rondy

FWIW: I (@rondy) am not the creator of the content shared here, which is an excerpt from Edmond Lau's book. I simply copied and pasted it from another location and saved it as a personal note, before it gained popularity on news.ycombinator.com. Unfortunately, I cannot recall the exact origin of the original source, nor was I able to find the author's name, so I am can't provide the appropriate credits.

---

Effective Engineer - Notes

• By Edmond Lau
• Highly Recommended 👍
• http://www.theeffectiveengineer.com/

What's an Effective Engineer?

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

bastman

Docker - How to cleanup (unused) resources

Once in a while, you may need to cleanup resources (containers, volumes, images, networks) ...

delete volumes

// see: https://github.com/chadoe/docker-cleanup-volumes

$ docker volume rm $(docker volume ls -qf dangling=true)

$ docker volume ls -qf dangling=true | xargs -r docker volume rm

myusuf3

To remove a submodule you need to:

• Delete the relevant section from the .gitmodules file.
• Stage the .gitmodules changes git add .gitmodules
• Delete the relevant section from .git/config.
• Run git rm --cached path_to_submodule (no trailing slash).
• Run rm -rf .git/modules/path_to_submodule (no trailing slash).
• Commit git commit -m "Removed submodule "
• Delete the now untracked submodule files rm -rf path_to_submodule

DavidKuennen

(function (context, trackingId, options) {
    const history = context.history;
    const doc = document;
    const nav = navigator || {};
    const storage = localStorage;
    const encode = encodeURIComponent;
    const pushState = history.pushState;
    const typeException = 'exception';
    const generateId = () => Math.random().toString(36);
    const getId = () => {

rauschma

Cheat sheet: JavaScript Array methods

Deriving a new Array from an existing Array:

['■','●','▲'].slice(1, 3)          ⟼ ['●','▲']
['■','●','■'].filter(x => x==='■') ⟼ ['■','■']
    ['▲','●'].map(x => x+x)        ⟼ ['▲▲','●●']
    ['▲','●'].flatMap(x => [x,x])  ⟼ ['▲','▲','●','●']

jacobsapps

\documentclass[11pt, oneside]{article}
\usepackage[margin=0.5in]{geometry}
\geometry{letterpaper}           
\usepackage[parfill]{parskip}    
\usepackage{graphicx}				
\usepackage{amssymb}
\usepackage{xcolor}
\pagecolor{white}
\usepackage[colorlinks = true, linkcolor = blue, urlcolor  = blue]{hyperref}
\pagestyle{empty}

marcedwards

/* ---------------------------------------------------------- */
/*                                                            */
/* A media query that captures:                               */
/*                                                            */
/* - Retina iOS devices                                       */
/* - Retina Macs running Safari                               */
/* - High DPI Windows PCs running IE 8 and above              */
/* - Low DPI Windows PCs running IE, zoomed in                */
/* - Low DPI Windows PCs and Macs running Firefox, zoomed in  */
/* - Android hdpi devices and above                           */

jasdeepkhalsa

<?php
$image = imagecreatefromjpeg($_GET['src']);
$filename = 'images/cropped_whatever.jpg';

$thumb_width = 200;
$thumb_height = 150;

$width = imagesx($image);
$height = imagesy($image);

havvg

jQuery(function($) {
    $('form[data-async]').live('submit', function(event) {
        var $form = $(this);
        var $target = $($form.attr('data-target'));

        $.ajax({
            type: $form.attr('method'),
            url: $form.attr('action'),
            data: $form.serialize(),