Python 2.5 quick reference |  |
Python 2.5 quick reference | |
The purpose of the dir() function is to find
out what names are defined in a given namespace, and return a
list of those names. If called without arguments, it returns
a list of the names defined in the local namespace. This
function can be very handy for finding out what items are in a
module or class.
Certain special names are found in most or all namespaces:
__doc__ is present in every namespace.
Initially None, you can store
documentation there.
__name__ is the name of the current
module (minus the .py extension).
In the top-level script or in conversational mode, this
name is set to the string '__main__'.
__builtins__ is a list of the names of
all built-in functions and variables.
In this example sequence, we'll show you what is in the global
namespace just after starting up Python. Then we'll import
the math module and display its names.
>>> dir() ['__builtins__', '__doc__', '__name__'] >>> x=5; forkTail='Tyrannus' >>> dir() ['__builtins__', '__doc__', '__name__', 'forkTail', 'x'] >>> print __doc__ None >>> print __name__ __main__ >>> import math >>> print math.__name__ math >>> dir(math) ['__doc__', '__file__', '__name__', 'acos', 'asin', 'atan', 'atan2', 'ceil' , 'cos', 'cosh', 'degrees', 'e', 'exp', 'fabs', 'floor', 'fmod', 'frexp', ' hypot', 'ldexp', 'log', 'log10', 'modf', 'pi', 'pow', 'radians', 'sin', 'si nh', 'sqrt', 'tan', 'tanh'] >>> print math.__doc__ This module is always available. It provides access to the mathematical functions defined by the C standard. >>> print math.log10.__doc__ log10(x) -> the base 10 logarithm of x. >>> print __builtins__ <module '__builtin__' (built-in)> >>> dir(__builtins__) ['ArithmeticError', 'AssertionError', 'AttributeError', 'BaseException', 'D eprecationWarning', 'EOFError', 'Ellipsis', 'EnvironmentError', 'Exception' , 'False', 'FloatingPointError', 'FutureWarning', 'GeneratorExit', 'IOError ', 'ImportError', 'ImportWarning', 'IndentationError', 'IndexError', 'KeyEr ror', 'KeyboardInterrupt', 'LookupError', 'MemoryError', 'NameError', 'None ', 'NotImplemented', 'NotImplementedError', 'OSError', 'OverflowError', 'Pe ndingDeprecationWarning', 'ReferenceError', 'RuntimeError', 'RuntimeWarning ', 'StandardError', 'StopIteration', 'SyntaxError', 'SyntaxWarning', 'Syste mError', 'SystemExit', 'TabError', 'True', 'TypeError', 'UnboundLocalError' , 'UnicodeDecodeError', 'UnicodeEncodeError', 'UnicodeError', 'UnicodeTrans lateError', 'UnicodeWarning', 'UserWarning', 'ValueError', 'Warning', 'Zero DivisionError', '_', '__debug__', '__doc__', '__import__', '__name__', 'abs ', 'all', 'any', 'apply', 'basestring', 'bool', 'buffer', 'callable', 'chr' , 'classmethod', 'cmp', 'coerce', 'compile', 'complex', 'copyright', 'credi ts', 'delattr', 'dict', 'dir', 'divmod', 'enumerate', 'eval', 'execfile', ' exit', 'file', 'filter', 'float', 'frozenset', 'getattr', 'globals', 'hasat tr', 'hash', 'help', 'hex', 'id', 'input', 'int', 'intern', 'isinstance', ' issubclass', 'iter', 'len', 'license', 'list', 'locals', 'long', 'map', 'ma x', 'min', 'object', 'oct', 'open', 'ord', 'pow', 'property', 'quit', 'rang e', 'raw_input', 'reduce', 'reload', 'repr', 'reversed', 'round', 'set', 's etattr', 'slice', 'sorted', 'staticmethod', 'str', 'sum', 'super', 'tuple', 'type', 'unichr', 'unicode', 'vars', 'xrange', 'zip']