to interoperate with libraries that expect those names. User-defined literals are a very concise notation for creating objects of user- defined types. 20 • Providing a correct, consistent, and unsurprising guidelines that you might forget if you are used to the prevalent Windows style: • Do not use Hungarian notation (for example, naming an integer iNum). Use the Google naming conventions, including the .cc extension

stop() 3. Objects and Methods: avoid S4 objects and methods when possible; never mix S3 and S4 1 Notation and Naming File Names File names should end in .R and, of course, be meaningful. GOOD: predict_ad_revenue

Readable). 13 There are no specific rules or even well-established conventions for naming an- notation types. Test classes are named starting with the name of the class they are testing, and ending

when there is a clear advantage. Definition: Decorators for Functions and Methods (a.k.a ”the @ notation”). The most common decorators are @classmethod and @staticmethod, for con- verting ordinary methods