如何检查哈希键是否匹配数组中的值 [英] How to check if hash keys match value from array

问题描述

我有:

arr = ['test', 'testing', 'test123']
ht = {"test": "abc", "water": "wet", "testing": "fun"}

如何在键与arr匹配的ht中选择值?

How can I select the values in ht whose key matches arr?

ht_new = ht.select {|hashes| arr.include? hashes}
ht_new # => "{"test": "abc", "testing": "fun"}"

此外，我们如何从以下位置返回值:

Additionally, how can we return values from:

arr = ["abc", "123"]
ht = [{"key": "abc", "value": "test"}, {"key": "123", "value": "money"}, {"key": "doremi", "value": "rain"}}]
output # => [{"key": "abc", "value": "test"}, {"key": "123", "value": "money"}]

推荐答案

只需稍作更改:

ht.select { |k,_| arr.include? k.to_s }
  ##=> {:test=>"abc", :testing=>"fun"}

请参见哈希#select .

块变量_(有效的局部变量)，它是键k的值，向读者表示该变量未在块计算中使用.有些人更喜欢写|k,_v|或类似的东西.

The block variable _ (a valid local variable), which is the value of key k, signifies to the reader that it is not used in the block calculation. Some prefer writing that |k,_v|, or some-such.

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