A unary prefix operator that returns 1 if the operand evaluate to true, otherwise 0 is returned; !3 returns 0.
A unary prefix operator that returns 1 if the operand evaluate to false, otherwise 0 is returned; !3 returns 0.
A "shallow copy" only duplicates the containing (root level) array or dictionary, not its (nested child) values.A "deep copy" also duplicates every element value in an array and/or entry value in a dictionary, and any nested (child) values therein, and so on.