python迭代器自定义类的具体方法

1、说明

迭代器还具有迭代用户定制类别的能力。迭代对象需要支持两种方式:_iter__()和next(),前者返回迭代本身,后者返回下一个元素。

2、实例

class example(object):
  def __init__(self,num):
    self.num=num
  def __iter__(self):
    return self
  def __next__(self):
    if self.num <= 0:
      raise StopIteration
    tmp = self.num
    self.num -= 1
    return tmp
  
a = example(3)
print(a.__next__())
print(a.__next__())
print(a.__next__())
print(a.__next__())

知识点扩展

python自定义类并使用的方法

class Person:
 def __init__(self, first, middle, last, age):
  self.first = first;
  self.middle = middle;
  self.last = last;
  self.age = age;
 def __str__(self):
  return self.first + ' ' + self.middle + ' ' + self.last + \
  ' ' + str(self.age)
 def initials(self):
  return self.first[0] + self.middle[0] + self.last[0]
 def changeAge(self, val):
  self.age += val
myPerson = Person('Raja', 'I', 'Kumar', 21)
print(myPerson)
myPerson.changeAge(5)
print(myPerson)
print(myPerson.initials())

运行结果如下:

Raja I Kumar 21
Raja I Kumar 26
RIK