blocks|key|2066788|text|符号是用来表示名称和字符串的东西。当你可能需要多次使用一个字符串时，你会想要使用一个符号，因为这更容易，也更有效率。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2066789|刚刚通过谷歌找到了这个，这可能会提供更多的细节：Here+you+go|offset|length|2066790|entityMap|0|LINK|mutability|MUTABLE|url|http://glu.ttono.us/articles/2005/08/19/understanding-ruby-symbols^0|0|O|B|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|O|8|@]|9|@$D|P|E|Q|1|R]]|A|$]]|$1|F|3|-4|5|6|7|S|8|@]|9|@]|A|$]]]|G|$H|$5|I|J|K|A|$L|M]]]]

A symbol is something you use to represent names and strings. You would want to use a symbol when you may have need to use a string several times as this far easier and more productive.

And just found this via google, which may offer greater detail: <a href="http://glu.ttono.us/articles/2005/08/19/understanding-ruby-symbols" rel="nofollow noreferrer">Here you go</a>

blocks|key|2066797|text|符号和字符串是完全不同的，this+post对它们的区别有一些了解。至于何时何地使用它们，在has+many+:through上有一个关于这个主题的相当广泛的帖子。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|2066798|entityMap|0|LINK|mutability|MUTABLE|url|http://onestepback.org/index.cgi/Tech/Ruby/SymbolsAreNotImmutableStrings.red|1|http://blog.hasmanythrough.com/2008/4/19/symbols-are-not-pretty-strings^0|D|9|0|1A|H|1|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@$A|O|B|P|1|Q]|$A|R|B|S|1|T]]|C|$]]|$1|D|3|-4|5|6|7|U|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]|L|$5|G|H|I|C|$J|M]]]]

Symbols and strings are completely different <a href="http://onestepback.org/index.cgi/Tech/Ruby/SymbolsAreNotImmutableStrings.red" rel="nofollow noreferrer">this post</a> has a little insight into the differences. As to when and where to use them, there is a pretty extensive post on this subject over on <a href="http://blog.hasmanythrough.com/2008/4/19/symbols-are-not-pretty-strings" rel="nofollow noreferrer">has many :through</a>.

blocks|key|2066809|text|主要区别在于表示单个值的多个符号是相同的，而对于字符串则不是这样。例如：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2066810|irb(main):007:0>+:test.object_id
=>+83618
irb(main):008:0>+:test.object_id
=>+83618
irb(main):009:0>+:test.object_id
=>+83618|code-block|syntax|javascript|2066811|这是对符号:test的三个引用，它们都是同一个对象。|offset|length|style|CODE|2066812|irb(main):010:0>+"test".object_id
=>+-605770378
irb(main):011:0>+"test".object_id
=>+-605779298
irb(main):012:0>+"test".object_id
=>+-605784948|2066813|这是对字符串"test“的三个引用，但它们都是不同的对象。|2066814|这意味着，根据应用程序的不同，使用符号可能会节省大量内存。比较符号的相等性也更快，因为它们是相同的对象，比较相同的字符串要慢得多，因为需要比较字符串值，而不仅仅是对象ids。|2066815|至于什么时候使用它，我通常使用字符串来处理几乎所有的事情，除了像散列键这样的东西，我真的想要一个唯一的标识符，而不是字符串。|2066816|entityMap^0|0|0|5|5|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Y|8|@$I|Z|J|10|K|L]]|9|@]|A|$]]|$1|M|3|N|5|D|7|11|8|@]|9|@]|A|$E|F]]|$1|O|3|P|5|6|7|12|8|@]|9|@]|A|$]]|$1|Q|3|R|5|6|7|13|8|@]|9|@]|A|$]]|$1|S|3|T|5|6|7|14|8|@]|9|@]|A|$]]|$1|U|3|-4|5|6|7|15|8|@]|9|@]|A|$]]]|V|$]]

The main difference is that multiple symbols representing a single value are identical whereas this is not true with strings. For example:

<pre><code>irb(main):007:0&gt; :test.object_id
=&gt; 83618
irb(main):008:0&gt; :test.object_id
=&gt; 83618
irb(main):009:0&gt; :test.object_id
=&gt; 83618
</code></pre>

Those are three references to the symbol <code>:test</code>, which are all the same object.

<pre><code>irb(main):010:0&gt; "test".object_id
=&gt; -605770378
irb(main):011:0&gt; "test".object_id
=&gt; -605779298
irb(main):012:0&gt; "test".object_id
=&gt; -605784948
</code></pre>

Those are three references to the string "test", but are all different objects.

This means that using symbols can potentially save a good bit of memory depending on the application. It is also faster to compare symbols for equality since they are the same object, comparing identical strings is much slower since the string values need to be compared instead of just the object ids.

As far as when to use which, I usually use strings for almost everything except things like hash keys where I really want a unique identifier, not a string.

blocks|key|2066827|text|String和Symbol之间的另一个不同之处在于，String上有更多用于字符串操作的方法，而Symbol是相对较少的对象。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2066828|查看String+class和Symbol+class的文档。|2066829|entityMap|0|LINK|mutability|MUTABLE|url|http://www.ruby-doc.org/core/classes/String.html|1|http://www.ruby-doc.org/core/classes/Symbol.html^0|0|6|7|6|Q|6|1C|6|0|2|6|F|6|2|C|0|F|C|1|0^^$0|@$1|2|3|4|5|6|7|R|8|@$9|S|A|T|B|C]|$9|U|A|V|B|C]|$9|W|A|X|B|C]|$9|Y|A|Z|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|10|8|@$9|11|A|12|B|C]|$9|13|A|14|B|C]]|D|@$9|15|A|16|1|17]|$9|18|A|19|1|1A]]|E|$]]|$1|H|3|-4|5|6|7|1B|8|@]|D|@]|E|$]]]|I|$J|$5|K|L|M|E|$N|O]]|P|$5|K|L|M|E|$N|Q]]]]

An additional difference between <code>String</code> and <code>Symbol</code> is that a <code>String</code> has a lot more methods on it for string manipulation, while a <code>Symbol</code> is a relatively lean object.

Check out the documentation for the <a href="http://www.ruby-doc.org/core/classes/String.html" rel="noreferrer"><code>String</code> class</a> and the <a href="http://www.ruby-doc.org/core/classes/Symbol.html" rel="noreferrer"><code>Symbol</code> class</a>.

blocks|key|2066841|text|字符串是可变的，符号是不可变的|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2066842|注意:可变对象可以在赋值后更改，而不可变对象只能被覆盖http://www.robertsosinski.com/2009/01/11/the-difference-between-ruby-symbols-and-strings/|offset|length|2066843|entityMap|0|LINK|mutability|MUTABLE|url|http://www.robertsosinski.com/2009/01/11/the-difference-between-ruby-symbols-and-strings/^0|0|R|2H|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|O|8|@]|9|@$D|P|E|Q|1|R]]|A|$]]|$1|F|3|-4|5|6|7|S|8|@]|9|@]|A|$]]]|G|$H|$5|I|J|K|A|$L|M]]]]

Strings are Mutable , Symbols arre immutable 
Note:Mutable objects can be changed after assignment while immutable objects can only
be overwritten
<a href="http://www.robertsosinski.com/2009/01/11/the-difference-between-ruby-symbols-and-strings/" rel="nofollow">http://www.robertsosinski.com/2009/01/11/the-difference-between-ruby-symbols-and-strings/</a>

blocks|key|1852947|text|symbol是不可变的，而string是可变的。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1852948|当我们对字符串执行任何操作时，它会创建一个新对象并占用内存。当我们对字符串执行越来越多的操作时，意味着我们消耗了越来越多的内存。|1852949|符号是不变的对象，这意味着如果我们执行任何操作，那么它将在原始对象中执行更改，它不会创建任何对象，这就是为什么它更有利可图。|1852950|有关更多信息，请访问click+here|offset|length|1852951|entityMap|0|LINK|mutability|MUTABLE|url|http://www.robertsosinski.com/2009/01/11/the-difference-between-ruby-symbols-and-strings/^0|0|0|0|A|A|0|0^^$0|@$1|2|3|4|5|6|7|R|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|S|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|T|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|U|8|@]|9|@$H|V|I|W|1|X]]|A|$]]|$1|J|3|-4|5|6|7|Y|8|@]|9|@]|A|$]]]|K|$L|$5|M|N|O|A|$P|Q]]]]

symbol is immutable and string is mutable.

when we perform any operation on string then it create a new object and take memory. As we perform more and more operation on string means we are consuming more and more memory.

symbol is object that are immutable mean if we perform any operation then it performs changes in original object, It will not create any object, that's why it is more profitable.

for more info, you can <a href="http://www.robertsosinski.com/2009/01/11/the-difference-between-ruby-symbols-and-strings/" rel="nofollow noreferrer">click here</a>

blocks|key|2066886|text|符号可能是灾难的情况。假设您的rails控制器中有params.map(&:to_sym)。现在，如果由于某些原因，您正在将用户提供的数据转换为符号，那么这可能是危险的。如果用户提供的数据太大，并且我们知道symbol不是垃圾收集器，那么最终可能会耗尽服务器的内存，从而导致网站瘫痪。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2066887|entityMap^0|P|K|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|K|8|@]|D|@]|E|$]]]|G|$]]

Case where symbol can be disaster. Lets say you have
<code>params.map(&amp;:to_sym)</code> in your rails controller .
Now here if you are converting the data provided by the user to symbol due to some reason then it could be dangerous. If the data provided by the user is too large and as we know that symbol is not a garbage collector, you might end up exhausting your server's memory which can takedown your website.

blocks|key|2066898|text|主要区别在于，字符串可以在变量中包含值，而符号则不可以。例如：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2066899|x+++++=+++++"hello"
p+x++=>+++++"hello"
p+:x+=>+++++:x|code-block|syntax|javascript|2066900|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

The main difference is that string can have value inside a variable whereas symbol not . For example:
<pre><code>x = &quot;hello&quot;
p x =&gt; &quot;hello&quot;
p :x =&gt; :x
</code></pre>

What's the difference between a string and a symbol in Ruby and when should I use one over the other?

What's the difference between a string and a symbol in Ruby?

数据转换

服务器

在Ruby中，字符串和符号有什么不同?什么时候我应该使用一个而不是另一个？

问在Ruby中字符串和符号有什么区别？
EN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问在Ruby中字符串和符号有什么区别？EN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问在Ruby中字符串和符号有什么区别？
EN