There’s one important exception to the idiom of using pass as a do-nothing statement. In classes, functions, and methods, using a constant string expression will cause the expression to be used as the object’s
And you then tried to do this fromanother_mod.py: importmodmybar =mod.Bar() You’d get an uglyAttributeErrorexception. Why? Because, as reportedhere, when the interpreter shuts down, the module’s global variables are all set toNone. As a result, in the above example, at the point ...
event_type,event_value):"""Event callback"""pass# Do nothingdefload_plugins():api=create_api_...
# The"else"clause is optional and is # executed onlyifthe loop didn't"break".pass # Do nothingifrangelist[1]==2: print"The second item (lists are 0-based) is 2"elif rangelist[1]==3: print"The second item (lists are 0-based) is 3"else: print"Dunno"whilerangelist[1]==1: p...
>>> 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...
永远不要用捕获全部异常的except:语句,或者捕获Exception或者StandardError除非: Python在这个方面容忍度很高,并且except:语句会捕获包括拼写错误,sys.exit(),Ctrl+C终止,单元测试失败和和所有你并没有想到捕获的其他异常. 再次抛出这个异常 在程序中异常不会继续但是会被记录以及消除(例如通过保护最外层的方式保护线程不...
Python's binary releases also ship an add-on module together with it. Tcl Tcl 是一种动态解释型编程语言,正如 Python 一样。尽管它可作为一种通用的编程语言单独使用,但最常见的用法还是作为脚本引擎或 Tk 工具包的接口嵌入到 C 程序中。Tcl 库有一个 C 接口,用于创建和管理一个或多个 Tcl 解释器实例...
You can find some discussion around this here or in this StackOverflow thread. Python 3.7.6 onwards, you'll see RuntimeError: dictionary keys changed during iteration exception if you try to do this.▶ Stubborn del operationclass SomeClass: def __del__(self): print("Deleted!")...
import socket import jsonfromoptparse import OptionParserfromoptparse import OptionGroupfromstringimport Template import codecs import platform def isWindows():returnplatform.system() =='Windows'DATAX_HOME=os.path.dirname(os.path.dirname(os.path.abspath(__file__))) ...
defcalculate_value(self,foo,bar,baz):try:result=self._do_calculation(foo,bar,baz)except:self.user_screwups+=1raisereturnresult Here, we have a member function doing some calculation. We want to keep some statistics on how often the function is misused and throws an exception, but we have...