私有方法'eval'调用了Math：Module（NoMethodError）
[英]private method 'eval' called for Math:Module (NoMethodError)
问题描述
I can not figure out how to use this method. 
我不知道如何使用此方法。 It seems really strange to me that it should be a private method within Math, as that would make it completely non-accessible for developers (as far as I can tell). 在我看来，这应该是Math中的私有方法真的很奇怪，因为这会使开发人员完全无法访问它（据我所知）。 What am I missing? 我想念什么？
My code is below: 我的代码如下：
str = "(5+9)/(3+4)"
puts Math.eval(str)
1 个解决方案
解决方案1
1 已采纳 2015-07-16 17:11:30
I am not sure, what you are trying to achieve, but while str has a valid ruby syntax (the one from the example above has), here you go: 我不确定您要实现的目标，但是当str具有有效的ruby语法（上面示例中的语法）时，您可以执行以下操作：
▶ str = "(5+9)/(3+4)"
#⇒ "(5+9)/(3+4)"
▶ instance_eval str
#⇒ 2
声明:本站的技术帖子网页，遵循CC BY-SA 4.0协议，如果您需要转载，请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.
相关问题
Sinatra Activerecord：为Psych：Module调用的私有方法“ load”（NoMethodError） - Sinatra Activerecord: private method `load' called for Psych:Module (NoMethodError)
为 ActionDispatch::Assertions:Module (NoMethodError) 调用私有方法“include” - private method `include' called for ActionDispatch::Assertions:Module (NoMethodError)
应用：为 URI:Module 调用私有方法打开 (NoMethodError) - apply: private method open called for URI:Module (NoMethodError)
私有方法，称为noMethodError ruby - private method called noMethodError ruby
私有方法`select'调用了nil：NilClass（NoMethodError） - private method `select' called for nil:NilClass (NoMethodError)
私有方法`split'调用了nil：NilClass（NoMethodError） - private method `split' called for nil:NilClass (NoMethodError)
私有方法“ chomp”调用了nil：NilClass（NoMethodError） - private method `chomp' called for nil:NilClass (NoMethodError)
私有方法“ puts”需要“ string”：String（NoMethodError） - private method `puts' called for “string”:String (NoMethodError)
私有方法`puts'调用nil：NilClass（NoMethodError） - private method `puts' called for nil:NilClass (NoMethodError)
`map！'：调用String的私有方法（NoMethodError） - `map!': private method called for String (NoMethodError)
相关标签