ruby 将数组转换为哈希，其中键是索引
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Convert an array to hash, where keys are the indices
提问by MxLDevs
I am transforming an array into a hash, where the keys are the indices and values are the elements at that index.
我正在将数组转换为散列，其中键是索引，值是该索引处的元素。
Here is how I have done it
这是我如何做到的
# initial stuff
arr = ["one", "two", "three", "four", "five"]
x = {}
# iterate and build hash as needed
arr.each_with_index {|v, i| x[i] = v}
# result
>>> {0=>"one", 1=>"two", 2=>"three", 3=>"four", 4=>"five"}
Is there a better (in any sense of the word "better") way to do it?
有没有更好的（在任何意义上的“更好”这个词）的方法来做到这一点？
回答by Kyle
arr = ["one", "two", "three", "four", "five"]
x = Hash[(0...arr.size).zip arr]
# => {0=>"one", 1=>"two", 2=>"three", 3=>"four", 4=>"five"}
回答by tokland
Ruby < 2.1:
红宝石 < 2.1：
Hash[arr.map.with_index { |x, i| [i, x] }]
#=> {0=>"one", 1=>"two", 2=>"three", 3=>"four", 4=>"five"}
Ruby >= 2.1:
红宝石 >= 2.1：
arr.map.with_index { |x, i| [i, x] }.to_h
回答by sawa
x = Hash.new{|h, k| h[k] = arr[k]}
回答by Shairon Toledo
%w[one two three four five].map.with_index(1){ |*x| x.reverse }.to_h
Remove (1)if you want to start the index from 0.
(1)如果要从 开始索引，请删除0。
回答by mober
Here is a solution making use of Object#tap, to add values to a newly-created hash:
这是一个使用Object#tap, 将值添加到新创建的哈希的解决方案：
arr = ["one", "two", "three", "four", "five"]
{}.tap do |hsh|
arr.each_with_index { |item, idx| hsh[idx] = item }
end
#=> {0=>"one", 1=>"two", 2=>"three", 3=>"four", 4=>"five"}
回答by Camille Drapier
Many good solutions already, just adding a variant (provided you do not have duplicated values):
已经有很多好的解决方案，只需添加一个变体（前提是您没有重复的值）：
["one", "two", "three", "four", "five"].map.with_index.to_h.invert
# => {0=>"one", 1=>"two", 2=>"three", 3=>"four", 4=>"five"}
回答by hurikhan77
You could monkey patch Arrayto provide a new method:
您可以使用猴子补丁Array来提供一种新方法：
class Array
def to_assoc offset = 0
# needs recent enough ruby version
map.with_index(offset).to_h.invert
end
end
Now you can do:
现在你可以这样做：
%w(one two three four).to_assoc(1)
# => {1=>"one", 2=>"two", 3=>"three", 4=>"four"}
This is a common operation I'm doing in Rails apps so I keep this monkey patch around in an initializer.
这是我在 Rails 应用程序中执行的常见操作，因此我将这个猴子补丁保留在初始化程序中。
