“人造太阳”计划

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I'm trying to stream Server-Sent Events from my Pyramid application, but I can't figure out how to stream the response body from my view. Here's the test view I'm using (it totally doesn't implement SSE, it's just to work out the streaming portion): @view_config(route_name='iter_test') def iter_test(request): import time def test_iter(): i = 0 while True: i += 1 if i == 5: raise StopIteration yield str(time.time()) print time.time() time.sleep(1) return test_iter() This produces ValueError: Could not convert return value of the view callable

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 由 翻译 强力驱动 问题: A simple snippet in Python 3.6.1: import datetime j = iter ( datetime . datetime . now , None ) next ( j ) returns: Traceback ( most recent call last ): File "<stdin>" , line 1 , in <module> StopIteration instead of printing out the classic now() behavior with each next() . I've seen similar code working in Python 3.3, am I missing something or has something changed in version 3.6.1? 回答1: This is definitely a bug introduced in Python 3.6.0b1. The iter() implementation recently switched to using _PyObject_FastCall() (an optimisation

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: Do you know if there is a way to get python's random.sample to work with a generator object. I am trying to get a random sample from a very large text corpus. The problem is that random.sample() raises the following error. TypeError: object of type 'generator' has no len() I was thinking that maybe there is some way of doing this with something from itertools but couldn't find anything with a bit of searching. A somewhat made up example: import random def list_item(ls): for item in ls: yield item random.sample( list_item(range(100)), 20 )

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: Is there a way to iterate over the keys, not the pairs of a C++ map? 回答1: If you really need to hide the value that the "real" iterator returns (for example because you want to use your key-iterator with standard algorithms, so that they operate on the keys instead of the pairs), then take a look at Boost's transform_iterator . [Tip: when looking at Boost documentation for a new class, read the "examples" at the end first. You then have a sporting chance of figuring out what on earth the rest of it is talking about :-)] 回答2: map is

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: Note that this question refers to a version of Rust before Rust 1.0. Although the syntax has changed, the concepts are still valid. You can easily implement a forwards only linked list using owned pointers, something like: struct Node<T> { next: Option<~Node<T>>, data: T } Imagine, though, if you want to efficiently implement a queue that supports four basic operations: push : add to end of list pop : remove and return from the end of the list unshift : add to the front of the list shift : remove and return from the end of the list In a

版权所有，未经许可，禁止转载 章节 Python 介绍 Python 开发环境搭建 Python 语法 Python 变量 Python 数值类型 Python 类型转换 Python 字符串(String) Python 运算符 Python 列表(list) Python 元组(Tuple) Python 集合(Set) Python 字典(Dictionary) Python If … Else Python While 循环 Python For 循环 Python 函数 Python Lambda Python 类与对象 Python 继承 Python 迭代器(Iterator) Python 模块 Python 日期(Datetime) Python JSON Python 正则表达式(RegEx) Python PIP包管理器 Python 异常处理(Try…Except) Python 打开文件(File Open) Python 读文件 Python 写文件 Python 删除文件与文件夹 Python 迭代器(Iterator) 迭代器是一个包含有限数量值的对象。 迭代器是一个可以被迭代的对象，可以遍历迭代器中的所有值。 从技术上讲，在Python中，迭代器是实现迭代器协议的对象，该协议由方法 __iter__() 和 __next__() 组成。

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I'm new to Angular and I'm stuck with a issue relating IE. Here is the IE Error that I'm getting. Webpage error details User Agent: Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident/5.0) Timestamp: Thu, 13 Dec 2012 04:00:46 UTC Message: 10 $digest() iterations reached. Aborting! Watchers fired in the last 5 iterations: [["fn: function $locationWatch() {\n var oldUrl = $browser.url();\n\n if (!changeCounter || oldUrl != $location.absUrl()) {\n\tchangeCounter++;\n\t$rootScope.$evalAsync(function() {\n\t if ($rootScope.$broadcast('

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: Each row in a Pandas dataframe contains lat/lng coordinates of 2 points. Using the Python code below, calculating the distances between these 2 points for many (millions) of rows takes a very long time! Considering that the 2 points are under 50 miles apart and accuracy is not very important, is it possible to make the calculation faster? from math import radians, cos, sin, asin, sqrt def haversine(lon1, lat1, lon2, lat2): """ Calculate the great circle distance between two points on the earth (specified in decimal degrees) """ # convert

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I need something similar to these 2 SO questions, but using Informix SQL syntax. Concatenate several fields into one with SQL SQL Help: Select statement Concatenate a One to Many relationship My data coming in looks like this: id codes 63592 PELL 58640 SUBL 58640 USBL 73571 PELL 73571 USBL 73571 SUBL I want to see it come back like this: id codes 63592 PELL 58640 SUBL, USBL 73571 PELL, USBL, SUBL See also group_concat() in Informix . 回答1: I believe that the answer you need is a user-defined aggregate, similar to this one: CREATE FUNCTION gc

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: Is there any way to rename the first and second accessor functions of a map iterator. I understand they have these names because of the underlying pair which represents the key and value, but I'd like the iterators to be a little more readable. I think this might be possible using an iterator adaptor, but I'm not sure how to implement it. Please note that I can't use boost. Example of what I mean: map adjacency_list; for(map ::iterator it = adjacency_list.begin(); it != adjacency_list.end(); ++it) { Vertex v = it->first; //instead I would