python3有多少个bif

BIF（built-in functions）顾名思义，就是Erlang内建函数。它们通常用来完成那此无法用Erlang完成的任务。比如将列表转换为元组或者获取当前的时间和日期。完成这些操作的函数，我们称之为BIF。python中提供了大量的内置功能函数，这就意味着你可以少些很多的代码。Python3中共提供了72个BIF。

我们可以在python或IDLE shell中，输入dir(__builtins__)级可看到python的内置方法列表，"builtins"的前后都是两个下划线，shell会给出一个庞大的列表，如下：

['ArithmeticError','AssertionError','AttributeError','BaseException','BlockingIOError','BrokenPipeError',
'BufferError','BytesWarning','ChildProcessError','ConnectionAbortedError','ConnectionError',
'ConnectionRefusedError','ConnectionResetError','DeprecationWarning','EOFError','Ellipsis','EnvironmentError',
'Exception','False','FileExistsError','FileNotFoundError','FloatingPointError','FutureWarning','GeneratorExit',
'IOError','ImportError','ImportWarning','IndentationError','IndexError','InterruptedError','IsADirectoryError',
'KeyError','KeyboardInterrupt','LookupError','MemoryError','NameError','None','NotADirectoryError',
'NotImplemented','NotImplementedError','OSError','OverflowError','PendingDeprecationWarning','PermissionError',
'ProcessLookupError','ReferenceError','ResourceWarning','RuntimeError','RuntimeWarning','StopIteration',
'SyntaxError','SyntaxWarning','SystemError','SystemExit','TabError','TimeoutError','True','TypeError',
'UnboundLocalError','UnicodeDecodeError','UnicodeEncodeError','UnicodeError','UnicodeTranslateError',
'UnicodeWarning','UserWarning','ValueError','Warning','WindowsError','ZeroDivisionError','_'，
'__build_class__','__debug__','__doc__','__import__','__loader__','__name__','__package__','__spec__',
'abs','all','any','ascii','bin','bool','bytearray','bytes','callable','chr','classmethod','compile',
'complex','copyright','credits','delattr','dict','dir','divmod','enumerate','eval','exec','exit',
'filter','float','format','frozenset','getattr','globals','hasattr','hash','help','hex','id','input',
'int','isinstance','issubclass','iter','len','license','list','locals','map','max','memoryview','min',
'next','object','oct','open','ord','pow','print','property','quit','range','repr','reversed','round',
'set','setattr','slice','sorted','staticmethod','str','sum','super','tuple','type','vars','zip']

要查看某个BIF是干什么的，可以在shell中键入help(方法名)，如：help(isinstance)就会得到这个BIF的功能描述。如下：

>>>help(isinstance)
Helponbuilt-infunctionisinstanceinmodulebuiltins:
isinstance(...)
isinstance(object,class-or-type-or-tuple)->bool
Returnwhetheranobjectisaninstanceofaclassorofasubclassthereof.
Withatypeassecondargument,returnwhetherthatistheobject'stype.
Theformusingatuple,isinstance(x,(A,B,...)),isashortcutfor
isinstance(x,A)orisinstance(x,B)or...(etc.).

就可以得到isinstance函数的介绍和使用方法。