从 Ruby 中的变量创建哈希键？
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Creating a hash key from a variable in Ruby?
提问by James McMahon
I have a variable idand I want to use it as a key in a hash so that the value assigned to the variable is used as key of the hash.
我有一个变量id，我想将它用作散列中的键，以便将分配给该变量的值用作散列的键。
For instance, if I have the variable id = 1the desired resulting hash would be { 1: 'foo' }.
例如，如果我有变量，id = 1则所需的结果散列将是{ 1: 'foo' }.
I've tried creating the hash with,
我试过用，
{
id: 'foo'
}
But that doesn't work, instead resulting in a hash with the symbol :idto 'foo'.
但这不起作用，而是导致散列符号:id为 to 'foo'。
I could have sworn I've done this before but I am completely drawing a blank.
我可以发誓我以前做过这件事，但我完全画了一个空白。
回答by Gumbo
If you want to populate a new hash with certain values, you can pass them to Hash::[]:
如果要使用某些值填充新哈希，可以将它们传递给Hash::[]：
Hash["a", 100, "b", 200] #=> {"a"=>100, "b"=>200}
Hash[ [ ["a", 100], ["b", 200] ] ] #=> {"a"=>100, "b"=>200}
Hash["a" => 100, "b" => 200] #=> {"a"=>100, "b"=>200}
So in your case:
所以在你的情况下：
Hash[id, 'foo']
Hash[[[id, 'foo']]]
Hash[id => 'foo']
The last syntax id => 'foo'can also be used with {}:
最后一种语法id => 'foo'也可以用于{}：
{ id => 'foo' }
Otherwise, if the hash already exists, use Hash#=[]:
否则，如果哈希已经存在，请使用Hash#=[]：
h = {}
h[id] = 'foo'
