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# -*- coding: utf-8 -*-

"""
Three threads print A B C in order.
"""


from threading import Thread, Condition

condition = Condition()

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# -*- coding: utf-8 -*-

import redis
import random
import string
import time

COUNT = 1_000_000

r = redis.Redis(host="localhost", port=6379, db=0)

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# -*- coding: utf-8 -*-

import time
from concurrent.futures import ThreadPoolExecutor

pool = ThreadPoolExecutor(max_workers=5)


def sleep():
    time.sleep(20)

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# -*- coding: utf-8 -*-

def func(**kwargs):
    print(kwargs)


func(**{"foo": "bar"})
func(**{"foo": "bar"}, **{"hello": "world"})

# PEP 0448

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In [4]: def func(a, b):
   ...:     a, b = b ,a
   ...:

In [5]: dis.dis(func)
  2           0 LOAD_FAST                1 (b)
              2 LOAD_FAST                0 (a)
              4 ROT_TWO
              6 STORE_FAST               0 (a)
              8 STORE_FAST               1 (b)

laixintao

https://hackernoon.com/why-is-python-so-slow-e5074b6fe55b 笔记。

为什么Python这么慢？

GIL

GIL 用于解决多线程操作引用计数的难题。副作用是Python无法同时运行多个线程。

JS使用标记清除GC ；同时 JS 也是单线程异步的语言。

laixintao

# -*- coding: utf-8 -*-

TYPE = {
    ("ALARM_ANALYSIS", "报警分析"),
    ("DAILY_REPORT", "日报")
}

for k, v in TYPE:
    print(k, v)

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# -*- coding: utf-8 -*-
"""
Since we have GIL, should we add Lock for global variable read/write?
"""

import threading


shared_resource_with_no_lock = 0
COUNT = 100000

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➜  tmp curl -Iv http://ruanyifeng.com/
*   Trying 23.251.96.135...
* TCP_NODELAY set
* Connected to ruanyifeng.com (23.251.96.135) port 80 (#0)
> HEAD / HTTP/1.1
> Host: ruanyifeng.com
> User-Agent: curl/7.54.0
> Accept: */*
>
< HTTP/1.1 404 Not Found

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➜ [takachiho] takachiho git:(feat/locator) ipython
Python 3.6.5 (default, May 24 2018, 20:41:21)
Type 'copyright', 'credits' or 'license' for more information
IPython 6.4.0 -- An enhanced Interactive Python. Type '?' for help.

In [1]: x = 1

In [2]: [x for x in range(10)]
Out[2]: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]