Elvis operator

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In certain computer programming languages, the Elvis operator, often written ?:, is a binary operator that returns the first operand if its value is logically true (according to a language-dependent convention, in other words, a truthy value) or returns its second operand if the first operand is not true. That is, it is a short-circuit OR, which returns its first truthy operand. The syntax of the Elvis operator was inspired by the ternary conditional operator, ? :, since the Elvis operator expression A ?: B is approximately equivalent to the ternary conditional expression A ? A : B. It is called the "Elvis operator" because the notation ?:, when viewed sideways, resembles an emoticon of Elvis Presley with his signature hairstyle. A similar operator is the null coalescing operator, where the boolean truth(iness) check is replaced with a check for non-null instead. This is usually written ??, and can be seen in languages like C# or Dart.