루비 사용자 가이드 - 배열

ruby> ary = [1, 2, "3"]
   [1, 2, "3"]

ary = Array.new       # => []
Array.new(3)           # => [nil,nil,nil]
Array.new(3, true)     # => [nil,nil,nil]

# 해쉬의 배열
Array.new(4) {Hash.new}  # => [{}, {}, {}, {}]

# 2차원 배열
Array.new(3){Array.new(3)}
[[nil, nil, nil],[nil, nil, nil],[nil, nil, nil]]

arr = [1, 2, 3, 4, 5, 6]
arr[2]    #=> 3
arr[100]  #=> nil
arr[-3]   #=> 4
arr[2, 3] #=> [3, 4, 5]
arr[1..4] #=> [2, 3, 4, 5]

arr.at(3) #=> 4

arr=[1,2,3,4,5,6]
puts arr.fetch(100)  # `fetch': index 100 outside of array bounds: -6...6 (IndexError)

arr = [1,2,3,4,5,6]
arr.first # 1
arr.last  # 6

arr.drop(3)  #=> [4, 5, 6]

browsers = ['Chrome', 'Firefox', 'Safari', 'Opera', 'IE']
browsers.length #=> 5
browsers.count #=> 5

browser.empty?  #=>false

browser.include?('Konqueror') #=> false

arr = [1,2,3,4]
arr.push(5)     #=> [1,2,3,4,5]
arr << 6        #=> [1,2,3,4,5,6]

arr = [1,2,3,4]
arr.unshift(0)  #=> [0,1,2,3,4]

arr = [1,2,3,4,5]
arr.insert(3, 'apple') #=>[1,2,3,'apple',4,5]

arr = [1,2,3,4,5]
arr.insert(3, 'apple', 'pear', 'orange') #=>[1,2,3,"apple","pear","orange",4,5,6]

ruby> ary + ["foo", "bar"]
   [1, 2, "3", "foo", "bar"]
ruby> ary * 2
   [1, 2, "3", 1, 2, "3"]

ruby> str = ary.join(":")
   "1:2:3"
ruby> str.split(":")
   ["1", "2", "3"]

ruby> h = {1 => 2, "2" => "4"}
   {1=>2, "2"=>"4"}
ruby> h[1]
   2
ruby> h["2"]
   "4"
ruby> h[5]
   nil
ruby> h[5] = 10    # appending an entry
   10
ruby> h
   {5=>10, 1=>2, "2"=>"4"}
ruby> h.delete 1   # deleting an entry by key
   2
ruby> h[1]
   nil
ruby> h
   {5=>10, "2"=>"4"}