在 Mathematica 中将控件定义为变量 [英] Define control as variable in Mathematica

问题描述

当我使用 Manipulate 时，我可以:

When I use Manipulate I can do:

Manipulate[x, {u, 1, 10}]

实际上我的控件很多而且很复杂，所以我更愿意采用它们的Manipulate 表达式之外的定义，如下所示:

In reality my controls are many and complicated, so I would prefer to take their definition out of the Manipulate expression, like that:

control = {u, 1, 10}
Manipulate[x, control]

但这确实会导致错误:

Manipulate argument control does not have the correct form for a \
variable specification.

为什么它不能那样工作?

Why doesn't it work that way?

推荐答案

Manipulate 有 HoldAll 属性.您可以强制 control 进行评估，一切正常

Manipulate has the HoldAll attribute. You can force control to evaluate and everything works ok

control = {u, 1, 10};
Manipulate[x[u], Evaluate[control]]

问题在于变量 u 没有正确本地化，所以如果您已经在某处设置了例如 u=1，那么 操作会返回错误.

The problem with this is that the variable u is not properly localised, so if you have already set, e.g., u=1 somewhere, then the Manipulate will return an error.

如果您使用适当的作用域结构(例如 With 或 DynamicModule)，这可能会更好，具体取决于您要执行的操作.

It might be better if you use appropriate scoping constructs such as With or DynamicModule depending on exactly what you're trying to do.

这可能有点矫枉过正，但它确保 u 是本地的并将 control 移到操作之外:

This is maybe overkill, but it ensures that u is local and moves control outside of the manipulate:

DynamicModule[{u}, With[{control = {u, 1, 10}}, Manipulate[x[u], control]]]

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