yield

I thought it would be nice to do something like this (with the lambda doing a yield return): public IList<T> Find<T>(Expression<Func<T, bool>> expression) where T : class, new() { IList<T> list = GetList<T>(); var fun = expression.Compile(); var items = () => { foreach (var item in list) if (fun.Invoke(item)) yield return item; // This is not allowed by C# } return items.ToList(); } However, I found out that I can't use yield in anonymous method. I'm wondering why. The yield docs just say it is not allowed. Since it wasn't allowed I just created List and added the items to it. Eric Lippert

What are the behavioural differences between the following two implementations in Ruby of the thrice method? module WithYield def self.thrice 3.times { yield } # yield to the implicit block argument end end module WithProcCall def self.thrice(&block) # & converts implicit block to an explicit, named Proc 3.times { block.call } # invoke Proc#call end end WithYield::thrice { puts "Hello world" } WithProcCall::thrice { puts "Hello world" } By "behavioural differences" I include error handling, performance, tool support, etc. I think the first one is actually a syntactic sugar of the other. In

I am creating a HoloLens app using Unity which has to take data from a REST API and display it. I am currently using WWW datatype to get the data and yield return statement in a coroutine that will be called from the Update() function. When I try to run the code, I get the latest data from the API but when someone pushes any new data onto the API, it does not automatically get the latest data in real time and I have to restart the app to see the latest data. My Code: using UnityEngine; using UnityEngine.UI; using System.Collections; using System; using Newtonsoft.Json; using System.Collections

I'm aware of os.listdir , but as far as I can gather, that gets all the filenames in a directory into memory, and then returns the list. What I want, is a way to yield a filename, work on it, and then yield the next one, without reading them all into memory. Is there any way to do this? I worry about the case where filenames change, new files are added, and files are deleted using such a method. Some iterators prevent you from modifying the collection during iteration, essentially by taking a snapshot of the state of the collection at the beginning, and comparing that state on each move

I came up with this simple experiment after reading the documentation on generators from MDN : var nodes = { type: 'root', value: [ { type: 'char', value: 'a' }, { type: 'char', value: 'b' }, { type: 'char', value: 'c' }, ], }; function* recursiveGenerator(node) { if (node.type === 'root') { node.value.forEach(function (subnode) { for (var suffix of recursiveGenerator(subnode)) { yield suffix; } }); } else { yield node.value; } } for (generated of recursiveGenerator(nodes)) { console.log(generated); } Running it on node.js v0.11.9 with the --harmony flag set produces the following error: alix

1. 格式化输出：利用format "{1} {0} {1}".format("hello", "world") # 设置指定位置 'world hello world' 或 %s,%d % str1,int1 * format的四种玩法（python推荐使用format做格式化输出） ```python # 第一种 按位置占位 跟%s原理一致 str1 = 'my name is {}, my age is {}'.format(18,'age') print(str1) # 第二种 按索引占位 str1 = 'my name is {1}, my age is {0}'.format('egon',18) print(str1) # 第三种 指名道姓占位（关键字传参） str1 = 'my name is {name}, my age is {age}'.format(name='egon',age=18) print(str1) #第四种 format简写,两个变量进行拼接时用 name='egon' age=18 str1 = f'my name is {name}, my age is {age}' print(str1) ``` 2. 形参 实参 位置参数 关键字参数 默认参数 形参： def func(arg1,arg2) arg1,arg2即为形参 实参

今天早上六点多起来妙妙，然后继续睡，眼睛一闭一睁八点零六，炸毛了，弹射起步，十分钟全部搞定，滑滑板来到教室，太赶了，让我一天的状态都是懵的，这种感觉真的太难受了，困，不必说，站起来也听不进去，这导致了我今天的听课效率比国家人均GDP都低。然后老师讲课的时候会问，这个听懂的举手 即使我没听懂，我还是举手了 根本没跟上啊。。。。 好了 今天的打气流程 。。。。。 今日洗脑金句：加油，最后悔的事不是失败，而是“你本可以”。 三元表达式 dog_name = 'crazy_dog1' print('疯狂舔🐕') if dog_name == 'crazy_dog' else print('666') 这个是什么意思，其实和原来的逻辑判断一样，只不过，这个逼格更高，但是不推荐，因为用的人少，而且大家都看不懂，公司就会把你开了，找一个写代码让人看的懂的程序员来。 那么这句的意思是什么，就是如果 dog_name == ‘crazy_dog' ,就打印疯狂舔狗，不然的话就打印666。 不过你们可以别听我的，尽管去用，要知道，你写的代码如果只有你自己看的懂，你就是公司不可或缺的员工，如果你的bug很多，不停地改，公司就会觉得你很牛逼，很能改bug。 所以放手去做吧，工作可以再找，被磨平的棱角一去不复返！ 列表推导式 别去管这个原理，根本就是找罪受。没必要，也不用。 lt = [] for i in

I've got some example Python code that I need to mimic in C++. I do not require any specific solution (such as co-routine based yield solutions, although they would be acceptable answers as well), I simply need to reproduce the semantics in some manner. Python This is a basic sequence generator, clearly too large to store a materialized version. def pair_sequence(): for i in range(2**32): for j in range(2**32): yield (i, j) The goal is to maintain two instances of the sequence above, and iterate over them in semi-lockstep, but in chunks. In the example below the first_pass uses the sequence of