last, 
 and the second element. 

 This way works: 



 This way also works: 



 The last solution, however had, puts me a bit off, in the sense that I dislike 
 the mixing of `[]` [] with longer `.method_name`, .method_name, such as `.first` .first and `.last`. .last. 

 In the last case, I think this would read better: 



 I do not know if this has been suggested before; quite possibly it may have been 
 suggested before. If anyone knows then perhaps there was a reason why the latter 
 was not added. 

 To me, personally, from my point of view, I like a "symmetry" in the code here. 

 I have found in my own code when I end up with a situation like this: 



 Then I tend to much prefer that one instead: 


     array[-1] # Or another way to get the last element such as array.size instead. 

 The reason for the latter is mostly that I feel it "reads" better. But if I use 
 `.first` .first and `.last`, .last, then I would prefer a positional name, such as `.second`. .second. 

 You may wonder why I do not suggest `.fourth`, `.fifth` .fourth, .fifth and so forth. Well, yes, 
 this could be done too, but I think people will use these variants less and less. 
 How often may it happen that you wanted to use `.fifth`, .fifth, aka `[4]`? [4]? Probably not that 
 often compared to `.first`, .first, or `.last`, .last, or even `[1]`. [1]. So my reasoning here is mostly 
 about common use cases; I think `.second` .second and perhaps `.third` .third will be more common 
 than e. g. .fifth. `.second` .second is probably significantly more frequent than `.third` .third 
 too - but I have no problem if more names would be available either. To me this 
 is mostly a detail, not the big picture. I am trying to keep my suggestion here 
 smallish, though, to make it simpler if it is decided that this may be a useful 
 or wanted addition. 

 I should also add that I do not have any problem keeping using the `[]` [] variants. 
 My use case is really motivated almost exclusively from `.first` .first and `.last` .last alone. 
 These two names are probably by far the most commonly used method names, but 
 I think `.second` .second may also be useful. And my reasoning is really mostly with the 
 above explanation alone e. g. "symmetry" in code use between `array.first` array.first and 
 `array[1]`. array[1]. 

 Please feel free to comment in any way as you see fit. I think this was perhaps 
 suggested before but I can not find any older discussion (or perhaps it was 
 many years ago or so, in which case it may be useful to have this more recent 
 discussion too, if only to be able to point others to it if it may come up 
 again in the future). 

 I also agree that the real benefit will be very small; at the same time, there 
 should not be any major problem with the feature either. (Although, perhaps if 
 matz may approve, it should come after ruby 3.0, just to not confuse people 
 about this working; it may be easier to add it past ruby 3.0, so that ruby 
 users do not have to wonder for now whether more method names to numbers may 
 be available. I assume that Active* in rails may have this, but I don't know, 
 I am still not using rails really, so I come from a non-rails point of view 
 as well; I do use sinatra though, it's great - minimal code is great for 
 being able to "build" flexible software.) 

 PS: I limited this to class `Array`. Array. Perhaps the above would fit to other enumerable 
 or enumerators (I mix these up all the time), but my common use case is really 
 motivated almost exclusively by and for class `Array`. Array. The reason is because I 
 tend to end up with array data structures often; they are so easy to work with 
 in ruby.