I wonder what is better to do: d = {'a': 1, 'b': 2} 'a' in d True or: d = {'a': 1, 'b': 2} d.has_key('a') True in is definitely more pythonic. In fact has_key() was removed in Python 3.x. in wins hands-down, not just in elegance (and not being deprecated;-) but also in performance, eg: $ python -mtimeit -s'd=dict.fromkeys(range(99))' '12 in d' 10000000 loops, best of 3: 0.0983 usec per l
我不知道什么是更好的做法： d = {'a': 1, 'b': 2} 'a' in d True 要么： d = {'a': 1, 'b': 2} d.has_key('a') True in肯定更pythonic。 实际上， has_key()在Python 3.x中被删除了。 in胜利手中，不仅仅在优雅（而不是被弃用;-)而且在表现中，例如： $ python -mtimeit -s'd=dict.fromkeys(range(99))' '12 in d' 10000000 loops, best of 3: 0.0983 usec per loop $ python -mtimeit -s'd=dict.fromkeys(range(99))'
You can specify types of parameters in Python docstrings like this: def __init__(self, canvas, segments): """Class constructor. :param canvas: the PDF canvas object :param segment: The layer segments to be drawn. :type canvas: `canvas.Canvas` :type segments: list of str """ ... With Sphinx' autodoc feature, this yields the parameters list, and each parameter is
您可以在Python文档中指定参数类型，如下所示： def __init__(self, canvas, segments): """Class constructor. :param canvas: the PDF canvas object :param segment: The layer segments to be drawn. :type canvas: `canvas.Canvas` :type segments: list of str """ ... 借助狮身人面像的autodoc功能，这将生成参数列表，并且每个参数都可以正确标记其类型。 但是，我如何使用实例属性来
This question already has an answer here: Using global variables in a function other than the one that created them 18 answers If you are asking how to reference the same telnet object in all of the functions, you need to use a global variable. Add the declaration "global tn" inside any functions which binds tn to a new object. Try this: import telnetlib tn = None def Function
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 如果您问如何在所有函数中引用同一个telnet对象，则需要使用全局变量。 添加声明“全球TN”内部结合的任何功能tn到一个新的对象。 尝试这个： import telnetlib tn = None def Function1(): #for connection only global tn tn = telnetlib.Telnet(ip) #code def Function2(): #to run command 1 tn.write() def Function3
This question already has an answer here: Using global variables in a function other than the one that created them 18 answers If you go without the global statement, you will be creating a local variable with the name _run_wsgi_app , and then will use it, but nothing will change in the global namespace. Using global _run_wsgi_app you ensure that you are re-binding the global name to the new
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 如果你没有global语句，你将会创建一个名为_run_wsgi_app的局部变量，然后将使用它，但是在全局名字空间中什么都不会改变。 使用global _run_wsgi_app确保您将全局名称重新绑定到新函数。 请记住global的基本用法： def foo(): x = 2 def bar(): global x x = 3 x = 1 print(x) # --> 1 foo() print(x) # --> 1 bar() pri
This question already has an answer here: Using global variables in a function other than the one that created them 18 answers The fragment def Startup(): global PasswordSkip does not declare PasswordSkip to be global everywhere. It declares that within this function, references to setting PasswordSkip should be taken to be the global variable PasswordSkip rather than some local variab
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 片段 def Startup(): global PasswordSkip 并没有宣布PasswordSkip在全球各地都是全球性的。 它声明在这个函数中，设置PasswordSkip引用应该被认为是全局变量PasswordSkip而不是某个局部变量。 现在在函数PasswordRemove ，您不会声明PasswordSkip是一个全局的函数，它将被引入到范围中。 因此，像PasswordSkip = True这样的语句会设
This question already has an answer here: Using global variables in a function other than the one that created them 18 answers You mixed two different ideas in Python, a " global statement" and an "augmented assignment statement." A " global statement" has a very simple syntax: "global" identifier ("," identifier)* No expression is allowed in a global stateme
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 你在Python中混合了两个不同的想法，一个“ global声明”和一个“扩充赋值语句”。 “ global声明”的语法非常简单： "global" identifier ("," identifier)* global声明中不允许表达式。 也许你想说： global counter counter += 1
This question already has an answer here: Using global variables in a function other than the one that created them 18 answers Python scans a function body for any assignments, and if they aren't explicitly declared global , then it creates a local scope variable for that name. Because you assign to first in your reverse() function, and you haven't explicitly declared first to be glo
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 Python为任何赋值扫描一个函数体，如果它们没有明确声明为global ，那么它会为该名称创建一个本地作用域变量。 由于您在reverse()函数中first分配，并且您没有在该函数的作用域中first显式声明为全局变量，python会创建一个名为first的局部变量来隐藏全局变量。 比较之后的任务并不重要; python隐式地声明了函数开头的所有局部变量。 为了
This question already has an answer here: Using global variables in a function other than the one that created them 18 answers You could try this: def confirm_upload(): global upload_confirm upload_confirm = True Since you are doing upload_confirm = True in a local scope, Python treat it like a local variable. Hence, your global variable stays the same. 您需要将global语句放在要访
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 你可以试试这个： def confirm_upload(): global upload_confirm upload_confirm = True 由于您在本地范围内执行upload_confirm = True ，因此Python将其视为本地变量。 因此，您的全局变量保持不变。 您需要将global语句放在要访问全局变量的范围内，即： upload_confirm = False def confirm_upload(): global upload_confirm
This question already has an answer here: Using global variables in a function other than the one that created them 18 answers It's because of a thing called scope. You can read up about it, but essentially it means that inside a function, you may not have access to things defined on the outside. To make the function aware of these variables, you need to pass them in. Try this: a = 2
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 这是因为一个叫做范围的东西。 你可以阅读它，但实际上这意味着在一个函数内部，你可能无法访问外部定义的东西。 为了让这个函数知道这些变量，你需要传递它们。试试这个： a = 2 b = 3 def add(x, y) : x = x + y print(str(x)) add(a, b) 值得注意的是，这些值正在传递到函数中，但实际上并未自行修改。 我不会深入讨论变量传
This question already has an answer here: Using global variables in a function other than the one that created them 18 answers To protect programmers from globals, globals are not considered to exist in a function until you declare they do with global variablename . In maincrypt you do not declare global newtext nor do you create a local newtext by assigning to it. The += operator requires
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 为了保护程序员免受全局变量的影响，全局变量不会被认为存在于函数中，除非您声明他们使用global variablename 。 在maincrypt中，您不要声明global newtext也不要通过分配给它创建本地新newtext 。 + =运算符要求左手已经存在 - 它还没有，所以抛出异常。 顺便说一下，如果你打算在其他任何地方重用这个程序，最好使用类变量而不是全局变量