python' built-in classes table provides summary of commonly usedbuilt-in classes in pythonwe take particular note of which classes are mutable and which are immutable class is immutable if each object of that class has fixed value upon instantiation that cannot subsequently be changed for examplethe float class is immutable once an instance has been createdits value cannot be changed (although an identifier referencing that object can be reassigned to different valueclass bool int float list tuple str set frozenset dict description boolean value integer (arbitrary magnitudefloating-point number mutable sequence of objects immutable sequence of objects character string unordered set of distinct objects immutable form of set class associative mapping (aka dictionaryimmutable table commonly used built-in classes for python in this sectionwe provide an introduction to these classesdiscussing their purpose and presenting several means for creating instances of the classes literal forms (such as exist for most of the built-in classesand all of the classes support traditional constructor form that creates instances that are based upon one or more existing values operators supported by these classes are described in section more detailed information about these classes can be found in later as followslists and tuples ()strings and and appendix )sets and dictionaries (the bool class the bool class is used to manipulate logical (booleanvaluesand the only two instances of that class are expressed as the literals true and false the default constructorbool)returns falsebut there is no reason to use that syntax rather than the more direct literal form python allows the creation of boolean value from nonboolean type using the syntax bool(foofor value foo the interpretation depends upon the type of the parameter numbers evaluate to false if zeroand true if nonzero sequences and other container typessuch as strings and listsevaluate to false if empty and true if nonempty an important application of this interpretation is the use of nonboolean value as condition in control structure