21天 Ruby-------- symbol

最新推荐文章于 2025-11-07 13:34:03 发布

最新推荐文章于 2025-11-07 13:34:03 发布 · 143 阅读

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本文通过几个Ruby脚本示例介绍了对象ID的概念及其在不同情况下的表现，包括字符串、数字对象以及类属性的处理方式。

Test1.rb


print "1: "
puts "name".object_id
print "1: "
puts "name".object_id
print "1: "
puts "name".object_id

print "2: "
puts :name.object_id
print "2: "
puts :name.object_id
print "2: "
puts :name.object_id

print "3: "
puts 123456.object_id
print "3: "
puts 123456.object_id
print "3: "
puts 123456.object_id

# output
#1: 21719110
#1: 21719080
#1: 21719050 
#  "name".object --> 对象的Id
#2: 34258
#2: 34258
#2: 34258
#  :name.object_id  -->  对象的值的Id
#3: 246913
#3: 246913
#3: 246913

==>
1.对象的相同的字符串，他们的对象不同，但是属性的值的Id相同
像java里面的Long与long区别
3.数字型的对象Id相等

Test2.rb


class A
  attr_accessor :name
end

a = A.new
print "a.name = "
puts a.name

a.name = "Lily"
print "a.name = "
puts a.name

class B
  def name
    @name
  end

  def name=(name)
    @name = name
  end
end

b = B.new
print "b.name = "
puts b.name

b.name = "Lily"
print "b.name = "
puts b.name

# output
#a.name = nil
#a.name = Lily
#b.name = nil
#b.name = Lily

==>
1. 对象属性没有值的时候，为nil，感觉是"Null Object"
2. ttr_accessor :name 的效果当然于class B里面的

Test3.rb


class Symbol
  def to_proc
    proc {|obj, *args| obj.send(self, *args)}
  end
end

words = %w(abc bcd cde def efg)
list = words.map(&:capitalize)
print "1: "
puts list.inspect

list2 = words.map {|w| w.send(:capitalize)}
print "2: "
puts list2.inspect

==>
1. ruby中的神奇函数inspect，
2. capitalize顾名思义
#TODO