I know that I can do: try: # do something that may fail except: # do this if ANYTHING goes wrong I can also do this: try: # do something that may fail except IDontLikeYouException: # say please except YouAreTooShortException: # stand on a ladder But if I want to do the same thing inside two different exceptions, the best I can think of right now is to do this: try: #
我知道我可以这样做： try: # do something that may fail except: # do this if ANYTHING goes wrong 我也可以这样做： try: # do something that may fail except IDontLikeYouException: # say please except YouAreTooShortException: # stand on a ladder 但是如果我想在两种不同的例外情况下做同样的事情，我现在能想到的最好办法就是这样做： try: # do something that may fail except IDon
我如何在Python中引发异常，以便稍后通过except块捕获它？ How do I manually throw/raise an exception in Python? Use the most specific Exception constructor that semantically fits your issue. Be specific in your message, eg: raise ValueError('A very specific bad thing happened.') Don't raise generic exceptions Avoid raising a generic Exception. To catch it, you'll have to catch all o
我如何在Python中引发异常，以便稍后通过except块捕获它？ 如何在Python中手动抛出/引发异常？ 使用语义上适合您问题的最具体的Exception构造函数。 具体在你的信息中，例如： raise ValueError('A very specific bad thing happened.') 不要提出一般例外 避免提出一个通用的异常。 要捕捉它，你必须捕获所有其他更具体的异常的子类。 问题1：隐藏错误 raise Exception('I know Python!') # Don't! If you catch, lik
When you just want to do a try-except without handling the exception, how do you do it in Python? Is the following the right way to do it? try: shutil.rmtree(path) except: pass try: doSomething() except: pass or try: doSomething() except Exception: pass The difference is, that the first one will also catch KeyboardInterrupt , SystemExit and stuff like that, which are deriv
当你只是想做一个尝试 - 除了没有处理异常，除了Python，你怎么做？ 以下是正确的做法吗？ try: shutil.rmtree(path) except: pass try: doSomething() except: pass 要么 try: doSomething() except Exception: pass 不同之处在于，第一个也会捕获KeyboardInterrupt ， SystemExit等类似的东西，它们直接来自exceptions.BaseException ，而不是exceptions.Exception 。 详情请参阅文档： 尝试声明
I'm trying to have OpenCV process a frame in the middle of a gstreamer pipe. I have one gstreamer pipe generating the stream, sending it to appsink for OpenCV code to receive: v4l2src ! ffmpegcolorspace ! jpegenc ! appsink name=sink And another pipe getting it from appsrc (to which OpenCV sends data) and outputting it on the screen: appsrc name=src ! jpegdec ! xvimagesink I open every f
我试图让OpenCV在gstreamer管道中处理一个框架。 我有一个gstreamer管道生成流，将其发送到appsink以获取OpenCV代码： v4l2src ! ffmpegcolorspace ! jpegenc ! appsink name=sink 另一个管道从appsrc（OpenCV向其发送数据）中获取它并将其输出到屏幕上： appsrc name=src ! jpegdec ! xvimagesink 我在sink上打开每一个带有缓冲区请求的帧，并用OpenCV处理它，然后在src上使用push-buffer。 我正在用Python做所有的事情
Django's ForeignRelatedObjectsDescriptor.create_manager(...) function dynamically creates the RelatedManager classes and subsequently initializes an instance of the dynamically created class. If I wanted to override the RelatedManager.add(...) method, how would I do it? The RelatedManager classes are created in file: django/db/models/fields/related.py . An example of how I'd like to
Django的ForeignRelatedObjectsDescriptor.create_manager(...)函数动态地创建RelatedManager类，并随后初始化动态创建的类的实例。 如果我想覆盖RelatedManager.add(...)方法，我该怎么做？ RelatedManager类在文件中创建： django/db/models/fields/related.py 。 我想如何使用自定义RelatedManager是...... class Record(Model): string = CharField() class Managed(Model): record = ForeignKey('Record')
I'm looking for a python library that provides simple set of financial calculations, such as MACD, EMAs and other indicators. I've been looking around for it, but either all projects that were trying to do it are dead, or non-existent. Is there a library like that in the existence? Thanks. ActiveState has a recommendation for must have python packages when dealing with finance indus
我正在寻找一个提供简单的财务计算，如MACD，EMA和其他指标的Python库。 我一直在寻找它，但是所有试图做它的项目都是死的，或者根本不存在。 存在这样的图书馆吗？ 谢谢。 ActiveState建议在处理金融业相关问题时必须有python包。 你有没有检查，并确实包含你正在寻找的任何东西？ 看看TA-Lib。 熊猫可能拥有从头开始构建这些计算的所有工具，但该库几乎包含了所有可用于简单功能的常见技术指标。 熊猫拥有所有这些
I want to write a function that will execute a shell command and return its output as a string , no matter, is it an error or success message. I just want to get the same result that I would have gotten with the command line. What would be a code example that would do such a thing? For example: def run_command(cmd): # ?????? print run_command('mysqladmin create test -uroot -pmysqladmin
我想编写一个函数来执行一个shell命令并将其输出作为一个字符串返回，不管它是错误还是成功消息。 我只想得到和命令行一样的结果。 什么是可以做这种事情的代码示例？ 例如： def run_command(cmd): # ?????? print run_command('mysqladmin create test -uroot -pmysqladmin12') # Should output something like: # mysqladmin: CREATE DATABASE failed; error: 'Can't create database 'test'; database exists'
Short and simple. I've got a huge list of date-times like this as strings: Jun 1 2005 1:33PM Aug 28 1999 12:00AM I'm going to be shoving these back into proper datetime fields in a database so I need to magic them into real datetime objects. Any help (even if it's just a kick in the right direction) would be appreciated. Edit: This is going through Django's ORM so I can
简短而简单。 我有一个像这样的日期时间的巨大列表作为字符串： Jun 1 2005 1:33PM Aug 28 1999 12:00AM 我将把它们推回到数据库中适当的日期时间字段，所以我需要将它们变成真正的日期时间对象。 任何帮助（即使这只是一个正确的方向踢），将不胜感激。 编辑：这是通过Django的ORM，所以我不能使用SQL做插入转换。 datetime.strptime是将字符串解析到日期时间的主要例程。 它可以处理各种格式，其格式由您给出的格式
I'm coming from the Java world and reading Bruce Eckels' Python 3 Patterns, Recipes and Idioms. While reading about classes, it goes on to say that in Python there is no need to declare instance variables. You just use them in the constructor, and boom, they are there. So for example: class Simple: def __init__(self1, str): print("inside the simple constructor")
我来自Java世界并阅读Bruce Eckels的Python 3 Patterns，Recipes和Idioms。 在阅读类时，它继续说在Python中不需要声明实例变量。 你只是在构造函数中使用它们，并且繁荣，它们在那里。 例如： class Simple: def __init__(self1, str): print("inside the simple constructor") self1.s = str def show(self1): print(self1.s) def showMsg (self, msg): print (msg + ':', s
I have a list of arbitrary length, and I need to split it up into equal size chunks and operate on it. There are some obvious ways to do this, like keeping a counter and two lists, and when the second list fills up, add it to the first list and empty the second list for the next round of data, but this is potentially extremely expensive. I was wondering if anyone had a good solution to this fo
我有一个任意长度的列表，我需要将它分成相同大小的块并对其进行操作。 有一些明显的方法可以做到这一点，比如保留一个计数器和两个列表，当第二个列表填满时，将其添加到第一个列表并清空下一轮数据的第二个列表，但这可能非常昂贵。 我想知道是否有人对任何长度的列表都有很好的解决方法，例如使用生成器。 我在itertools中寻找一些有用的东西，但是我找不到任何明显有用的东西。 虽然可能错过了它。 相关问题：什么是