hellerbarde

Latency numbers every programmer should know

L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns
L2 cache reference ........................... 7 ns
Mutex lock/unlock ........................... 25 ns
Main memory reference ...................... 100 ns             
Compress 1K bytes with Zippy ............. 3,000 ns  =   3 µs
Send 2K bytes over 1 Gbps network ....... 20,000 ns  =  20 µs
SSD random read ........................ 150,000 ns  = 150 µs

Read 1 MB sequentially from memory ..... 250,000 ns = 250 µs

dergachev

OS X Screencast to animated GIF

This gist shows how to create a GIF screencast using only free OS X tools: QuickTime, ffmpeg, and gifsicle.

Instructions

To capture the video (filesize: 19MB), using the free "QuickTime Player" application:

jmdobry

Start your rethinkdb instance with this flag: --bind all (or bind=all in the configuration file for your instance)

Block external access to the web UI with these two commands: sudo iptables -A INPUT -i eth0 -p tcp --dport 8080 -j DROP sudo iptables -I INPUT -i eth0 -s 127.0.0.1 -p tcp --dport 8080 -j ACCEPT

Install nginx: sudo apt-get install nginx

wookiecooking

# Rails Stuff
alias stoprails='kill -9 $(lsof -i :3000 -t)'
alias startrails='rails server -d'
alias restartrails='stopRails && startRails'

#Check PHP For Erroes
alias phpcheck='find ./ -name \*.php | xargs -n 1 php -l'

# ROT13-encode text. Works for decoding, too! ;)
alias rot13='tr a-zA-Z n-za-mN-ZA-M'

tsiege

ANNOUNCEMENT

I have moved this over to the Tech Interview Cheat Sheet Repo and has been expanded and even has code challenges you can run and practice against!






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bsweger

Useful Pandas Snippets

A personal diary of DataFrame munging over the years.

Data Types and Conversion

Convert Series datatype to numeric (will error if column has non-numeric values)
(h/t @makmanalp)

1328

import random
from collections import defaultdict

from pprint import pprint

class City(object):
    def __init__(self, data=None):
        self.name = None
        self.neighbors = {}
        if data is not None:

comerford

storage:
    dbPath: "/ssd/db/wt_zlib"
    engine: "wiredTiger"
    wiredTiger:
        collectionConfig: "block_compressor=zlib"
systemLog:
    destination: file
    path: "/data/wt_zlib/mongodb.log"
processManagement:
    fork: true

attacus

This guide is unmaintained and was created for a specific workshop in 2017. It remains as a legacy reference. Use at your own risk.

Running your own encrypted chat service with Matrix and Riot

Workshop Instructor:

• Lilly Ryan @attacus_au

This workshop is distributed under a CC BY-SA 4.0 license.

What are we doing here?

steven2358

FFmpeg cheat sheet

A list of useful commands for the FFmpeg command line tool.

Download FFmpeg: https://www.ffmpeg.org/download.html

Full documentation: https://www.ffmpeg.org/ffmpeg.html

Basic conversion