/Users/lechucico/.rbenv/versions/2.4.0/lib/ruby/2.4.0/x86_64-darwin16/openssl.bundle: warning: already initialized constant OpenSSL::X509::V_FLAG_CRL_CHECK /Users/lechucico/.rbenv/versions/2.4.0/lib/ruby/2.4.0/x86_64-darwin16/openssl.bundle: warning: already initialized constant OpenSSL::...
Safe navigation operator: # badfoo&.barfoo&.barfoo&.bar# goodfoo&.bar Safe navigation Avoid long chains of&.. The longer the chain is, the harder it becomes to track what on it could be returning anil. Replace with.and an explicit check. E.g. if users are guaranteed to have an ad...
Operator Overloading Exception Handling Iterators and Closures Garbage Collection Dynamic Loading of Object Files (on some architectures) Highly Portable (works on many Unix-like/POSIX compatible platforms as well as Windows, macOS, etc.) cf. https://docs.ruby-lang.org/en/master/maintainers_md....
Good idea is to use Null Object Pattern instead. class Toptaller attr_reader :name def self.find(id) return nil if id == '' new(id) end def initialize(name) @name = name end def self.get_toptaller(name) case name when nil NilToptaller.new else Toptaller.find(name) end end end...
def change add_check_constraint :users, "char_length(name) >= 1", name: "name_check", validate: false validate_check_constraint :users, name: "name_check" end end Note: If you forget disable_ddl_transaction!, the migration will fail. Setting NOT NULL on an existing column ❌ Bad Se...
To update an element in the array, assign a new value to the element’s index by using the assignment operator, just like you would with a regular variable. Given a new array of sharks, with "Hammerhead" at index 0, you’ll replace "Hammerhead" with "Angel": sharks = ["Hammerhead",...
Active Support 作为 Ruby on Rails 的一个组件,可以用来添加 Ruby 语言扩展、工具集以及其他这类事物。 它从语言的层面上进行了强化,既可起效于一般 Rails 程序开发,又能增强 Ruby on Rails 框架自身。 读完本文,你将学到: 核心扩展是什么。 如何加载全部扩展。
Safe Navigation Operator (&.) 1 user&.profile&.name # Avoids NoMethodError if user or profile is nil Symbol vs. String 1 2 :my_symbol # Immutable, faster lookup "my_string" # Mutable, slower lookup &:Shortcut for Blocks Ruby allows a shorthand syntax for passing methods as blocks using...
{if(format ==null)returnToString();stringformatUpper =format.ToUpper();switch(formatUpper) {case"N":return"||"+ Norm().ToString() +"||";case"VE":returnString.Format("( {0:E}, {1:E}, {2:E} )", x, y, z);case"IJK": ...
(:/)#=> true# Special values are objectsnil# equivalent to null in other languagestrue# truthfalse# falsehoodnil.class#=> NilClasstrue.class#=> TrueClassfalse.class#=> FalseClass# Equality1==1#=> true2==1#=> false# Inequality1!=1#=> false2!=1#=> true# Apart from false itself,...