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  • R语言学习笔记-变量的作用域

    R语言是如何将变量值和变量绑定的

    在r语言中,当前的 workspace就是global enviroment,当输入变量名时,首先会在global enviroment中搜索该变量,如有,则将它显示出来。

    第二步,如在global enviroment中没有找到该变量民,则搜索search list中的各个包,search list 中的内容可以用search()得到

    如果用户使用library()load了一个package ,则这个package将在search list中处于第二的位置

    Lexical scoping in R means that:

    the values of free variables are searched for in the environment in which the function
    was defined.

    If the value of a symbol is not found in the environment in which a function was defined,
    then the search is continued in the parent environment.
    • The search continues down the sequence of parent environments until we hit the top-level
    environment; this usually the global environment (workspace) or the namespace of a package.
    • After the top-level environment, the search continues down the search list until we hit the
    empty environment.

    If a value for a given symbol cannot be found once the empty environment is arrived at, then an
    error is thrown.

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  • 原文地址:https://www.cnblogs.com/wpzy2311/p/4600745.html
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