Merge arrays to hash and use duplicates [closed]

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Closed 5 years ago.

How do I keep duplicates and maintain order? For example:

keys   = [1, 2, 1]
values = ["a", "b", "c"]
Hash[keys.zip(values)] # => {1=>"c", 2=>"b"}

回答1:

As Justin & Luca said:

Hashes don't allow duplicate keys.

Best you can do is by having array of values, found this solution in this SO question:

Hash.new.tap { |h| keys.zip(values).each { |k, v| (h[k] ||= []) << v } }
# => {1=>["a", "c"], 2=>["b"]} 

回答2:

You cannot keep duplicates if you use the keys array as hash key. They must be unique

来源：https://stackoverflow.com/questions/25446731/merge-arrays-to-hash-and-use-duplicates