ruby-on-rails - 哈希删除除特定键之外的所有内容

Question

我想从散列中删除除给定键之外的所有键。

例如:

{
 "firstName": "John",
 "lastName": "Smith",
 "age": 25,
 "address":
 {
     "streetAddress": "21 2nd Street",
     "city": "New York",
     "state": "NY",
     "postalCode": "10021"
 },
 "phoneNumber":
 [
     {
       "type": "home",
       "number": "212 555-1234"
     },
     {
       "type": "fax",
       "number": "646 555-4567"
     }
 ]
}

我想删除除“firstName”和/或“address”之外的所有内容。

Answer 1

切片呢？

hash.slice('firstName', 'lastName')
 # => { 'firstName' => 'John', 'lastName' => 'Smith' }

从 2.5 开始在 Ruby 中可用