生成器的原理基于迭代器(iterators)和生成器函数(generator functions)。 def even_numbers(n): for i in range(1, n+1): if i % 2 == 0: yield i # 创建生成器对象 even_generator = even_numbers(10) # 打印生成的偶数 for number in even_generator: print(number) 生成器函数 生成器通过生成器...
Python中的*args用来将值集合args中的元素拆分为多个单独的值,**argv用来将dict的元素拆分为多对值。 >>>f(0,1,2)# Normal positionals0,1,and2>>>f(*range(3))# Unpack range values: iterable in 3.X0,1,and2>>>f(*(iforiinrange(3)))# Unpack generator expression values0,1,and2 Python...
Python custom iteratorTo create a custom iterator, it must implement the iterator protocol: the __iter__ and __next__ functions. inf_seq.py #!/usr/bin/python class InfSeq: def __init__(self): self.x = 0 def __next__(self): self.x += 1 return self.x ** self.x def __...
迭代是Python最强大的功能之一,是访问集合元素的一种方式。 Iteration one of Python's most powerful functions and a way to access colleaction elements. 迭代器是一个可以记住遍历位置的对象。 An iterator is an object that can remenber to traverse the location. 迭代器对象从集合的第一个元素开始访问,直...
On the other hand, for every iterator we can callnext(), and we can also loop over it with aforandinstatement. Conclusion¶ In this tutorial, we have learned about iterators and iterables in Python. We have also learned how to useiter()andnext()functions. To learn more about iterator...
Iterators are all over the place in Python.For example the built-in enumerate, zip, and reversed functions all return iterators.>>> enumerate("hey") <enumerate object at 0x7f016721ca00> >>> reversed("hey") <reversed object at 0x7f01672da250> >>> zip("hey", (4, 5, 6)) <zip ...
为了让上述程序代码得以运行,我们必须为此iterator class定义!=, *, ++等运算符。与定义member functions的唯一差别就是不需要指定方法名称,只需要在运算符符号之前加上关键词operator即可。 4.6.1 begin()和end()方法 首先,我们需要为Stack添加begin和end方法,返回类型为StackIterator,由于StackIterator还没有被声明...
The iterator protocol is used byforloops, tuple unpacking, and all built-in functions that work on generic iterables. Using the iterator protocol (either manually or automatically) is the only universal way to loop over any iterable in Python. ...
In Python 3,enumerate,zip,reversed, and a number of other built-in functions return iterators: >>>enumerate(numbers)<enumerateobjectat0x7f04384ff678>>>zip(numbers,numbers)<zipobjectat0x7f043a085cc8>>>reversed(numbers)<list_reverseiteratorobjectat0x7f043a081f28> Generators...
Two functions in particular, chain and islice, are exposed as addition and slicing operators, which results in terse and yet more readable (IMHO) code. 1 comment Christopher Dunn 17 years, 4 months ago Interesting. This makes Python look more like Ruby....