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Python abstract base classes and multiple inheritance [duplicate]

拟墨画扇 提交于 2020-02-24 19:01:34
问题 This question already has answers here : python abstractmethod with another baseclass breaks abstract functionality (2 answers) Closed 22 days ago . I am trying to create a python (3.5) class structure where I use abstract methods to indicate which methods should be implemented. The following works as expected: from abc import ABC, abstractmethod class Base(ABC): @abstractmethod def foo(self): pass class Derived(Base, object): # Inheriting from object probably is superfluous (?) pass Derived(

Python abstract base classes and multiple inheritance [duplicate]

此生再无相见时 提交于 2020-02-24 18:59:50
问题 This question already has answers here : python abstractmethod with another baseclass breaks abstract functionality (2 answers) Closed 22 days ago . I am trying to create a python (3.5) class structure where I use abstract methods to indicate which methods should be implemented. The following works as expected: from abc import ABC, abstractmethod class Base(ABC): @abstractmethod def foo(self): pass class Derived(Base, object): # Inheriting from object probably is superfluous (?) pass Derived(

python正则

放肆的年华 提交于 2020-02-09 08:27:39
import re # 元字符 . ^ $ * + ? {} [] () | \ # findall() # 简单匹配 # res = re.findall("abc", "abcabcabcaaaddd") # 模糊匹配 # res = re.findall("a.c", "abcadcaabc") # .表示一位占位符 # res = re.findall("^abc", "abcabc") # 从头开始匹配 # res = re.findall("abc$", "abcabcaaabc") # 从尾开始匹配 # res = re.findall("abc*", "ab") # 表示匹配[0,+00) # res = re.findall("abc+", "abccc") # 表示匹配[1,+00) # res = re.findall("abc{2}", "abccc") # 指定次数匹配 # res = re.findall("abc{1,3}", "abccccc") # res = re.findall("abc?", "abcc") # 表示匹配[0,1] # res = re.findall("abc|adc", "abcadc") # 表示俩边或者 # res = re.findall("ab[cde]", "abcabdabe") # 或者其中之一 # res

正则表达式 2020.2.7

随声附和 提交于 2020-02-07 23:36:43
正则表达式 *通用的字符串表达框架 *简介表达一组字符串的表达式 *判断某字符串的特征归属 例: 'PY' 'PYY' 'PYYY' 'PYYYY' ...... P后面有无穷多个Y ---->正则表达式:PY+ 例: 'PY'开头 后续存在不多于10个字符 后续字符不能是'P'或'Y' 如: 'PYABC' √ 'PYKXYZ' × 用正则表达式----> PY[^PY]{0,10} 正则表达式的常用操作符 符号  含义 例子 . 表示任何单个字符(换行除外) [] 字符集对单个字符给出取值范围 [abc]表示a、b、c,[a-z]表示a到z单个字符 [^] 非字符集,对单个字符给出排除范围 [^abc]表示非a或b或c的单个字符 * 前一个字符0次或无限次拓展 abc*表示ab、abc、abcc、abccc...... + 前一个字符1次或无限次拓展 abc+表示abc、abcc、abccc...... ? 前一个字符0次或一次拓展 abc?表示ab、abc | 左右表达式任意一个 abc|def表示abc、def {m} 拓展前一个字符m次 ab{2}c表示abbc {m,n} 拓展前一个字符m至n次 ab{1,2}表示abc、abbc ^ 匹配字符串开头 ^abc表示abc且在第一个字符串开头 $ 匹配字符串结尾 abc$表示abc且在一个字符串的结尾 () 分组标记

面试题:三个线程ABC,将名字按顺序输出到控制台,如ABCABC.....

你。 提交于 2020-01-29 19:47:23
题目:有三个线程,名字为A,B,C,现在需要将它们的名字有序的打印在控制台上,顺序为ABCABC… 思路: 因为要控制某个线程的执行顺序,所以采用lock+condition+ewait+signalAll的方式 执行线程方法的类: class ABC { private int num = 1 ; Lock lock = new ReentrantLock ( ) ; // 每一个Condition控制一个线程,让它们有序的执行 Condition condition1 = lock . newCondition ( ) ; Condition condition2 = lock . newCondition ( ) ; Condition condition3 = lock . newCondition ( ) ; public void lockA ( ) { lock . lock ( ) ; try { if ( num != 1 ) { try { condition1 . await ( ) ; } catch ( InterruptedException e ) { e . printStackTrace ( ) ; } } System . out . println ( Thread . currentThread ( ) . getName ( ) ) ;

Is it possible to be a virtual subclass of a built in type?

自闭症网瘾萝莉.ら 提交于 2020-01-24 05:42:26
问题 Is it possible to make a user defined type be a virtual subclass of a built in type in python? I would like my class to be considered a subclass of int , however I don't want to inherit directly like this: class MyInt(int): '''Do some stuff kind of like an int, but not exactly''' pass Since then my class becomes effectively immutable, whether I want it to be or not. For instance, it becomes impossible to use methods like __iadd__ and __isub__ since int has no way to modify itself. I could

ASP.NET Core:创建一个Core项目

霸气de小男生 提交于 2020-01-23 14:32:01
ylbtech-ASP.NET Core:创建一个Core项目 1. 返回顶部 1、 2、 3、 4、 5、 2. 返回顶部 1、新建Razor页面 2、 3、 4、Abc 4.1、Abc.cshtml @page @model WebAppCore.Pages.AbcModel @{ ViewData["Title"] = "Abc"; Layout = "~/Pages/_Layout.cshtml"; } <h2>Abc</h2> @section Scripts { @{await Html.RenderPartialAsync("_ValidationScriptsPartial");} } 4.2、Abc.cshtml.cs using System; using System.Collections.Generic; using System.Linq; using System.Threading.Tasks; using Microsoft.AspNetCore.Mvc; using Microsoft.AspNetCore.Mvc.RazorPages; namespace WebAppCore.Pages { public class AbcModel : PageModel { public void OnGet() { } } } 5、_Layout

abc.abstractmethod + property

此生再无相见时 提交于 2020-01-14 14:44:10
问题 According to the docs it should work to combine @property and @abc.abstractmethod so the following should work in python3.3: import abc class FooBase(metaclass=abc.ABCMeta): @property @abc.abstractmethod def greet(self): """ must be implemented in order to instantiate """ pass @property def greet_comparison(self): """ must be implemented in order to instantiate """ return 'hello' class Foo(FooBase): def greet(self): return 'hello' test the implementation: In [6]: foo = Foo() In [7]: foo.greet

What is a “nearly-empty” class?

家住魔仙堡 提交于 2020-01-11 10:32:36
问题 Compile the following class class Interface { virtual void doIt() = 0; virtual ~Interface() = 0; }; inline Interface::~Interface() {} using gcc -fdump-class-hierarchy . gcc emits Class Interface size=4 align=4 base size=4 base align=4 Interface (0x1a779c0) 0 nearly-empty vptr=((& Interface::_ZTV9Interface) + 8u) What is the significance of "nearly-empty"? What does it mean? 回答1: The C++ ABI provides a definition of "nearly empty" classes and an interesting discussion of how they affect vtable

Excluding abstractproperties from coverage reports

可紊 提交于 2019-12-30 01:39:15
问题 I have an abstract base class along the lines of: class MyAbstractClass(object): __metaclass__ = ABCMeta @abstractproperty def myproperty(self): pass But when I run nosetests (which coverage) on my project, it complains that the property def line is untested. It can't actually be tested (AFAIK) as instantiation of the abstract class will result in an exception being raised.. Are there any workarounds to this, or do I just have to accept < 100% test coverage? Of course, I could remove the