Question: What are semantics of %Q and %{} in Ruby? What is difference between them?

Answer: 
[Jim Hoskins](http://jimhoskins.com/2008/10/07/ruby-percent-syntax-percent-functions/) clears it up.

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> %Q is the equivalent to a double-quoted ruby string. #{expression} evaluation works just like in double-quoted strings, even if you use %Q{} as your delimiter!
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> You can also leave off the Q and it will have the same functionality. I recommend leaving the Q in to be more clear.
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There are in effect the same. Both follow double-quoted string semantics