vasanthk

System Design Cheatsheet

Picking the right architecture = Picking the right battles + Managing trade-offs

Basic Steps

1. Clarify and agree on the scope of the system

• User cases (description of sequences of events that, taken together, lead to a system doing something useful)
  • Who is going to use it?
  • How are they going to use it?

yrevar

{0: 'tench, Tinca tinca',
 1: 'goldfish, Carassius auratus',
 2: 'great white shark, white shark, man-eater, man-eating shark, Carcharodon carcharias',
 3: 'tiger shark, Galeocerdo cuvieri',
 4: 'hammerhead, hammerhead shark',
 5: 'electric ray, crampfish, numbfish, torpedo',
 6: 'stingray',
 7: 'cock',
 8: 'hen',
 9: 'ostrich, Struthio camelus',

tanyuan

Smart Caps Lock: Remap to Control AND Escape (Linux, Mac, Windows)

把 Caps Lock 變成智慧的 Control 以及 Escape ：

• 單獨輕按一下就是 Escape 。
• 若按下時同時按著其他鍵，就會是 Control 。

這應該是 Vim 和 Emacs 的最佳解了！(Emacs? Bash 的快捷鍵就是 Emacs 系列的)

• Send Escape if you tap Caps Lock alone.

yoki

# 10_basic.py
# 15_make_soup.py
# 20_search.py
# 25_navigation.py
# 30_edit.py
# 40_encoding.py
# 50_parse_only_part.py

jamesmacwhite

Converting mkv to mp4 with ffmpeg

Essentially just copy the existing video and audio stream as is into a new container, no funny business!

The easiest way to "convert" MKV to MP4, is to copy the existing video and audio streams and place them into a new container. This avoids any encoding task and hence no quality will be lost, it is also a fairly quick process and requires very little CPU power. The main factor is disk read/write speed.

With ffmpeg this can be achieved with -c copy. Older examples may use -vcodec copy -acodec copy which does the same thing.

These examples assume ffmpeg is in your PATH. If not just substitute with the full path to your ffmpeg binary.

Single file conversion example

littlecodersh

#coding=utf8
import itchat
# tuling plugin can be get here:
# https://github.com/littlecodersh/EasierLife/tree/master/Plugins/Tuling
from tuling import get_response

@itchat.msg_register('Text')
def text_reply(msg):
    if u'作者' in msg['Text'] or u'主人' in msg['Text']:
        return u'你可以在这里了解他：https://github.com/littlecodersh'

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?

nickkraakman

FFmpeg Cheat Sheet for 360º video

Brought to you by Headjack

 
FFmpeg is one of the most powerful tools for video transcoding and manipulation, but it's fairly complex and confusing to use. That's why I decided to create this cheat sheet which shows some of the most often used commands.

 
Let's start with some basics:

• ffmpeg calls the FFmpeg application in the command line window, could also be the full path to the FFmpeg binary or .exe file

killeent

A Tour of PyTorch Internals (Part I)

The fundamental unit in PyTorch is the Tensor. This post will serve as an overview for how we implement Tensors in PyTorch, such that the user can interact with it from the Python shell. In particular, we want to answer four main questions:

1. How does PyTorch extend the Python interpreter to define a Tensor type that can be manipulated from Python code?
2. How does PyTorch wrap the C libraries that actually define the Tensor's properties and methods?
3. How does PyTorch cwrap work to generate code for Tensor methods?
4. How does PyTorch's build system take all of these components to compile and generate a workable application?

Extending the Python Interpreter

PyTorch defines a new package torch. In this post we will consider the ._C module. This module is known as an "extension module" - a Python module written in C. Such modules allow us to define new built-in object types (e.g. the Tensor) and to call C/C++ functions.

mcchae

# USAGE
# python image_diff.py --first images/original_01.png --second images/modified_01.png

# import the necessary packages
from skimage.measure import compare_ssim
import argparse
import imutils
import cv2

# construct the argument parse and parse the arguments