yield

Since python 2.5 there is the ability to send() , throw() , close() into a generator. Inside the defined generator one can 'catch' the sent data by doing something like: def gen(): while True: x = (yield) if x == 3: print('received 3!!') break else: yield x What i am trying to play with is doing something like: def gen2(): while True: yield (yield) Noticed that it is a legal generator which does something.. First thing i'm trying to figure out is: Is there a good usage for such writing? Also when doing something like: g = gen2() next(g) g.send(10) # output: 10 g.send(2) # output: nothing g

I've to Parallelize a function which involves a certain "yield". This is only a simple replica of the whole program that I've to work on, but sums up the problems i'm facing. Here I'm try to understand multiprocessing, apply_async and yield for my project In this example I've used a multiprocessing.pool and have used the apply_async to parallelize. I've put some print statements in the "parallel" function, but they aren't getting printed. When i replace yield with return the the print statements are getting reflected. I'm not certain about the nature of yield. I know its a generator and can be

I need to generate multiple results but one at a time, as opposed to everything at once in an array. How do I do that in Matlab with a generator like syntax as in Python? When executing functions that use the yield keyword, they actually return a generator. Generators are a type of iterators. While MATLAB does not provide the syntax for either, you can implement the "iterator interface" yourself. Here is an example similar to xrange function in python: classdef rangeIterator < handle properties (Access = private) i n end methods function obj = rangeIterator(n) obj.i = 0; obj.n = n; end

1.迭代器 定义 能被next()函数进行调用且不断返回下一个值的对象。其内置方法中包含 __iter__ （返回迭代器本身）和 __next__ （返回容器的下一个元素）。 特征 迭代器会生成惰性序列，它通过计算把值依次的返回，一边循环一边计算，而不是一次性得到所有的数据。 优点 需要数据的时候，一次取一个，可以在很大程度上节省内容空间，而不是一次性把所有的数据存入内存中；此外，可以遍历无限量的数据。 创建 使用 iter() 函数来创建。 string = iter('abcd') print(next(string)) print(next(string)) print(next(string)) print(next(string)) # 遍历完成之后继调用 print(next(string)) # 输出结果 StopIteration a b c d # 注意：当遍历完序列时，会引发一个StopIteration异常。使用for循环可以规避整个问题（for循环的底层使用了next方法）。 string = iter('abcd') for item in string: print(item) # 输出结果 a b c d 2. 生成器 定义 包含了yield语句的函数。 特征 执行生成器函数时，其内部代码不执行，而是返回一个生成器对象（ 特殊的迭代器 ）

一 闭包 在嵌套函数内,内部函数使用外部非全局变量 作用:保护数据的安全性 装饰器的本质就是闭包 def func(): avg_lst = [] # 自由变量 def foo(pirce): avg_lst.append(pirce) avg = sum(avg_lst) / len(avg_lst) return avg return foo ret = func() print(ret(150000)) print(ret.__closure__) # 查询是不是闭包 print(ret.__code__.co_freevars) # 获取的是自由变量 print(ret.__code__.co_varnames) # 获取的是局部变量 二 迭代器 2.1 可迭代对象 查看 dir() 内部含有__iter__方法的对象，都是可迭代对象。 优点:使用灵活,可以直接查看值 缺点:占内存,不能迭代取值 2.2 迭代器 只要具有__iter__()方法__next__()方法就是迭代器 优点:节省内存,内存机制 缺点:使用不灵活,操作比较繁琐,不能直接查看元素 特点:一次性的(用完就没了),不可逆性(不可后退),惰性机制 2.3 将可迭代对象转换成迭代器 lst = [1,2,3,4,6] new_list = lst.__iter__() #将可迭代对象转换成迭代器 2.4

I'm migrating a Website from Rails 2 (latest) to Rails 3 (beta2). Testing with Ruby 1.9.1p378 and Ruby 1.9.2dev (2010-04-05 trunk 27225) Stuck in a situation, i don't know which part will work well. Suspect yield is the problem, but don't know exactly. In my Layout Files I use the following technique quite often: app/views/layouts/application.html.erb : <%= yield(:sidebar) || render('shared/sidebar') %> For Example the partial look like: app/views/shared/_sidebar.html.erb : <p>Default sidebar Content. Bla Bla</p> Now it is time for the key part! In any view, I want to create a content_for

In javadoc there is said that yield method Causes the currently executing thread object to temporarily pause and allow other threads to execute. And Katherine Sierra and Bert Bates SCJP book says that yield() is supposed to do is make the currently running thread head back to runnable to allow other threads of the same priority to get their turn. So what actually method is doing? Given a multi-threaded application, yield will cause the currently executing thread to pause execution and be set in a waiting state. The JVM will then begin running another thread that was previously in a waiting

今天既然看到这里了，就做个笔记。这个玩意已经花过我很多时间。 可迭代对象只要有__iter__属性的都可以称呼可迭代(Interable)。 迭代器只要拥有__iter__与__next__属性就是迭代器(Iterator)。 Python里面可以通过iter方法生成迭代器(Iterator)，iter(可迭代(Interable)) 生成器(generator)，可以用简单生成器(i,for i in range(10)),写法跟列表生成器样式通用，把[]换成()， 还有可以通过自定义方法用yield生成。 生成器肯定是迭代器，更加是可迭代对象，生成器的功能是最多的 相对迭代器有三个生成器对象的专属方法： send throw close 简单的来说，迭代器只能从对象里面取值，生成器可以互动了，你还可以向对象里面送值。 yield，send,throw,close。我这里不写了，篇幅很长。 可以参考：https://blog.csdn.net/jpch89/article/details/87036970 一般用的最多也就yield及send,携程的时候要用。 还有可以通过自定义方法用yield生成。 [Hái yǒu kěyǐ tōngguò zì dìngyì fāngfǎ yòng yield shēngchéng.] There can be used a method