• TOC

Background

Well, actually I already has a blog on python cheat sheet, but I found that writing those code in gists make loading time of the page unbearable long. So I decided to put the python notes into plain markdown.

Code

check whether x is a subsequence of s

def isSubsequence(x, s):
    it = iter(s)
    return all(c in it for c in x)

Notes

• Int: in python3, the plain int type is unbounded.

Global interpreter lock (GIL):

• The mechanism used by the CPython interpreter to assure that only one thread executes Python bytecode at a time. https://docs.python.org/3/glossary.html#term-global-interpreter-lock

Threading

Lock

• 有acquire() 和release()，就是简单的让不让进

Condition

• acquire() and release()

Semaphore

• 可以是Semaphore(value=3)，会保证计数$\ge 0$

Event

• thread间通信，one thread signals an event and other threads wait for it.
• set() and clear()

Barrier

• 也是通信，Barrier(parties=2)，当有parties这么多个threads同时等待时，一起释放

f-string

handling {

• 推荐直接使用 `` 直接上 4 层就行了 f'}}''