blocks|key|693835|text|Ruby风格的赋值是新的Ruby1.9散列语法的一部分，因此请记住，这种语法不适用于旧版本的key:+value。此外，关键字将是符号。如果您可以接受这两个约束，那么新的哈希的工作方式就像旧的哈希一样；没有理由(也许除了样式之外)转换它们。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|693836|entityMap^0|1A|A|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|$]]

The <code>key: value</code> JSON-style assignments are a part of the new Ruby 1.9 hash syntax, so bear in mind that this syntax will not work with older versions of Ruby. Also, the keys are going to be symbols. If you can live with those two constraints, new hashes work just like the old hashes; there's no reason (other than style, perhaps) to convert them.

blocks|key|477838|text|key:+"value"是Ruby1.9的一个便利特性；只要您知道您的环境将支持它，我就认为没有理由不使用它。只是输入一个冒号要比输入一个火箭容易得多，而且我认为它看起来更干净。如果你还不了解文件操作和正则表达式，那么对于你来说，这似乎是一个理想的学习体验。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|477839|entityMap^0|0|C|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|$]]

<code>key: "value"</code> is a convenience feature of Ruby 1.9; so long as you know your environment will support it, I see no reason not to use it. It's just much easier to type a colon than a rocket, and I think it looks much cleaner. As for there being a gem to do the conversion, probably not, but it seems like an ideal learning experience for you, if you don't already know file manipulation and regular expressions.

blocks|key|693932|text|是的，这是有区别的。这些是合法的：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|693933|h+=+{+:$in+=>+array+}
h+=+{+:'a.b'+=>+'c'+}
h[:s]+=+42|code-block|syntax|javascript|693934|但这些不是：|693935|h+=+{+$in:+array+}
h+=+{+'a.b':+'c'+}+#+but+this+is+okay+in+Ruby2.2%2B
h[s:]+=+42|693936|您还可以在=>中使用任何内容作为键，因此可以执行以下操作：|offset|length|style|CODE|693937|h+=+{+C.new+=>+11+}
h+=+{+23+=>+'pancakes+house?'+}|693938|但你不能这样做：|693939|h+=+{+C.new:+11+}
h+=+{+23:+'pancakes+house?'+}|693940|只有当你所有的哈希键都是“简单”符号时，JavaScript样式(key:+value)才有用(或多或少与/\A[a-z_]\w*\z/i匹配的东西解析器对这些键使用它的标签模式)。|693941|在使用MongoDB时，散列样式的符号显示得比较多，所以如果使用MongoDB，最终会混合使用:$in样式。而且，如果您曾经使用特定的散列键(h[:k])而不仅仅是整个散列(h+=+{+...+})，那么对于符号，仍然必须使用冒号优先样式；对于在散列之外使用的符号，也必须使用前导冒号样式。我更喜欢保持一致，所以我根本不会为JavaScript风格而烦恼。|693942|JavaScript风格的一些问题已经在Ruby2.2中得到了修复。现在，如果符号不是有效的标签，则可以使用引号，例如：|693943|h+=+{+'where+is':+'pancakes+house?',+'$set':+{+a:+11+}+}|693944|但是如果你的key不是符号，你仍然需要hashrocket。|693945|entityMap^0|0|0|0|0|5|2|0|0|0|0|X|A|1H|G|0|1B|4|1Z|5|2F|B|0|0|0|0^^$0|@$1|2|3|4|5|6|7|18|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|19|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|1A|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|1B|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|1C|8|@$M|1D|N|1E|O|P]]|9|@]|A|$]]|$1|Q|3|R|5|D|7|1F|8|@]|9|@]|A|$E|F]]|$1|S|3|T|5|6|7|1G|8|@]|9|@]|A|$]]|$1|U|3|V|5|D|7|1H|8|@]|9|@]|A|$E|F]]|$1|W|3|X|5|6|7|1I|8|@$M|1J|N|1K|O|P]|$M|1L|N|1M|O|P]]|9|@]|A|$]]|$1|Y|3|Z|5|6|7|1N|8|@$M|1O|N|1P|O|P]|$M|1Q|N|1R|O|P]|$M|1S|N|1T|O|P]]|9|@]|A|$]]|$1|10|3|11|5|6|7|1U|8|@]|9|@]|A|$]]|$1|12|3|13|5|D|7|1V|8|@]|9|@]|A|$E|F]]|$1|14|3|15|5|6|7|1W|8|@]|9|@]|A|$]]|$1|16|3|-4|5|6|7|1X|8|@]|9|@]|A|$]]]|17|$]]

Yes, there is a difference. These are legal:

<pre><code>h = { :$in =&gt; array }
h = { :'a.b' =&gt; 'c' }
h[:s] = 42
</code></pre>

but these are not:

<pre><code>h = { $in: array }
h = { 'a.b': 'c' } # but this is okay in Ruby2.2+
h[s:] = 42
</code></pre>

You can also use anything as a key with <code>=&gt;</code> so you can do this:

<pre><code>h = { C.new =&gt; 11 }
h = { 23 =&gt; 'pancakes house?' }
</code></pre>

but you can't do this:

<pre><code>h = { C.new: 11 }
h = { 23: 'pancakes house?' }
</code></pre>

The JavaScript style (<code>key: value</code>) is only useful if all of your Hash keys are "simple" symbols (more or less something that matches <code>/\A[a-z_]\w*\z/i</code>, AFAIK the parser uses its label pattern for these keys).

The <code>:$in</code> style symbols show up a fair bit when using MongoDB so you'll end up mixing Hash styles if you use MongoDB. And, if you ever work with specific keys of Hashes (<code>h[:k]</code>) rather than just whole hashes (<code>h = { ... }</code>), you'll still have to use the colon-first style for symbols; you'll also have to use the leading-colon style for symbols that you use outside of Hashes. I prefer to be consistent so I don't bother with the JavaScript style at all.

Some of the problems with the JavaScript-style have been fixed in Ruby 2.2. You can now use quotes if you have symbols that aren't valid labels, for example:

<pre><code>h = { 'where is': 'pancakes house?', '$set': { a: 11 } }
</code></pre>

But you still need the hashrocket if your keys are not symbols.

blocks|key|693981|text|做:key+=>+value和做key:+value是一样的，实际上只是为了方便。我还没有见过其他使用=>的语言，但是像Javascript这样的其他语言在它们的Hash等价数据类型中使用了key:+value。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|693982|至于一个gem来转换你写散列的方式，我只会坚持你当前项目的方式。|693983|*请注意，在使用key:+value时，键将是一个符号，要在foo散列中访问存储在该键中的值，仍将是foo[:key]。|693984|entityMap^0|1|D|G|A|1F|2|2N|A|0|0|8|A|U|3|1E|9|0^^$0|@$1|2|3|4|5|6|7|L|8|@$9|M|A|N|B|C]|$9|O|A|P|B|C]|$9|Q|A|R|B|C]|$9|S|A|T|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|U|8|@]|D|@]|E|$]]|$1|H|3|I|5|6|7|V|8|@$9|W|A|X|B|C]|$9|Y|A|Z|B|C]|$9|10|A|11|B|C]]|D|@]|E|$]]|$1|J|3|-4|5|6|7|12|8|@]|D|@]|E|$]]]|K|$]]

Doing <code>:key =&gt; value</code> is the same as doing <code>key: value</code>, and is really just a convenience. I haven't seen other languages that use the <code>=&gt;</code>, but others like Javascript use the <code>key: value</code> in their Hash-equivalent datatypes. 

As for a gem to convert the way you wrote out your hashes, I would just stick with the way you are doing it for your current project. 

*Note that in using <code>key: value</code> the key will be a symbol, and to access the value stored at that key in a <code>foo</code> hash would still be <code>foo[:key]</code>.

Is there any difference between <code>:key =&gt; "value"</code> (hashrocket) and <code>key: "value"</code> (Ruby 1.9) notations?

If not, then I would like to use <code>key: "value"</code> notation. Is there a gem that helps me to convert from <code>:x =&gt;</code> to <code>x:</code> notations?

Is there any difference between the `:key => "value"` and `key: "value"` hash notations?

MongoDB

:key => "value" (hashrocket)和key: "value" (Ruby1.9)符号有什么不同吗？如果不是，那么我想使用key: "value"表示法。有没有能帮助我从:x =>转换成x:符号的gem？

问`:key => "value"`和`key："value"`散列符号有什么区别吗？
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问`:key => "value"`和`key："value"`散列符号有什么区别吗？
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