CODEWITHSUNDEEP
python
Adam
Adam

Reputation: 29079

Where do I find Python Classes?

where do I find the documentation for classes like object or dict ? I would like to know which methods they have and what attributes. I found most stuff at http://docs.python.org/2 but I could not find methods and attributes for class object.

Upvotes: 1

Views: 169

Answers (4)

Ashwini Chaudhary
Ashwini Chaudhary

Reputation: 251096

For detailed docmentation visit online documentation.

pydoc server. It's an offline version of documentation, not a detailed one though :

$ python -m pydoc -p 5555

It starts a pydocs server at localhost and you can access docs on that link.

For quick lookup you can use dir() it will return all the attributes of an object:

>>> dir(object)
['__class__', '__delattr__', '__doc__', '__format__', '__getattribute__', '__hash__', '__init__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__']
>>> dir(dict)
['__class__', '__cmp__', '__contains__', '__delattr__', '__delitem__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__getitem__', '__gt__', '__hash__', '__init__', '__iter__', '__le__', '__len__', '__lt__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__setitem__', '__sizeof__', '__str__', '__subclasshook__', 'clear', 'copy', 'fromkeys', 'get', 'has_key', 'items', 'iteritems', 'iterkeys', 'itervalues', 'keys', 'pop', 'popitem', 'setdefault', 'update', 'values', 'viewitems', 'viewkeys', 'viewvalues']

For some info on an attribute use help()

>>>help(dict.get)
get(...)
    D.get(k[,d]) -> D[k] if k in D, else d.  d defaults to None.

You can also use the module pydoc:

>>> import pydoc

>>> print pydoc.getdoc(dict)
dict() -> new empty dictionary
dict(mapping) -> new dictionary initialized from a mapping object's
    (key, value) pairs
dict(iterable) -> new dictionary initialized as if via:
    d = {}
    for k, v in iterable:
        d[k] = v
dict(**kwargs) -> new dictionary initialized with the name=value pairs
    in the keyword argument list.  For example:  dict(one=1, two=2)

>>> print pydoc.getdoc(dict.get)
D.get(k[,d]) -> D[k] if k in D, else d.  d defaults to None.

Upvotes: 5

Lennart Regebro
Lennart Regebro

Reputation: 172309

There really isn't any difference between the built in classes or anything else. These are the steps to find out more info for any object:

First try help():

>>> help(dict)
Help on class dict in module __builtin__:

class dict(object)
 |  dict() -> new empty dictionary
 |  dict(mapping) -> new dictionary initialized from a mapping object's
 |      (key, value) pairs
 |  dict(iterable) -> new dictionary initialized as if via:
 |      d = {}
 |      for k, v in iterable:
 |          d[k] = v
 |  dict(**kwargs) -> new dictionary initialized with the name=value pairs
 |      in the keyword argument list.  For example:  dict(one=1, two=2)
 |  
 |  Methods defined here:
 |  
 |  __cmp__(...)
 |      x.__cmp__(y) <==> cmp(x,y)
 ...

You can also get a list of attributes and methods with dir():

>>> dir(list)
['__add__', '__class__', '__contains__', '__delattr__', '__delitem__', '__delslice__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__getitem__', '__getslice__', '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__iter__', '__le__', '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__reversed__', '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__sizeof__', '__str__', '__subclasshook__', 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove', 'reverse', 'sort']

And you can find much of it's data by looking at the __dict__:

>>> sys.__dict__
{'setrecursionlimit': <built-in function setrecursionlimit>, 
'dont_write_bytecode': False, 'getrefcount': <built-in function getrefcount>,
'long_info': sys.long_info(bits_per_digit=15, sizeof_digit=2), 'path_importer_cache':
{'': None, '/usr/lib/python2.7/encodings': None, 
'/usr/local/lib/python2.7/dist-packages/docutils-0.10-py2.7.egg': None, 
'/usr/lib/python2.7/plat-linux2': None,
...

Although many built-in types doesn't have on, or have very little in it.

>>> 'foo'.__dict__
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'str' object has no attribute '__dict__'

And for more explanation, visit the documentation. For even more details, read the source code.

Upvotes: 1

girardengo
girardengo

Reputation: 725

For a list of method, try:

help(object)

ie 

help(dict)

Upvotes: 0

Bhavish Agarwal
Bhavish Agarwal

Reputation: 673

>>> dir({})
['__class__', '__cmp__', '__contains__', '__delattr__', '__delitem__', '__doc__',      
'__eq__', '__format__', '__ge__', '__getattribute__', '__getitem__', '__gt__', 
'__hash__', '__init__', '__iter__', '__le__', '__len__', '__lt__', '__ne__', '__new__',   
'__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__setitem__', '__sizeof__',  
'__str__', '__subclasshook__', 'clear', 'copy', 'fromkeys', 'get', 'has_key', 'items',   
'iteritems', 'iterkeys', 'itervalues', 'keys', 'pop', 'popitem', 'setdefault',  
 'update',   
 'values', 'viewitems', 'viewkeys', 'viewvalues']

Similarly:

>>> o = object()
>>> dir(o)

Upvotes: 0

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