This question already has an answer here: Using global variables in a function other than the one that created them 18 answers 如果您只想与其他功能共享，请使用全局功能id = 0 def main(): global id ... id = 0 # declare it in the global scope def main(): # using the global keyword will let you access it in the function scope global id input = file(infile, 'r') lines = in
这个问题在这里已经有了答案： 在不同于创建它们的函数中使用全局变量18个答案 如果您只想与其他功能共享，请使用全局功能id = 0 def main(): global id ... id = 0 # declare it in the global scope def main(): # using the global keyword will let you access it in the function scope global id input = file(infile, 'r') lines = input.readlines() input.close() i = 0 for l
Possible Duplicate: Using global variables in a function other than the one that created them How can I define a global variable. For example I have Foo1 class and Foo2 class and I want to use FooVariable in this classes as a global variable. 看到这个答案在创建它们的函数中使用全局变量 If you wanted a global variable named foo , you would just have to put global foo at the top of any functi
可能重复： 在创建它们的函数中使用全局变量 我怎样才能定义一个全局变量。 例如，我有Foo1类和Foo2类，我想在这个类中使用FooVariable作为全局变量。 看到这个答案在创建它们的函数中使用全局变量 如果你想要一个名为foo的全局变量，你只需要将global foo放在任何使用它的函数的顶部。 例如， def do_something(): global foo foo = foo + 1 print foo 请注意，Python“全局”变量只对它们出现的模块是全局
Possible Duplicate: Using global variables in a function other than the one that created them I have the following script: COUNT = 0 def increment(): COUNT = COUNT+1 increment() print COUNT I just want to increment global variable COUNT, but this gives me the following error: Traceback (most recent call last): File "test.py", line 6, in <module> increment() File "test.
可能重复： 在创建它们的函数中使用全局变量 我有以下脚本： COUNT = 0 def increment(): COUNT = COUNT+1 increment() print COUNT 我只想增加全局变量COUNT，但是这给了我以下错误： Traceback (most recent call last): File "test.py", line 6, in <module> increment() File "test.py", line 4, in increment COUNT = COUNT+1 UnboundLocalError: local variable 'COUNT' referenced before
Possible Duplicate: Using global variables in a function other than the one that created them I'm using functions so that my program won't be a mess but I don't know how to make a local variable into global. Here are two methods to achieve the same thing: Using parameters and return (recommended) def other_function(parameter): return parameter + 5 def main_function():
可能重复： 在创建它们的函数中使用全局变量 我正在使用函数，以便我的程序不会一团糟，但我不知道如何将局部变量变为全局变量。 以下是实现相同目标的两种方法： 使用参数并返回（推荐） def other_function(parameter): return parameter + 5 def main_function(): x = 10 print x x = other_function(x) print x 当你运行main_function ，你会得到以下输出 >>> 10 >>>
This question already has an answer here: How to change a variable after it is already defined in Python 5 answers Using global variables in a function other than the one that created them 18 answers Python doesn't have variable declarations, so it has to figure out the scope of variables itself. It does so by a simple rule: If there is an assignment to a variable inside a function, th
这个问题在这里已经有了答案： 在Python 5中已经定义的变量之后如何更改变量的答案 在不同于创建它们的函数中使用全局变量18个答案 Python没有变量声明，所以它必须找出变量本身的范围。 它通过一个简单的规则来实现：如果函数内部有一个变量赋值，那么该变量被认为是局部的[1]。 因此，线 counter += 1 隐式地使counter本地increment() 。 尽管如此，尝试执行这一行，会尝试在分配之前读取局部变量counter的值，导致
I used to use perl -c programfile to check the syntax of a Perl program and then exit without executing it. Is there an equivalent way to do this for a Python script? 你可以通过编译来检查语法： python -m py_compile script.py You can use these tools: PyChecker Pyflakes Pylint import sys filename = sys.argv[1] source = open(filename, 'r').read() + 'n' compile(source, filename, 'exec') 将
我曾经使用perl -c programfile来检查Perl程序的语法，然后退出而不执行它。 是否有一种等同的方式来为Python脚本执行此操作？ 你可以通过编译来检查语法： python -m py_compile script.py 你可以使用这些工具： PyChecker Pyflakes pylint的 import sys filename = sys.argv[1] source = open(filename, 'r').read() + 'n' compile(source, filename, 'exec') 将其保存为checker.py并运行python checker.py yourpyfil
I have a friend who likes to use metaclasses, and regularly offers them as a solution. I am of the mind that you almost never need to use metaclasses. Why? because I figure if you are doing something like that to a class, you should probably be doing it to an object. And a small redesign/refactor is in order. Being able to use metaclasses has caused a lot of people in a lot of places to us
我有一个喜欢使用元类的朋友，并定期提供它们作为解决方案。 我记住你几乎不需要使用元类。 为什么？ 因为我认为如果你正在为一个类做类似的事情，你应该把它做到一个对象。 而一个小的重新设计/重构是为了。 能够使用元类已经导致许多地方的许多人将类用作某种二级对象，这对我来说似乎是灾难性的。 编程是否被元编程所取代？ 不幸的是，类装饰器的添加使其更加可以接受。 所以请，我非常想知道你在Python中对元类的
There seem to be many ways to define singletons in Python. Is there a consensus opinion on Stack Overflow? I don't really see the need, as a module with functions (and not a class) would serve well as a singleton. All its variables would be bound to the module, which could not be instantiated repeatedly anyway. If you do wish to use a class, there is no way of creating private classes o
似乎有很多方法可以在Python中定义单例。 关于Stack Overflow是否有共识？ 我真的没有看到需要，因为具有函数（而不是类）的模块可以很好地用作单例。 它的所有变量都将绑定到模块，无论如何都不能重复实例化。 如果你想使用一个类，就没有办法在Python中创建私有类或私有构造函数，所以你不能保护多个实例，除了通过使用API的惯例。 我仍然只是将方法放在模块中，并将模块视为单例。 这是我自己实现的单身人士。 你
I want to run my fabric script locally, which will in turn, log into my server, switch user to deploy, activate the projects .virtualenv, which will change dir to the project and issue a git pull. def git_pull(): sudo('su deploy') # here i need to switch to the virtualenv run('git pull') I typically use the workon command from virtualenvwrapper which sources the activate file and th
我想在本地运行我的结构脚本，然后再登录到我的服务器，切换用户进行部署，激活项目.virtualenv，这将改变目录到项目并发出git pull。 def git_pull(): sudo('su deploy') # here i need to switch to the virtualenv run('git pull') 我通常使用来自virtualenvwrapper的workon命令，其中激活文件和postactivate文件将把我放到项目文件夹中。 在这种情况下，由于织物从外壳运行，控制权交给织物，所以我不能使用
This question already has an answer here: How to make a chain of function decorators? 15 answers Simplest: @event.listens_for(MyClass.collection, 'append') @event.listens_for(MyClass.collection, 'remove') @event.listens_for(MyClass.collection, 'set') def update_count(target, value, initiator): target.count = len(target.collection) ie, just put the decorators one after the other before
这个问题在这里已经有了答案： 如何创建一个函数装饰器链？ 15个答案 最简单的： @event.listens_for(MyClass.collection, 'append') @event.listens_for(MyClass.collection, 'remove') @event.listens_for(MyClass.collection, 'set') def update_count(target, value, initiator): target.count = len(target.collection) 即，在def之前将装饰器依次放置。 当然，这可能会导致开销，例如，如果每个装饰器将装饰