blocks|key|1348320|text|我会说使用$:.unshift+File.dirname(__FILE__)而不是另一个，原因很简单，因为我在代码中看到它比$LOAD_PATH使用得更多，而且它也更短！|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1348321|entityMap^0|5|X|1Q|A|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|$]]

I would say go with <code>$:.unshift File.dirname(__FILE__)</code> over the other one, simply because I've seen much more usage of it in code than the <code>$LOAD_PATH</code> one, and it's shorter too!

blocks|key|1348403|text|Ruby+load+path通常被写成$：，但是仅仅因为它很短，并不能让它变得更好。如果你更喜欢清晰而不是聪明，或者如果为了简洁而让你发痒，你不需要仅仅因为其他人都这样做。向……问好|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1348404|$LOAD_PATH|code-block|syntax|javascript|1348405|..。向…说再见。|1348406|#+I+don't+quite+understand+what+this+is+doing...
$:|1348407|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|$]]

The Ruby load path is very commonly seen written as $: , but just because it is short, does not make it better. If you prefer clarity to cleverness, or if brevity for its own sake makes you itchy, you needn't do it just because everyone else is. 
Say hello to ...

<pre><code>$LOAD_PATH
</code></pre>

... and say goodbye to ...

<pre><code># I don't quite understand what this is doing...
$:
</code></pre>

blocks|key|1563914|text|在使用Rspec时，我遇到的最好的方法是通过相对路径添加dir。我发现它足够冗长，但仍然是一个很好的线性程序。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1563915|$LOAD_PATH.unshift(File.join(File.dirname(__FILE__),+'..',+'lib'))|code-block|syntax|javascript|1563916|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|$]]

Best I have come across for adding a dir via relative path when using Rspec. I find it verbose enough but also still a nice one liner.

<pre><code>$LOAD_PATH.unshift(File.join(File.dirname(__FILE__), '..', 'lib'))
</code></pre>

blocks|key|1348443|text|有一个gem可以让你用更好更干净的代码设置你的加载路径。看看这个：https://github.com/nayyara-samuel/load-path。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1348444|它也有很好的文档|1348445|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/nayyara-samuel/load-path^0|X|17|0|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@$A|O|B|P|1|Q]]|C|$]]|$1|D|3|E|5|6|7|R|8|@]|9|@]|C|$]]|$1|F|3|-4|5|6|7|S|8|@]|9|@]|C|$]]]|G|$H|$5|I|J|K|C|$L|M]]]]

There is a gem which will let you setup your load path with nicer and cleaner code. Check this out: <a href="https://github.com/nayyara-samuel/load-path" rel="nofollow">https://github.com/nayyara-samuel/load-path</a>.

It also has good documentation

blocks|key|1348541|text|我知道这个问题已经提出很长时间了，但我有一个额外的答案想和大家分享。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1348542|我有几个Ruby应用程序，它们是由另一个程序员花了几年时间开发的，它们在不同的应用程序中重用了相同的类，尽管它们可能访问相同的数据库。因为这违反了DRY规则，所以我决定创建一个由所有Ruby应用程序共享的类库。我本可以把它放在主Ruby库中，但这会将自定义代码隐藏在公共代码库中，这是我不想做的。|1348543|我遇到了一个问题，在已经定义的名称"profile.rb“和我正在使用的类之间存在名称冲突。在我尝试创建公共代码库之前，这种冲突并不是问题。通常，Ruby首先搜索应用程序位置，然后转到$LOAD_PATH位置。|1348544|application_controller.rb找不到我创建的类，并在原始定义中抛出错误，因为它不是类。因为我从应用程序的app/model部分删除了类定义，所以Ruby在那里找不到它，并在Ruby路径中寻找它。|1348545|因此，我修改了$LOAD_PATH变量，使其包含我所使用的库目录的路径。这可以在初始化时在environment.rb文件中完成。|1348546|即使将新目录添加到搜索路径中，Ruby也会抛出错误，因为它优先使用系统定义的文件。$LOAD_PATH变量中的搜索路径优先搜索Ruby路径。|1348547|因此，我需要更改搜索顺序，以便Ruby在搜索内置库之前在我的公共库中找到该类。|1348548|下面的代码在environment.rb文件中做到了这一点：|1348549|Rails::Initializer.run+do+%7Cconfig%7C

*+*+*+*+*

path+=+[]
path.concat($LOAD_PATH)
$LOAD_PATH.clear
$LOAD_PATH+<<+'C:\web\common\lib'
$LOAD_PATH+<<+'C:\web\common'
$LOAD_PATH.concat(path)

*+*+*+*+*

end|code-block|syntax|javascript|1348550|我不认为你可以在这个级别使用前面给出的任何高级编码构造，但如果你想在应用程序初始化时设置一些东西，它就可以很好地工作。在将原始$LOAD_PATH变量重新添加到新变量时，必须保持该变量的原始顺序，否则一些主要的Ruby类将丢失。|1348551|在application_controller.rb文件中，我简单地使用了|1348552|require+'profile'
require+'etc'+#etc|1348553|这会加载整个应用程序的定制库文件，也就是说，我不必在每个控制器中都使用require命令。|1348554|对我来说，这就是我正在寻找的解决方案，我想我应该将它添加到这个答案中，以传递信息。|1348555|entityMap^0|0|0|0|0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|16|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|17|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|18|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|19|8|@]|9|@]|A|$]]|$1|H|3|I|5|6|7|1A|8|@]|9|@]|A|$]]|$1|J|3|K|5|6|7|1B|8|@]|9|@]|A|$]]|$1|L|3|M|5|6|7|1C|8|@]|9|@]|A|$]]|$1|N|3|O|5|6|7|1D|8|@]|9|@]|A|$]]|$1|P|3|Q|5|R|7|1E|8|@]|9|@]|A|$S|T]]|$1|U|3|V|5|6|7|1F|8|@]|9|@]|A|$]]|$1|W|3|X|5|6|7|1G|8|@]|9|@]|A|$]]|$1|Y|3|Z|5|R|7|1H|8|@]|9|@]|A|$S|T]]|$1|10|3|11|5|6|7|1I|8|@]|9|@]|A|$]]|$1|12|3|13|5|6|7|1J|8|@]|9|@]|A|$]]|$1|14|3|-4|5|6|7|1K|8|@]|9|@]|A|$]]]|15|$]]

I know it's been a long time since this question was first asked, but I have an additional answer that I want to share.

I have several Ruby applications that were developed by another programmer over several years, and they re-use the same classes in the different applications although they might access the same database. Since this violates the DRY rule, I decided to create a class library to be shared by all of the Ruby applications. I could have put it in the main Ruby library, but that would hide custom code in the common codebase which I didn't want to do.

I had a problem where I had a name conflict between an already defined name "profile.rb", and a class I was using. This conflict wasn't a problem until I tried to create the common code library. Normally, Ruby searches application locations first, then goes to the $LOAD_PATH locations.

The application_controller.rb could not find the class I created, and threw an error on the original definition because it is not a class. Since I removed the class definition from the app/models section of the application, Ruby could not find it there and went looking for it in the Ruby paths.

So, I modified the $LOAD_PATH variable to include a path to the library directory I was using. This can be done in the environment.rb file at initialization time.

Even with the new directory added to the search path, Ruby was throwing an error because it was preferentially taking the system-defined file first. The search path in the $LOAD_PATH variable preferentially searches the Ruby paths first.

So, I needed to change the search order so that Ruby found the class in my common library before it searched the built-in libraries.

This code did it in the environment.rb file:

<pre><code>Rails::Initializer.run do |config|

* * * * *

path = []
path.concat($LOAD_PATH)
$LOAD_PATH.clear
$LOAD_PATH &lt;&lt; 'C:\web\common\lib'
$LOAD_PATH &lt;&lt; 'C:\web\common'
$LOAD_PATH.concat(path)

* * * * *

end
</code></pre>

I don't think you can use any of the advanced coding constructs given before at this level, but it works just fine if you want to setup something at initialization time in your app. You must maintain the original order of the original $LOAD_PATH variable when it is added back to the new variable otherwise some of the main Ruby classes get lost.

In the application_controller.rb file, I simply use a

<pre><code>require 'profile'
require 'etc' #etc
</code></pre>

and this loads the custom library files for the entire application, i.e., I don't have to use require commands in every controller.

For me, this was the solution I was looking for, and I thought I would add it to this answer to pass the information along.

I have seen two commonly used techniques for adding the directory of the file currently being executed to the $LOAD_PATH (or $:). I see the advantages of doing this in case you're not working with a gem. One seems more verbose than the other, obviously, but is there a reason to go with one over the other?

The first, verbose method (could be overkill):

<pre><code>$LOAD_PATH.unshift(File.expand_path(File.dirname(__FILE__))) unless $LOAD_PATH.include?(File.expand_path(File.dirname(__FILE__)))
</code></pre>

and the more straightforward, quick-and-dirty:

<pre><code>$:.unshift File.dirname(__FILE__)
</code></pre>

Any reason to go with one over the other?

Adding a directory to $LOAD_PATH (Ruby)

数据库

我看到了两种常用的技术，用于将当前正在执行的文件的目录添加到$LOAD_PATH (或$:)。我看到了在你不使用gem的情况下这样做的好处。显然，其中一个看起来比另一个更冗长，但有理由使用一个而不是另一个吗？第一个，详细的方法(可能是过度杀伤力)：$LOAD_PATH.unshift(File.expand_path(File.dirname(__FILE__))) unless $LOAD_PA

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