A summary of some common file operations in Ruby and a summary of ruby operations
A lot of Ruby beginners need to learn. Now we are trying to use Ruby to write a script. Many file-related operations are used, which are sorted in stages here. This facilitates subsequent searches.
Whether the file or directory exists
Collections writing guide in Ruby and Ruby collections writing guide
Preference array and the literal representation of Hash (unless you need to pass parameters to their constructor ).
# bad arr = Array.new hash = Hash.new # good arr = [] hash = {}
When you need an array with elements of words (no spaces or special characters), you always use % w to define a string array. Apply this rule to only two
Installation will not say, the official website has, but today released ruby2.3, so updateEnter the. Rbenv directory, perform a git pull update, but update rbenv, execute rbenv install-l and do not have the latest 2.3.0 release version.Then I looked at the git repository for the Ruby-build plugin, with 2.3 code. Suspect this also to be updated, so.Go to the. Rbenv/plugins/ruby-build directory and execute gi
Ruby parsing JSONRuby Parsing JSON Example:
JSON = ' ["A", "B", "C"] '
puts "Unsafe #{unsafe_json
(JSON). Inspect}"
#输出Unsafe
["A", "B", "C"]
Ruby parses JSON to parse the above JSON string into array. Such a method is not safe, for example:
JSON = ' puts ' Danger'll
Robinson '
puts ' Unsafe #{unsafe_json
(JSON). Inspect} "
And what should we export? Unfortunately, there is
Rack is a framework between the Ruby server and the rack application, Rails,sinatra is built on rack and belongs to the rack application.
Rack provides a standard interface for interacting with the server. The standard rack program is an object that responds to call, can be an object, a Proc, a lambda, or even method, which receives the env parameter (the Environment object) and returns an array that inclu
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
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
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
GitHub advocates a summary of Ruby coding styles, while github advocates ruby code.
Source code layout: 1. All source files are UTF-8 encoded2. indent with two spaces3. Use Unix-style line breaks (\ n) and windows (\ r \ n ). You can use git config -- global core. autocrlf true to prevent the generation of windows-style line breaks.4. After ',', ';', add spaces before and after the operator (except for expo
Common Ruby file operation code instances and ruby code instances
# Create a 222. rb file and the input character File = file. open ("222.rb"," w + ") file. puts "123 \ nwadwa \ n12124124 \ ndwdw" file. close # output 222. rb content File. open ("222.rb"," r + ") do | file | while line = file. getsputs lineendend # directly use IO to operate the file IO. foreach ("222.rb") do | line | puts line if line = ~
Ruby-implemented file self-deletion code sharing, ruby-implemented code sharing
Because the File Deletion mechanism in windows is different from that in unix like, so does not guarantee that the following code can be used in windows. Which of the following kids shoes can help me test it in windows!
Copy codeThe Code is as follows:#! /Usr/bin/ruby
5. times do |
1. Auxiliary methods2. StringEnter "IRB" into the ruby command-line development environment, and the controller starts by executing "rails console" on the command line.(1) String connection>>"foo"+"bar"="foobar" (2) Interpolation by special syntax #{}>>first_name="Amy" ="Amy">>" #{first_name} Sun"+"Amy Sun "(3) The difference between a single-quote string and a double-quote string: Single-quote strings they really are literal values, contain only the
When I started my ruby journey, I wrote my study notes for people with other OO language experiences. Let's take a look at the magic ruby.
The first sample! First meeting.
#
! /Usr/bin/ENV Ruby
Class
MegagreeterAttr_accessor: names
#
Create the object
Def
Initialize (names
=
"
World
"
)@ Names
=
NamesEnd
#
Say hi
Matrix concatenation algorithm implemented by Ruby and ruby matrix concatenation
Dynamic Planning solves the problem of matrix concatenation, generates matrix sequences randomly, and outputs results in the form of (A1 (A2A3) (A4A5.
Code:
#encoding: utf-8=beginauthor: xu jin, 4100213date: Oct 28, 2012MatrixChainto find an optimum order by using MatrixChain algorithmexample output:The given array is:[30, 35,
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