按數字排序數組列表，然后按字母排序

Question

我有字符串數組列表：

"1A", "12A", "12B", "6", "A", "5B", "B", "13" 。

如果我做myList.Sort(); 然后我得到：

"1A", "12A", "12B", "13", "5B", "6", "A", "B" 。

但我需要的是先按照前面的數字排序，然后按字母排序：

"1A", "5B", "6", "12A", "12B", "13", "A", "B" 。

我可以用

public class CustomComparer : IComparer
{
    Comparer _comparer = new Comparer(System.Globalization.CultureInfo.CurrentCulture);

    public int Compare(object x, object y)
    {
        // Convert string comparisons to int
        return _comparer.Compare(Convert.ToInt32(x), Convert.ToInt32(y));
    }
}

但它拋出異常。 我如何得到我需要的東西？

Answer 1

你的比較器太簡單了。 您的比較需要將每個值拆分為數字和其余值，然后首先比較數字，然后比較字符串是否相等。 所以它會是這樣的：

public sealed class NumberStringComparer : IComparer<string>
{
    public int Compare(string x, string y)
    {
        return NumberString.Parse(x).CompareTo(NumberString.Parse(y));
    }


    private struct NumberString : IComparable<NumberString>
    {
        private readonly int? number;
        private readonly string text;

        private NumberString(int? number, string text)
        {
            this.number = number;
            this.text = text;
        }

        internal static NumberString Parse(string text)
        {
            // TODO: Find where the digits stop, parse the number
            // (if there is one), call the constructor and return a value.
            // (You could use a regular expression to separate the parts...)
        }

        public int CompareTo(NumberString other)
        {
            // TODO: Compare numbers; if they're equal, compare
            // strings
        }
    }
}

如果您有一定的待辦事項的問題（花一些時間嘗試后 ），你可以要求更具體的幫助-但，這是一般的方法我會使用。

Answer 2

您不能簡單地將字符串"1A"或"5B"傳遞給Convert.ToInt32(x) ，因為它的一部分不是Int32一部分。

相反，您應該首先將字符串拆分為兩部分 - 數字和其他所有部分，然后使用tie tie進行比較。

一種方法是編寫兩個輔助方法，然后使用LINQ的OrderBy和ThenBy ：

static int ExtractPrefix(string s) {
    // Parse the digits and stop; return the number
}
static string ExtractSuffix(string s) {
    // Skip digits, and return everything else
}
...
var sorted = unsorted.OrderBy(ExtractPrefix).ThenBy(ExtractSuffix).ToList();

Answer 3

試試這個：

public class CustomComparer : IComparer<string> {
  Comparer _comparer = new Comparer(System.Globalization.CultureInfo.CurrentCulture);

  public int Compare(string x, string y) {
     string numxs = string.Concat(x.TakeWhile(c => char.IsDigit(c)).ToArray());
     string numys = string.Concat(y.TakeWhile(c => char.IsDigit(c)).ToArray());

     int xnum;
     int ynum;
     if (!int.TryParse(numxs, out xnum) || !int.TryParse(numys, out ynum)) {
        return _comparer.Compare(x, y);
     }
     int compareNums = xnum.CompareTo(ynum);
     if (compareNums != 0) {
        return compareNums;
     }
     return _comparer.Compare(x, y);
  }
}

Answer 4

試試這個實現？

http://www.dotnetperls.com/alphanumeric-sorting

從上面的鏈接：

public class AlphanumComparatorFast : IComparer
{
    public int Compare(object x, object y)
    {
    string s1 = x as string;
    if (s1 == null)
    {
        return 0;
    }
    string s2 = y as string;
    if (s2 == null)
    {
        return 0;
    }

    int len1 = s1.Length;
    int len2 = s2.Length;
    int marker1 = 0;
    int marker2 = 0;

    // Walk through two the strings with two markers.
    while (marker1 < len1 && marker2 < len2)
    {
        char ch1 = s1[marker1];
        char ch2 = s2[marker2];

        // Some buffers we can build up characters in for each chunk.
        char[] space1 = new char[len1];
        int loc1 = 0;
        char[] space2 = new char[len2];
        int loc2 = 0;

        // Walk through all following characters that are digits or
        // characters in BOTH strings starting at the appropriate marker.
        // Collect char arrays.
        do
        {
        space1[loc1++] = ch1;
        marker1++;

        if (marker1 < len1)
        {
            ch1 = s1[marker1];
        }
        else
        {
            break;
        }
        } while (char.IsDigit(ch1) == char.IsDigit(space1[0]));

        do
        {
        space2[loc2++] = ch2;
        marker2++;

        if (marker2 < len2)
        {
            ch2 = s2[marker2];
        }
        else
        {
            break;
        }
        } while (char.IsDigit(ch2) == char.IsDigit(space2[0]));

        // If we have collected numbers, compare them numerically.
        // Otherwise, if we have strings, compare them alphabetically.
        string str1 = new string(space1);
        string str2 = new string(space2);

        int result;

        if (char.IsDigit(space1[0]) && char.IsDigit(space2[0]))
        {
        int thisNumericChunk = int.Parse(str1);
        int thatNumericChunk = int.Parse(str2);
        result = thisNumericChunk.CompareTo(thatNumericChunk);
        }
        else
        {
        result = str1.CompareTo(str2);
        }

        if (result != 0)
        {
        return result;
        }
    }
    return len1 - len2;
    }
}

Answer 5

以下比較器的實現應符合您的要求：

public int Compare(string x, string y)
{
    var rx = new Regex("^(d+)");

    var xRes = rx .Match(x);
    var yRes = rx .Match(y);

    if (xRes.Success 
         && yRes.Success)
    {
        return int.Parse(xRes.Groups[1].Value).
               CompareTo(int.Parse(yRes.Groups[1].Value));
    }

    return x.CompareTo(y);
}