Using Ruby 2.3:
In example 1, the string key \"a\" is automatically converted to a symbol, whereas with example 2, it stays a string.
\"a\"
Example 1
In Ruby 2.3(.0), these are all the same:
{:"a" => 1} {"a": 1}, {:a => 1} {a: 1}
They all translate to the same thing: a is a symbol in all these cases.
a
{"a"=>1} is different: a is a string in this case.
{"a"=>1}