Tutorial by Examples: ha

You can use an environment filter to change the author of commits. Just modify and export $GIT_AUTHOR_NAME in the script to change who authored the commit. Create a file filter.sh with contents like so: if [ "$GIT_AUTHOR_NAME" = "Author to Change From" ] then export GIT_A...

A has_many :through association is often used to set up a many-to-many connection with another model. This association indicates that the declaring model can be matched with zero or more instances of another model by proceeding through a third model. For example, consider a medical practice where p...

A has_one :through association sets up a one-to-one connection with another model. This association indicates that the declaring model can be matched with one instance of another model by proceeding through a third model. For example, if each supplier has one account, and each account is associated...

A has_and_belongs_to_many association creates a direct many-to-many connection with another model, with no intervening model. For example, if your application includes assemblies and parts, with each assembly having many parts and each part appearing in many assemblies, you could declare the models...

Consumable Managed Products are products that can be bought multiple times such as in-game currency, game lives, power-ups, etc. In this example, we are going to implement 4 different consumable managed products "item1", "item2", "item3", "item4". Steps in...

Any lodash collection method has two syntaxes. Without chaining: var arr1 = [10, 15, 20, 25, 30, 15, 25, 35]; var arr2 = _.filter(arr1, function(item){ return item % 10 === 5 }); // arr2 now contains [15, 25, 15, 25, 35] var arr3 = _.uniq(arr2); // arr3 now contains [15, 25, 35] var arr...

The following examples can be tested on https://ellie-app.com/m9vmQ8NcMc/0. import Html exposing (..) import Json.Decode payload = """ [ { "bark": true, "tag": "dog", "name": "Zap", "playful": true } , { "w...

A hash is a function that converts a variable length sequence of bytes to a fixed length sequence. Hashing files can be advantageous for many reasons. Hashes can be used to check if two files are identical or verify that the contents of a file haven't been corrupted or changed. You can use hashlib ...

DROP PROCEDURE if exists displayNext100WithName; DELIMITER $$ CREATE PROCEDURE displayNext100WithName ( nStart int, tblName varchar(100) ) BEGIN DECLARE thesql varchar(500); -- holds the constructed sql string to execute -- expands the sizing of the output buffer to accomoda...

In most cases you want to define several border properties (border-width, border-style and border-color) for all sides of an element. Instead of writing: border-width: 1px; border-style: solid; border-color: #000; You can simply write: border: 1px solid #000; These shorthands are also ava...

Writes an error message to the console if the assertion is false. Otherwise, if the assertion is true, this does nothing. console.assert('one' === 1); Multiple arguments can be provided after the assertion–these can be strings or other objects–that will only be printed if the assertion is fals...

Type erasure is a way to hide the type of an object from code using it, even though it is not derived from a common base class. In doing so, it provides a bridge between the worlds of static polymorphism (templates; at the place of use, the exact type must be known at compile time, but it need not b...

When an exception is thrown from within a Future, you can (should) use recover to handle it. For instance, def runFuture: Future = Future { throw new FairlyStupidException } val itWillBeAwesome: Future = runFuture ...will throw an Exception from within the Future. But seeing as we can predic...

.message color: white background: black .message-important @extend .message font-weight: bold .message-error @extend .message-important font-style: italic This code causes .message-error to extend from .message-important, which means that it will contain code from both .me...

data.table extends reshape2's melt & dcast functions (Reference: Efficient reshaping using data.tables) library(data.table) ## generate some data dt <- data.table( name = rep(c("firstName", "secondName"), each=4), numbers = rep(1:4, 2), value = rnorm(8) ) ...

library(tidyr) ## example data set.seed(123) df <- data.frame( name = rep(c("firstName", "secondName"), each=4), numbers = rep(1:4, 2), value = rnorm(8) ) df # name numbers value # 1 firstName 1 -0.56047565 # 2 firstName 2 -0.2301...

Generic parameters can also be bound to more than one type using the T extends Type1 & Type2 & ... syntax. Let's say you want to create a class whose Generic type should implement both Flushable and Closeable, you can write class ExampleClass<T extends Flushable & Closeable> { }...

article.twig.html <article> <h1>{{ article.title }}</h1> {% block content %} <p>{{ article.content }}</p> {% endblock %} </article> articles.twig.html {# use default template for article #} {% for article in articles %} {% include &...

Rails is shipped by default with ActiveRecord, an ORM (Object Relational Mapping) derived from the pattern with the same name. As an ORM, it is built to handle relational-mapping, and more precisely by handling SQL requests for you, hence the limitation to SQL databases only. However, you can stil...

Fired when one or more of the component or directive properties have been changed. import { Component, OnChanges, Input } from '@angular/core'; @Component({ selector: 'so-onchanges-component', templateUrl: 'onchanges-component.html', styleUrls: ['onchanges-component.'] }) class ...