随笔分类 - python基础
python基础
摘要：import geventfrom gevent import monkeyimport time# monkey.patch_all() # 补丁包，协程有IO等待时，触发协程切换def work1(): for i in range(10): print(f' work1 {i}') # tim
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摘要：from greenlet import greenletdef work1(): for i in range(10): print(f' work1 {i}') g2.switch()def work2(): for i in range(10): print(f' work2 {i}') g1
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摘要：from queue import Queueq = Queue()def func1(): while not q.empty(): i = q.get() print(f' func1 {i}') yield idef func2(): while not q.empty(): i = q.ge
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摘要：进程与进程之间不共享全局变量 from multiprocessing import Process, Queueimport time,osdef func1(q:Queue): while not q.empty(): print(' func1 {0} {1}'.format(q.get(),
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摘要：from multiprocessing import Pool, Managerimport time,osdef func1(q): print(' func1 {0} {1}'.format(q.get(), os.getpid())) time.sleep(1)if __name__ ==
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摘要：import queuefrom threading import Threadimport timeq = queue.Queue()class Productor(Thread): def run(self) -> None: count = 0 while True: if q.qsize()
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摘要：队列： import queue# 1. 先进先出q1 = queue.Queue(5)q1.put(11)q1.put(22, block=False) # 插入不等待q1.put_nowait(33) # 插入不等待print(q1.qsize()) # 队列长度q1.get()q1.get(b
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摘要：线程效率： 1、CPU计算密集型：单线程 比多线程 快 2、网络IO密集型：多线程 比 单线程 快 import requestsimport threadingimport timenum = 0def func1(): for i in range(100): # global num # nu
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摘要：多个线程互相等待锁，会导致死锁 import threadingimport timemetalocA = threading.Lock()metalocB = threading.Lock()num = 0def func1(): for i in range(1000000): global n
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摘要：加锁的作用： 1、多个线程同时修改同一个全局变量时，确保不被CPU切片阻断 2、加锁会加长执行时间 import threadingimport timemetalocA = threading.Lock()# metalocB = threading.Locknum = 0def func1():
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摘要：import threadingimport timeimport requestsclass MyThreading(threading.Thread): def __init__(self, url): self.url = url # 给run方法传参，只能通过 self的属性 super()
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摘要：import threadingimport timefrom time import sleepdef func1(): for i in range(4): sleep(1) print(' func1 ', threading.current_thread())def func2(): for
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摘要：（1）使用type直接创建类 Test = type('Test01', (object,), {'name': 'haha', 'age': 18})t1 = Test()print(type(t1))print(Test.__dict__) （2）继承type，用继承类创建类 class MyT
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摘要：（1）描述器类 class Field: # 设置描述器类对象属性时调用 def __set__(self, instance, value): print(' __set__ ') self.value = value # 获取描述器对象属性时调用 def __get__(self, instan
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摘要：class MyClass(object): # 设置对象属性时调用 def __setattr__(self, key, value): print(' __setattr__ ') super().__setattr__(key, value) # 访问属性不存在，__getattribute_
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摘要：（1）私有属性 class MyClass: attr1 = 'attr1' # 共有属性 _attr2 = '_attr2' # 私有属性，可直接访问 __attr3 = '__attr3' # 私有属性，改变了属性名：_MyClass__attr3m1 = MyClass()print(m1.a
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摘要：class Animal: def run(self): print(' animal run ')class Cat(Animal): def run(self): print(' cat run ')class Dog(Animal): def run(self): print(' dog ru
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摘要：class MyOperator: def __init__(self, data): self.data = data def __add__(self, other): return self.data + other.data def __sub__(self, other): return
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摘要：（1）文件读取--上下文管理器 with open(filename,'w') as f : class MyOpen: def __init__(self, filename, mode, encoding='utf-8'): self.filename = filename self.mode
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摘要：class Decorator: def __init__(self, func): self.func = func def __call__(self, *args, **kwargs): print(' call ') return self.func(*args, **kwargs)@Dec
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