Python’s default arguments are evaluated once when the function is defined, not each time the function is called (like it is in say, Ruby). This means that if you use a mutable default argument and mutate it,
__defaults__[0][:] = [] >>> function() [1] >>> function.__defaults__ ([1],) 不过,你最好别这么干(修改一些你不了解的的东西,比如私有变量或者系统变量,会导致一些神奇的后果)。 另一个对默认参数进行重置的方法就是重新执行同样的 def 函数定义语句,也即,把 function 定义再执行一次。当你这...
Default argument value is mutable less... (Ctrl+F1) 默认参数值是可变的 This inspection detects when a mutable value as list or dictionary is detected in a default value for an argument. Default argument values are evaluated only once at function definition time, which means that modifying the ...
When Python executes a “def” statement, it takes some ready-made pieces (including the compiled code for the function body and the current namespace), and creates a new function object. When it does this, it also evaluates the default values. The various components are available as attribut...
defmy_function(food): forxinfood: print(x) fruits = ["apple","banana","cherry"] my_function(fruits) Try it Yourself » Return Values To let a function return a value, use thereturnstatement: Example defmy_function(x): return5* x ...
LEGB规定了查找一个名称的顺序为:local-->enclosing function locals-->global-->builtin 举例来说明: 代码语言:javascript 代码运行次数:0 运行 AI代码解释 [root@Node3 src]# vi test1.py [root@Node3 src]# cat test1.py #!/usr/local/bin/python2.7 x=1 def foo(): x=2 def innerfoo(): ...
Default parameter values are evaluated when the function definition is executed. 也就是说默认函数参数是在写def时就已经被赋值(引用)了! 这样你可以把默认参数理解成function对象的一个类似于'member variable'之类的东西来对待!! 这也就是说如果默认参数是可变的,如果function改变了这个参数(append or something...
方法(method)和函数(function)大体来说是可以互换的两个词,它们之间有一个细微的区别:函数是独立的功能,需要将数据或者参数传递进去进行处理。方法则与对象有关,不需要传递数据或参数就可以使用。举个例子,前面我们讲到的type()就是一个函数,你需要将一个变量或者数据传入进去它才能运作并返回一个值,举例如下: ...
if FunctionSignature.signature_downgrade: self.name = name self.args = "*args, **kwargs" self.rtype = "typing.Any" lvl = logging.WARNING if FunctionSignature.ignore_invalid_signature else logging.ERROR logger.log(lvl, "Generated stubs signature is degraded to `(*args, **kwargs) ...
https://docs.python.org/2/reference/compound_stmts.html#function-definitions 其中有下面一段 "Default parameter values are evaluated when the function definition is executed. This means that the expression is evaluated once, when the function is defined, and that the same “pre-computed” value is...