This question already has an answer here: How to clone or copy a list? 17 answers Variable assignment and modification (in python) 6 answers Consider this example: In [20]: a = [[1], [2], [3]] In [21]: b = a In [22]: x = a[1] In [23]: a Out[23]: [[1], [2], [3]] In [24]: b Out[24]: [[1], [2], [3]] In [25]: x Out[25]: [2] In [26]: a[1][0] = 4 In [27]: a Out[27]: [[1], [4], [3]] In [
这个问题在这里已经有了答案： 如何克隆或复制列表？ 17个答案 变量赋值和修改（在Python中）6个答案 考虑这个例子： In [20]: a = [[1], [2], [3]] In [21]: b = a In [22]: x = a[1] In [23]: a Out[23]: [[1], [2], [3]] In [24]: b Out[24]: [[1], [2], [3]] In [25]: x Out[25]: [2] In [26]: a[1][0] = 4 In [27]: a Out[27]: [[1], [4], [3]] In [28]: b Out[28]: [[1], [4], [3]] In [29]: x Out[29]: [
Ok, this is my first time asking a question on here, so please be patient with me ;-) I'm trying to create a series of subplots (with two y-axes each) in a figure using matplotlib and then saving that figure. I'm using GridSpec to create a grid for the subplots and realised that they're overlapping a little, which I don't want. So I'm trying to use tight_layout() to sort t
好的，这是我第一次在这里问一个问题，所以请耐心等待我;-) 我试图用matplotlib在图中创建一系列子图（每个都有两个y轴），然后保存该图。 我使用GridSpec为子图创建网格，并意识到它们重叠了一点，这是我不想要的。 所以我试图用tight_layout（）来解决这个问题，根据matplotlib文档应该可以正常工作。 简化一下，我的代码看起来像这样： import matplotlib.pyplot as plt import matplotlib.gridspec as gridspec fig =
Can't install pycurl with pip, win xp x32, python 2.7. here is the log pip install pycurl Downloading/unpacking pycurl Downloading pycurl-7.19.3.1.tar.gz (116Kb): 116Kb downloaded Running setup.py egg_info for package pycurl Please specify --curl-dir=/path/to/built/libcurl Complete output from command python setup.py egg_info: Please specify --curl-dir=/path/to/built/libcur
无法用pip安装pycurl，win xp x32，python 2.7。 这里是日志 pip install pycurl Downloading/unpacking pycurl Downloading pycurl-7.19.3.1.tar.gz (116Kb): 116Kb downloaded Running setup.py egg_info for package pycurl Please specify --curl-dir=/path/to/built/libcurl Complete output from command python setup.py egg_info: Please specify --curl-dir=/path/to/built/libcurl ---------------
Now I use: pageHeadSectionFile = open('pagehead.section.htm','r') output = pageHeadSectionFile.read() pageHeadSectionFile.close() But to make the code look better, I can do: output = open('pagehead.section.htm','r').read() When using the above syntax, how do I close the file to free up system resources? You don't really have to close it - Python will do it automatically either during ga
现在我使用： pageHeadSectionFile = open('pagehead.section.htm','r') output = pageHeadSectionFile.read() pageHeadSectionFile.close() 但为了使代码看起来更好，我可以这样做： output = open('pagehead.section.htm','r').read() 使用上述语法时，如何关闭文件以释放系统资源？ 你不必关闭它 - Python会在垃圾回收或程序退出时自动执行它。 但是正如@delnan所指出的那样，最好由于各种原因明确关闭它。 所以，
I would like to understand if there is a difference between assigning an empty value and an empty output, as follows: 1> Assigning a value like this string = "" 2> An empty value returned as output string = "abcd:" str1, str2 = split(':') In other words, is there a difference in values of 'string' in 1> and 'str2' in 2>? And how would a method see the value of &
我想了解是否在分配空值和空输出之间存在差异，如下所示： 1>分配一个像这样的值 string = "" 2>作为输出返回空值 string = "abcd:" str1, str2 = split(':') 换句话说，1>和'2>中的'str2'中的'string'值是否有差异？ 如果一个方法作为参数传递，如何看到'str2'的值？ 使用==检查相等性 >>> string = "" >>> s = "abcd:" >>> str1, str2 = s.split
This question should be related to: How to get the current branch name in Git? Get git current branch/tag name How to get the name of the current git branch into a variable in a shell script? How to programmatically determine the current checked out Git branch But I am wondering how to do that through pygit2? From PyGit Documentation Either of these should work head = repo.lookup_r
这个问题应该涉及到： 如何在Git中获取当前分支名称？ 获取git当前分支/标签名称 如何获取当前git分支的名字到shell脚本中的变量中？ 如何以编程方式确定当前签出的Git分支 但我想知道如何通过pygit2来做到这一点？ 从PyGit文档 这些都应该工作 head = repo.lookup_reference('HEAD').resolve() head = repo.head branch_name = head.name 要获得传统的“速记”名称： from pygit2 import Repository Repository('
Summary: How do I set the print range settings from xlwt? I have a document that is currently set as four pages for the purposes of printing, and I need to make it so that the print range is set to only treat it as one page. The documentation for xlwt (outside of the basics) is hard to find. The only things I've been able to find so far are: A Visual Basic answer, but the answer doesn&
简介：如何设置xlwt的打印范围设置？ 我有一个目前设置为四页用于打印目的的文档，并且我需要使其打印范围设置为仅将其作为一页来处理。 xlwt的文档（基础之外）很难找到。 到目前为止我唯一能找到的是： 一个Visual Basic的答案，但答案没有描述术语或它是如何工作的。 Google网上论坛的讨论也没有解释任何价值。 尝试 worksheet.fit_num_pages=1 或者是worksheet.set_fit_num_pages(1) ，它们都缩小一切以适合一
How often does sys.stderr flush its buffer, and is this standard among different environments? >>> import sys >>> sys.__stderr__ <open file '<stderr>', mode 'w' at 0x2b4fcb7ac270> I see that it is just a standard file type, but I don't know what value of buffering it's supposed to be. dir() does not seem to yield any useful information either. On Python
sys.stderr刷新其缓冲区的频率是多少，并且在不同的环境中是否是这个标准？ >>> import sys >>> sys.__stderr__ <open file '<stderr>', mode 'w' at 0x2b4fcb7ac270> 我发现它只是一个标准的文件类型，但我不知道缓冲应该是什么值。 dir()似乎也没有产生任何有用的信息。 在Python 2中，我无法找到文件sys.stderr的缓冲区的指定位置。 我期望在C中的stderr与没有缓冲的（Windows除外）行为
I've been looking to squeeze a little more performance out of my code; recently, while browsing this Python wiki page, I found this claim: Multiple assignment is slower than individual assignment. For example "x,y=a,b" is slower than "x=a; y=b". Curious, I tested it (on Python 2.7): $ python -m timeit "x, y = 1.2, -1.4" 10000000 loops, best of 3: 0.0365 usec per loo
我一直在寻找挤出我的代码更多的性能; 最近，在浏览这个Python维基页面时，我发现这个说法： 多个分配比个别分配慢。 例如“x，y = a，b”比“x = a; y = b”慢。 好奇，我测试了它（在Python 2.7上）： $ python -m timeit "x, y = 1.2, -1.4" 10000000 loops, best of 3: 0.0365 usec per loop $ python -m timeit "x = 1.2" "y = -1.4" 10000000 loops, best of 3: 0.0542 usec per loop 我以不同的顺序重复了几次，但是
Python __str__和__repr__什么区别？ Alex summarized well but, surprisingly, was too succinct. First, let me reiterate the main points in Alex's post: The default implementation is useless (it's hard to think of one which wouldn't be, but yeah) __repr__ goal is to be unambiguous __str__ goal is to be readable Container's __str__ uses contained objects' __repr__ Defa
Python __str__和__repr__什么区别？ 亚历克斯总结得很好，但令人惊讶的是，它太简洁了。 首先，让我重申Alex的帖子中的主要观点： 默认的实现是无用的（很难想象一个不会的，但是是的） __repr__目标是明确的 __str__目标是可读的 容器的__str__使用包含的对象' __repr__ 默认实现是无用的 这大部分是令人惊讶的，因为Python的默认值相当有用。 但是，在这种情况下，具有__repr__的默认值，其行为如下： re