ColdFusion isDefined

Question

I am trying to check to see if data exist in my form If data does not exist I want to assign it to O. How can I do this.

Answer 1

Generally the best practice is considered to be to avoid isDefined. This is because isDefined will search all scopes until it finds a matching variable. So it's more efficient to use structKeyExists, eg:

Also, another way to achieve this is to use cfparam, and specify 0 as the default: