check if object has property ruby

ruby on rails - How to check if a model has a certain column/attribute ...
Nov 10, 2009 - For a class. Use Class.column_names.include? attr_name where attr_name is the ... I believe if an object delegates a method to another object, this method will erroneously suggest the column exists. I was checking my ...

ruby - Check if property exists in object - Stack Overflow
Aug 8, 2015 - If you want to see if there is such a method: x.respond_to?(:place). If you want to see if there is an instance variable (which you really shouldn't in 99% ...

ruby on rails - What is the best way to check if an attribute exists and is ...
Oct 6, 2013 - You could use presence : = link_to @element.title, (@element.link.presence ... link_to action, one of the models has a link attribute and the other doesn't. ... a key => value mapping of all of an activerecord object's attributes. if ...

How do I check if object has an attribute named "foo" or not ...
I'm looking for a way to check an object to find out if it has an attribute by name like: object.foo? #when there is no "foo" column name in the ...

how do i check if an object has a particular field? - Ruby Forum
I want to check that the object has the field before i query the contents ... Are you using this particular property to determine which type of model ...

Determining if an object property exists - NCZOnline
Jul 27, 2010 - In this code, the object person has only one own property, which is name . ... Let's say you want to determine if a given object has a property of ...

Check If A Ruby Method Exists - DZone IoT
Check If A Ruby Method Exists .... to allow their customers complete control to defend, protect and monitor their families and property from a single user interface.

has_attribute? (ActiveRecord::Base) - APIdock
Returns true if the given attribute is in the attributes hash. Show source. # File activerecord/lib/active_record/base.rb, line 1661 def has_attribute?(attr_name) ...

exists? (ActiveRecord::Base) - APIdock
Returns true if a record exists in the table that matches the id or conditions given, or false otherwise. The argument ... takes ActiveRecord object as an arg as well.

Check if key exists in hash - Ruby in Rails
Jan 4, 2014 - In Ruby on Rails Programming you might have to check if key exists in ... or not by using has_key? method available for the hash object in ruby.

has_fields - ReQL command reference - RethinkDB
Test if an object has one or more fields. An object has a field if it has that key and the key has a non-null value. For instance, the object {'a': 1,'b': 2,'c': null} has ...

Ruby Quicktips - How to check if an ActiveRecord attribute is...
Apr 28, 2010 - How to check if an ActiveRecord attribute is present You can use attribute names followed ... Your post has been linked at the drink rails blog.

Ruby: Is nil? - Lukasz Wrobel
Sep 11, 2010 - So, to check whether object is nil (NULL), one should compare it with ... the nil? method has been moved to the very top of the object tree - to ...

Class: Object (Ruby 2.3.1) - Ruby-Doc.org
Returns true if two objects do not match (using the =~ method), otherwise false. .... When using dup, any modules that the object has been extended with will not be .... This function must have the property that a.eql?(b) implies a.hash == b.hash . The hash value is used along with eql? by the Hash class to determine if two ...

ActiveModel::Dirty - Ruby on Rails API
Provides a way to track changes in your object in the same way as Active Record does. ... Call [attr_name]_will_change! before each change to the tracked attribute. ... Note that Active Record can detect in-place modifications automatically.

Check whether a getter is an attribute or an association - makandropedia
Sometimes you might want to know if an attribute is an associated object or a ... We are makandra and do test-driven, agile Ruby on Rails software development. ... Let's take an arbitrary object such as a blog article as an example that has ...

solnic.eu - Virtus - Attributes For Your Plain Ruby Objects
Jun 6, 2011 - If you like how properties work in DataMapper and would like to use ... corresponding attribute object will check if the value has the correct type.

Sequel::Model::InstanceMethods
The hash of attribute values. Keys are symbols with the ... If pk is not nil, true only if the objects have the same class and pk. If pk is nil, false. Artist[1] ..... If a column is given, specifically check if the given column has been modified: a.modified?

Proposal for a better Ruby Hash#include? - Olivier Lacan
May 1, 2014 - it "sets the anonymous key to true" do expect(properties).to include { a: true } end ... You want to check whether y is included within x or not. ... when someone wants to show the object-oriented power of the language. ... me at Code School and also often has the need to check whether a Hash is partially or ...

How to check if the object/element exist in JavaScript and jQuery ...
Agile senior Ruby/Rails/JS software developer. Home Page ... How to check if element in DOM exists, i.e. if the selector $(‚.some_class') is not empty? The simplest: ... How to check if JavaScript object's property exists? This is tricky, as there ...

Using method_missing and respond_to? to create dynamic methods ...
method_missing is a well-known tool in the Ruby metaprogramming toolbox. ... For example, if your User has an email attribute, you can ... is often forgotten though. respond_to? is used to determine if an object responds to a method. It is often ...

`have_attributes` matcher - Built in matchers - RSpec Expectations ...
Use the have_attributes matcher to specify that an object's attributes match the ... The matcher will fail if actual doesn't respond to any of the expected attributes:

Ruby Equality And Object Comparison - Skorks
Sep 16, 2009 - Ruby has three main equality test methods, ==, eql? and equal? ... Inside the Object class all there methods do exactly the same thing, they test if two ..... object and if you look up the database id property on the two objects, ...

Check if a variable is undefined or null - CodeCodex
Aug 22, 2012 - Implementations[edit]. The following code examples show how to determine if a variable or object is null. FreeMarker[edit]. <#if variable_to_test ...

Classes, Objects, and Variables @ Programming Ruby - Phrogz.net
We're going to be looking at how you create classes and objects in Ruby, and at some of the ... The answer has to do with inheritance, subclassing, and how Ruby determines what ... To test out our class, though, we'll just use a string. .... In Ruby, the attributes of an object can be accessed as if they were any other variable.

Module: Mongoid::Attributes — Documentation for ... - RubyDoc.info
#assign_attributes(attrs = nil) ⇒ Object ... Determine if the attribute is missing from the document, due to loading it from the ... Determine if an attribute is present.

Check for nil and initialize on a single line | Ruby Fleebie
Check for nil and initialize on a single line ... Sometimes, you want to initialize a variable to some value only if that variable is ... 1. x = get_some_object if x.nil?

how to find if a key name exists in a JSON object - Experts Exchange
Jun 27, 2014 - Hi, I have this JSON object: var jTest = { couponCodeOne : , couponCodeTwo-3 : }; I'm trying to find if ... I was using qUnit to test it. ... how to find if a key name exists in a JSON object ... if(jTest.hasOwnProperty('couponCodeOne')){ // has property } .... Our community has technology experts around the world.

Validating Presence of Associations and Foreign Keys in Rails ...
Dec 31, 2013 - ... or it may be that only a “new” (i.e. not persisted) object has been created. ... of the User association: first by checking the presence of the object if the foreign key ... record.send("#{attribute}_id".to_sym).blank? record.errors[attribute] ... be a little tricky if you're not too familiar with metaprogramming in Ruby, ...

$exists — MongoDB Manual 3.2
If <boolean> is false, the query returns only the documents that do not contain the field. MongoDB $exists does not correspond to SQL operator exists. For SQL ...

Instance Variables In Ruby - Zach Dennis
Instance Variables In Ruby 23 Jun 2007 Instance variables are the heart of an object's ... can be used to determine whether an instance variable has been defined ... You can break object encapsulation in ruby pretty easily due to it's dynamic and ... end class Person include ActAsNamedParameters def initialize(attributes) ...

How to track changes of a model in a `after_callbacks ... - Ruby Journal
Sep 23, 2013 - By using ActiveRecord::Dirty, we could tell if the model or attribute name ... us previous_changes method which entails what changes has made previously. ... We uses after_update callback to check if any changes previously ...

Rhomobile | Rhom Ruby API
Records 21 - 40 - Returns true if a Rhodes model object has local database changes that ... Determine if a rhom model has local database changes that need to be synchronized. ... Deletes all records from the property bag and model tables.

#HAML: Checking variables in partials · GitHub
Check if a local variable has been passed at the partial call ... Setting nil as false param in a ternary operator causes the property (class in the example) to be ...

Understanding "Prototypes" in JavaScript - Yehuda Katz
Aug 12, 2011 - In JavaScript, objects are pairs of keys and values (in Ruby, this structure is called a Hash; ... Obviously, a property has a name and a value. .... on Object.prototype to check whether a property was defined on the object itself.

Determining if a javascript object is empty? - Web Developer
var someObj = {} Is there something I use to determine that someObj is empty? It's still a typeof object but has no attributes.

Go's reflection example - Merbist
Jun 27, 2011 - It also has some features that Rubyists, Pythonistas and ... Ruby works slightly differently in the sense that defining attribute ... Another way of checking on the accessors is to check the methods defined on the object: ... TypeOf(m) // if a pointer to a struct is passed, get the type of the dereferenced object if typ.

ruby element | ruby object - Windows app development
Members. The ruby object has these types of members: ... pointerType property to determine the type of contact that the click originated from (touch, mouse, or pen). abort ... Checks whether the given element is contained within the object.

14.1. How to Identify and Access Objects
If the object has an object name, using just the type and name properties is sufficient ... to an object we can access its properties, for example, to check them against ... Ruby payButtonName = "{type='QPushButton' text='Pay' unnamed='1'" + ...

How Ruby method dispatch works – The If Works

https://blog.jcoglan.com/2013/05/08/how-ruby-method-dispatch-works/
May 8, 2013 - I'm going to explain how Ruby's object system works, including method .... When you see D(A)#foo , it means D has inherited the #foo method from A .... Now we come to the second special property of classes, beyond their ability to create objects. .... The ancestry of Test goes [Test, Y, X] , so clearly if we call ...

Mutable and Immutable Objects: Ruby Study Notes - Best Ruby Guide ...

rubylearning.com/satishtalim/mutable_and_immutable_objects.html
If part of an object's state is stored in an immutable object, then accessor methods ... In Ruby, Mutability is a property of an instance, not of an entire class. ... Note: Whenever an object in Ruby has no reference to it, then that object is marked for ...

Class and Instance Variables In Ruby // RailsTips by John Nunemaker

www.railstips.org/blog/archives/.../class-and-instance-variables-in-ruby/
Nov 18, 2006 - Ruby is the first language I have learned that has involved more than just picking up a new ... Objects can have class and instance variables.

Test for Empty Values in Javascript - SitePoint

https://www.sitepoint.com/testing-for-empty-values/
Nov 3, 2012 - HTML & CSS · JavaScript · PHP · Ruby · Mobile · Design & UX · Entrepreneur · Web ... For example, if you query a web storage object using object syntax, a value that isn't ... The third condition in empty() handles anything with a length property. This will detect empty strings and arrays with no members.

Type introspection - Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Type_introspection
Wikipedia
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In computing, type introspection is the ability of a program to examine the type or properties of an object at runtime. ... In Ruby, the Object class (ancestor of every class) provides .... Type introspection has been a part of Object Pascal since the original ... The language includes an is operator, to determine if an object is or ...

Getting the class name from an object instance - Scribu

scribu.net/blog/object-introspection.html
Jul 15, 2013 - In Ruby, every object responds to a class message, which returns an ... In Python, every object has a __class__ property, which contains a type ...

Retrieve a customer - Stripe

https://stripe.com/docs/api?lang=ruby
Stripe
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To make the API as explorable as possible, accounts have test mode and live mode API keys. There is ... The Ruby library will then automatically send this key in each request. All API .... Many objects contain the ID of a related object in their response properties. ...... Details about the dispute if the charge has been disputed.

Checking for the css class of the found element in capybara – Code ...

https://sideshowcoder.com/.../checking-for-the-css-class-of-the-found-ele...
Jan 22, 2013 - and trying to check if the class is set to “.some-class”. page.find("#some-id").has_css? ... it still easy to check it by accessing the attributes hash.

JSON Validation with JSON Schema - David Walsh Blog

https://davidwalsh.name/json-validation
Nov 23, 2010 - Properties within the schema are defined and with another object containing their expected type. ... The object has a users property; The users property is an array; The users array ... If the result fails validation, valid will be false and the errors property will .... The car.json test (JSONSchemaTest) fails.

Different Ways to Set Attributes in ActiveRecord (Rails 4)

www.davidverhasselt.com/set-attributes-in-activerecord/
Jan 29, 2014 - Ruby On Rails. Rails 4 allows the ... This article has been updated for Rails 4. Check out the old Rails 3 version if you're using that version. ... In Depth. For the following examples we'll set the name attribute on the user object.

Ruby on Enums, Queries and Rails 4.1 - HackHands

https://hackhands.com/ruby-on-enums-queries-and-rails-4-1/
Oct 21, 2014 - Rails is actually not able to detect that the ? is for status and that it is an enum. ... attribute on an ActiveRecord instance (say a Conversation object), .... I hope this article has convinced you that it's worth understanding Ruby as ...

A Beginner's Guide To Ruby - HackHands

https://hackhands.com/beginners-guide-ruby/
Nov 21, 2014 - If you tried to do capitalize on an object that is not a string, Ruby ... When we check the class of num1 , by calling the .class method, ... num1 is an object (a local variable) that has inherited the properties of the class String .

11 Steps To Make Your RSpec Specs Awesome – Web Development ...

https://railsadventures.wordpress.com/.../11-steps-to-make-your-rspec-sp...
Sep 25, 2013 - There are many blog posts about refactoring your ruby code to ... test code with as much care as we treat our actual ruby code, if not even more. .... RSpec has many syntactic sugars that makes your specs more readable .... Rule #11: Use RSpec's expect {} block to describe a change in the state of an object.

RubyMonk - Ruby Primer: Ascent - Instance Variables and Accessors
Every instance of a class has a different set of instance variables. ... This is enforced by Ruby - if your variable does not start with a @ , it is considered ... But the fact that we store the color as a separate attribute inside our object should .... However, I recommend you check out this article by Allen Holub that talks about object ...

2.5 Object-Oriented Programming - Composing Programs
A class definition specifies the attributes and methods shared among objects of that class. .... We can also test whether an object has a named attribute with hasattr. ..... In others such as Python, Ruby, and Go, any object with the appropriate ...

House 9: valid? vs errors.any? in rails
Aug 18, 2010 - The blog has moved to http://jessehouse.com/ . ... Recently got bit by checking valid? in some rails code, thought I would share. ... to the errors collection of an ActiveRecord object and then calling valid? to see if the object ... it would check the current state of my objects attributes and 're-validate' the object.

Ruby for Newbies: Testing with Rspec - Code - Tuts+
Aug 10, 2011 - Re-run the test ( rspec spec ), and you'll find it's passing fine. We don't have an initialize method, so calling Ruby#new has no effect right now. ... or the method eql both return true if the two objects have the same content. .... However, it shows that we need to have a books property that is an array of the ...

Chapter 6: Modeling users | Ruby on Rails Tutorial (Rails 5 ...
Moreover, Rails has a feature called migrations to allow data definitions to be written ... property of persistence: when we created a User object at the Rails console, .... (If you're using the cloud IDE, you should first download the database file to the ..... Listing 6.4: The practically blank default User test. test/models/user_test.rb.

Javascript/InDesign: Check if Object has certain property - EBanshi
Is there an event checking if the 'innerText' property of HtmlElement has changed? I'm running c#'s ... How do I detect if a object has a certain property or not? I am trying to find a .... I am writing some tests for a ruby gem... How do I check to see ...

amd-utils / object : AMD-Utils
Tests whether all properties in the object pass the test implemented by the .... Returns a boolean indicating whether the object has the specified property.

#109 Tracking Attribute Changes - RailsCasts
May 21, 2008 - /Library/Ruby/Gems/1.8/gems/activerecord-2.0.2/lib/active_record/base.rb: ... To do this, add a condition to see if the attribute has changed before running the validation. ... If the attribute is left blank, it wont check be changed. ... a serialized attribute called "email" that stores a TMail object, and you try this:.

FactoryGirl Tips and Tricks by Arjan van der Gaag
Written on 20 jun 2012 and tagged code, ruby, testing .... This could come in handy when, for example, your Post object has a author attribute that actually refers to an .... If your test value is random or outside your control, how can you prove ...

The 10 Most Common Mistakes That Rails Developers Make | Toptal
There are many Ruby on Rails best practices that can help you avoid these ... Logic for finding the right model object given the parameters passed in from ..... But what happens if your external service has an outage or starts running very slowly? ... A common Rails mistake is to check a new migration into your source repo ...

Callbacks and Dirty Objects in Rails - Crafting Ruby
Jan 13, 2014 - We have to store the previous value of the comment in the previous_content attribute if the comment has been edited. Luckily Rails makes this ...

lodash documentation
... groups the length of size . If array can't be split evenly, the final chunk will be the remaining elements. .... The `_.property` iteratee shorthand. _. ...... Returns. (boolean): Returns true if any element passes the predicate check, else false . ...... is object-like. A value is object-like if it's not null and has a typeof result of "object".

Underscore.js
The iteratee is bound to the context object, if one is passed. .... Returns the values in list without the elements that the truth test (predicate) passes. ... If iteratee is a string instead of a function, groups by the property named by iteratee on ..... Defers invoking the function until the current call stack has cleared, similar to using ...

How To Efficiently Search A JSON Array · MattSnider.com
Aug 23, 2008 - Lets consider the following JSON Array for a list of tag objects: ... The more efficient way to test if a value exists inside of one of the contained objects, is to ... The hasTag method in Example 4 has a negligible performance hit, ...

Accessors Are Evil
If that is what you need, why don't you skip the accessors altogether? ... tests) about who uses the accessor, and then determine whether this is a good use. .... an object's attributes (RubyLanguage only has one, I'd be curious if there are more ...

Adding Type Checking to Ruby - Code Commit
Feb 6, 2008 - Ruby has some excellent unit test frameworks (such as RSpec) ... Types can check not only the kind of the object but also to what methods it responds. .... Statically checking for types which satisfy certain properties is really quite useful. ... There are a jillion languages that support type-checking, and if I ...

Australian Ruby on Rails developers blog: ES6 classes and ...
Feb 10, 2015 - Every object in JavaScript has a special related object called the prototype. ... It will walk along the chain until it finds the attribute or return undefined if it can't be found. If you'd .... Let's double check by modifying this prototype:

Overview about nil?, blank?, present?, presence, try and other basic ...
Mar 13, 2014 - This is a post about basic things and if you are an experienced user you might ... but in Ruby it's much nicer! var = foo || "bar" would result in var being foo if it is ... A string attribute in ActiveRecord only returns either nil or the string. ... With Rails 4 try also won't call the method if the object is truthy but doesn't ...

Braintree::Transaction | Ruby - Braintree Developer Documentation
Ruby SDK ... Attributes. add_ons. Array of Braintree::AddOn objects. The collection of add-ons ... This field is populated if there was an error when checking AVS or the ..... open - Dispute has been opened by the customer and funds have been ...

Entity - SketchUp Ruby API
Therefore an Edge has all of the methods defined in Drawingelement and Entity. The Object.is_a? method is the common way of determining what sort of Entity ... The attribute_dictionary method is used to retrieve an attribute dictionary with a given ... The deleted? method is used to determine if your entity is still valid (not ...

NodeJS: Detect if an Object is empty or not - JavaScript - Snipplr ...
Dec 8, 2013 - NodeJS: Detect if an Object is empty or not ... exports.test = function(req, res){ ... Assume if it has a length property with a non-zero value.

XML.com: REXML: Processing XML in Ruby
Nov 9, 2005 - REXML (Ruby Electric XML) is the XML processor of choice for Ruby programmers. ... If the Document constructor takes a Document as its argument, all its Element .... Each Element object has an Attributes object named attributes which acts .... irb(main):043:0> doc3.root.text = "test the &entity;" => "test the ...

Ruby C Extension API Documentation (Ruby 1.8) - eqqon
Jul 10, 2009 - You can determine whether a VALUE is pointer or not by checking its LSB. ..... If object has references to other Ruby objects, they should be marked by ... object, VALUE module) Extend the object with the module's attributes.

Skilldrick » Understanding typeof, instanceof and constructor in ...
Sep 18, 2011 - Again, Angus Croll has written more on this subject than I have space for here. ... constructor is a property available on all objects' prototypes, and it is a reference to ... be useful for checking if an object member or a function argument is a function. ... I love all things dynamic, especially JavaScript and Ruby.

Chef Style Guide — Chef Docs
For example, it's useful to know how to check the syntax of a Ruby file, such as the contents .... compiles source files into object files), light (links and binds object files to an installer ... For example, using an if statement with the platform node attribute: ... Because Chef has the file resource, use File to use the Ruby File class.

Death to Javascript! Or, Writing Javascript with Ruby
Jan 18, 2016 - If a Javascript object looks just like a Ruby hash, and can even be defined or ... We've use it to declare an object with two properties, title and author . ..... we check to see if the method being called on the hash has the same ...

Perl hash key - How to test to see if a Perl hash contains a given key ...
Jun 3, 2016 - Perl hash key FAQ: How do I test to see if a Perl hash containts a given key? You can use the Perl exists function to see if a key can be found in ...

Ruby on Windows: Automating Outlook with Ruby: Saving File ...
Dec 6, 2007 - The Attachment object has few properties and methods, but one you will ... the file, then check the saved file's size and delete it if necessary.

Undefined values - Rosetta Code
Jan 4, 2016 - ActionScript also has a null value: see Null object#ActionScript. Ada[edit]. Works with: GNAT. Ada language provides attribute 'Valid used to check if a scalar value is ...... I don't know any way of undefining a variable in Ruby

Ryan's Scraps: What's New in Edge Rails: Dirty Objects
Mar 31, 2008 - tags: ruby, rubyonrails ... You're asking the parent object if attribute x has changed, not asking the attribute itself if it's changed, so your suggested syntax .... Mode-3 Inconsistent dirty check with flags – as implemented today.

Validating JSON Schemas with an RSpec Matcher - Thoughtbot
Sep 23, 2014 - If you've worked on a test-driven JSON API written in Ruby before, you've ... While this approach has the benefit of ensuring the response object includes the expected values for the specified properties, it is also verbose and ...

Assignments - The Ruby Programming Language [Book]
Variables, constants, attributes, and array elements are lvalues in Ruby. .... Typically, it will check that the value is of the desired type and within the desired ... If an object has a []= method that expects three arguments, then it can be indexed ...

Bounded Verification of Ruby on Rails Data Models - UCSB Computer ...
tion techniques to check if these properties hold on all the instances of the given .... whether the as- sociated object(s) itself has associations with the :dependent.

Rails: Prevent the destruction of Child object when Parent requires its ...
Apr 26, 2014 - Rails: Prevent the destruction of Child object when Parent requires its presence ... The unless option tells the app to skip the presence validation if the other .... For more details, read the documentation for Active Record Nested Attributes. ... I tried modifying the before_destroy callback to check if the Location ...

PutItem - Amazon DynamoDB - AWS Documentation
If an item that has the same primary key as the new item already exists in the specified ... key doesn't exist), or replace an existing item if it has certain attribute values. ... Each element in the Item map is an AttributeValue object. .... If Exists is true , DynamoDB will check to see if that attribute value already exists in the table.

javascript – check if object has child property | Brooklyn Q&A
May 20, 2016 - Assuming an object like this var a = { b: { c: } }; I want to check if e is valid. Currently I am using multiple if conditions like if.

Types — Julia Language 0.4.7-pre documentation
Julia also has a predefined abstract “bottom” type, at the nadir of the type graph, which is written as Union{} . .... as Python and Ruby, all values are objects whether they are composites or not. .... Because of these shared properties, these types are internally represented as ...... Check if a Nullable object has a missing value.

Enumerated Types in ActiveRecord - Foraker Labs
Sep 20, 2014 - the struct has an integer member to store the vector magnitude ... Any object is replacable by any other object, provided that the replacing object ... Enumerated types could be considered inconsistent with Ruby's design philosophy. .... EnumeratedType classes are enumerable, so we can use 'detect'. detect ...

Python Generated Code | Protocol Buffers | Google Developers
Ruby Reference .... Since version 2 of Python Protocol Buffers has a completely different ... You can also call the Is() method to check if the Any message represents the .... Repeated fields are represented as an object that acts like a Python ...

How I learned to test my Rails applications, Part 4: Controller specs ...
Apr 7, 2012 - If you're new to RSpec or Rails testing in general, I recommend reading ... which generates a hash of values as opposed to a Ruby object. .... Then we need to test that those things don't happen if invalid attributes are passed .... Your approach has been great and has been just what I've been looking for.

How to Use JSON files in Node.js | Codementor
May 20, 2015 - Node.js has emerged as a leading platform for creating fully ... JSON can either be represented as a hash of properties and values(for e.g. an Object) or as a list of .... If you're required to check whether the JSON object has a specific key or ... Learn Ruby on Rails Learn AngularJS Learn React Learn Python ...

Metaprogramming in ES6: Symbols and why they're awesome
Jun 18, 2015 - Take for example Ruby, in Ruby you can specify operators as methods ... Symbols can be assigned as keys to Objects (kind of like String keys), ..... As of ES6 the way Array#concat will determine if any of its ..... Any Object passed to Object#toString() will be checked to see if it has a property of [Symbol.

Truthy & Falsey – James Padolsey
Oct 19, 2011 - The easiest way to determine if something is truthy is to determine that it's not falsey. ... el is not a boolean, it's just an object (in this case, a DOM Element object). ... If element has a property addEventListener and its value is something truthy, .... In Ruby I want to create an object which is falsey, but I can't.

A Rule of Thumb for Strong Parameters - Pat Shaughnessy
Jun 16, 2014 - To whitelist an array of nested objects, you pass it a hash, including that ... Let's suppose a post has many comments, and each comment has a single text attribute. ... If you happened to know that Rails 4 saves the parameters inside an .... something that complicated in the strong parameters permit check.

Using select, reject, collect, inject and detect. - matthewcarriere.com
Jun 23, 2008 - So if this is you, then stop. Ruby has plenty more iterators where each came from. Which one you should be using depends on what operation ...

How to determine if an ActiveRecord object attribute ... - Simply Binary
Sep 12, 2012 - How to determine if an ActiveRecord object attribute was previously dirty If you ... If you ever wish to track changes in a ruby object it is extremely simple to do ... This is very useful within a transaction but what if the change has ...

How to Test Rails Models with RSpec - Semaphore
Apr 28, 2016 - Ruby Subscribe to new Ruby tutorials. 1. Brought to you by ... Models can sometimes be full-blown objects with rich behaviour. ... to the model, our model object will be valid without specifying any attributes. ..... After adding a new Bid to the Auction , we need to check if the bid is bigger than the previous one.

GeoJSON Specification
Jun 16, 2008 - A GeoJSON object may represent a geometry, a feature, or a collection of features. ... a geometry object and additional properties, and a feature collection .... If an object has no crs member, then its parent or grandparent ...