# stuff if __name__ == "__main__": # do stuff 本文将尽可能使用简单的样例来解释这里发生了什么,以及使用if __name__=="__main__"的情形。请注意,上述代码中name和main前后有2个下划线字符。 闲话少说,我们直接开始吧! 2. 特殊变量 当我们正常运行我们的Python脚本时,该脚本中的变量__name_...
from datetimeimportdatetimeimportasyncioasyncdefdo_washing():print(datetime.now(),':开始洗衣服')awaitasyncio.sleep(0.5)foriinrange(10000):ifi%4000==0:print('洗衣服')print(datetime.now(),':衣服洗好了')asyncdefdo_cooking():print(datetime.now(),':开始煲饭')foriinrange(100000):ifi%20000==...
同时显示内部函数 fromline_profilerimportLineProfilerimportrandomdefdo_other_stuff(numbers):s=sum(numbers)defdo_stuff(numbers):do_other_stuff(numbers)l=[numbers[i]/43foriinrange(len(numbers))]m=['hello'+str(numbers[i])foriinrange(len(numbers))]numbers=[random.randint(1,100)foriinrange(100...
deffrom_file(cls,file):# Alternative constructor d=cls.__new__(cls)# Do stuff...returnd 这里定义from_file方法,它作为构造函数,首先使用__new__创建实例,然后在不调用__init__的情况下配置它。 下一个与元编程相关的神奇方法是__getattr__。当普通属性访问失败时调用此方法。这可以用来将对缺失方法...
#Example#1classFastClass:defdo_stuff(self):temp=self.value#thisspeedsuplookupinloopforiinrange(10000):...#Dosomethingwith`temp`here#Example#2importrandomdeffast_function():r=random.randomforiinrange(10000):print(r())#calling`r()`here,isfasterthanglobalrandom.random()使用函数 这也许有些反直觉...
def do_stuff(self): temp = self.value # this speeds up lookup in loop for i in range(10000): ... # Do something with `temp` here # Example #2 import random def fast_function(): r = random.random for i in range(10000): ...
do_stuff(f) else: 1. 2. 3. 4. 5. 6. 7. 8. do_stuff(file_name)注意:再次提醒,可能更常见的情况是,我们直接把 do_stuff() 放在外部,作为一个私有函数,但显然,必要时我们也可以把它作为内部函数隐藏起来。 我们可以写一个更具体的例子。
Everything these three functions do can be replicated with the newer run() function. The older API is mainly still there for backwards compatibility, and you won’t cover it in this tutorial. There’s also a fair amount of redundancy in the subprocess module, meaning that there are various...
# Example #1classFastClass: defdo_stuff(self): temp =self.value # this speeds up lookup in loop for i inrange(10000): ... # Do something with `temp` here# Example #2import randomdeffast_function(): r = random.random for i inrange(10000): print(r())...
do_stuff_in_transaction(conn)No: with conn: do_stuff_in_transaction(conn) 1. 2. 3. 4. 5. 后一个示例没有提供任何信息来表明__enter__和__exit__方法在执行事务后关闭连接之外的其他操作。在这种情况下,明确是很重要的。 (10)在返回语句中保持一致。函数中的所有返回语句都应该返回表达式,或者它们...