如何替换集合中的一系列项目，使用其他集合？ [英] How to replace a sequence of items in a collection, using other collections?

问题描述

假设我有一个int数组：

Let's say I have an int array:

var source = new int[] { 1, 2, 3, 4, 5 };

我想使用这些数组替换它的一部分：

I want to replace a portion of it using these arrays:

var fromArray = new int[] { 1, 2 };
var toArray = new int[] { 11, 12 };

我需要使用上面的数组产生的输出是： 11，12 ，3，4，5 。

The output I need to produce using the arrays above is: 11, 12, 3, 4, 5.

在更高级的场景中，我可能还需要使用多个参数替换源。认为 fromArray 和 toArray 来自字典< int []，int [] > ：

In a more advanced scenario, I may also need to replace the source using multiple arguments. Think that fromArray and toArray are coming from a Dictionary<int[], int[]>:

IEnumerable<T> Replace(IEnumerable<T> source,
                       IDictionary<IEnumerable<T>, IEnumerable<T>> values)
{
    // "values" parameter holds the pairs that I want to replace.
    // "source" can be `IList<T>` instead of `IEnumerable<T> if an indexer
    // is needed but I prefer `IEnumerable<T>`.
}

如何实现？

修改：项目的顺序很重要。认为它像 String.Replace ;如果 fromArray 的全部内容不在 source 中（如果源只有 1 ，而不是 2 ），该方法不应尝试替换它。例如：

The order of the items is important. Think it like String.Replace; if the whole content of the fromArray doesn't exist in source (if the source has only 1 and not 2, for example) the method shouldn't try to replace it. An example:

var source = new int[] { 1, 2, 3, 4, 5, 6 };
var dict = new Dictionary<int[], int[]>();

// Should work, since 1 and 2 are consecutive in the source.
dict[new int[] { 1, 2 }] = new int[] { 11, 12 }; 

// There is no sequence that consists of 4 and 6, so the method should ignore it.
dict[new int[] { 4, 6 }] = new int[] { 13, 14 };

// Should work.
dict[new int[] { 5, 6 }] = new int[] { 15, 16 };

Replace(source, dict); // Output should be: 11, 12, 3, 4, 15, 16

推荐答案

确定，这里是基于您编辑的问题的答案。完全未经测试当然。

OK, here's an answer based on your edited question. Completely untested of course.

static IEnumerable<T> Replace<T>(IEnumerable<T> source, IDictionary<IEnumerable<T>, IEnumerable<T>> values)
{
  foreach (var kvp in values)
    source = ReplaceOne(source, kvp.Key, kvp.Value);
  return source;
}

static IEnumerable<T> ReplaceOne<T>(IEnumerable<T> source, IEnumerable<T> fromSeq, IEnumerable<T> toSeq)
{
  var sArr = source.ToArray();

  int replLength = fromSeq.Count();
  if (replLength != toSeq.Count())
    throw new NotSupportedException();

  for (int idx = 0; idx <= sArr.Length - replLength; idx++)
  {
    var testSeq = Enumerable.Range(idx, replLength).Select(i => sArr[i]);
    if (testSeq.SequenceEqual(fromSeq))
    {
      Array.Copy(toSeq.ToArray(), 0, sArr, idx, replLength);
      idx += replLength - 1;
    }
  }

  return sArr;
}

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