“从包导入*"之间的性能和“导入包" [英] Performance between "from package import *" and "import package"

问题描述

from package import * 和 import package 在性能上有区别吗?

Is there any performance difference between from package import * and import package?

推荐答案

不，区别不是性能问题.在这两种情况下，都必须解析整个模块，并且将执行任何模块级代码.唯一的区别在于命名空间:首先，导入模块中的所有名称都将成为当前模块中的名称；第二种，在当前模块中只定义了包名.

No, the difference is not a question of performance. In both cases, the entire module must be parsed, and any module-level code will be executed. The only difference is in namespaces: in the first, all the names in the imported module will become names in the current module; in the second, only the package name is defined in the current module.

也就是说，很少有充分的理由使用 from foo import *.导入模块，或从中导入特定名称.

That said, there's very rarely a good reason to use from foo import *. Either import the module, or import specific names from it.

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