AudienceStream string attribute - how to set the rule "is not empty"


Dear all,

Often there is the need to make sure that an AudienceStream string attribute is not empty. E.g., an action should only be triggered if the string is assigned and its value is not empty. 

The rule condition definitions do not help to solve this problem. They only state that "is empty" and "is not empty" apply to attributes imported from iQ. 

For strings that contain email addresses the answer is quite simple, one can use the rule "contains @". But what about strings that do not have a common character?

Thank you and kind regards!