blocks|key|231692|text|它们对于转义带有JavaScript的超文本标记语言非常有用，因为你已经用完了引用方法：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|231693|link+=+%25q[<a+href="javascript:method('call')">link</a>]|code-block|syntax|javascript|231694|我还发现它们在处理多行SQL语句时非常有用：|231695|execute(%25Q[
++INSERT+INTO+table_a+(column_a)
++++SELECT+value
++++++FROM+table_b
++++++WHERE+key='value'
])|231696|这样做的好处是您不需要注意查询中使用的引号类型。它将与单人、双人或两者一起工作。它们也比HEREDOC风格的方法少了很多麻烦。|231697|Ruby提供了其他类似的方便方法，比如%25r，它可以构造正则表达式。这避免了在尝试编写处理http://之类的东西时使用斜杠-itis，否则这些东西必须进行转义。|offset|length|style|CODE|231698|entityMap^0|0|0|0|0|0|J|2|18|7|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|W|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|Y|8|@]|9|@]|A|$]]|$1|M|3|N|5|6|7|Z|8|@$O|10|P|11|Q|R]|$O|12|P|13|Q|R]]|9|@]|A|$]]|$1|S|3|-4|5|6|7|14|8|@]|9|@]|A|$]]]|T|$]]

They're extraordinarily useful for escaping HTML with JavaScript in it where you've already "run out" of quoting methods:

<pre><code>link = %q[&lt;a href="javascript:method('call')"&gt;link&lt;/a&gt;]
</code></pre>

I've also found them to be very useful when working with multi-line SQL statements:

<pre><code>execute(%Q[
 INSERT INTO table_a (column_a)
 SELECT value
 FROM table_b
 WHERE key='value'
])
</code></pre>

The advantage there is you don't need to pay attention to the type of quoting used within your query. It will work with either single, double, or both. They're also a lot less fuss than the HEREDOC style method.

Ruby provides other convenience methods like this such as <code>%r</code> which can construct regular expressions. That avoids slash-itis when trying to write one that handles stuff like <code>http://</code> that would otherwise have to be escaped.

blocks|key|228828|text|当字符串包含单引号或双引号时，它们很有用。这种情况并不经常发生，但这种技术在这种情况下非常有用。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|228829|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

They are useful when your string contains single- or double- quotes. This doesn't happen all that often, but the technique is very useful when it does.

blocks|key|2891696|text|概述|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2891697|除了“避免内部转义引号”和之前由@tadman提供的示例之外，还有其他用例：|2891698|使用与生成器本身相同的语言编写的|2891699|auto-generating代码(例如，Ruby生成的Ruby)|unordered-list-item|2891700|providing格式清晰的代码不会混淆文本编辑器的语法突出显示功能)|2891701|允许存储可能必须通过多个存储层的代码块(例如，与网站交互的数据库，或与文本编辑器交互的代码段管理系统，后者与子subshell交互，等等)|2891702|2891703|详细信息|2891704|这种方法是一种通用且健壮的习惯用法，适用于任何类型的自动代码生成工具，包括但不限于用其他语言编写样板代码的工具，或者管理IDE或文本编辑器的代码片段的工具。|2891705|除了@tadman已经提供的示例之外，还有生成代码的一般情况，其中生成的代码与生成程序的代码的语法相同或基本相似。|2891706|在这些情况下，解决方案不仅仅是帮助避免使用反斜杠来转义引号。如果没有这样的解决方案，在某些情况下，生成的代码可能会变得非常难以维护。|2891707|要查看此示例，请随意查看以下参考资料。|2891708|参考文献|2891709|[参见例如，|2891710|2891711|http://en.wikipedia.org/wiki/Leaning_toothpick_syndrome|offset|length|2891712|http://c2.com/cgi/wiki?QuineProgram|2891713|http://en.wikipedia.org/wiki/Delimiter#Delimiter_collision|2891714|http://en.wikipedia.org/wiki/Quine_(computing)|2891715|2891716|]|2891717|entityMap|0|LINK|mutability|MUTABLE|url|1|2|3^0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|1J|0|0|0|Z|1|0|0|1M|2|0|0|1A|3|0|0|0^^$0|@$1|2|3|4|5|6|7|1P|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|1Q|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|1R|8|@]|9|@]|A|$]]|$1|F|3|G|5|H|7|1S|8|@]|9|@]|A|$]]|$1|I|3|J|5|H|7|1T|8|@]|9|@]|A|$]]|$1|K|3|L|5|H|7|1U|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|1V|8|@]|9|@]|A|$]]|$1|N|3|O|5|6|7|1W|8|@]|9|@]|A|$]]|$1|P|3|Q|5|6|7|1X|8|@]|9|@]|A|$]]|$1|R|3|S|5|6|7|1Y|8|@]|9|@]|A|$]]|$1|T|3|U|5|6|7|1Z|8|@]|9|@]|A|$]]|$1|V|3|W|5|6|7|20|8|@]|9|@]|A|$]]|$1|X|3|Y|5|6|7|21|8|@]|9|@]|A|$]]|$1|Z|3|10|5|6|7|22|8|@]|9|@]|A|$]]|$1|11|3|-4|5|6|7|23|8|@]|9|@]|A|$]]|$1|12|3|13|5|H|7|24|8|@]|9|@$14|25|15|26|1|27]]|A|$]]|$1|16|3|17|5|H|7|28|8|@]|9|@$14|29|15|2A|1|2B]]|A|$]]|$1|18|3|19|5|H|7|2C|8|@]|9|@$14|2D|15|2E|1|2F]]|A|$]]|$1|1A|3|1B|5|H|7|2G|8|@]|9|@$14|2H|15|2I|1|2J]]|A|$]]|$1|1C|3|-4|5|6|7|2K|8|@]|9|@]|A|$]]|$1|1D|3|1E|5|6|7|2L|8|@]|9|@]|A|$]]|$1|1F|3|-4|5|6|7|2M|8|@]|9|@]|A|$]]]|1G|$1H|$5|1I|1J|1K|A|$1L|13]]|1M|$5|1I|1J|1K|A|$1L|17]]|1N|$5|1I|1J|1K|A|$1L|19]]|1O|$5|1I|1J|1K|A|$1L|1B]]]]

<h3>Overview</h3>
Apart from &quot;avoid internally escaping quotes&quot; and the examples previously provided by @tadman there are other use-cases as well:
<ul>
<li>auto-generating code in the same language as the generator itself (e.g., Ruby generating Ruby)</li>
<li>providing cleanly-formatted code that does not confuse the syntax-highlighting feature of your text editor</li>
<li>allow storage of codeblocks that may have to pass through multiple storage layers (such as a database interacting with a website, or a snippets management system interacting with a text editor, which interacts with a subshell, and so forth)</li>
</ul>
<h3>Details</h3>
This approach is a general-purpose and robust idiom that works well with any kind of tool that does automated code generation, including but not limited to tools that write boilerplate code in other languages, or tools that manage code snippets for an IDE or text editor.
Besides the examples already provided by @tadman, there is the general case of generating code where the code being generated is the same or substantially similar syntax as the code of the generating program.
In these cases, the solution does a lot more than help with avoiding the use of backslashes to escape quotes. Without a solution like this, there are cases where the generated code can get extremely difficult to maintain.
To see examples of this, feel free to take a look at the following references.
<h3>References</h3>
[ See e.g.,
<ul>
<li><a href="http://en.wikipedia.org/wiki/Leaning_toothpick_syndrome" rel="noreferrer">http://en.wikipedia.org/wiki/Leaning_toothpick_syndrome</a></li>
<li><a href="http://c2.com/cgi/wiki?QuineProgram" rel="noreferrer">http://c2.com/cgi/wiki?QuineProgram</a></li>
<li><a href="http://en.wikipedia.org/wiki/Delimiter#Delimiter_collision" rel="noreferrer">http://en.wikipedia.org/wiki/Delimiter#Delimiter_collision</a></li>
<li><a href="http://en.wikipedia.org/wiki/Quine_(computing)" rel="noreferrer">http://en.wikipedia.org/wiki/Quine_(computing)</a></li>
</ul>
]

blocks|key|3105736|text|也许值得注意的是，在生成gemspec的摘要/描述部分时，bundler和珠宝商默认使用%25q。这可以防止有人在摘要或描述中使用引号，从而破坏了gemspec。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3105737|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

Its perhaps worth noting that %q is used by bundler and jeweler by default when generating gemspecs, for the summary/description section of the gemspec. This prevents someone from using quotes in the summary or description and breaking the gemspec.

blocks|key|3105744|text|我知道这是一个旧线程，但我在生产中调用system命令并想要插值一些值时使用过它们，如下所示：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|3105745|+system(%25Q(ffmpeg+-y+-i+"#{input_filepath}"+-qscale:a+2+"#{output_filepath}"))|code-block|syntax|javascript|3105746|超级方便。|3105747|entityMap|0|LINK|mutability|MUTABLE|url|https://apidock.com/ruby/Kernel/system^0|J|6|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@$A|T|B|U|1|V]]|C|$]]|$1|D|3|E|5|F|7|W|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|X|8|@]|9|@]|C|$]]|$1|K|3|-4|5|6|7|Y|8|@]|9|@]|C|$]]]|L|$M|$5|N|O|P|C|$Q|R]]]]

I know this is an old thread, but I have used them in production when calling a <a href="https://apidock.com/ruby/Kernel/system" rel="noreferrer">system</a> command and wanting to interpolate some values, like so:

<pre><code> system(%Q(ffmpeg -y -i "#{input_filepath}" -qscale:a 2 "#{output_filepath}"))
</code></pre>

Super handy.

I've been reading through Thomas' Programming Ruby 1.9 and came upon the alternative delimited single and double-quoting methods (<code>%q / %Q</code>). I've known of them from other Ruby language references as well.

<pre><code>%q/I'm acting like a single-quoted string/

%Q|"I'm acting like a double-quoted string" --Anonymous|
</code></pre>

I have not been working with Ruby for long, but I have never encountered this quoting method in production code.

Other than the obvious ability to avoid internally escaping quotes with backslashes, what are the common use cases for this method of quoting over regular single or double quotes? Are they typically used in single or multiline strings? If used in multiline strings, are they ever favored over HEREDOC strings? Is there a particular Ruby idiom where they're commonly found?

What is the use case for Ruby's %q / %Q quoting methods?

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我一直在阅读托马斯的“Ruby1.9编程”，发现了另一种分隔的单引号和双引号方法(%q / %Q)。我也从其他Ruby语言参考资料中了解到它们。%q/I'm acting like a single-quoted string/%Q|"I'm acting like a double-quoted string" --...

问Ruby的%q / %Q引用方法的用例是什么？
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