C#拆分数组

时间:2009-12-03 16:48:58

标签: c# arrays

我需要在中点将一个不确定大小的数组拆分成两个独立的数组。

使用ToArray()从字符串列表生成数组。

        public void AddToList ()
        {
            bool loop = true;
            string a = "";

            Console.WriteLine("Enter a string value and press enter to add it to the list");
            while (loop == true)
            {
                a = Console.ReadLine();

                if (a != "")
                {
                    mylist.Add(a);
                }
                else
                {
                    loop = false;
                }
            }

        }

        public void ReturnList()
        {
            string x = "";
            foreach (string number in mylist)
            {
                x = x + number + " ";
            }
            Console.WriteLine(x);
            Console.ReadLine();
        }

    }

    class SplitList
    {
        public string[] sTop;
        public string[] sBottom;

        public void Split(ref UList list)  
        {
            string[] s = list.mylist.ToArray();

            //split the array into top and bottom halfs

        }
    }

    static void Main(string[] args)
    {
        UList list = new UList();
        SplitList split = new SplitList();

        list.AddToList();
        list.ReturnList();

        split.Split(ref list);
    }
}

}

9 个答案:

答案 0 :(得分:47)

您可以使用以下方法将数组拆分为2个单独的数组

public void Split<T>(T[] array, int index, out T[] first, out T[] second) {
  first = array.Take(index).ToArray();
  second = array.Skip(index).ToArray();
}

public void SplitMidPoint<T>(T[] array, out T[] first, out T[] second) {
  Split(array, array.Length / 2, out first, out second);
}

答案 1 :(得分:9)

使用通用拆分方法:

public static void Split<T>(T[] source, int index, out T[] first, out T last)
{
    int len2 = source.Length - index;
    first = new T[index];
    last = new T[len2];
    Array.Copy(source, 0, first, 0, index);
    Array.Copy(source, index, last, 0, len2);
}

答案 2 :(得分:6)

我还想添加一个解决方案,将一个数组拆分成几个包含确定数量单元格的较小数组。

一种不错的方法是创建一个通用/扩展方法来拆分任何数组。这是我的:

/// <summary>
/// Splits an array into several smaller arrays.
/// </summary>
/// <typeparam name="T">The type of the array.</typeparam>
/// <param name="array">The array to split.</param>
/// <param name="size">The size of the smaller arrays.</param>
/// <returns>An array containing smaller arrays.</returns>
public static IEnumerable<IEnumerable<T>> Split<T>(this T[] array, int size)
{
    for (var i = 0; i < (float)array.Length / size; i++)
    {
        yield return array.Skip(i * size).Take(size);
    }
}

此外,该解决方案被推迟。然后,只需在您的阵列上调用split(size)

var array = new byte[] {10, 20, 30, 40, 50};
var splitArray = array.Split(2);

玩得开心:)

答案 3 :(得分:5)

在处理具有大量元素(即字节数组)的数组时,我遇到了Linq的Skip()和Take()函数的问题,其中元素数量是数百万。

这种方法大大减少了我的分割执行时间。

public static IEnumerable<IEnumerable<T>> Split<T>(this ICollection<T> self, int chunkSize)
{
    var splitList = new List<List<T>>();
    var chunkCount = (int)Math.Ceiling((double)self.Count / (double)chunkSize);

    for(int c = 0; c < chunkCount; c++)
    {
        var skip = c * chunkSize;
        var take = skip + chunkSize;
        var chunk = new List<T>(chunkSize);

        for(int e = skip; e < take && e < self.Count; e++)
        {
            chunk.Add(self.ElementAt(e));
        }

        splitList.Add(chunk);
    }

    return splitList;
}

答案 4 :(得分:1)

如果您没有Linq,可以使用Array.Copy:

public void Split(ref UList list)
{
    string[] s = list.mylist.ToArray();

    //split the array into top and bottom halfs
    string[] top = new string[s.Length / 2];
    string[] bottom = new string[s.Length - s.Length / 2];
    Array.Copy(s, top, top.Length);
    Array.Copy(s, top.Length, bottom, 0, bottom.Length);

    Console.WriteLine("Top: ");
    foreach (string item in top) Console.WriteLine(item);
    Console.WriteLine("Bottom: ");
    foreach (string item in bottom) Console.WriteLine(item);
}

答案 5 :(得分:0)

为什么不分配两个数组并复制内容?

编辑:你走了:

        String[] origin = new String[4];
        origin[0] = "zero";
        origin[1] = "one";
        origin[2] = "two";
        origin[3] = "three";

        Int32 topSize = origin.Length / 2;
        Int32 bottomSize = origin.Length - topSize;
        String[] sTop = new String[topSize];
        String[] sBottom = new String[bottomSize];
        Array.Copy(origin, sTop, topSize);
        Array.Copy(origin, topSize , sBottom, 0, bottomSize);

答案 6 :(得分:0)

为什么要将UList作为参考号传递?似乎没有必要这样做。

如果我需要这样做,我会使用通用Split方法:

public void Split<T>(T[] array, out T[] left, out T[] right)
{
    left = new T[array.Length / 2];
    right = new T[array.Length - left.Length];

    Array.Copy(array, left, left.Length);
    Array.Copy(array, left.Length, right, 0, right.Length);
}

答案 7 :(得分:0)

我认为你要找的是Array类,特别是Array.Copy静态方法。如果C#数组有方法,你可以认为该类包含的方法是数组的实例方法。

答案 8 :(得分:0)

如果需要考虑功能范例,这可能会有所帮助:

   public static IEnumerable<IEnumerable<T>> Split<T>(this IEnumerable<T> seq, Int32 sizeSplits) {
     Int32 numSplits = (seq.Count() / sizeSplits) + 1;
     foreach ( Int32 ns in Enumerable.Range(start: 1, count: numSplits) ) {
        (Int32 start, Int32 end) = GetIndexes(ns);
        yield return seq.Where((_, i) => (start <= i && i <= end));
     }

     (Int32 start, Int32 end) GetIndexes(Int32 numSplit) {
        Int32 indBase1 = numSplit * sizeSplits;
        Int32 start = indBase1 - sizeSplits;
        Int32 end = indBase1 - 1;
        return (start, end);
     }
  }