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An Introduction to Python
by Guido van Rossum and Fred L. Drake, Jr.
Paperback (6"x9"), 124 pages
ISBN 0954161769
RRP £12.95 ($19.95)

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6.3 The dir() Function

The built-in function dir() is used to find out which names a module defines. It returns a sorted list of strings:

    >>> import fibo, sys
    >>> dir(fibo)
    ['__name__', 'fib', 'fib2']
    >>> dir(sys)
    ['__displayhook__', '__doc__', '__excepthook__',
     '__name__', '__stderr__', '__stdin__', '__stdout__',
     '_getframe', 'api_version', 'argv',
     'builtin_module_names', 'byteorder', 'callstats',
     'copyright', 'displayhook', 'exc_clear', 'exc_info',
     'exc_type', 'excepthook', 'exec_prefix', 'executable',
     'exit', 'getdefaultencoding', 'getdlopenflags',
     'getrecursionlimit', 'getrefcount', 'hexversion',
     'maxint', 'maxunicode', 'meta_path', 'modules', 'path',
     'path_hooks', 'path_importer_cache', 'platform',
     'prefix', 'ps1', 'ps2', 'setcheckinterval',
     'setdlopenflags', 'setprofile', 'setrecursionlimit',
     'settrace', 'stderr', 'stdin', 'stdout', 'version',
     'version_info', 'warnoptions']

Without arguments, dir() lists the names you have defined currently:

    >>> a = [1, 2, 3, 4, 5]
    >>> import fibo
    >>> fib = fibo.fib
    >>> dir()
    ['__builtins__', '__doc__', '__file__', '__name__', 'a',
     'fib', 'fibo', 'sys']

Note that it lists all types of names: variables, modules, functions, etc.

dir() does not list the names of built-in functions and variables. If you want a list of those, they are defined in the standard module ‘__builtin__’ :

    >>> import __builtin__
    >>> dir(__builtin__)
    ['ArithmeticError', 'AssertionError', 'AttributeError',
     'DeprecationWarning', 'EOFError', 'Ellipsis',
     'EnvironmentError', 'Exception', 'False',
     'FloatingPointError', 'FutureWarning', 'IOError',
     'ImportError', 'IndentationError', 'IndexError',
     'KeyError', 'KeyboardInterrupt', 'LookupError',
     'MemoryError', 'NameError', 'None', 'NotImplemented',
     'NotImplementedError', 'OSError', 'OverflowError',
     'PendingDeprecationWarning', 'ReferenceError',
     'RuntimeError', 'RuntimeWarning', 'StandardError',
     'StopIteration', 'SyntaxError', 'SyntaxWarning',
     'SystemError', 'SystemExit', 'TabError', 'True',
     'TypeError', 'UnboundLocalError', 'UnicodeDecodeError',
     'UnicodeEncodeError', 'UnicodeError',
     'UnicodeTranslateError', 'UserWarning', 'ValueError',
     'Warning', 'WindowsError', 'ZeroDivisionError', '_',
     '__debug__', '__doc__', '__import__', '__name__', 'abs',
     'apply', 'basestring', 'bool', 'buffer', 'callable',
     'chr', 'classmethod', 'cmp', 'coerce', 'compile',
     'complex', 'copyright', 'credits', 'delattr', 'dict',
     'dir', 'divmod', 'enumerate', 'eval', 'execfile',
     'exit', 'file', 'filter', 'float', 'frozenset',
     'getattr', 'globals', 'hasattr', 'hash', 'help', 'hex',
     'id', 'input', 'int', 'intern', 'isinstance',
     'issubclass', 'iter', 'len', 'license', 'list',
     'locals', 'long', 'map', 'max', 'min', 'object', 'oct',
     'open', 'ord', 'pow', 'property', 'quit', 'range',
     'raw_input', 'reduce', 'reload', 'repr', 'reversed',
     'round', 'set', 'setattr', 'slice', 'sorted',
     'staticmethod', 'str', 'sum', 'super', 'tuple', 'type',
     'unichr', 'unicode', 'vars', 'xrange', 'zip']
ISBN 0954161769An Introduction to PythonSee the print edition