How do I assign values to variables that are not pre-assigned?

Question

For example, the variable "abc" is set in a global variable and assigned by other calculation procedures.
But since that calculation did not occur, there is no assignment of the variable "abc".
An error occurs when the variable "abc" is used later.
How do you assign a value to the variable "abc" at this point?

Thanks!

txnelson · Accepted Answer

You can use the Try() function or you can test to see

if( isEmpty( abc ) == 1,  abc = 1 );