swift3 - Swift 3 Convert Double to String -

i keep getting error "initializer conditional binding must have optional type, not 'double'". trying display core data values , 1 double. ive tried work around same way had store values when converting it.

heres code gives me error:

func displaystats() {            // display other attributes if have values         if let servingsize  = mealstats.serving {             servingslabel.text = servingsize          } 

mealstats.serving of type "double" , not "double?"
since not optional cannot unwrapped. right way use be

func displaystats() {     // display other attributes if have values     servingslabel.text = "\(mealstats.serving)" }