yield | 易学教程

Meaning of the word yield

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问题 Currently I'm reading "The Well-Grounded Rubyist" by David A. Black, and I stuck at 10.9 chapter (Enumerators and the next dimension of enumerability). My question is about yield method. What is the meaning of the word yield in Ruby context? My native language is Russian, and Google Translate shows me a bunch of translation variants, that are confusing me. There are some of them: give , bring , surrender ( give up ), produce , agree , comply and many others. UPD: please, pay attention to the

小邵教你玩转Generator+co/async await

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本文转载于: 猿2048 网站▶ https://www.mk2048.com/blog/blog.php?id=h122c02icb 前言：大家好，我叫邵威儒，大家都喜欢喊我小邵，学的金融专业却凭借兴趣爱好入了程序猿的坑，从大学买的第一本vb和自学vb，我就与编程结下不解之缘，随后自学易语言写游戏辅助、交易软件，至今进入了前端领域，看到不少朋友都写文章分享，自己也弄一个玩玩，以下文章纯属个人理解，便于记录学习，肯定有理解错误或理解不到位的地方，意在站在前辈的肩膀，分享个人对技术的通俗理解，共同成长！后续我会陆陆续续更新javascript方面，尽量把javascript这个学习路径体系都写一下包括前端所常用的es6、angular、react、vue、nodejs、koa、express、公众号等等都会从浅到深，从入门开始逐步写，希望能让大家有所收获，也希望大家关注我~ 源码地址： https://github.com/iamswr/promiseAplus 在看这篇文章之前可以先看看整个异步的发展 https://juejin.im/post/5b6e5cbf51882519ad61b67e Author: 邵威儒 Email: 166661688@qq.com Wechat: 166661688 github: https://github.com/iamswr/

C# IEnumerator/yield structure potentially bad?

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问题 Background: I've got a bunch of strings that I'm getting from a database, and I want to return them. Traditionally, it would be something like this: public List<string> GetStuff(string connectionString) { List<string> categoryList = new List<string>(); using (SqlConnection sqlConnection = new SqlConnection(connectionString)) { string commandText = "GetStuff"; using (SqlCommand sqlCommand = new SqlCommand(commandText, sqlConnection)) { sqlCommand.CommandType = CommandType.StoredProcedure;

Pitfalls of (Mis)Using C# Iterators to Implement Coroutines

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问题 I am writing refactoring a Silverlight program to consumes a portion of its existing business logic from a WCF service. In doing so, I've run into the restriction in Silverlight 3 that only allows asynchronous calls to WCF services to avoid cases where long-running or non-responsive service calls block the UI thread (SL has an interesting queuing model for invoking WCF services on the UI thread). As a consequence, writing what once was straightforward, is becoming rapidly more complex ( see

What is the preferred way to implement 'yield' in Scala?

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问题 I am doing writing code for PhD research and starting to use Scala. I often have to do text processing. I am used to Python, whose 'yield' statement is extremely useful for implementing complex iterators over large, often irregularly structured text files. Similar constructs exist in other languages (e.g. C#), for good reason. Yes I know there have been previous threads on this. But they look like hacked-up (or at least badly explained) solutions that don't clearly work well and often have

第十章 Scala 容器基础(十)：使用for循环来遍历一个集合

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Problem 我想使用for循环来遍历容器的所有元素，或者通过for yield来创建一个新的集合。 Solution 你可以使用for循环遍历所有的Traversable类型(基本上所有的sequency都可以)： scala> val fruits = Traversable("apple", "banana", "orange") fruits: Traversable[String] = List(apple, banana, orange) scala> for (f <- fruits) println(f) apple banana orange scala> for (f <- fruits) println(f.toUpperCase) APPLE BANANA ORANGE 如果你的循环体代码很长，那么你同样可以像正常使用for循环一样，执行多行的代码块： scala> for (f <- fruits) { | val s = f.toUpperCase | println(s) | } APPLE BANANA ORANGE 使用一个计数器当作下标来访问一个集合： scala> val fruits = IndexedSeq("apple", "banana", "orange") fruits: IndexedSeq[String] = Vector

Is Yield Return == IEnumerable & IEnumerator?

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问题 Is yield return a shortcut for implementing IEnumerable and IEnumerator ? 回答1: Yes, it is. You can find out a lot more about it in chapter 6 of my book, C# in Depth. Fortunately chapter 6 is available for free from Manning's web site. I also have two other articles on the book's web site. Feedback welcome. 回答2: To add to the link-fest, Raymond Chen did a nice little series on C# iterators a few months ago: http://blogs.msdn.com/oldnewthing/archive/2008/08/12/8849519.aspx http://blogs.msdn.com

Python: How to use a generator to avoid sql memory issue

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I have following method that access mysql database and the query get executed in a server that I don't have any access to change anything on regarding increasing memory. I am new to generators and started to read more about it and thought I could convert this to be use generator. def getUNames(self): globalUserQuery = ur'''SELECT gu_name FROM globaluser WHERE gu_locked = 0''' global_user_list = [] try: self.gdbCursor.execute(globalUserQuery) rows = self.gdbCursor.fetchall() for row in rows: uName = unicode(row['gu_name'], 'utf-8') global_user_list.append(uName) return global_user_list except

How does this class implement the “iter” method without implementing “next”?

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问题 I have the following code in django.template: class Template(object): def __init__(self, template_string, origin=None, name='<Unknown Template>'): try: template_string = smart_unicode(template_string) except UnicodeDecodeError: raise TemplateEncodingError("Templates can only be constructed from unicode or UTF-8 strings.") if settings.TEMPLATE_DEBUG and origin is None: origin = StringOrigin(template_string) self.nodelist = compile_string(template_string, origin) self.name = name def __iter__

Python3 迭代器与生成器

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迭代器迭代是Python最强大的功能之一，是访问集合元素的一种方式。迭代器是一个可以记住遍历的位置的对象。迭代器对象从集合的第一个元素开始访问，直到所有的元素被访问完结束。迭代器只能往前不会后退。迭代器有两个基本的方法： iter() 和 next() 。字符串，列表或元组对象都可用于创建迭代器：生成器在 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() 方法时从当前位置继续运行。调用一个生成器函数，返回的是一个迭代器对象。以下实例使用 yield 实现斐波那契数列：函数：参数以下是调用函数时可使用的正式参数类型：必需参数关键字参数默认参数不定长参数默认参数调用函数时，如果没有传递参数，则会使用默认参数。以下实例中如果没有传入 age 参数，则使用默认值：不定长参数你可能需要一个函数能处理比当初声明时更多的参数。这些参数叫做不定长参数，和上述 2 种参数不同，声明时不会命名。基本语法如下：(待补充) 匿名函数 python 使用 lambda 来创建匿名函数。所谓匿名

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