ruby pry

Four Methods for Equality judgment in Ruby and four methods for ruby equality judgment It has long been known that ruby has four equality judgment methods: "=", "=", and "equal ?" And "eql ?", It is used in common programs, but I feel that I lack a deep understanding of it. When I read some of the rails source code today, I cannot determine the meaning of one of

We strongly recommend that you use the following Online Learning Websites: http://tryruby.org: 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, which can be eliminated by cho

Basic Learning notes for Ruby metaprogramming and ruby learning notes Note 1:The Code contains variables, classes, and methods, collectively referred to as language construct ). # test.rbclass Greeting def initialize(text) @text = text end def welcome @text endendmy_obj = Greeting.new("hello")puts my_obj.classputs my_obj.class.instance_methods(false) #false means not inheritedputs my_obj.instance_variable

Assignment related operations in Ruby programming and ruby programming assignment In earlier versions of Ruby, the return value of the value assignment statement is the return value of the method that sets this attribute. In Ruby1.8, the value of the value assignment statement is always the value of the parameter, and the return value of the method is lost. class

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

Example of writing code for exception handling in Ruby, and ruby Exception Handling A single exception uses the fail keyword only when an exception is caught and thrown repeatedly (because you do not fail here, but are accurate and intentionally throw an exception ). begin fail 'Oops' rescue => error raise if error.message != 'Oops' end Do not specify an accurate RuntimeError for fail/raise. # bad

Tutorial on interrupt and return in Ruby programming and tutorial on ruby programming usage The use of the return, break, and next keywords involves the issue of jumping out of the scope. Their difference lies in the different scopes of different keywords jumping out, because there are code blocks, you need to pay special attention to them.ReturnCommon Methods Generally, the return statement is the same as

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.

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