free-variable | 易学教程

How can “NameError: free variable 'var' referenced before assignment in enclosing scope” occur in real code?

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问题 While I was hanging out in the Python chatroom, someone dropped in and reported the following exception: NameError: free variable 'var' referenced before assignment in enclosing scope I'd never seen that error message before, and the user provided only a small code fragment that couldn't have caused the error by itself, so off I went googling for information, and ... there doesn't seem to be much. While I was searching, the user reported their problem solved as a "whitespace issue", and then

What are free variables?

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Javascript closure definition says : A "closure" is an expression (typically a function) that can have free variables together with an environment that binds those variables (that "closes" the expression). Can some one explain to me the concept of free variables ? Is this concept Javascript specific or applies to other languages also ? Free variables are simply the variables that are neither locally declared nor passed as parameter. Source : In computer programming, the term free variable refers to variables used in a function that are not local variables nor parameters of that function. 1 The

What are free variables?

阅读更多关于 What are free variables?

问题 Javascript closure definition says : A "closure" is an expression (typically a function) that can have free variables together with an environment that binds those variables (that "closes" the expression). Can some one explain to me the concept of free variables ? Is this concept Javascript specific or applies to other languages also ? 回答1: Free variables are simply the variables that are neither locally declared nor passed as parameter. Source : In computer programming, the term free