Rails lists have .first and .second – is there a .hundredth or .sixty_nineth ?

Question

Is there a class or other extension for Rails that allows more than the first few elements in a series (and the last)? These work:

[2,45,2,14,53,23,634,346,34,46,643,634,346,34,34].fifth
# -> 53
[2,45,2,14,53,23,634,346,34,46,643,634,346,34,34].last
# -> 34

so where is?

list.sixth
list.hundredth

Is it possible to access this on a collection of objects, like `Client.where( active: true ).second`? — Joshua Pinter, Sep 01 '14 at 17:24
@JoshPinter it should be, given that [ActiveRecord collections are naturally Array class, but mimic being something else](http://stackoverflow.com/questions/14065425/why-are-rails-model-association-results-not-naturally-activerecordrelations). The link here is to a discussion I had on the same issue. — New Alexandria, Sep 01 '14 at 18:22
Yup, after giving it a quick try, this does indeed work. What **doesn't** work is `Client.second` or `Client.third`. Acting directly on the Class, only `Client.first` and `Client.last` work. Cheers. — Joshua Pinter, Sep 01 '14 at 18:53

tadman · Accepted Answer · 2021-02-11T21:31:00.840

70

There was a time when Rails added these, but there was a lot of controversy so most were removed. The only remnant of this experiment is Array#forty_two:

(1..100).to_a.forty_two
# => 42

edited Feb 11 '21 at 21:31

answered Oct 11 '11 at 18:28

tadman

208,517
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Hehe - very funny! Didn't know this. – Dom Mar 28 '12 at 07:52
2

It's actually Array#forty_second :) – Archonic Apr 03 '13 at 15:13
2

@Archonic in Rails 3.2 it was still `#forty_two` – New Alexandria Apr 14 '14 at 14:23
nice info! will not forget this!! – Abhi Jul 18 '14 at 12:38
3

you made my day, lol - btw. in rails4 it's still Array#fourty_two – mfittko Feb 04 '15 at 16:52

score 17 · Answer 2 · answered Oct 11 '11 at 18:26

17

You can just use square brackets:

list[6]
list[100]

answered Oct 11 '11 at 18:26

Tim

14,447
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18

ooh- technically list[5], list[99] (since it starts at 0) – Tim Oct 11 '11 at 18:26
If you need stuff from the end, you can use `list[-1]`, `list[-5]`. – totymedli Dec 19 '19 at 17:04

score 5 · Answer 3 · answered Oct 11 '11 at 19:19

In activesupport, it does monkey patching few of these methods into Array class. If you really want more, you can take a look how to implement from activesupport:

https://github.com/rails/rails/blob/master/activesupport/lib/active_support/core_ext/array/access.rb

Rails lists have .first and .second – is there a .hundredth or .sixty_nineth ?

3 Answers3

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