dir()返回所有名称的列表，包括给定对象的属性和可从它访问的属性
但是，我希望能够以简单的方式过滤 dir() 的结果，类似于 unix grep工具
>>> dir(list)
['__add__', '__class__', '__contains__', ...... ,'remove', 'reverse', 'sort']
上面返回了一个巨大的属性列表，为了简洁起见，其中一些属性被隐藏了。
>>> # How can I do something like this, which allows me to reduce the list.
>>> dir(list,filter='<regular-expression>')
例子：
>>> dir(list,'in')
['__contains__', '__init__', 'index', 'insert']
所有过滤后的元素都具有属性，其中包含表达式“ in ”。
如何使用 python dir() 函数或类似函数实现这种基于正则表达式的过滤？
列表推导是最简单的方法
>>> [a for a in dir(list) if re.match(r'__\w{,2}__',a)]
['__eq__', '__ge__', '__gt__', '__le__', '__lt__', '__ne__']
>>> [a for a in dir(list) if 'in' in a]
['__contains__', '__init__', 'index', 'insert']
不要忘记help：
>>> help(list)
Help on class list in module __builtin__:
class list(object)
| list() -> new empty list
| list(iterable) -> new list initialized from iterable's items
|
| Methods defined here:
|
| __add__(...)
| x.__add__(y) <==> x+y
|
| __contains__(...)
| x.__contains__(y) <==> y in x
|
| __delitem__(...)
| x.__delitem__(y) <==> del x[y]
|
| __delslice__(...)
| x.__delslice__(i, j) <==> del x[i:j]
|
| Use of negative indices is not supported.
|
| __eq__(...)
| x.__eq__(y) <==> x==y
|
| __ge__(...)
| x.__ge__(y) <==> x>=y
|
| __getattribute__(...)
| x.__getattribute__('name') <==> x.name
|
| __getitem__(...)
| x.__getitem__(y) <==> x[y]
|
| __getslice__(...)
| x.__getslice__(i, j) <==> x[i:j]
|
| Use of negative indices is not supported.
|
| __gt__(...)
| x.__gt__(y) <==> x>y
|
| __iadd__(...)
| x.__iadd__(y) <==> x+=y
|
| __imul__(...)
| x.__imul__(y) <==> x*=y
|
| __init__(...)
| x.__init__(...) initializes x; see x.__class__.__doc__ for signature
|
| __iter__(...)
| x.__iter__() <==> iter(x)
|
| __le__(...)
| x.__le__(y) <==> x<=y
|
| __len__(...)
| x.__len__() <==> len(x)
|
| __lt__(...)
| x.__lt__(y) <==> x<y
|
| __mul__(...)
| x.__mul__(n) <==> x*n
|
| __ne__(...)
| x.__ne__(y) <==> x!=y
|
| __repr__(...)
| x.__repr__() <==> repr(x)
|
| __reversed__(...)
| L.__reversed__() -- return a reverse iterator over the list
|
| __rmul__(...)
| x.__rmul__(n) <==> n*x
|
| __setitem__(...)
| x.__setitem__(i, y) <==> x[i]=y
|
| __setslice__(...)
| x.__setslice__(i, j, y) <==> x[i:j]=y
|
| Use of negative indices is not supported.
|
| __sizeof__(...)
| L.__sizeof__() -- size of L in memory, in bytes
|
| append(...)
| L.append(object) -- append object to end
|
| count(...)
| L.count(value) -> integer -- return number of occurrences of value
|
| extend(...)
| L.extend(iterable) -- extend list by appending elements from the iterable
|
| index(...)
| L.index(value, [start, [stop]]) -> integer -- return first index of value.
| Raises ValueError if the value is not present.
|
| insert(...)
| L.insert(index, object) -- insert object before index
|
| pop(...)
| L.pop([index]) -> item -- remove and return item at index (default last).
| Raises IndexError if list is empty or index is out of range.
|
| remove(...)
| L.remove(value) -- remove first occurrence of value.
| Raises ValueError if the value is not present.
|
| reverse(...)
| L.reverse() -- reverse *IN PLACE*
|
| sort(...)
| L.sort(cmp=None, key=None, reverse=False) -- stable sort *IN PLACE*;
| cmp(x, y) -> -1, 0, 1
|
| ----------------------------------------------------------------------
| Data and other attributes defined here:
|
| __hash__ = None
|
| __new__ = <built-in method __new__ of type object>
| T.__new__(S, ...) -> a new object with type S, a subtype of T