How to Set Varibale Value based on dropdown selection

If I have a drop down field say with two values "Yes" and "No" and I want to then create a "on user input" script that sets a variable "p" to 0.5 if Yes and to 0.8 if No can you provide me with the syntax. I tried
if((input.live_near == "Yes"))
{
else
{
l=1;
}
l=2;
}

but need to set the variable type to integer and can't get the syntax correct.

Many thanks