Ruby-on-rails Array.join("\n") 不是用换行符加入的方式吗？
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Array.join("\n") not the way to join with a newline?
提问by jdimona
I have an array..
我有一个数组..
[1,2,3,4]
and I want a string containing all the elements separated by a newline..
我想要一个包含由换行符分隔的所有元素的字符串..
1
2
3
4
but when I try [1,2,3,4].join("\n")I get
但是当我尝试[1,2,3,4].join("\n")我得到
1\n2\n3\n4
I feel like there is an obvious answer but I can't find it!
我觉得有一个明显的答案，但我找不到！
回答by Cody Caughlan
Yes, but if you print that string out it will have newlines in it:
是的，但是如果您打印出该字符串，它将在其中包含换行符：
irb(main):001:0> a = (1..4).to_a
=> [1, 2, 3, 4]
irb(main):002:0> a.join("\n")
=> "1\n2\n3\n4"
irb(main):003:0> puts a.join("\n")
1
2
3
4
So it does appear to achieve what you desire (?)
所以它似乎实现了你想要的（？）
回答by Screamer
A subtle error that can occur here is to use single quotes instead of double. That also has the effect of rendering the newlines as \n. So
这里可能发生的一个微妙错误是使用单引号而不是双引号。这也具有将换行符呈现为 \n 的效果。所以
puts a.join("\n") # correct
is not the same as
不一样
puts a.join('\n') # incorrect
There is an excellent write up on why this is the case here.
还有为什么是这样一个优秀的写了这里。
回答by Ajay
Just in case anyone searching for this functionality in ERB template then try this :
以防万一有人在 ERB 模板中搜索此功能，请尝试以下操作：
(1..5).to_a.join("<br>").html_safe
回答by khelll
Try this also:
也试试这个：
puts (1..4).to_a * "\n"
回答by Allison
You may not want to use html_safe, like ajay said, depending on context. Html safe can be a security issue. This depends on if the original input was actuallyhtml safe. HTML safe should not be called on input direct from a user and typically should be called before the view.
根据上下文，您可能不想使用 html_safe，就像 ajay 所说的那样。Html 安全可能是一个安全问题。这取决于原始输入是否实际上是html 安全的。HTML 安全不应在用户直接输入时调用，通常应在视图之前调用。
https://bibwild.wordpress.com/2013/12/19/you-never-want-to-call-html_safe-in-a-rails-template/
https://bibwild.wordpress.com/2013/12/19/you-never-want-to-call-html_safe-in-a-rails-template/
[edited in response to comment below]
[编辑以回应下面的评论]
回答by staxim
As some of the other answers above imply, Rails may be escaping your code before rendering as html. Here's a sample that addresses this problem (first sanitizing the inputs, so that you can "safely" call html_safeon the result):
正如上面的一些其他答案所暗示的那样，Rails 可能会在呈现为 html 之前转义您的代码。这是解决此问题的示例（首先清理输入，以便您可以“安全地”调用html_safe结果）：
my_array = [1, 2, 3, 4]
my_array.map{ |i| i.to_s.sanitize }.join("\n").html_safe
You only need sanitizeif you don't trust the inputs.
仅sanitize当您不信任输入时才需要。
回答by Hetal Khunti
How about this If you wanted to print each element on new line..
这个怎么样如果你想在新行上打印每个元素..
> a = [1, 2, 3, 4]
> a.each{|e| puts e}
1
2
3
4
=> [1, 2, 3, 4]
回答by Eddie
Use the Enter or Return key on your typing surface. .-.
在打字面上使用 Enter 或 Return 键。.-.
[1,2,3,4].join("
[1,2,3,4].join("
")
”）
