if语句具有变量运算符 [英] if statement to have variable operator

问题描述

假设我有一个循环，可从操作员字段中检索操作员.
例如，返回的变量strOperator是以下值之一:

操作员
--------
=
>

Hi,
Let say I have a loop which retrieves the operators from the operator field.
For example the variable strOperator returned is one of the following values:

Operator
--------
=
>

推荐答案

您将不得不编写一个(非常小的)解释器(或者它可能更像是编译器，在加载时进行映射).像这样的东西:

You will have to write a (very small) interpreter (or it might be more like a compiler, doing the mapping at load time). Something like:

static Dictionary<string, Func<int, int, bool>> map = new Dictionary<string, Func<int, int, bool>>();

static constructor(){
 map["="] = (a, b) => a == b;
 map["<"] = (a, b) => a < b;
 // ... etc
}

void method(){
 string comparator = "<";
 int a = 5, b = 8;
 if(map[comparator](a, b)){
  // ...
 }
}

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