Rails将哈希数组映射到单个哈希 [英] Rails mapping array of hashes onto single hash

问题描述

我有一系列的散列，如下所示:

I have an array of hashes like so:

 [{"testPARAM1"=>"testVAL1"}, {"testPARAM2"=>"testVAL2"}]

我正在尝试将其映射到单个散列上，如下所示:

And I'm trying to map this onto single hash like this:

{"testPARAM2"=>"testVAL2", "testPARAM1"=>"testVAL1"}

我已经使用

  par={}
  mitem["params"].each { |h| h.each {|k,v| par[k]=v} } 

但是我想知道是否有可能以更惯用的方式做到这一点(最好不使用局部变量).

But I was wondering if it's possible to do this in a more idiomatic way (preferably without using a local variable).

我该怎么做?

推荐答案

您可以编写Enumerable#reduce和Hash#merge来完成所需的操作.

You could compose Enumerable#reduce and Hash#merge to accomplish what you want.

input = [{"testPARAM1"=>"testVAL1"}, {"testPARAM2"=>"testVAL2"}]
input.reduce({}, :merge)
  is {"testPARAM2"=>"testVAL2", "testPARAM1"=>"testVAL1"}

减少数组的排序，就像在每个元素之间插入一个方法调用一样.

Reducing an array sort of like sticking a method call between each element of it.

例如[1, 2, 3].reduce(0, :+)就像说0 + 1 + 2 + 3并给出6.

在我们的示例中，我们执行了类似的操作，但是使用了合并功能，该功能合并了两个哈希.

In our case we do something similar, but with the merge function, which merges two hashes.

[{:a => 1}, {:b => 2}, {:c => 3}].reduce({}, :merge)
  is {}.merge({:a => 1}.merge({:b => 2}.merge({:c => 3})))
  is {:a => 1, :b => 2, :c => 3}

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