Meaning of #{ } in Ruby?

Why This Is a Good Question

This is a tough question to Google for unless you know the right search terms. The #{} operator technically performs expression substitution inside a string literal.

The Answer

The #{} literal is the operator used for interpolation inside double-quoted strings the same way that the backticks or $() construct would be used in Bash. From a practical point of view, the expression inside the literal is evaluated, and then the entire #{} expression (including both the operator and the expression it contains) is replaced in situ with the result.

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