C# 先数字后字符的排序方法

以你之姓@ 2022-10-22 09:24 122阅读 0赞

C\# 先数字后字符的排序方法

发现前一篇文章在sql中的排序还是有太多不尽人意的地方，因而花了一些时间到看了一些外文网站，找到了以下的方法。

public class AlphanumComparatorFastString : IComparer<String>
        {
            public int Compare(string s1, string s2)
            {
                if (s1 == null)
                    return 0;
    
                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;
            }
        }