Macro expression for drop-down list on form

I try to use macro expression as value of the drop-down list for a form field but couldn't get it to work:

{% if (TravelOutside.value=="Yes") {"xxx@xxx.com","xxx@xxx.com"} else {"",""} #%}

I want the drop-down list to have the email when the TravelOutside field value is "Yes", otherwise blank.

Thanks! Wei Wang

drop-down list macro expression

{% if (TravelOutside == "Yes") {"xxx@xxx.com;xxx@xxx.com"} else {";"} #%}

{% (TravelOutside == "Yes")? "xxx@xxx.com": "" %};{%(TravelOutside == "Yes")? "xxx@xxx.com": "" %}

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Thanks Peter, but none of them work :(

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Thanks Peter, it's working now after I took off the macro brackets.

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