Python的三个帮助函数

q66262

　　type:查看指定变量的类型，如

>>> type(dog);
<class 'type'>
>>> type('a');
<class 'str'>
　　help:查看指定变量的详细介绍，如：

>>> class man:
def a(self):
print('kkk')

>>> help(man);
Help on class man in module __main__:
class man(builtins.object)
|  Methods defined here:
|  
|  a(self)
|  
|  ----------------------------------------------------------------------
|  Data descriptors defined here:
|  
|  __dict__
|      dictionary for instance variables (if defined)
|  
|  __weakref__
|      list of weak references to the object (if defined)

>>> help('a');
bigger than 5
Help on module a:
NAME
a
FILE
e:\xuhs\python31\a.py
DATA
a = 10


>>> help('bb');
no Python documentation found for 'bb'

　　dir：查看指定变量可用的属性或方法，如：

>>> dir(man);
['__class__', '__delattr__', '__dict__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__gt__', '__hash__', '__init__', '__le__', '__lt__', '__module__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', '__weakref__', 'a']
>>> man.__class__
<class 'type'>
>>> dir(123);
['__abs__', '__add__', '__and__', '__bool__', '__ceil__', '__class__', '__delattr__', '__divmod__', '__doc__', '__eq__', '__float__', '__floor__', '__floordiv__', '__format__', '__ge__', '__getattribute__', '__getnewargs__', '__gt__', '__hash__', '__index__', '__init__', '__int__', '__invert__', '__le__', '__lshift__', '__lt__', '__mod__', '__mul__', '__ne__', '__neg__', '__new__', '__or__', '__pos__', '__pow__', '__radd__', '__rand__', '__rdivmod__', '__reduce__', '__reduce_ex__', '__repr__', '__rfloordiv__', '__rlshift__', '__rmod__', '__rmul__', '__ror__', '__round__', '__rpow__', '__rrshift__', '__rshift__', '__rsub__', '__rtruediv__', '__rxor__', '__setattr__', '__sizeof__', '__str__', '__sub__', '__subclasshook__', '__truediv__', '__trunc__', '__xor__', 'bit_length', 'conjugate', 'denominator', 'imag', 'numerator', 'real']

>>> dir('abc');
['__add__', '__class__', '__contains__', '__delattr__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__getitem__', '__getnewargs__', '__gt__', '__hash__', '__init__', '__iter__', '__le__', '__len__', '__lt__', '__mod__', '__mul__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__rmod__', '__rmul__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', '_formatter_field_name_split', '_formatter_parser', 'capitalize', 'center', 'count', 'encode', 'endswith', 'expandtabs', 'find', 'format', 'index', 'isalnum', 'isalpha', 'isdecimal', 'isdigit', 'isidentifier', 'islower', 'isnumeric', 'isprintable', 'isspace', 'istitle', 'isupper', 'join', 'ljust', 'lower', 'lstrip', 'maketrans', 'partition', 'replace', 'rfind', 'rindex', 'rjust', 'rpartition', 'rsplit', 'rstrip', 'split', 'splitlines', 'startswith', 'strip', 'swapcase', 'title', 'translate', 'upper', 'zfill']
>>>
　　由例子可以看出，type的功能比较简单，dir和help功能比较丰富，dir列举出指定变量可用的属性及方法，help不仅列举出可用的属性及方法，还加以详细说明。