news.gitea.happylizard.me/bin/gems/facets-3.1.0/demo/core/indexable.md

Indexable

Indexable it a module, like Enumerable, but provides methods specific to an indexable collection. The Indexable module can be used independently, but Facets can also automatically use it to extend Array.

require 'facets/array/indexable'

Indexable#head

a = [1,2,3,4,5]
a.head.assert = [1]

Indexable#tail

a = [1,2,3,4,5]
a.tail.assert = [2,3,4,5]

Indexable#foot

a = [1,2,3,4,5]
a.foot.assert = [5]

Indexable#body

a = [1,2,3,4,5]
a.body.assert = [1,2,3,4]

Indexable#mid

a = [1,2,3,4,5]
b = [1,2,3,4,5,6]
a.mid.assert = 3
b.mid.assert = 4
a.mid(1).assert = 4
b.mid(1).assert = 5
b.mid(2).assert = 6
b.mid(-1).assert = 3

Indexable#middle

a = [1,2,3,4,5]
b = [1,2,3,4,5,6]
a.middle.assert = [3]
b.middle.assert = [3,4]

Indexable#thru

[0,1,2,3,4,5].thru(2,4).assert = [2,3,4]
[0,1,2,3,4,5].thru(0,1).assert = [0,1]

Indexable#first=

a = [1,2]
a.first = 0
a.assert = [0,2]

Indexable#last=

a = [1,2]
a.last = 3
a.assert = [1,3]

Indexable#ends

[1,2,3,4,5].ends.assert = 4

Indexable#pos

a = [1,2,3,4,5]
a.pos(1).assert = 0
a.pos(-1).assert = 4

Indexable#range

a = [1,2,3,4,5]
b = [1,2,3,4,5,6]
a.range.assert = (0..4)
b.range.assert = (0..5)
a.range(2,4).assert = (1..3)
b.range(2,3).assert = (1..2)
b.range(4,2).assert = (3..1)

Indexable#first!

a = [1,2,3]
a.first!.assert = 1
a.assert = [2,3]

Indexable#last!

a = [1,2,3]
a.last!.assert = 3
a.assert = [1,2]