testing for empty string

Hi,

 

I am very new to iRules. Two quesitons:

 

1.) Is there a function to test if a string variable is the empty string? In my particular case, I am using regexp to populate a string variable and later in the irule, I want to know if the string was populated or not.

 

2.) How do you define an integer variable? I want to capture the output of the regexp call and store it in an integer variable and later I can test if that variable equals 0 or 1.

 

 

Thanks