如您所知,在Ruby中,两个相同的字符串没有相同的object_id,而两个相同的符号却没有。例如:
irb(main):001:0> :george.object_id == :george.object_id
=> true
irb(main):002:0> "george".object_id == "george".object_id
=> false
但是,在下面的代码中,它显示两个具有相同值“一个”的字符串具有相同的object_id。
class MyArray < Array
def ==(x)
comparison = Array.new()
x.each_with_index{|item, i| comparison.push(item.object_id.equal?(self[i].object_id))}
if comparison.include?(false) then
false
else
true
end
end
end
class MyHash < Hash
def ==(x)
y = Hash[self.sort]
puts y.class
puts y
x = Hash[x.sort]
puts x.class
puts x
puts "______"
xkeys = MyArray.new(x.keys)
puts xkeys.class
puts xkeys.to_s
puts xkeys.object_id
puts xkeys[0].class
puts xkeys[0]
puts xkeys[0].object_id
puts "______"
xvals = MyArray.new(x.values)
puts "______"
selfkeys = MyArray.new(y.keys)
puts selfkeys.class
puts selfkeys.to_s
puts selfkeys.object_id
puts selfkeys[0].class
puts selfkeys[0]
puts selfkeys[0].object_id
puts "______"
selfvals = MyArray.new(y.values)
puts xkeys.==(selfkeys)
puts xvals.==(selfvals)
end
end
a1 = MyHash[{"one" => 1, "two" => 2}]
b1 = MyHash[{"one" => 1, "two" => 2}]
puts a1.==(b1)
并得到
Hash
{"one"=>1, "two"=>2}
Hash
{"one"=>1, "two"=>2}
______
MyArray
["one", "two"]
21638020
String
one
21641920
______
______
MyArray
["one", "two"]
21637580
String
one
21641920
______
true
true
从结果中可以看到,两个具有相同值“一个”的String对象具有相同的object_id 21641920,而应该具有不同的ID。因此,在这种情况下,谁能给我一些提示或告诉我如何获得不同的ID?最好的祝福。
当将某个String
对象用作a中的键时Hash
,哈希将在内部复制并冻结字符串,并将该副本用作其键。
参考:Hash#store
。
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