将列表应用于 Mathematica 中的参数 [英] Apply list to arguments in Mathematica

问题描述

我将如何将列表中的每个元素应用于函数中的每个参数?有点像 Map，只是参数数量可变.

How would I go about applying each element in a list to each argument in a function? Kind of like Map, except with a variable number of arguments.

例如，如果我有一个函数 action[x1_,x2_,x3_]:=...，并且我有一个列表 {1,2,3}，我将如何创建一个函数来调用 action 和 action[1,2,3]?

So for example, if I have a function action[x1_,x2_,x3_]:=..., and I have a list {1,2,3}, how would I create a function to call action with action[1,2,3]?

我希望这个函数能够处理我将 action 更改为 action[x1_,x2] 以及其他任何内容，并且列表现在是 {1,2}，并立即使用 action[1,2] 调用操作.

I would like this function be able to handle me changing action to action[x1_,x2], and anything else, also, with the list now being {1,2}, and to call action now with action[1,2].

推荐答案

基于有点像 Map，但参数数量可变."我想您可能正在寻找 Apply 到级别 1.这是通过以下方式完成的:

Based on "Kind of like Map, except with a variable number of arguments." I think you might be looking for Apply to level 1. This is done with:

Apply[function, array, {1}]

或简写:

function @@@ array

这是它的作用:

array = {{1, 2, 3}, {a, b, c}, {Pi, Sin, Tan}};

action @@@ array

   {action[1, 2, 3], action[a, b, c], action[Pi, Sin, Tan]}  

<小时>

我在上面使用的术语可能会产生误导，并限制了 Apply 的力量.您应用 action 的表达式不需要是矩形数组.它甚至不需要是一个 List: {...} 或者它的元素是列表.以下是包含这些可能性的示例:

---

The terminology I used above could be misleading, and limits the power of Apply. The expression to which you apply action does not need to be a rectangular array. It does not even need to be a List: {...} or have its elements be lists. Here is an example incorporating these possibilities:

args = {1, 2} | f[a, b, c] | {Pi};

action @@@ args

   action[1, 2] | action[a, b, c] | action[Pi] 

• args 不是 List 而是一组 Alternatives
• 传递给 action 的参数数量不同
• args 的元素之一有头部 f
• args is not a List but a set of Alternatives
• the number of arguments passed to action varies
• one of the elements of args has head f

注意:

• action 替换 args 的每个元素的头部，无论它是什么.
• args 的头部保留在输出中，在本例中为 Alternatives(缩写:a | b | c)
• action replaces the head of each element of args, whatever it may be.
• The head of args is preserved in the output, in this case Alternatives (short form: a | b | c)

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