如何将此Ruby String转换为数组？

What is the best way to turn the following Ruby String into an Array (I'm using ruby 1.9.2/Rails 3.0.11)

将以下Ruby String转换为数组的最佳方法是什么（我使用的是ruby 1.9.2 / Rails 3.0.11）

Rails console:

Rails控制台：

>Item.first.ingredients
=> "[\"Bread, whole wheat, 100%, slice\", \"Egg Substitute\", \"new, Eggs, scrambled\"]"
>Item.first.ingredients.class.name
=> "String"
>Item.first.ingredients.length
77

The desired output:

所需的输出：

>Item.first.ingredients_a
["Bread, whole wheat, 100%, slice", "Egg Substitute", "new, Eggs, scrambled"]
>Item.first.ingredients_a.class.name
=> "Array
>Item.first.ingredients_a.length
=> 3

If I do this, for instance:

如果我这样做，例如：

>Array(Choice.first.ingredients)

I get this:

我明白了：

=> ["[\"Bread, whole wheat, 100%, slice\", \"Egg Substitute\", \"new, Eggs, scrambled\", \"Oats, rolled, old fashioned\", \"Syrup, pancake\", \"Water, tap\", \"Oil, olive blend\", \"Spice, cinnamon, ground\", \"Seeds, sunflower, kernels, dried\", \"Flavor, vanilla extract\", \"Honey, strained/extracted\", \"Raisins, seedless\", \"Cranberries, dried, swtnd\", \"Spice, ginger, ground\", \"Flour, whole wheat\"]"] 

I'm sure there must be some obvious way to solve this.

我敢肯定必须有一些明显的方法来解决这个问题。

For clarity, this will be editable in a textarea field in a form, so should be made as secure as possible.

为清楚起见，这将在表单中的textarea字段中进行编辑，因此应尽可能安全。

6 个解决方案

#1

class Item
  def ingredients_a
    ingredients.gsub(/(\[\"|\"\])/, '').split('", "')
  end
end

1. strip off the extraneous characters
2. 去除无关的角色
3. split into array elements using the separating pattern
4. 使用分离模式分割成数组元素

#2

What you have looks like JSON, so you can do:

你有什么看起来像JSON，所以你可以这样做：

JSON.parse "[\"Bread, whole wheat, 100%, slice\", \"Egg Substitute\", \"new, Eggs, scrambled\"]"
#=> ["Bread, whole wheat, 100%, slice", "Egg Substitute", "new, Eggs, scrambled"]

this avoids a lot of the horrors of using eval.

这避免了使用eval的许多恐怖。

Though you should really think about why you're storing your data like that in the first place, and consider changing it so you don't have to do this. Further, it's likely that you should be parsing it to an array in ingredients so that the method returns something more meaningful. If you're almost always doing the same operation on a method's return value, the method is wrong.

虽然您应该首先考虑为什么要存储这样的数据，并考虑更改它，这样您就不必这样做了。此外，您可能应该将其解析为成分中的数组，以便该方法返回更有意义的内容。如果您几乎总是对方法的返回值执行相同的操作，则该方法是错误的。

#3

It looks like the ingredients method returns the .inspect output of the resulting return array. It is not very useful output that way. Do you have the ability to change it to return a plain array?

看起来，ingredients方法返回结果返回数组的.inspect输出。这种输出不是很有用。你有能力改变它以返回普通阵列吗？

What I would not do is use eval, which will just increase the hackiness of already hacky code.

我不会做的是使用eval，这只会增加已经hacky代码的hackiness。

#4

Like Mark Thomas said, modify your ingredients method, unless you really want two separate methods that return a string and an array, respectively. I'll assume you really only want to return an array. For the sake of argument, let's say your ingredients method currently returns a variable named ingredients_string. Modify your method like so:

就像Mark Thomas所说，修改你的成分方法，除非你真的想要两个分别返回字符串和数组的独立方法。我假设你真的只想要返回一个数组。为了论证，让我们说你的成分方法当前返回一个名为ingredients_string的变量。像这样修改你的方法：

def ingredients
  ...
  ingredients_array = ingredients_string.split('"')
  ingredients_array.delete_if { |element| %(", "[", "]").include? element }
  ingredients_array
end

#5

Not sure if this comes into play, but what happens if you want to use an array as an attribute, you might want to consider serialize..

不确定这是否起作用，但如果你想使用数组作为属性会发生什么，你可能要考虑序列化..

class Item << ActiveWhatever
  serialize :ingredients, Array

  ...
end

More info on serialize here http://api.rubyonrails.org/classes/ActiveRecord/Base.html

有关序列化的更多信息，请访问http://api.rubyonrails.org/classes/ActiveRecord/Base.html

#6

If your string-array is standard JSON format, just use JSON.parse()

如果你的字符串数组是标准的JSON格式，只需使用JSON.parse（）