We have seen val
and def
in previous SKBs but we haven't encountered the keyword lazy
before.
Try to figure out by yourself what lazy
does. Make sure to read the print statements in the console as you run the code.
Did you figure it out ?
The keyword lazy
allows a value to not be evaluated until the very first time it is called. If you call the value again, the previously computed value will be used.
With val
the value is computed instantly as the value is declared. You were able to see the print statement early in the log, before all the others.
And for def
, this is a method, so each time you call the method, you are recomputing the result.
Summary:
val
: Computed once when declaredlazy val
: Computed once when calleddef
: Computed each time it is called