objects in python python is an object-oriented language and classes form the basis for all data types in this sectionwe describe key aspects of python' object modeland we introduce python' built-in classessuch as the int class for integersthe float class for floating-point valuesand the str class for character strings more thorough presentation of object-orientation is the focus of identifiersobjectsand the assignment statement the most important of all python commands is an assignment statementsuch as temperature this command establishes temperature as an identifier (also known as name)and then associates it with the object expressed on the right-hand side of the equal signin this case floating-point object with value we portray the outcome of this assignment in figure float temperature figure the identifier temperature references an instance of the float class having value identifiers identifiers in python are case-sensitiveso temperature and temperature are distinct names identifiers can be composed of almost any combination of lettersnumeralsand underscore characters (or more general unicode charactersthe primary restrictions are that an identifier cannot begin with numeral (thus lives is an illegal name)and that there are specially reserved words that cannot be used as identifiersas shown in table false none true and as assert break class continue def del elif reserved words else from in except global is finally if lambda for import nonlocal not or pass raise return try while with yield table listing of the reserved words in python these names cannot be used as identifiers