ruby 如何将多个值添加到同一个键
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How to add several values to the same key
提问by user2211703
how can I add several values to the same key? Something like this:
如何将多个值添加到同一个键？像这样的东西：
x = {}
x["k1"] = nil
x["k1"] << {"a" => "a"}
x["k1"] << {"b" => "b"}
well, this doesn't work like with array.
好吧，这与数组不同。
回答by Arup Rakshit
You can do as below :
您可以执行以下操作：
For Arrayas value to the key of a Hash:
对于Array作为价值的关键Hash：
h = Hash.new{|hsh,key| hsh[key] = [] }
h['k1'].push 'a'
h['k1'].push 'b'
p h # >> {"k1"=>["a", "b"]}
For Hashas value to the key of a Hash:
对于Hash作为价值的关键Hash：
h = Hash.new{|hsh,key| hsh[key] = {} }
h['k1'].store 'a',1
h['k1'].store 'b',1
p h # >> {"k1"=>{"a"=>1, "b"=>1}}
回答by Some Guy
Depends on just what you're trying to accomplish here. If you want a hash of arrays, that's easy enough:
取决于你想在这里完成什么。如果你想要一个数组的散列，那很容易：
x = {}
x['k1'] = Array.new
x['k1'] << 'a'
x['k1'] << 'b'
or if you want nested hashes, simple enough as well
或者如果你想要嵌套的哈希，也很简单
x = {}
x['k1'] = {}
x['k1']['a'] = 'a'
x['k1']['b'] = 'b'
the values in a hash are just objects. They can be arrays, other hashes, or whatever else you might want.
散列中的值只是对象。它们可以是数组、其他散列或您可能想要的任何其他内容。
回答by struthersneil
So, you want the value of key 'k1' to be a hash, and you want to add key/value pairs to that hash. You can do it like this:
因此，您希望键 'k1' 的值是一个散列，并且您希望将键/值对添加到该散列中。你可以这样做：
2.0.0-p195 :111 > x = {}
=> {}
2.0.0-p195 :112 > x['k1'] = { 'a' => '1' }
=> {"a"=>"1"}
2.0.0-p195 :117 > x['k1'].merge!({ 'b' => '2' })
=> {"a"=>"1", "b"=>"2"}
Or, you can do it like this:
或者，您可以这样做：
2.0.0-p195 :119 > x['k1']['c'] = 3
=> 3
2.0.0-p195 :120 > x['k1']
=> {"a"=>"1", "b"=>"2", "c"=>3}
回答by toms
The short answer is you can't: a hash key has only one value by definition.
In addition, you are trying to use the shovel operator <<, an array method, to set the value. But even if you used =, every time you set the key to a new value, the old value is lost:
简短的回答是你不能：根据定义，哈希键只有一个值。此外，您正在尝试使用 shovel 运算符<<（一种数组方法）来设置值。但即使你使用了=，每次你将键设置为新值时，旧值也会丢失：
x = {}
=> {}
x["k1"] = {"a" => "a"}
=> {"a"=>"a"}
x["k1"] = {"b" => "b"}
=> {"b"=>"b"}
As others have pointed out, if you want "several values" per key, you should use some kind of collection
正如其他人指出的那样，如果您希望每个键有“几个值”，则应该使用某种集合
x = {}
=> {}
x["k1"] = {"a" => "a", "b" => "b"}
=> {"a"=>"a", "b"=>"b"}
