1. classmethod

classmethod 修飾符對應(yīng)的函數(shù)不需要實(shí)例化，不需要 self 參數(shù)。第一個(gè)參數(shù)需要是表示自身類的 cls 參數(shù)，能調(diào)用類的屬性、方法、實(shí)例等。

class People(object):def __init__(self, number, name):self.number = numberself.name = namedef instance_method(self):print("This is instance method")return self@classmethoddef class_method(cls):print("This is class method")return cls@classmethoddef print_class_info(cls):print("類名為 {}".format(cls.__name__))People.class_method()
People.print_class_info()

2. delattr(object, name)

刪除對象的屬性，在不需要某個(gè)或某些屬性時(shí)，這個(gè)方法就會(huì)很有用。

In [1]: class People(object):...:     def __init__(self, number, name):...:         self.number = number...:         self.name = name...:         In [2]: wohu = People(1, "wohu")In [3]: delattr(wohu, 'number')In [4]: wohu.number
---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-4-d950a0aab65b> in <module>
----> 1 wohu.numberAttributeError: 'People' object has no attribute 'number'In [5]: hasattr(wohu, 'number')
Out[5]: FalseIn [6]: hasattr(wohu, 'name')
Out[6]: True

3. dir([object])

不帶參數(shù)時(shí)，返回當(dāng)前范圍內(nèi)的變量、方法和定義的類型列表；帶參數(shù)時(shí)返回參數(shù)的屬性、方法列表。

In [7]: dir(wohu)
Out[7]: 
['__class__','__delattr__','__dict__','__dir__','__doc__','__eq__','__format__','__ge__','__getattribute__','__gt__','__hash__','__init__','__init_subclass__','__le__','__lt__','__module__','__ne__','__new__','__reduce__','__reduce_ex__','__repr__','__setattr__','__sizeof__','__str__','__subclasshook__','__weakref__','name']

4. hasattr(object, name)

判斷對象是否有某個(gè)屬性

In [5]: hasattr(wohu, 'number')
Out[5]: FalseIn [6]: hasattr(wohu, 'name')
Out[6]: True

5. getattr(object, name[, default])

獲取對象的屬性：

In [8]: getattr(wohu, 'name')
Out[8]: 'wohu'

6. callable(object)

判斷對象是否可被調(diào)用，能被調(diào)用的對象就是一個(gè) callable 對象，比如函數(shù) str 、 int 等都是可被調(diào)用的。

In [9]: callable(int)
Out[9]: TrueIn [10]: callable(str)
Out[10]: True

如下代碼，默認(rèn)實(shí)例化對象是不可調(diào)用的，

In [12]: class People(object):...:     def __init__(self, number, name):...:         self.number = number...:         self.name = name...:         In [13]: wohu = People(1, "wohu")In [14]: callable(wohu)
Out[14]: False

如果想要讓實(shí)例化對象能調(diào)用，如 wohu() 則需要增加 __call__ 方法：

In [15]: class People(object):...:     def __init__(self, number, name):...:         self.number = number...:         self.name = name...:     def __call__(self):...:         print("can be called")...:         print("my name is {}".format(self.name))...:         In [16]: wohu = People(1, "wohu")In [17]: callable(wohu)
Out[17]: TrueIn [18]: wohu()
can be called
my name is wohu

總結(jié)

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