Ruby

In many cases, when you design your application, you may want to implement a method that is used only for internal use by one object and not for other objects. Ruby provides three keywords to restrict access to methods. Private: A method that can

Rexml is a processor written entirely in Ruby, with a variety of APIs, two classic APIs that are distinguished by dom-like and sax-like. The first is to read the entire file into memory and then store it as a layered form (that is, a tree). The

Introduced This is a short introduction to Ruby and it takes only 20 minutes to complete the reading. This assumes that the reader has already installed Ruby, and if you are not installing it, please visit the official Ruby website for download and

Global variables begin with $. They can be accessed anywhere in the program. The global variable has a special value nil before initialization. ruby> $foo nil ruby> $foo = 5 5 ruby> $foo 5 Global variables should be used with caution. They are

1 RSS Standard Library RSS is xml-based, so you can simply parse it as an XML. But, in fact, he has a higher level of proprietary parsers to parse him out. The standard of RSS is also very confusing. He has a lot of inconvenience, is the standard

1 detect whether the file exists and its size Filetest's exist? Method can detect whether a file exists: Flag = filetest::exist? ("Lochnessmonster") Flag = filetest::exists? ("UFO") # exists? is a synonym for exist? If we want to know if the

Ruby handles strings like numbers. We enclose them in single quotes (' ... ') or double quotes ("..."). Ruby> "abc" "abc" ruby> ' abc ' "abc" Single and double quotes have different effects in some cases. A string enclosed in double quotes

A local variable starts with a lowercase letter or an underscore (_). Local variables do not contain nil values like global and real variables before initialization. ruby> $foo Nil ruby> @foo nil ruby> foo ERR: (eval): 1:undefined local variable

Ruby Regular Expression Three methods of representation: Regexp.new (' ^s*[a-z] ') /^s*[a-z]/ %r ... {^s*[a-z]} Test code: Def show_reqexp (A, re) if a =~ re "#{$ '} > #{$ '} ' else ' no match "End end puts Show_reqexp" ("Fats Waller",/ll/)　　　　

Standard type for Ruby: A. Number Class Test 3.times {print "X"} 1.upto (5) {|i| Print I, ""} 99.downto {|i| Print I, ""} 50.step (80,5) {|i| Print I, "" "" "" a = "" B = " puts" " puts A + b puts integer (a) + integer (b) end　　　　　　 Output:

1. Read-write properties of member variables: Attr_reader and Attr_writer class Test Def initialize (name) @name = name end attr_reader:name attr_writer:name end test = Test.new ("AAA") puts test.name test.name = "BBB" puts Test.name　　　　　　 If

How is polymorphism defined in Java? I understand this: Polymorphism needs to be implemented by means of interfaces, that is, all classes that implement this particular interface are like him. What is duck type? This is defined in programming

We often deal with code like this: Name=person?person.name:nil Take a property of an object, first determine whether the object is nil, not nil return the object property, otherwise return nil. This kind of code is more disgusting, is there a more

To prove that Ruby really works, Hello World can write so succinctly: Copy Code code as follows: Puts ' Hello World ' 1. Input/output Copy Code code as follows: Print (' Enter your name ') Name=gets () Puts

Ruby, which absorbs Perl's regular expressions and Python's readability, is a very human and flexible way to count values, which can be illustrated here:First , print 7 times "Hello,world", as follows: Copy Code code as follows:

Recently because to do a class, so yesterday installed a Windows, feel free to do nothing, want to install a Ruby play. Official Rubygems source Because some resources are placed on the Amazon S3, so sometimes the ventilation, in Linux I use

Notes: Ruby returns the last value in the method by default.If you need to return more than one value, you can use an array to implement it.A value can be returned by forcing a declaration of return.The basis of the output method is to use puts

(i) Conditional judgmentthe condition is judged as the basic type: Copy Code code as follows: If expression Code End If the expression is not false or nil, then the Code section can be executed, so if it is false or nil for

In an MVC based Web application, the application logic and the access to the data are accomplished by C, the controller, in MVC. Therefore, a deep understanding of the controller provided by the MVC framework is essential for developing an efficient,

This article discusses one of the basic services provided in ROR: Action view. Action views enable you to present data more quickly to the user. The services for some action views are described in this article, and an example is given to illustrate