python类中的__call__()函数

函数可调用的，类是不可调用的，若想类被调用，则需要添加 __call__() 函数:
举例：

class Student:
    def __init__(self, name, id):
        self.name = name
        self.id = id
    def __call__(self):
        print("Student %s is created." %self.name)
        print("His ID is：", self.id)

a = Student('ZhangSan', 1)
a()

输出为:

Student ZhangSan is created.
His ID is： 1

当然 __call__() 函数也可以有参数， 举例：

class Student:
    def __init__(self, name, id):
        self.name = name
        self.id = id
    def __call__(self, grade):
        print("Student %s is created." %self.name)
        print("His ID is：", self.id)
        self.grade = grade
        if (grade>=90):
            print("%s's grade is great." %self.name)
        else:
            return;
a = Student('ZhangSan', 1)
a(94)
print("")
b =Student('LiSi', 2)
b(58)  

输出为:

Student ZhangSan is created.
His ID is： 1
ZhangSan's grade is great.

Student LiSi is created.
His ID is： 2