[セットトップ]rubyオブジェクトをコピーする方法(dupとclone)
3629 ワード
Ruby Object#clone Object#dup copy ， dup ， clone ， singleton method
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s = "cat"
def s.upcase
"CaT"
end
s_dup = s.dup
s_clone = s.clone
s_dup.upcase #=> "CAT" (singleton method not copied)
s_clone.upcase #=> "CaT" (uses singleton method)
dup clone Shallow Copy， ， ， 。
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arr1 = [ 1, "flipper", 3 ]
arr2 = arr1.dup
arr2[2] = 99
arr2[1][2] = 'a'
arr1 #=> [1, "flapper", 3]
arr2 #=> [1, "flapper", 99]
arr1 String ， arr2 ， arr2 ，arr1 。
Deep Copy， Marshal
[ruby] view plaincopyprint?
arr1 = [ 1, "flipper", 3 ]
arr2 = Marshal.load(Marshal.dump(arr1))
arr2[2] = 99
arr2[1][2] = 'a'
arr1 #=> [1, "flipper", 3]
arr2 #=> [1, "flapper", 99]
arr2 String arr1 ， 。。。 Marshal
class initialize_copy， ，
[ruby] view plaincopyprint?
class Document
attr_accessor :title, :text
attr_reader :timestamp
def initialize(title, text)
@title, @text = title, text
@timestamp = Time.now
end
end
doc1 = Document.new("Random Stuff", "Haha")
sleep 10
doc2 = doc1.clone
doc1.timestamp == doc2.timestamp #=> true
， initialize ， timestamp 。 ， Document initialize_copy 。initialize_copy
[ruby] view plaincopyprint?
class Document #Reopen the class
def initialize_copy(other)
@timestamp = Time.now
end
end
doc3 = Document.new("More Stuff", "Haha")
sleep 10
doc4 = doc1.clone
doc3.timestamp == doc4.timestamp #=> false
Ruby 。。。
PS： The Ruby Way
Ruby (object) . google , .
, b = a ? :
>> a= [0,[1,2]]
>> b=a
>> b[0]=88
>> b[1][0]=99
>> b
=> [88, [99, 2]]
>> a
=> [88, [99, 2]]
, b, a . :
>> b.equal?(a)
=> true
b a object, . b = a .
b = a.dup ?? :
>> a= [0,[1,2]]
>> b=a.dup
>> b[0]=88
>> b[1][0]=99
>> b
=> [88, [99, 2]]
>> a
=> [0, [99, 2]]
, b , a .(0 , 1 99).
dup ( Array ), .
, b = a.clone ? :
>> a= [0,[1,2]]
>> b=a.clone
>> b[0]=88
>> b[1][0]=99
>> b
=> [88, [99, 2]]
>> a
=> [0, [99, 2]]
dup . clone !
ruby dup clone shallow , object .
, Ruby ? , :
>> a= [0,[1,2]]
>> b=Marshal.load(Marshal.dump(a))
>> b[0]=88
>> b[1][0]=99
>> b
=> [88, [99, 2]]
>> a= [0,[1,2]]
=> [0, [1, 2]]
b a !!! !!!
" " ? object Marshal.dump . :
>> t=Object.new
>> def t.test; puts ‘test’ end
>> Marshal.dump(t)
TypeError: singleton can’t be dumped
from (irb):59:in `dump’
from (irb):59
ruby deep clone , :
http://d.hatena.ne.jp/pegacorn/20070417/1176817721
http://www.artima.com/forums/flat.jsp?forum=123&thread=40913