Ruby: Creating a hash key and value from a variable in Ruby [duplicate]
If you want to populate a new hash with certain values, you can pass them to 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:
Hash[id, 'foo']
Hash[[[id, 'foo']]]
Hash[id => 'foo']
The last syntax id => 'foo' can also be used with {}:
{ id => 'foo' }
Otherwise, if the hash already exists, use Hash#=[]:
h = {}
h[id] = 'foo'