zoukankan      html  css  js  c++  java
  • [Ruby] Ruby Variable Scope

    Scope defines where in a program a variable is accessible. Ruby has four types of variable scope, local,globalinstance and class. In addition, Ruby has one constant type. Each variable type is declared by using a special character at the start of the variable name as outlined in the following table.

    Name Begins With Variable Scope
    $ A global variable
    @ An instance variable
    [a-z] or _ A local variable
    [A-Z] A constant
    @@ A class variable

    It is useful to know, however, that a number of pre-defined global variables are available to you as a Ruby developer to obtain information about the Ruby environment. A brief summary of each of these variables is contained in the following table.

    Variable Name Variable Value
    $@ The location of latest error
    $_ The string last read by gets
    $. The line number last read by interpreter
    $& The string last matched by regexp
    $~ The last regexp match, as an array of subexpressions
    $n The nth subexpression in the last match (same as $~[n])
    $= The case-insensitivity flag
    $/ The input record separator
    $ The output record separator
    $0 The name of the ruby script file currently executing
    $* The command line arguments used to invoke the script
    $$ The Ruby interpreter's process ID
    $? The exit status of last executed child process
  • 相关阅读:
    保存windows 10的登录界面壁纸
    Python 从剪贴板中生成二维码
    SpringBoot
    IDEA8条配置
    Nodejs-hexoBlog
    Mybatis-Plus
    Javaweb文件上传
    GIt基本语法
    JS常用部分整合
    javaweb-maven学习总结
  • 原文地址:https://www.cnblogs.com/yxwkf/p/5306963.html
Copyright © 2011-2022 走看看