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设计模式-迭代器模式-iterator-python

2017-08-10

设计模式-迭代器模式-iterator-python。它提供一种方法访问一个容器对象中各个元素, 而又不需暴露该对象的内部细节。

def

它提供一种方法访问一个容器对象中各个元素, 而又不需暴露该对象的内部细节。

usage

迭代器模式提供了遍历容器的方便性, 容器只要管理增减元素就可以了, 需要遍历时交由迭代器进行。

code

from __future__ import print_function


def count_to(count):
    """Counts by word numbers, up to a maximum of five"""
    numbers = ["one", "two", "three", "four", "five"]
    # enumerate() returns a tuple containing a count (from start which
    # defaults to 0) and the values obtained from iterating over sequence
    for pos, number in zip(range(count), numbers):
        yield number

# Test the generator
count_to_two = lambda: count_to(2)
count_to_five = lambda: count_to(5)

print('Counting to two...')
for number in count_to_two():
    print(number, end=' ')

print()

print('Counting to five...')
for number in count_to_five():
    print(number, end=' ')

print()

### OUTPUT ###
# Counting to two...
# one two
# Counting to five...
# one two three four five
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