are often built on top of built-in types such as lists and dictionaries for instancea stack data structure may be implemented as class that manages or customizes built-in list built-in objects are often more efficient than custom data structures python' built-in types employ already optimized data structure algorithms that are implemented in for speed although you can write similar object types on your ownyou'll usually be hard-pressed to get the level of performance built-in object types provide built-in objects are standard part of the language in some wayspython borrows both from languages that rely on built-in tools ( lispand languages that rely on the programmer to provide tool implementations or frameworks of their own ( ++although you can implement unique object types in pythonyou don' need to do so just to get started moreoverbecause python' built-ins are standardthey're always the sameproprietary frameworkson the other handtend to differ from site to site in other wordsnot only do built-in object types make programming easierbut they're also more powerful and efficient than most of what can be created from scratch regardless of whether you implement new object typesbuilt-in objects form the core of every python program python' core data types table - previews python' built-in object types and some of the syntax used to code their literals--that isthe expressions that generate these objects some of these types will probably seem familiar if you've used other languagesfor instancenumbers and strings represent numeric and textual valuesrespectivelyand file objects provide an interface for processing real files stored on your computer to some readersthoughthe object types in table - may be more general and powerful than what you are accustomed to for instanceyou'll find that lists and dictionaries alone are powerful data representation tools that obviate most of the work you do to support collections and searching in lower-level languages in shortlists provide ordered collections of other objectswhile dictionaries store objects by keyboth lists and dictionaries may be nestedcan grow and shrink on demandand may contain objects of any type in this bookthe term literal simply means an expression whose syntax generates an object--sometimes also called constant note that the term "constantdoes not imply objects or variables that can never be changed ( this term is unrelated to ++' const or python' "immutable"-- topic explored in the section "immutabilityon page python' core data types