rubocop 作为ruby代码检查工具，对规范代码风格有很强的作用。使用 -D 参数会显示错误类型，方便总结归类。 下面总结我遇到的一些问题及对策，也许还需要不断更新，也很希望能对大家有帮助，有问题也欢迎和我探讨。
| message | meaning |
|---|---|
| Style/UnneededInterpolation: Prefer to_s over string interpolation. | 需要使用 to_s 来进行字符串插值，#中包含的内容要用to_s 转换。 |
| Style/StringLiterals: Prefer single-quoted strings when you don't need string interpolation or special symbols | 如果没有字符串插值，则使用单引号 |
| Style/HashSyntax: Use the new Ruby 1.9 hash syntax. | 使用ruby 1.9 的hash 语法 my_hash = { :key => 'value' }之类的 变成 my_hash = |
| Lint/UselessAssignment: Useless assignment to variable - iteration. | 不必要的变量定义 |
| Lint/AssignmentInCondition: Assignment in condition - you probably meant to use == | 需要使用条件的地方，使用了赋值语句。while line = STDIN.gets {block } 会报错 |
| Style/GlobalVars: Do not introduce global variables. | 不要使用全局变量，尽量吧 |
| Metrics/AbcSize: Assignment Branch Condition size for xxx is too high | 某个函数的条件太复杂了 |
| Metrics/CyclomaticComplexity: Cyclomatic complexity for xxx is too high | 某个函数的圈复杂度太高了 |
| Metrics/MethodLength: Method has too many lines. | 某个方法定义的太长了 |
| Metrics/PerceivedComplexity: Perceived complexity for function is too high | 某个方法的感知复杂度太高了 |
| Lint/HandleExceptions: Do not suppress exceptions. | 不要禁止异常 |
| Lint/RescueException: Avoid rescuing the Exception class. Perhaps you meant to rescue StandardError? | |
| Lint/ScriptPermission: Script file array_2d.rb doesn't have execute permission. | 某个文件没有执行权限 设置gitconfig 中 Filemode |
| Lint/StringConversionInInterpolation: Redundant use of Object#to_s in interpolation. | |
| Shadowing outer local variable | 代码块中，作为参数的变量名在代码块外出现过 |
| Lint/UnreachableCode: Unreachable code detected. | 检测到了不能到达的代码段 |
| Lint/LiteralInCondition: Literal true appeared in a condition. | 条件中不能包含字符串 |
| Lint/NonLocalExitFromIterator: Non-local exit from iterator, without return value. next, break, Array#find, Array#any?, etc. is preferred | 在非正常退出迭代器时，return 之后没有值 |
| Lint/ParenthesesAsGroupedExpression: (...) interpreted as grouped expression. | 圆括号会被解释为分组表达式 ，函数和参数括号之间不能有空格 |
| Lint/RescueException: Avoid rescuing the Exception class. Perhaps you meant to rescue StandardError? | 希望不用Exception类 |
