book of ruby

Example parsing for Hook methods in Ruby and ruby hook instance Parsing By using the Hook method, we can intervene in the life cycle of Ruby classes or modules, greatly improving programming flexibility.The following hook methods related to lifecycle are available: Classes and modules Class # inherited Module # include Module # prepended Module # extend_

Let's get back to our jukebox for a moment (remember the jukebox ?). At some point We'll be working on the code that handles the user interface-the buttons that people Press to select songs and control the jukebox. We'll need to associate actions Those buttons: press START and the music starts. It turns out that Ruby's blocks are A convenient way to do this. Let's start by assuming that the people who made Hardware implemented a Ruby extension that gi

1. Debug comment Print output debugRuby is an interpreted language, a script, and on Linux, scripts cannot be executed in three ways:1. Run the script with the interpreterInterpreter script FileThat is:Ruby script File2. Run the script directlyIn the script file, use the#! Script InterpreterDefine the script interpreter path, then grant the script execute permission, then run directly./script FileCan.3. Run the script inside the interpreter[Email protected]:/home/ywt/ror_tests/ruby_tests# irb

The example explains the Hook method in Ruby and adds a hook to the method call. The example explains ruby. The Hook method is similar to the event-driven device. You can execute a specific callback function after a specific event occurs. This callback function is the hook method (more vividly described: The Hook method can be like a hook, hook up a specific event .), In Rails, The before \ after function i

Detailed description of the code block and parameter transfer in Ruby, detailed description of ruby code transfer 1. Block DeclarationAfter the function is called, the block declaration is enclosed by {...}, Or do. end encapsulation. {} Is generally used in single-line statements, and do... end is used in multi-line statements. (1 .. 4). each {| v | print "# {v}"} # output 1 2 3 4 Blocks can contain paramet

The example parses the value types and constants in Ruby AND the ruby numerical constants. Number)Integer)There are two types of integer types. If the value is within 31 characters (four bytes), it is a Fixnum instance. If the value is exceeded, it is a Bignum instance.The integer ranges from-230 to 230-1 or-262 to 262-1. Integers in this range are Fixnum-like objects, and integers out of this range are sto

Ruby class inheritance, abstract classes, class expansion, proxy class instances, ruby instances Summarize the class extensions encountered in the work: 1. class inheritance: When multiple classes share many methods, you can extract the public methods and inherit the required classes. Example: Copy codeThe Code is as follows:Class A DefP "it was"EndEnd Class B End Class C End B. new. a # => "it was"C. new.

Ruby implements batch code sharing by adding prefixes to files, and ruby Prefix code sharing From the perspective of the designer, we get a large number of images, and the results are all file names such as 1.png and 2.png. We also need to convert these files into readable file names and do not want to modify them one by one, so we wrote a simple script, you can add prefixes to multiple files in batches. Yo

Statistics on the number of file lines, number of words, and number of characters in Ruby, and number of ruby lines In Ruby, we define a wc method to count the number of lines, words, and characters in the file. The ruby code program is as follows:Copy codeThe Code is as follows:Def wc (filename)Nline = nword = nchar

Tutorial on creating and using hash in Ruby and ruby hash Hash is a set of key-value pairs similar to "employee" => "salary. Hash indexes are completed by any key of any object type, rather than an integer index. Others are similar to arrays. The hash traversal order by key or value seems random, and is generally not in the insertion order. If you try to access the hash using a key that does not exist, the

An example is provided to explain the regular expressions in Ruby and the regular expressions in ruby. A regular expression is a special character sequence that can help match or find other strings or strings. The pattern used maintains a special syntax. The regular expression text is a slash between a pattern or any separator % r is as follows:Syntax: Copy codeThe Code is as follows:/pattern//Pattern/im #

Ruby meta-programming summary, ruby Summary When I was asked such questions today, I used to think that this is a broad concept. Even if I have used these features, but I still don't know this is called "metaprogramming" until today when I was asked, I just had an epiphany, and then I made a small summary on the Internet with some of my actual metaprogramming. The so-called meta-programming in

For Ruby introduction, see: http://www.ruby-lang.org/zh_CN/about/ I. IRB Interactive Ruby help and consoleProgramIn Windows. You can directly execute Ruby in IRB.Code. For example: Code highlighting produced by Actipro CodeHighlighter (freeware)http://www.CodeHighlighter.com/--> IRB (main ): 001 : 0 > " Hello World " => " Hello W

Enter the command line in ruby to compile sass (ruby) and rubysass Ruby(Or cmd) Enter the command line to compile sass as follows: (1) For example: first, create a total folder under drive F, such as the test folder, and then create folders such as html, images, js, and sass under the folder. (2) Create the sass file to be used in the sass folder. For example, co

I have always been very interested in Ruby on Rails. I want to see something that has been praised by many people, but I have been working on windows development, it is still a headache to build the development environment of Ruby on Rails, Which is why Ruby on rails has not been studied. I just saw InstantRails In javaeye, an All-In-One suite, which can help you

Ruby implements the insertion Sorting Algorithm and the advanced two-way insertion sorting code example, ruby two-way BasicInsert a record to a sorted table to obtain an ordered table with one added record. In addition, the most critical point is that it moves all records larger than the current element to leave the insert position "self. After n-1 troughs are inserted, the record is an ordered sequence. De

Read Ruby metaprogramming and ruby metaprogrammingUsing many spells and Ruby's programming skills to implement many clever programming:Array parametersSurrounding aliasWhiteboardClass ExtensionClass ExtensionClass instance variablesClass macrosClean RoomCode ProcessorContext probesDelayed executionDynamic DistributionDynamic MethodDynamic proxyFlat ScopeGhost MethodHook methodKernel MethodInertia instance v

Import Java.io.BufferedReader;Import Java.io.InputStreamReader;public class Cmd_ruby {private static string Execmd (String commandstr) {BufferedReader br = null;try {Process p = runtime.getruntime (). exec (COMMANDSTR);br = new BufferedReader (New InputStreamReader (P.getinputstream ()));String line = null;StringBuilder sb = new StringBuilder ();while (line = Br.readline ()) = null) {Sb.append (line + "\ n");}System.out.println (Sb.tostring ());return sb.tostring ();} catch (Exception e) {E.prin

1. Invocation of the method2. Custom method3. Custom methods with default values4. Custom method with return valueA method, or a function, actually contains a piece of code to perform a particular process.def Add (a=3,b=2) return A +bend' /study/ruby/intro_rails/maizi/381-4026/08function.rb '= = TRUEIRB (main):003:0> Add= 5irb (main):004:0> add 4=> 6IRB (main):005:0> Add 4,5=> 9IRB (main):"Ruby on Rails

Ruby-implemented image filter algorithm code, ruby-implemented Filter Algorithm Source image I. grayscale Algorithms The color values of each pixel in a color photo are composed of three values: Red, green, and blue. The values of red, green, and blue are different. Therefore, the color values of pixels can also contain many color values, this is the principle of a color image, while a gray-scale image has