Practicing with Arrays in Ruby on Rails

gistfile1.txt

irb(main):001:0> [1,1,1] - [1]
=> []
irb(main):002:0> [1,2,3,5].delete(5)
=> 5
irb(main):003:0> [1,2,3,5].delete_at(2)
=> 3
irb(main):004:0> [1,2,3,5].pop(1)
=> [5]
irb(main):005:0> [1,2,3,5].pop(8)
=> [1, 2, 3, 5]
irb(main):006:0> [1,2,3,5].pop(3)
=> [2, 3, 5]
irb(main):008:0> Array.try_convert [1,2,3,5]
=> [1, 2, 3, 5]
irb(main):009:0> (Array.try_convert [1,2,3,5]).at(2)
=> 3
irb(main):014:0> [1] | [23]
=> [1, 23]
irb(main):015:0> [1, [1,2] , [[9,7,[666]]] ].flatten
=> [1, 1, 2, 9, 7, 666]

irb(main):016:0> [1, [1,2] , [[9,7,[666]]] ].flatten 1
=> [1, 1, 2, [9, 7, [666]]]

irb(main):017:0> [1, [1,2] , [[9,7,[666]]] ].include? 5
=> false
irb(main):018:0> [1, [1,2] , [[9,7,[666]]] ].include? 7
=> false
irb(main):019:0> [1, [1,2] , [[9,7,[666]]] ].include? 9
=> false
irb(main):020:0> [1, [1,2] , [[9,7,[666]]] ].flatten.include? 9
=> true
irb(main):021:0> [1, [1,2] , [[9,7,[666]]] ].flatten.include? 5
=> false
irb(main):022:0> [1, [1,2] , [[9,7,[666]]] ].flatten.include? 1
=> true
irb(main):023:0> [1, [1,2] , [[9,7,[666]]] ].flatten.index(2)
=> 2
irb(main):024:0> [1, [1,2] , [[9,7,[666]]] ].flatten.index(1)
=> 0
irb(main):025:0> [1, [1,2] , [[9,7,[666]]] ].flatten.index(9)
=> 3
irb(main):032:0> [].replace ["e","p","c"]
=> ["e", "p", "c"]
irb(main):034:0> ([].replace ["e","p","c"] ).to_s
=> "[\"e\", \"p\", \"c\"]"
irb(main):036:0> ["2","5","7" , [9]].join("-")
=> "2-5-7-9"
irb(main):045:0> [2,5,7 , 9].first
=> 2
irb(main):046:0> [2,5,7 , 9].last
=> 9
irb(main):047:0> [2,5,7 , 9].map{|x| x*2}
=> [4, 10, 14, 18]
irb(main):051:0> [2,5,7 , 9].permutation(2)
=> #<Enumerator: [2, 5, 7, 9]:permutation(2)>
irb(main):052:0> [2,5,7 , 9].permutation(2).to_a
=> [[2, 5], [2, 7], [2, 9], [5, 2], [5, 7], [5, 9], [7, 2], [7, 5], [7, 9], [9,
2], [9, 5], [9, 7]]
irb(main):053:0> [] << 2
=> [2]