python Iterator Custom Class Concrete Method

1. Description

Iterators also have the ability to iterate over user-customized categories. Iteration objects need to support two ways: _iter__ (), which returns the iteration itself, and next (), which returns the next element.

2. Examples

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__())

Knowledge point expansion

python Custom Classes and Methods Used

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())

The running results are as follows:

Raja I Kumar 21
Raja I Kumar 26
RIK