eloquent ruby

Methods (functions) in Ruby, ruby Functions 1. The method name and variable name naming rules in Ruby are the same (Start with a lower-case letter, and separate words with "_",), but you can add it behind the method name! (Major method) or? (Boolean return value ). 2. Use () for method parameters (),All parameters are local variables. You can set the default valu

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

Ruby image installation, ruby Image Because of the domestic network, the intermittent connection of resource files stored on Amazon S3 by rubygems.org fails. So you willgem install rackOrbundle installHalf a day without response.gem install rails -VTo view the execution process.This is a complete rubygems.org image. You can use this image to replace the official version. The synchronization frequency is cu

The example explains how Ruby uses the decorator mode in the design mode, and the ruby design mode. OverviewIf you are engaged in object-oriented development, adding behavior to a class or object and using inheritance mechanisms, this is a basic feature of all object-oriented languages. If an existing class lacks some methods, or you need to add more functions (CHARM) to the method ), you may just inherit t

Solve ruby Installation Problems: redis requires Ruby version amp, rubyredis I. Problem Description Today, we set up a redis cluster and encountered a problem when installing ruby and redis interface programs: redis requires Ruby version> = 2.2.2., as shown below: [root@localhost ~]# gem install redis-4.0.0.gem ERROR

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

Ruby metaprogramming and ruby Programming An object model Kernel Module Kernel. private_instance_methods.grep (/^ pr /) Private method 1. If a method receiver is not yourself, you must specify a receiver. 2. A private method can only specify one implicit receiver (a private method that can be called as a superclass) The Class itself is the object of the Class. The class name is a constant. Class

Ruby Study Notes 1: Ruby Study Notes Notes: Ruby returns the last value in the method by default.To return multiple values, you can use an array.You can return a value by forcibly declaring return.The basic output method is to use puts (output line) and print (print directly ).The Basic Input Method is gets (read a row that contains '\ n' at the end of the row, w

Multiple ruby traversal folder code instances collected, ruby instances 1. traverse all files in the folder and output file names Copy codeThe Code is as follows:Def traverse_dir (file_path)If File. directory? File_pathDir. foreach (file_path) do | file |If file! = "." And file! = ".."Traverse_dir (file_path + "/" + file)EndEndElsePuts "File :#{ File. basename (file_path)}, Size: # {File. size (file_path )}

Ruby implements the active mail push trigger program, and ruby implements mail triggering After receiving the email, the mail server pushes the notification program. Is there any way to achieve this? 1. Client polling2. The server actively pushes data. First, familiarize yourself with the protocol for sending and receiving emails:Net: SMTP (send mail)Net: POP3 (receive mail)Net: IMAP (receive mail) There ar

Ruby uses the simple factory mode and factory method mode in the design mode, and the ruby Design Mode I have read the ruby design pattern before, But I gradually forget it. Now I bought a big talk design pattern, which doesn't look so boring. By the way, I implemented the code in ruby. Simple factory mode: #-*-Encodin

It's pretty rare I recommend new blogs to follow on Ruby inside. Not because I don't like them-I link to their posts all the time!-But because it's hard to tell if a new blog is going to keep going and be worth your while. Well, the Ruby community has a new blog in its midst that's proving to be a must-read-Ruby Best Practices.It's a must-subscribe (RSS feed) fo

What is Ruby FPDF? Ruby FPDF is a Ruby portOlivier Plathey's excellent PDF generator,FPDF.FPDF is written in PHP, and as such can only be used from PHP scripts.Ruby FPDF, as the name suggests, is written in Ruby and can be usedFrom Ruby scripts.

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