blocks|key|646575|text|要回答您的问题，当您想要进行字符串插值时，您必须使用""：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|646576|a+=+2
puts+"#{a}"|code-block|syntax|javascript|646577|否则使用简单的引号。|646578|另外，如果您想知道在性能方面是否存在差异，有一个很好的question+about+this+on+StackOverflow.|646579|如果您是RoR的新手，我强烈建议您拿起一本像样的Ruby书来学习该语言的基础知识。它将帮助您理解您正在做什么(并将使您不再认为Rails是神奇的)。我个人推荐The+Well+grounded+Rubyist。|646580|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/questions/1836467/is-there-a-performance-gain-in-using-single-quotes-vs-double-quotes-in-ruby|1|http://www.manning.com/black2/^0|Q|2|0|0|0|R|11|0|0|27|P|1|0^^$0|@$1|2|3|4|5|6|7|10|8|@$9|11|A|12|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|13|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|14|8|@]|D|@]|E|$]]|$1|M|3|N|5|6|7|15|8|@]|D|@$9|16|A|17|1|18]]|E|$]]|$1|O|3|P|5|6|7|19|8|@]|D|@$9|1A|A|1B|1|1C]]|E|$]]|$1|Q|3|-4|5|6|7|1D|8|@]|D|@]|E|$]]]|R|$S|$5|T|U|V|E|$W|X]]|Y|$5|T|U|V|E|$W|Z]]]]

To answer your question, you have to use <code>""</code> when you want to do string interpolation:

<pre><code>a = 2
puts "#{a}"
</code></pre>

Use simple quotes otherwise.

Also if you are wondering about whether there is a difference in terms of performance, there is an excellent <a href="https://stackoverflow.com/questions/1836467/is-there-a-performance-gain-in-using-single-quotes-vs-double-quotes-in-ruby">question about this on StackOverflow.</a>

And if you are really new to RoR, I urge you to pick up a decent Ruby book to learn the basics of the language. It will help you understand what you are doing (and will keep you from thinking that Rails is magic). I personally recommend <a href="http://www.manning.com/black2/" rel="noreferrer">The Well grounded Rubyist</a>.

blocks|key|646605|text|"+"允许您进行字符串插值，例如：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|646606|world_type+=+'Mars'
"Hello+#{world_type}"|code-block|syntax|javascript|646607|entityMap^0|0|3|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

<code>" "</code> allows you to do string interpolation, e.g.:

<pre><code>world_type = 'Mars'
"Hello #{world_type}"
</code></pre>

blocks|key|646640|text|在这种特定情况下，您如何编写它并没有区别。它们是等效的。此外，您可能还想阅读更多Ruby指南/教程:)|type|unstyled|depth|inlineStyleRanges|entityRanges|data|646641|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|$]]

In this specific case, it makes no difference how you write it. They are equivalent. Also, you may want to read some more Ruby guides/tutorials :)

blocks|key|863978|text|除了插值，另一个不同之处是‘转义序列’在单引号中不起作用|type|unstyled|depth|inlineStyleRanges|entityRanges|data|863979|puts+'a\nb'+#+just+print+a\nb+
puts+"a\nb"+#+print+a,+then+b+at+newline+|code-block|syntax|javascript|863980|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|$]]

except the interpolation, another difference is that 'escape sequence' does not work in single quote

<pre><code>puts 'a\nb' # just print a\nb 
puts "a\nb" # print a, then b at newline 
</code></pre>

blocks|key|646703|text|与打印中的答案"\n“类似，下面是不同的另一种情况|type|unstyled|depth|inlineStyleRanges|entityRanges|data|646704|puts+"\1"++->+get+special+character
puts+'\1'++->+get+\1|code-block|syntax|javascript|646705|所以看起来*被转换为双引号中的转义字符，而不是单引号中的字符。顺便说一句，在正则表达式中使用时会影响输出，例如str.gsub(/regular+expression/，'\1，\2')|646706|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|$]]

Similar to the answer "\n" in printing, following is another case of the difference

<pre><code>puts "\1" -&gt; get special character
puts '\1' -&gt; get \1
</code></pre>

so looks like * was convert to escaped character in double quotes, but not in single quotes.
BTW, it will impact the output when using in regular expression
e.g.,
 str.gsub(/regular expression/, '\1,\2')

blocks|key|646776|text|您希望使用单引号的另一个原因是将正则模式作为字符串传递时：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|646777|此正则表达式模式将起作用，因为在单引号中传递：|646778|"123+ABC".match('\d')
=>+#<MatchData+"1">|code-block|syntax|javascript|646779|此正则表达式模式将失败，因为在双引号内传递(您必须对其进行双转义才能使其工作)：|646780|"123+ABC".match("\d")
=>+nil|646781|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|P|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|Q|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|R|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|S|8|@]|9|@]|A|$G|H]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

Another reason you would want to use single-quotes is when passing a regex pattern as a string:

This regex pattern will work because passed within single-quotes:

<pre><code>"123 ABC".match('\d')
=&gt; #&lt;MatchData "1"&gt;
</code></pre>

This regex pattern will fail because passed within double-quotes (you would have to double-escape it to get it to work):

<pre><code>"123 ABC".match("\d")
=&gt; nil
</code></pre>

I'm really new to Ruby and I'm trying to understand if there's a specific time when I should use <code>""</code> vs <code>''</code>.

I've been using single quotes most of the time because it's easier to type but I'm not sure if I should.

e.g. <code>get 'user/new'</code> vs <code>get "user/new"</code>

Double vs single quotes

我是Ruby的新手，我正在尝试理解是否有一个特定的时间我应该使用""和''。我大部分时间都在使用单引号，因为这样更容易打字，但我不确定是否应该这样做。例如get 'user/new'与get "user/new"

问双引号与单引号
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