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tap

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配列を変更する

p [].tap{|arr|
  5.times.each do|i|
    arr << i
  end 
} 
# 出力
# [0, 1, 2, 3, 4]

文字列を変更する

p 'a'.tap{|str|
  str << 'b' 
}
# 出力 
# ab

ActiveRecord を覗く

便利!

a = Foo.where(bar:'a').tap{|a| p a.to_sql}.all

配列の中身を見る

[1, 2, 3].tap{|a| p a }.push(4).tap{|a| p a }
# 出力
# [1, 2, 3]
# [1, 2, 3, 4]

ちょっとかっこいい

def foo
  a = []
  5.times.each{|i|
    a << i
  }
  a
end

上が下のように書ける。初期化とリターンがいらないけれど特に読みやすくないのでやっぱりあまりかっこよくないかもしれない。

def foo
  [].tap{|a|
    5.times.each{|i|
      a << i
    }
  }
end
annyamonnya
Rails 初心者
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