在 Ruby 中，“=>”代表什么？是什么意思以及它是如何工作的？
在学习 Ruby 时，我遇到了“=>”有时操作员。通常我会以 的形式看到它
:symbol => value
，并且在向函数传递值时似乎经常使用它。那个操作员到底叫什么名字？它有什么作用/意味着什么？它是内置在 Ruby 中还是由不同的框架（如 Rails 和 DataMapper）添加到符号类中？它只能与符号类一起使用吗？谢谢。
While learning Ruby I've come across the "=>" operator on occasion. Usually I see it in the form of
:symbol => value
and it seems to be used frequently when passing values to functions. What exactly is that operator called? What does it do/mean? Is it built into Ruby or is it something that different frameworks like Rails and DataMapper add to the symbol class? Is it only used in conjunction with the symbol class? Thanks.
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=>将哈希映射文字中的键与值分开。它不可重载，也没有专门连接到符号。哈希图文字的形式为
{key1 =>值1，键2 => value2, ...}，但是当用作函数的最后一个参数时，可以省略花括号。因此，当您看到像f(:a => 1, :b => 2)这样的函数调用时，f会使用一个参数进行调用，该参数是一个 hashmap具有键:a和:b以及值1和2。=>separates the keys from the values in a hashmap literal. It is not overloadable and not specifically connected to symbols.A hashmap literal has the form
{key1 => value1, key2 => value2, ...}, but when used as the last parameter of a function, you can leave off the curly braces. So when you see a function call likef(:a => 1, :b => 2),fis called with one argument, which is a hashmap that has the keys:aand:band the values1and2.您可能听说过这个运算符被称为“哈希火箭”，这意味着您在定义 ruby 哈希时使用它。
如果您不熟悉，这是 Ruby Hash 文档：http://www.ruby-doc。 org/core/classes/Hash.html
请注意，在 Ruby 1.9 中，如果您要定义使用符号作为键的哈希，现在可以使用替代语法： http://blog.peepcode.com/tutorials/2011/rip-ruby-hash-rocket-syntax
You might hear this operator referred to as a "hash rocket," meaning you use it when defining a ruby hash.
This is the Ruby Hash documentation, if you're not familiar: http://www.ruby-doc.org/core/classes/Hash.html
Note that in Ruby 1.9, if you're defining a hash that uses symbols as keys, there's now an alternative syntax available to you: http://blog.peepcode.com/tutorials/2011/rip-ruby-hash-rocket-syntax
提示：如果您在像
{:a =>; 这样的哈希中使用它“A”，：b => "B"}，在 Ruby 1.9 中，您可以像 JSON 哈希一样使用它：Tip: if you're using it in a hash like
{:a => "A", :b => "B"}, in Ruby 1.9, you can use it like a JSON hash:如果您想进一步进行谷歌搜索，
=>有时被称为 hashrocket，因为它看起来像火箭（与<=>看起来像火箭一样）像宇宙飞船），并且它用于哈希。或者您可以使用 SymbolHound。
If you want to do any further Googling,
=>is sometimes called a hashrocket, because it looks like a rocket (in the same sense that<=>looks like a spaceship), and it's used in hashes.Or you could use SymbolHound.
除了 在 Ruby 中还有什么“ =>”含义及其工作原理？：
您通常会看到
=>来定义函数的参数。将此视为一个很好的便利：您无需记住参数的正确顺序，因为所有参数都包装在一个巨大的散列中。因此，如果您有一个简单的辅助方法，例如link_to "My link", my_path, :confirm => “你确定吗？”这比
link_to "My link", my_path, null, null, null, null, "Are you certain?"更好，只是因为你想使用很少使用的参数。因此，使用散列传递参数只是 Ruby/Rails 中的一种约定，以使生活更轻松。
In addition to In Ruby what does "=>" mean and how does it work?:
You mostly will see the
=>to define parameters for a function. Think of this as a nice convenience: You need not remember the right order of your parameters, as all parameters are wrapped into a giant hash. So if you have a simple helper method likelink_to "My link", my_path, :confirm => "Are you sure?"this is way better than
link_to "My link", my_path, null, null, null, null, "Are you sure?"just because you want to use a rarely used parameter. So passing parameters with a hash is just a convention in Ruby/Rails to make life easier.