blocks|key|1554243|text|我建议改用sort_by：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1554244|objects.sort_by+{%7Cobj%7C+obj.attribute}|code-block|syntax|javascript|1554245|特别是在可以计算属性的情况下。|1554246|或者一种更简洁的方法：|1554247|objects.sort_by(&:attribute)|1554248|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|R|8|@]|9|@]|A|$]]|$1|K|3|L|5|D|7|S|8|@]|9|@]|A|$E|F]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

I recommend using sort_by instead:

<pre><code>objects.sort_by {|obj| obj.attribute}
</code></pre>

Especially if attribute may be calculated.

Or a more concise approach:

<pre><code>objects.sort_by(&amp;:attribute)
</code></pre>

blocks|key|1554092|text|是的，使用Array#sort!很容易。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1554093|myarray.sort!+{+%7Ca,+b%7C++a.attribute+<=>+b.attribute+}|code-block|syntax|javascript|1554094|entityMap|0|LINK|mutability|MUTABLE|url|http://www.ruby-doc.org/core/classes/Array.html#M002209^0|5|B|5|B|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]]|D|@$9|V|A|W|1|X]]|E|$]]|$1|F|3|G|5|H|7|Y|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Z|8|@]|D|@]|E|$]]]|L|$M|$5|N|O|P|E|$Q|R]]]]

Yes, using <a href="http://www.ruby-doc.org/core/classes/Array.html#M002209" rel="noreferrer"><code>Array#sort!</code></a> this is easy.

<pre><code>myarray.sort! { |a, b| a.attribute &lt;=&gt; b.attribute }
</code></pre>

blocks|key|1338799|text|升序：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1338800|objects_array.sort!+{+%7Ca,+b%7C++a.attribute+<=>+b.attribute+}|code-block|syntax|javascript|1338801|或|1338802|objects_array.sort_by{+%7Cobj%7C+obj.attribute+}|1338803|降序：|1338804|objects_array.sort!+{+%7Ca,+b%7C++b.attribute+<=>+a.attribute+}|1338805|1338806|objects_array.sort_by{+%7Cobj%7C+obj.attribute+}.reverse|1338807|entityMap^0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|T|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|U|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|V|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|W|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|X|8|@]|9|@]|A|$]]|$1|M|3|N|5|D|7|Y|8|@]|9|@]|A|$E|F]]|$1|O|3|H|5|6|7|Z|8|@]|9|@]|A|$]]|$1|P|3|Q|5|D|7|10|8|@]|9|@]|A|$E|F]]|$1|R|3|-4|5|6|7|11|8|@]|9|@]|A|$]]]|S|$]]

Ascending order :

<pre><code>objects_array.sort! { |a, b| a.attribute &lt;=&gt; b.attribute }
</code></pre>

or

<pre><code>objects_array.sort_by{ |obj| obj.attribute }
</code></pre>

Descending order : 

<pre><code>objects_array.sort! { |a, b| b.attribute &lt;=&gt; a.attribute }
</code></pre>

or

<pre><code>objects_array.sort_by{ |obj| obj.attribute }.reverse
</code></pre>

blocks|key|1554318|text|如果您需要按两个属性排序，其中第一个属性比第二个属性更重要(意味着只有在第一个参数相等时才考虑第二个参数)，那么您可以这样做|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1554319|myarray.sort{+%7Ca,b%7C+(a.attr1+==+b.attr1)+?+a.attr2+<=>+b.attr2+:+a.attr1+<=>+b.attr1+}|code-block|syntax|javascript|1554320|或者在数组数组的情况下|1554321|myarray.sort{+%7Ca,b%7C+(a[0]+==+b[0])+?+a[1]+<=>+b[1]+:+a[0]+<=>+b[0]+}|1554322|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

in case you need sorting by two attributes, where first one is more important then second (means taking in account second arguments only if first arguments are equal), then you may do like this

<pre><code>myarray.sort{ |a,b| (a.attr1 == b.attr1) ? a.attr2 &lt;=&gt; b.attr2 : a.attr1 &lt;=&gt; b.attr1 }
</code></pre>

or in case of array of arrays

<pre><code>myarray.sort{ |a,b| (a[0] == b[0]) ? a[1] &lt;=&gt; b[1] : a[0] &lt;=&gt; b[0] }
</code></pre>

blocks|key|1554378|text|您可以通过覆盖<=>方法使任何类都可排序：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1554379|class+Person

++attr_accessor+:first_name,+:last_name

++def+initialize(first_name,+last_name)
++++@first_name+=+first_name
++++@last_name+=+last_name
++end

++def+<=>(other)
++++@last_name+%2B+@first_name+<=>+other.last_name+%2B+other.first_name
++end

end|code-block|syntax|javascript|1554380|现在，Person对象的数组在last_name上是可排序的。|1554381|ar+=+[Person.new("Eric",+"Cunningham"),+Person.new("Homer",+"Allen")]

puts+ar++#+=>+[+"Eric+Cunningham",+"Homer+Allen"]++(Person+objects!)

ar.sort!

puts+ar++#+=>+[+"Homer+Allen",+"Eric+Cunningham"+]|1554382|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

You can make any class sortable by overriding the &lt;=> method:

<pre><code>class Person

 attr_accessor :first_name, :last_name

 def initialize(first_name, last_name)
 @first_name = first_name
 @last_name = last_name
 end

 def &lt;=&gt;(other)
 @last_name + @first_name &lt;=&gt; other.last_name + other.first_name
 end

end
</code></pre>

Now an array of Person objects will be sortable on last_name.

<pre><code>ar = [Person.new("Eric", "Cunningham"), Person.new("Homer", "Allen")]

puts ar # =&gt; [ "Eric Cunningham", "Homer Allen"] (Person objects!)

ar.sort!

puts ar # =&gt; [ "Homer Allen", "Eric Cunningham" ]
</code></pre>

blocks|key|1338852|text|更优雅的objects.sort_by(&:attribute)，如果你需要切换顺序，你可以添加一个.reverse。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1338853|entityMap^0|4|S|1E|8|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]|$9|K|A|L|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|M|8|@]|D|@]|E|$]]]|G|$]]

More elegant <code>objects.sort_by(&amp;:attribute)</code>, you can add on a <code>.reverse</code> if you need to switch the order.

blocks|key|1338500|text|如上所述，Array#sort运行良好：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1338501|myarray.sort!+{+%7Ca,+b%7C++a.attribute+<=>+b.attribute+}|code-block|syntax|javascript|1338502|但是，您需要确保为该属性实现了<=>操作符。如果它是Ruby原生数据类型，这不是问题。否则，编写您自己的实现，如果a<+b，则返回-1；如果它们相等，则返回0；如果a>+b，则返回1。|offset|length|style|CODE|1338503|entityMap^0|0|0|F|3|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@$I|R|J|S|K|L]]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

Array#sort works well, as posted above:

<pre><code>myarray.sort! { |a, b| a.attribute &lt;=&gt; b.attribute }
</code></pre>

BUT, you need to make sure that the <code>&lt;=&gt;</code> operator is implemented for that attribute. If it's a Ruby native data type, this isn't a problem. Otherwise, write you own implementation that returns -1 if a &lt; b, 0 if they are equal, and 1 if a > b.

blocks|key|1554027|text|是的，这是可能的|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1554028|http://ariejan.net/2007/01/28/ruby-sort-an-array-of-objects-by-an-attribute/|offset|length|1554029|entityMap|0|LINK|mutability|MUTABLE|url^0|0|0|24|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|N|8|@]|9|@$D|O|E|P|1|Q]]|A|$]]|$1|F|3|-4|5|6|7|R|8|@]|9|@]|A|$]]]|G|$H|$5|I|J|K|A|$L|C]]]]

Yes its possible

<a href="http://ariejan.net/2007/01/28/ruby-sort-an-array-of-objects-by-an-attribute/" rel="nofollow noreferrer">http://ariejan.net/2007/01/28/ruby-sort-an-array-of-objects-by-an-attribute/</a>

blocks|key|1338783|text|@model_name.sort!+{+%7Ca,b%7C+a.attribute+<=>+b.attribute+}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1338784|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>@model_name.sort! { |a,b| a.attribute &lt;=&gt; b.attribute }
</code></pre>

I have an array of objects in Ruby on Rails. I want to sort the array by an attribute of the object. Is it possible?

Sorting an array of objects in Ruby by object attribute?

我在Ruby on Rails中有一个对象数组。我想按对象的属性对数组进行排序。有可能吗？

问对Ruby对象属性中的对象数组进行排序？
EN

回答 9

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