Function simplification principle: save if you can

The principle of simplifying functions ： Able to save and save

1. return It can be omitted ,Scala The last line of the function body is used as the return value

2. If the body of a function has only one line of code , You can omit curly braces

3. If the return value type can be inferred , Then you can omit （: Omit with return value type ）

4. If there is return, The return value type cannot be omitted , Must specify

5. If the function explicitly states unit, So even if you use return Keywords don't work either

6. Scala If no return value type is expected , You can omit the equal sign

7. If the function has no parameters , But a list of parameters is declared , So when calling , parentheses , Yes, but not

8. If the function doesn't have a parameter list , Then brackets can be omitted , Parentheses must be omitted when calling

9. If you don't care about the name , It's just about logical processing , So the function name （def） It can be omitted