大家好，又见面了，我是全栈君。
Scope defines where in a program a variable is accessible. Ruby has four types of variable scope, local,global, instance 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 |
发布者：全栈程序员-用户IM，转载请注明出处：https://javaforall.cn/115614.html原文链接：https://javaforall.cn
【正版授权，激活自己账号】： Jetbrains全家桶Ide使用，1年售后保障，每天仅需1毛
【官方授权 正版激活】： 官方授权 正版激活 支持Jetbrains家族下所有IDE 使用个人JB账号...
![闲话WPF之十六（WPF中的资源 [2]）「建议收藏」](http://javaforall.cn/wp-content/themes/justnews/themer/assets/images/lazy.png)