{"id":2035,"date":"2013-02-13T10:47:29","date_gmt":"2013-02-13T01:47:29","guid":{"rendered":"http:\/\/www.techscore.com\/blog\/?p=2035"},"modified":"2018-11-14T16:33:56","modified_gmt":"2018-11-14T07:33:56","slug":"activesupport%e3%82%92%e8%aa%ad%e3%82%80-core_extarrayaccess-rb","status":"publish","type":"post","link":"https:\/\/www.techscore.com\/blog\/2013\/02\/13\/activesupport%e3%82%92%e8%aa%ad%e3%82%80-core_extarrayaccess-rb\/","title":{"rendered":"ActiveSupport\u3092\u8aad\u3080: core_ext\/array\/access.rb"},"content":{"rendered":"

\u3053\u3093\u306b\u3061\u306f\u3001\u9234\u6728\u3067\u3059\u3002<\/p>\n

 <\/p>\n

Ruby on Rails \u306e\u7e01\u306e\u4e0b\u306e\u529b\u6301\u3061\u3068\u3044\u3048\u3070 ActiveSupport \u3067\u3059\u3002<\/p>\n

\u666e\u6bb5\u304b\u3089\u300c\u4fbf\u5229\u3060\u306a\u3041\u300d\u3068\u601d\u3044\u306a\u304c\u3089\u4f7f\u3063\u3066\u3044\u308b\u3082\u306e\u306e\u3001\u3044\u304f\u3064\u304b\u306e\u826f\u304f\u4f7f\u3046\u30e1\u30bd\u30c3\u30c9\u3057\u304b\u77e5\u308a\u307e\u305b\u3093\u3002<\/p>\n

\u3068\u3044\u3046\u3053\u3068\u3067\u3001ActiveSupport \u306e\u30bd\u30fc\u30b9\u30b3\u30fc\u30c9\u3092\u8aad\u3093\u3067\u3001\u3057\u3063\u304b\u308a\u5b66\u3073\u305f\u3044\u3068\u601d\u3044\u307e\u3059\u3002<\/p>\n

\u4eca\u56de\u306f core_ext\/array\/access.rb<\/a> \u3092\u8aad\u307f\u307e\u3059\u3002<\/p>\n

 <\/p>\n

Array#from(position)<\/h2>\n

\u3053\u306e\u30e1\u30bd\u30c3\u30c9\u306f\u3001\u914d\u5217\u304b\u3089\u6307\u5b9a\u3057\u305f\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u4ee5\u964d\u306e\u8981\u7d20\u3092\u53d6\u308a\u51fa\u3057\u307e\u3059\u3002<\/p>\n

\u5b9f\u88c5\u306f\u4ee5\u4e0b\u306e\u3088\u3046\u306b\u306a\u3063\u3066\u3044\u307e\u3059\u3002<\/p>\n

def from(position)\r\n  self[position, length] || []\r\nend<\/pre>\n
Array#[](position, length) \u306f\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u304c position \u306e\u8981\u7d20\u304b\u3089 length \u500b\u3092\u53d6\u308a\u51fa\u3057\u307e\u3059\u3002<\/p>\n
\u5b9f\u969b\u306b\u52d5\u304b\u3057\u3066\u307f\u308b\u3068\u3001\u4ee5\u4e0b\u306e\u3088\u3046\u306b\u306a\u308a\u307e\u3059\u3002<\/p>\n
[0, 1, 2].from(0) # => [0, 1, 2]\r\n[0, 1, 2].from(1) # => [1, 2]\r\n[0, 1, 2].from(2) # => [2]\r\n\r\n# \u8ca0\u6570\u3092\u4e0e\u3048\u305f\u5834\u5408\u306f, \u672b\u5c3e\u304b\u3089\u306e\u30a4\u30f3\u30c7\u30c3\u30af\u30b9.\r\n[0, 1, 2].from(-1)  # => [2]\r\n\r\n# \u7bc4\u56f2\u5916\u306e\u5834\u5408\u306f\u7a7a\u306e\u914d\u5217.\r\n[0, 1, 2].from(3)   # => []\r\n[0, 1, 2].from(-10) # => []<\/pre>\n
 <\/p>\n
Array#to(position)<\/h2>\n
Array#to(position) \u306f Array#from(position) \u306e\u5bfe\u3068\u306a\u308b\u30e1\u30bd\u30c3\u30c9\u3067\u3059\u3002<\/p>\n
\u914d\u5217\u306e\u5148\u982d\u304b\u3089\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u304c position+1 \u307e\u3067\u306e\u8981\u7d20\u3092\u53d6\u308a\u51fa\u3057\u307e\u3059\u3002<\/p>\n
\u5b9f\u88c5\u306f\u4ee5\u4e0b\u306e\u3088\u3046\u306b\u306a\u3063\u3066\u3044\u307e\u3059\u3002<\/p>\n
def to(position)\r\n  first position + 1\r\nend<\/pre>\n
Array#first(length) \u306f\u914d\u5217\u306e\u5148\u982d\u304b\u3089 length \u8981\u7d20\u3092\u53d6\u308a\u51fa\u3059\u30e1\u30bd\u30c3\u30c9\u3067\u3059\u3002Array#first(length) \u3092\u5229\u7528\u3057\u3066\u300c\u5148\u982d\u304b\u3089 position+1 \u307e\u3067\u306e\u8981\u7d20\u3092\u53d6\u308a\u51fa\u3059\u300d\u3068\u3044\u3046\u51e6\u7406\u3092\u5b9f\u73fe\u3057\u3066\u3044\u307e\u3059\u3002<\/p>\n
\u52d5\u304b\u3057\u3066\u307f\u308b\u3068\u3001\u4ee5\u4e0b\u306e\u3088\u3046\u306b\u306a\u308a\u307e\u3059\u3002<\/p>\n
[0, 1, 2].to(0)  # => [0]\r\n[0, 1, 2].to(1)  # => [0, 1]\r\n[0, 1, 2].to(2)  # => [0, 1, 2]\r\n[0, 1, 2].to(3)  # => [0, 1, 2]\r\n[0, 1, 2].to(-1) # => []<\/pre>\n
 <\/p>\n
Array#second, third, fourth, fifth, forty_two<\/h2>\n
\u3053\u308c\u3089\u306e\u30e1\u30bd\u30c3\u30c9\u306f\u3001\u914d\u5217\u306e N \u756a\u76ee\u306e\u8981\u7d20\u3092\u53d6\u5f97\u3059\u308b\u30e1\u30bd\u30c3\u30c9\u3067\u3059\u3002<\/p>\n
\u4f8b\u3048\u3070\u3001Array#second \u306f 2 \u756a\u76ee\u306e\u8981\u7d20\u3001Array#third \u3067\u3042\u308c\u3070 3 \u756a\u76ee\u306e\u8981\u7d20\u3092\u8fd4\u3057\u307e\u3059\u3002<\/p>\n
2 \u756a\u76ee\uff08second\uff09\u30013 \u756a\u76ee\uff08third\uff09\u30014 \u756a\u76ee\uff08fourth\uff09\u30015 \u756a\u76ee\uff08fifth\uff09\u3001\u306e\u6b21\u304c 42 \u756a\u76ee\uff08forty_two\uff09\u3067\u3042\u308b\u306e\u306f\u3001reddit \u3068\u3044\u3046\u30b5\u30fc\u30d3\u30b9\u3067\u4f7f\u308f\u308c\u3066\u3044\u308b\u304b\u3089\u3060\u305d\u3046\u3067\u3059\u3002<\/p>\n
\u52d5\u304b\u3057\u3066\u307f\u308b\u3068\u3001\u4ee5\u4e0b\u306e\u3088\u3046\u306b\u306a\u308a\u307e\u3059\u3002<\/p>\n
[1, 2, 3, 4, 5].second # => 2\r\n[1, 2, 3, 4, 5].third  # => 3\r\n[1, 2, 3, 4, 5].fourth # => 4\r\n[1, 2, 3, 4, 5].fifth  # => 5\r\n\r\n# \u8981\u7d20\u304c\u7a7a\u306e\u5834\u5408.\r\n[].fifth # => nil<\/pre>\n
\u4eca\u5f8c\u306f ActiveSupport \u306e\u4ed6\u306e\u6a5f\u80fd\u306e\u30bd\u30fc\u30b9\u3082\u8aad\u3093\u3067\u307f\u3088\u3046\u3068\u601d\u3044\u307e\u3059\u3002<\/p>\n
 <\/p>\n","protected":false},"excerpt":{"rendered":"
\u3053\u3093\u306b\u3061\u306f\u3001\u9234\u6728\u3067\u3059\u3002<\/p>\n
 <\/p>\n
Ruby on Rails \u306e\u7e01\u306e\u4e0b\u306e\u529b\u6301\u3061\u3068\u3044\u3048\u3070 ActiveSupport \u3067\u3059\u3002<\/p>\n
\u666e\u6bb5\u304b\u3089\u300c\u4fbf\u5229\u3060\u306a\u3041\u300d\u3068\u601d\u3044\u306a\u304c\u3089\u4f7f\u3063\u3066\u3044\u308b\u3082\u306e\u306e\u3001\u3044\u304f\u3064\u304b\u306e\u826f\u304f\u4f7f\u3046\u30e1\u30bd\u30c3\u30c9\u3057\u304b\u77e5\u308a\u307e\u305b\u3093\u3002
\u7d9a\u304d\u3092\u8aad\u3080...<\/a><\/p>\n","protected":false},"author":4,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[89,18,84],"tags":[],"_links":{"self":[{"href":"https:\/\/www.techscore.com\/blog\/wp-json\/wp\/v2\/posts\/2035"}],"collection":[{"href":"https:\/\/www.techscore.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.techscore.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.techscore.com\/blog\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/www.techscore.com\/blog\/wp-json\/wp\/v2\/comments?post=2035"}],"version-history":[{"count":1,"href":"https:\/\/www.techscore.com\/blog\/wp-json\/wp\/v2\/posts\/2035\/revisions"}],"predecessor-version":[{"id":17957,"href":"https:\/\/www.techscore.com\/blog\/wp-json\/wp\/v2\/posts\/2035\/revisions\/17957"}],"wp:attachment":[{"href":"https:\/\/www.techscore.com\/blog\/wp-json\/wp\/v2\/media?parent=2035"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.techscore.com\/blog\/wp-json\/wp\/v2\/categories?post=2035"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.techscore.com\/blog\/wp-json\/wp\/v2\/tags?post=2035"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}