1 2 3 1、空语句 do nothing 2、保证格式完整 3、保证语义完整25、*arg和**kwarg作用1 2 3 4 5 6 7 *args代表位置参数,它会接收任意多个参数并把这些参数作为元组传递给函数。 **kwargs代表的关键字参数,允许你使用没有事先定义的参数名。 位置参数一定要放在关键字参数的前面。 作用:使用*args和*
However, if you need to handle some errors while ignoring others, then it’s more straightforward to have an empty except class with nothing except the pass statement. For example, if you wanted to have ensure_nonexistence() deal with directories as well as files, then you could use this ...
except ImportError: pass # If pyperclip is not installed, do nothing. It's no big deal. # Set up the constants: UPPER_LETTERS = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ' LOWER_LETTERS = 'abcdefghijklmnopqrstuvwxyz' print('ROT13 Cipher, by Al Sweigart email@protected') print() while True: # Main pro...
defdo_nothing():pass「raise」用于引发异常。raise ValueError("无效值。")「return」用于退出函数并返回值。defdouble(x):return x * 2「True」表示布尔值。x = Trueif x == True: print("x is True.")「try」用于指定要测试异常的代码块。try:# 可能引发异常的代码passexcept SomeException:# 处理...
__doc__ #This is self-defined function # #Do nothing 五、模块 模块就是一个包含了所有你定义的函数和变量的文件,模块必须以.py为扩展名。模块可以从其他程序中‘输入’(import)以便利用它的功能。 在python程序中导入其他模块使用’import’, 所导入的模块必须在sys.path所列的目录中,因为sys.path第一个...
类属性：定义在__init__外部的变量 类方法：定义在类中，且被@classmethod装饰的方法 实例对象：类对象...
>>> print(do_nothing()) None None is a special Python value that holds a place when there is nothing to say. keyword arguments To avoid positional argument confusion, you can specify arguments by the names of their corresponding parameters, even in a different order from their definition in...
importsysdefbar(i):ifi ==1:raiseKeyError(1)ifi ==2:raiseValueError(2)defgood(): exception =Nonetry: bar(int(sys.argv[1]))exceptKeyErrorase: exception = eprint('key error')exceptValueErrorase: exception = eprint('value error')print(exception) good() ...
This is no different from the earlier wrapper functions that you’ve seen, except that it’s using the num_times parameter that must be supplied from the outside.One step out, you’ll find the decorator function:Python def decorator_repeat(func): @functools.wraps(func) def wrapper_repeat...
e = 7 try: raise Exception() except Exception as e: passOutput (Python 2.x):>>> print(e) # prints nothingOutput (Python 3.x):>>> print(e) NameError: name 'e' is not defined💡 Explanation:Source: https://docs.python.org/3/reference/compound_stmts.html#except When an exception...