Huayi Zhang irachex

One-line Tree in Python

Using Python's built-in defaultdict we can easily define a tree data structure:

def tree(): return defaultdict(tree)

That's it!

You can use strace on a specific pid to figure out what a specific process is doing, e.g.:

strace -fp <pid>

You might see something like:

select(9, [3 5 8], [], [], {0, 999999}) = 0 (Timeout)

-#!/bin/bash
-set -eu
-shopt -s nullglob
-readonly base_dir=/var/lib/docker/registry
-readonly output_dir=$(mktemp -d -t trace-images-XXXX)
-readonly jq=/usr/bin/jq
-readonly repository_dir=$base_dir/repositories

	# -- coding: utf-8 --
	'''
	Created on Jan 11, 2013

	@author: Mourad Mourafiq

	About: This is an attempt to solve the Quora challenge Feed Optimizer.
	'''
	import itertools
	import copy

	from binascii import hexlify, unhexlify
	from hashlib import md5
	from Crypto.Cipher import AES
	try:
	from M2Crypto import EVP
	except ImportError:
	EVP = None


	def m2_encrypt(plaintext, key, iv, key_as_bytes=False, padding=True):

	Latency Comparison Numbers (~2012)
	----------------------------------
	L1 cache reference 0.5 ns
	Branch mispredict 5 ns
	L2 cache reference 7 ns 14x L1 cache
	Mutex lock/unlock 25 ns
	Main memory reference 100 ns 20x L2 cache, 200x L1 cache
	Compress 1K bytes with Zippy 3,000 ns 3 us
	Send 1K bytes over 1 Gbps network 10,000 ns 10 us
	Read 4K randomly from SSD* 150,000 ns 150 us ~1GB/sec SSD

	import redis
	import web

	SESSION = 'SESSION:'

	class RedisStore(web.session.Store):

	"""Store for saving a session in redis:
	import rediswebpy
	session = web.session.Session(app, rediswebpy.RedisStore(), initializer={'count': 0})