>>> iterator1 is iterator2 True 1. 2. Iterators 都是 iterable,所有的 iterator 都是他们自己的 iterators。 有点迷是吗? 让我们回顾下这些术语。 你可以遍历一个 iterable,而 iterator就是实际执行遍历操作的代理。 另外,Python 中 iterator 也是 iterable,而且他们也是自己
所以你可以从每一个 iterable 得到一个 iterator。对于 iterator 你可以做得唯一的一件事就是使用next函数取其下一项。但如果已经没有下一项了,那么你就会得到一个StopIteration错误。 Looping without a for loop 现在我们已经学习了 iterator 以及next和iter函数。我们将要尝试不通过 for 循环来遍历一个 iterable。
Getting Started With the Python for LoopIn programming, loops are control flow statements that allow you to repeat a given set of operations a number of times. In practice, you’ll find two main types of loops:for loops are mostly used to iterate a known number of times, which is common...
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. For loops: more complex than they seem We’re n...
This is less like theforkeyword in other programming languages, and works more like an iterator method as found in other object-orientated programming languages. With theforloop we can execute a set of statements, once for each item in a list, tuple, set etc. ...
Python for loop Syntax in Detail The first word of the statement starts with thekeyword “for”which signifies the beginning of the for loop. Then we have theiterator variablewhich iterates over the sequence and can be used within the loop to perform various functions ...
Python for loop with zip Thezipfunction creates an iterator from the given iterables. for_loop_zip.py #!/usr/bin/python words1 = ["cup", "bottle", "table", "rock", "apple"] words2 = ["trousers", "nail", "head", "water", "pen"] ...
iterable = [1,2,3] # Your date iterator = iter(iterable) # get the data iterator try : # wrap all in a try / except while 1 : item = iterator.next() print item # put the "for loop" code here except StopIteration, e : # make the process on the last element here print item...
在Python 中,使用了 yield 的函数被称为生成器(generator)。 跟普通函数不同的是,生成器是一个返回迭代器的函数,只能用于迭代操作,更简单点理解生成器就是一个迭代器。 在调用生成器运行的过程中,每次遇到 yield 时函数会暂停并保存当前所有的运行信息,返回 yield 的值, 并在下一次执行 next() 方法时从当前位...
python的for是从一个Iterator中取值，因此对于你的第一个问题，答案是可以实现，只要那个Iterator是无限的...