在C＃泛型列表扩展 [英] Generic List Extensions in C#

问题描述

我写了一些扩展，以模仿地图和减少Lisp语言功能

I am writing a few extensions to mimic the map and reduce functions in Lisp.

public delegate R ReduceFunction<T,R>(T t, R previous);
public delegate void TransformFunction<T>(T t, params object[] args);

public static R Reduce<T,R>(this List<T> list, ReduceFunction<T,R> r, R initial)
{
     var aggregate = initial;
     foreach(var t in list)
         aggregate = r(t,aggregate);

     return aggregate;
}
public static void Transform<T>(this List<T> list, TransformFunction<T> f, params object [] args)
{
    foreach(var t in list)
         f(t,args);
}

转换功能将减少像克鲁夫特：

The transform function will cut down on cruft like:

foreach(var t in list)
    if(conditions && moreconditions)
        //do work etc

这是否有道理？ ？难道是更好的。

Does this make sense? Could it be better?

推荐答案

这些看起来非常相似，在LINQ的扩展已经：

These look very similar to extensions in Linq already:

//takes a function that matches the Func<T,R> delegate
listInstance.Aggregate( 
    startingValue, 
    (x, y) => /* aggregate two subsequent values */ );

//takes a function that matches the Action<T> delegate
listInstance.ForEach( 
    x => /* do something with x */);

为什么第二个例子称为转换？你打算以某种方式更改列表中的值？如果是这样的情况下，你可以使用会更好 ConvertAll< T> 或选择< T>

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