python callable(object)
callable(object)中文说明:检查对象object是否可调用。如果返回True,object仍然可能调用失败;但如果返回False,调用对象ojbect绝对不会成功。
注意:类是可调用的,而类的实例实现了__call__()方法才可调用。
版本:该函数在python2.x版本中都可用。但是在python3.0版本中被移除,而在python3.2以后版本中被重新添加。
英文说明:Return True if the object argument appears callable, False if not. If this returns true, it is still possible that a call fails, but if it is false, calling object will never succeed. Note that classes are callable (calling a class returns a new instance); class instances are callable if they have a __call__() method.
代码实例:
[*]>>> callable(0)
[*]False
[*]>>> callable("mystring")
[*]False
[*]>>> def add(a, b):
[*]… return a + b
[*]…
[*]>>> callable(add)
[*]True
[*]>>> class A:
[*]… def method(self):
[*]… return 0
[*]…
[*]>>> callable(A)
[*]True
[*]>>> a = A()
[*]>>> callable(a)
[*]False
[*]>>> class B:
[*]… def __call__(self):
[*]… return 0
[*]…
[*]>>> callable(B)
[*]True
[*]>>> b = B()
[*]>>> callable(b)
[*]True
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