blocks|key|1115957|text|class+Person
++def+initialize(name,+lastName+=+nil)
++++name+=+name+%2B+"+"+%2B+lastName+unless+lastName.nil?
++++@name+=+name
++end
end|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1115958|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>class Person
 def initialize(name, lastName = nil)
 name = name + " " + lastName unless lastName.nil?
 @name = name
 end
end
</code></pre>

blocks|key|901186|text|我倾向于这样做|type|unstyled|depth|inlineStyleRanges|entityRanges|data|901187|class+Person
++def+self.new_using_both_names(first_name,+last_name)
++++self.new([first_name,+last_name].join("+"))
++end

++def+self.new_using_single_name(single_name)
++++self.new(single_name)
++end

++def+initialize(name)
++++@name+=+name
++end
end|code-block|syntax|javascript|901188|但我不知道这是不是最好的方法。|901189|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

I tend to do

<pre><code>class Person
 def self.new_using_both_names(first_name, last_name)
 self.new([first_name, last_name].join(" "))
 end

 def self.new_using_single_name(single_name)
 self.new(single_name)
 end

 def initialize(name)
 @name = name
 end
end
</code></pre>

But I don't know if this is the best approach.

blocks|key|1115993|text|class+StatementItem
++attr_reader+:category,+:id,+:time,+:amount

++def+initialize(item)
++++case+item
++++when+Order
++++++initialize_with_order(item)
++++when+Transaction
++++++initialize_with_transaction(item)
++++end
++end

++def+valid?
++++!(@category+&&+@id+&&+@time+&&+@amount).nil?
++end

++private
++++def+initialize_with_order(order)
++++++return+nil+if+order.status+!=+'completed'
++++++@category+=+'order'
++++++@id+=+order.id
++++++@time+=+order.updated_at
++++++@amount+=+order.price
++++end

++++def+initialize_with_transaction(transaction)
++++++@category+=+transaction.category
++++++@id+=+transaction.id
++++++@time+=+transaction.updated_at
++++++@amount+=+transaction.amount
++++end

end|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1115994|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>class StatementItem
 attr_reader :category, :id, :time, :amount

 def initialize(item)
 case item
 when Order
 initialize_with_order(item)
 when Transaction
 initialize_with_transaction(item)
 end
 end

 def valid?
 !(@category &amp;&amp; @id &amp;&amp; @time &amp;&amp; @amount).nil?
 end

 private
 def initialize_with_order(order)
 return nil if order.status != 'completed'
 @category = 'order'
 @id = order.id
 @time = order.updated_at
 @amount = order.price
 end

 def initialize_with_transaction(transaction)
 @category = transaction.category
 @id = transaction.id
 @time = transaction.updated_at
 @amount = transaction.amount
 end

end
</code></pre>

blocks|key|1116016|text|您可以使用Ruby在konstructor中声明多个构造函数并模拟重载：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1116017|class+Person
++def+initialize(name)
++++@name+=+name
++end

++konstructor
++def+from_two_names(first_name,+last_name)
++++@name+=+first_name+%2B+'+'+%2B+last_name
++end
end

Person.new('John+Doe')
Person.from_two_names('John',+'Doe')|code-block|syntax|javascript|1116018|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/snovity/konstructor^0|A|B|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@$A|R|B|S|1|T]]|C|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@]|C|$G|H]]|$1|I|3|-4|5|6|7|V|8|@]|9|@]|C|$]]]|J|$K|$5|L|M|N|C|$O|P]]]]

You can use <a href="https://github.com/snovity/konstructor" rel="nofollow noreferrer">konstructor</a> gem to declare multiple constructors in Ruby and imitate overloading:

<pre><code>class Person
 def initialize(name)
 @name = name
 end

 konstructor
 def from_two_names(first_name, last_name)
 @name = first_name + ' ' + last_name
 end
end

Person.new('John Doe')
Person.from_two_names('John', 'Doe')
</code></pre>

blocks|key|1116073|text|查看受Elixir+pattern+matching特性启发的functional-ruby+gem。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1116074|+++class+Person
+++++include+Functional::PatternMatching

+++++defn(:initialize,+String)+{+%7Cname%7C+
+++++++@name+=+name+
+++++}

+++++defn(:initialize,+String,+String)+{%7Cfirst_name,+last_name%7C+
++++++@name+=+first_name+%2B+'+'+%2B+last_name
+++++}
+++end|code-block|syntax|javascript|1116075|entityMap|0|LINK|mutability|MUTABLE|url|http://jerrydantonio.com/functional-ruby/Functional/PatternMatching.html|1|https://github.com/jdantonio/functional-ruby^0|A|G|0|V|F|1|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@$A|T|B|U|1|V]|$A|W|B|X|1|Y]]|C|$]]|$1|D|3|E|5|F|7|Z|8|@]|9|@]|C|$G|H]]|$1|I|3|-4|5|6|7|10|8|@]|9|@]|C|$]]]|J|$K|$5|L|M|N|C|$O|P]]|Q|$5|L|M|N|C|$O|R]]]]

checkout <a href="https://github.com/jdantonio/functional-ruby" rel="nofollow noreferrer">functional-ruby</a> gem which is inspired by Elixir <a href="http://jerrydantonio.com/functional-ruby/Functional/PatternMatching.html" rel="nofollow noreferrer">pattern matching</a> features.

<pre class="lang-rb prettyprint-override"><code> class Person
 include Functional::PatternMatching

 defn(:initialize, String) { |name| 
 @name = name 
 }

 defn(:initialize, String, String) {|first_name, last_name| 
 @name = first_name + ' ' + last_name
 }
 end
</code></pre>

In Java you can overload constructors:

<pre><code>public Person(String name) {
 this.name = name;
}
public Person(String firstName, String lastName) {
 this(firstName + " " + lastName);
}
</code></pre>

Is there a way in Ruby to achieve this same result: two constructors that take different arguments?

In Ruby is there a way to overload the initialize constructor?

Java

在Java中，您可以重载构造函数：public Person(String name) {  this.name = name;}public Person(String firstName, String lastName) {   this(firstName + " " + lastName);}在Ruby中有没...

问在Ruby中，有没有重载初始化构造函数的方法？
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