哪个更有效?开关与循环 [英] Which is more effective? Switch vs. Loop

问题描述

大家好，

只是一个简单的问题....总的来说(如果使用C#，则在C#中)，此开关比循环或另一种回合"更有效.谢谢！

Hi all,

Just a quick question.... in general (and in C# if that''s relevant) is a switch more effective than a loop or the other way ''round? Thanks!

推荐答案

它们是2种不同的东西..

您可以(应该)使用switch来避免多个if-else语句

只有一个代码执行

像for或foreach这样的循环将代码重复n次

they are 2 different things..

you can(should) use switch in order to avoid multple if-else statements

there is only one single code execution

loops like for or foreach repeteat the code n times

好了，读完您的注释后，您应该使用一种不允许重复的内容.

您实际上想做的是

Okay having read your comment, you should use a formulation that allows you not to repeat things.

What you''re actually trying to do is

return mapper.ResultByRowcountForGroupSearch(searchFacilitator_.SetId,
                                                           x,
                                                           dac);

...其中x是根据组类型设置的.

因此，我建议您设置一个Dictionary< int，string> (我认为您的组类型是int吗?)，然后以静态方式或在封闭类的构造函数中填充它(如果映射是您可以在编译时编写的，则可能是静态填充)，例如:

... where x is set based on the group type.

So I recommend you set up a Dictionary<int, string> (your group types are int I think?), and populate it either statically or in the constructor of the enclosing class (probably statically if the mappings are something you can write in at compile time), e.g.:

static Dictionary<int, string> groupTypeMap = new Dictionary<int, string>();
static ClassName(){ // static constructor
 groupTypeMap[BRGroupTypeIds.Audit] = GroupSearchBatchStrings.AUDIT_TEMPSPACE_NAME;
 // etc
}

然后，在您要询问的方法中，您可以做

Then in the method that you''re asking about, you can do

return mapper.ResultByRowcountForGroupSearch(searchFacilitator_.SetId,
                                                           groupTypeMap[searchFacilitator_.GroupType,
                                                           dac);

...，或者，如果可能不在一个组中，并且您不希望从查找中获取异常(即，您的switch语句的实际等效项):

... or, if it''s possible to not be in a group and you don''t want an exception from the lookup (i.e. the actual equivalent of your switch statement):

string typeName;
return groupTypeMap.TryGetValue(searchFacilitator_.GroupType, out typeName) ?
 mapper.ResultByRowcountForGroupSearch(searchFacilitator_.SetId, typename, dac) :
 0;

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