fxn

Ruby: The future of frozen string literals

What is a literal?

In programming languages, literals are textual representations of values in the source code. This is a syntactical concept.

Some examples:

7 # integer literal

pmkay

node: Platform built on V8 to build network applications
git: Distributed revision control system
wget: Internet file retriever
yarn: JavaScript package manager
python3: Interpreted, interactive, object-oriented programming language
coreutils: GNU File, Shell, and Text utilities
pkg-config: Manage compile and link flags for libraries
chromedriver: Tool for automated testing of webapps across many browsers
awscli: Official Amazon AWS command-line interface
automake: Tool for generating GNU Standards-compliant Makefiles

mankind

http://stackoverflow.com/questions/22667401/postgres-json-data-type-rails-query
http://stackoverflow.com/questions/40702813/query-on-postgres-json-array-field-in-rails

#payload: [{"kind"=>"person"}]
Segment.where("payload @> ?", [{kind: "person"}].to_json)

#data: {"interest"=>["music", "movies", "programming"]}
Segment.where("data @> ?",  {"interest": ["music", "movies", "programming"]}.to_json)
Segment.where("data #>> '{interest, 1}' = 'movies' ")
Segment.where("jsonb_array_length(data->'interest') > 1")

Kartones

PSQL

Magic words:

psql -U postgres

Some interesting flags (to see all, use -h or --help depending on your psql version):

• -E: will describe the underlaying queries of the \ commands (cool for learning!)
• -l: psql will list all databases and then exit (useful if the user you connect with doesn't has a default database, like at AWS RDS)

erikhenrique

Validação para cartão de crédito.

Bin e padrões para validação de cartão de crédito.

Bandeira	Começa com	Máximo de número	Máximo de número cvc
Visa	4	13,16	3
Mastercard	5	16	3

letanure

{
  "estados": [
    {
      "sigla": "AC",
      "nome": "Acre",
      "cidades": [
        "Acrelândia",
        "Assis Brasil",
        "Brasiléia",
        "Bujari",

MohamedAlaa

tmux shortcuts & cheatsheet

start new:

tmux

start new with session name:

tmux new -s myname

tsabat

Prereq:

apt-get install zsh
apt-get install git-core

Getting zsh to work in ubuntu is weird, since sh does not understand the source command. So, you do this to install zsh

wget https://github.com/robbyrussell/oh-my-zsh/raw/master/tools/install.sh -O - | zsh