Elvis operator

In certain <a href="/facts/Computer_programming/QmSsFnu0">computer programming</a> languages, the Elvis operator, often written ?:, is a <a href="/facts/Binary_operator/CYtow0bz">binary operator</a> that evaluates its first operand and returns it if its value is logically true (according to a language-dependent convention, in other words, a <a href="/facts/Truthy_(computing)/SY4e2w8l">truthy</a> value), and otherwise evaluates and returns its second operand. The second operand is only evaluated if it is to be returned (<a href="/facts/Short-circuit_evaluation/GYhompFd">short-circuit evaluation</a>). The notation of the Elvis operator was inspired by the ternary <a href="/facts/Conditional_operator/tB0uYuw0">conditional operator</a>, <a href="/facts/%253F%3a/3C8mgMD9">? :</a>, since the Elvis operator expression A ?: B is approximately equivalent to the ternary conditional expression A ? A : B.
The name "Elvis operator" refers to the fact that when its common notation, ?:, is viewed sideways, it resembles an <a href="/facts/Emoticon/f0jk3C14">emoticon</a> of <a href="/facts/Elvis_Presley/T0RDjznN">Elvis Presley</a> with his <a href="/facts/Pompadour_(hairstyle)/MqpN2ug3">signature hairstyle</a>.
A similar operator is the <a href="/facts/Null_coalescing_operator/U1T9KMKJ">null coalescing operator</a>, where the boolean truth(iness) check is replaced with a check for non-<a href="/facts/Null_pointer/66zwVEfL">null</a> instead. This is usually written ??, and can be seen in languages like <a href="/facts/C_Sharp_(programming_language)/UC2gxeyb">C#</a> or <a href="/facts/Dart_(programming_language)/xJ8tE6Tl">Dart</a>.

Elvis operator open-in-new

Elvis operator