1、元类编程 __getattr__和__getattribute__魔法函数 from datetime import date, datetime class User: def __init__(self, name, birthday, info={}): self.name = name self.birthday = birthday self.info = info def __getattr__(self, item): # 当类对象的属性不存在的时候,会调用此方法 print...
基类NodeVisitor的引入有助于我们调用getattr()获取当前的visit_函数。同时,我们使用push和pop方法来保护当前父作用域,同时创建出新的子作用域。例如,CompoundStatement节点中会引入大括号,从而将引入新的作用域,因此访问这个节点函数时,我们需要先将当前作用域压入栈,创建新的作用域,然后访问组成它的节点,访问完毕再从...
最后,把这个描述放在PyTypeObject内,最终的效果是这样的—— staticPyTypeObjectDate_type={PyVarObject_HEAD_INIT(NULL,0).tp_name="datetimecpy.date",.tp_basicsize=sizeof(Date),.tp_dealloc=(destructor)Date_dealloc,.tp_repr=(reprfunc)Date_repr,.tp_str=(reprfunc)Date_repr,.tp_getattro=(getattr...
(printfunc)int_print, /* tp_print */ 0, /* tp_getattr */ 0, /* tp_setattr */ (cmpfunc)int_compare, /* tp_compare */ ... int_new, /* tp_new */ (freefunc)int_free, /* tp_free */ }; PyTypeObject PyDict_Type = { PyVarObject_HEAD_INIT(&PyType_Type, 0) "dict", ...
visitor = getattr(self, method, self.generic_visit) # deep first for c in node.children(): self.visit(c, node) return visitor(node, parent) def generic_visit(self, node, parent): for c in node.children(): self.visit(c, node) ...
题目里描述的东西叫「反射」，C/C++ 是不支持的。但是如果你需要的只是「能通过字符串获取某属性」的...
cgetattr(0,&stored_settings); new_settings = stored_settings; /* disable canonical mode, and set buffer size to 1 byte */ new_settings.c_lflag &= (~icanon); new_settings.c_lflag &= (~echo); new_settings.c_cc[vtime] = 0; new_settings.c_cc[vmin] = 1; tcsetattr(0,tcsanow,...
getattr(obj,name) setattr(obj,str,val) delattr(obj,str) 看完四个方法的定义之后就来看看实战怎么用? 反射1 反射2 6 异常 常用异常 更多异常 来看看实例:KeyError IndexError ValueError 实例 异常的其他结构 当然,我们也可以自定义异常,通过raise来触发。
(here for binary compatibility) */hashfunc tp_hash;ternaryfunc tp_call;reprfunc tp_str;getattrofunc tp_getattro;setattrofunc tp_setattro;/* Functions to access object as input/output buffer */PyBufferProcs*tp_as_buffer;/* Flags to define presence of optional/expanded features */long tp_...
cgetattr(0,stored_settings); new_settings=stored_settings; /*Disablecanonicalmode,andsetbuffersizeto1byte*/ new_settings.c_lflag=(~ICANON); new_settings.c_lflag=(~ECHO); new_settings.c_cc[VTIME]=0; new_settings.c_cc[VMIN]=1; tcsetattr(0,TCSANOW,new_settings); return; } voidreset_...