Array.Sort 用于带有数字的字符串 [重复]

Question

我有以下示例代码：

List<string> test = new List<string>();
test.Add("Hello2");
test.Add("Hello1");
test.Add("Welcome2");
test.Add("World");
test.Add("Hello11");
test.Add("Hello10");
test.Add("Welcome0");
test.Add("World3");
test.Add("Hello100");
test.Add("Hello20");
test.Add("Hello3");

test.Sort();

但发生的情况是，test.Sort 会将数组排序为：

"Hello1", 
"Hello10", 
"Hello100", 
"Hello11", 
"Hello2", 
"Hello20", 
"Hello3", 
"Welcome0", 
"Welcome2", 
"World", 
"World3"

有没有办法对它们进行排序，以便string 也有正确的数字顺序？ （如果string 的末尾没有数字，那string 将始终排在最前面 - 在字母顺序之后）

预期输出：

"Hello1", 
"Hello2", 
"Hello3", 
"Hello10", 
"Hello11", 
"Hello20", 
"Hello100", 
"Welcome0", 
"Welcome2", 
"World", 
"World3"

Answer 1

这是使用 LINQ 的一种可能方式：

 var orderedList = test
            .OrderBy(x => new string(x.Where(char.IsLetter).ToArray()))
            .ThenBy(x =>
            {
                int number;
                if (int.TryParse(new string(x.Where(char.IsDigit).ToArray()), out number))
                    return number;
                return -1;
            }).ToList();

Answer 2

创建一个IComparer<string> 实现。与LINQ 建议相比，这样做的好处是您现在拥有一个可以传递给任何需要以这种方式排序的类，而不是在其他位置重新创建该 linq 查询。

这是特定于您从 LIST 调用排序的。如果你想叫它Array.Sort()，请看第二版：

列表版本：

public class AlphaNumericComparer : IComparer<string>
    {
        public int Compare(string lhs, string rhs)
        {
            if (lhs == null)
            {
                return 0;
            }

            if (rhs == null)
            {
                return 0;
            }

            var s1Length = lhs.Length;
            var s2Length = rhs.Length;
            var s1Marker = 0;
            var s2Marker = 0;

            // Walk through two the strings with two markers.
            while (s1Marker < s1Length && s2Marker < s2Length)
            { 
                var ch1 = lhs[s1Marker];
                var ch2 = rhs[s2Marker];

                var s1Buffer = new char[s1Length];
                var loc1 = 0;
                var s2Buffer = new char[s2Length];
                var loc2 = 0;

                // Walk through all following characters that are digits or
                // characters in BOTH strings starting at the appropriate marker.
                // Collect char arrays.
                do
                {
                    s1Buffer[loc1++] = ch1;
                    s1Marker++;

                    if (s1Marker < s1Length)
                    {
                        ch1 = lhs[s1Marker];
                    }
                    else
                    {
                        break;
                    }
                } while (char.IsDigit(ch1) == char.IsDigit(s1Buffer[0]));

                do
                {
                    s2Buffer[loc2++] = ch2;
                    s2Marker++;

                    if (s2Marker < s2Length)
                    {
                        ch2 = rhs[s2Marker];
                    }
                    else
                    {
                        break;
                    }
                } while (char.IsDigit(ch2) == char.IsDigit(s2Buffer[0]));

                // If we have collected numbers, compare them numerically.
                // Otherwise, if we have strings, compare them alphabetically.
                string str1 = new string(s1Buffer);
                string str2 = new string(s2Buffer);

                int result;

                if (char.IsDigit(s1Buffer[0]) && char.IsDigit(s2Buffer[0]))
                {
                    var thisNumericChunk = int.Parse(str1);
                    var thatNumericChunk = int.Parse(str2);
                    result = thisNumericChunk.CompareTo(thatNumericChunk);
                }
                else
                {
                    result = str1.CompareTo(str2);
                }

                if (result != 0)
                {
                    return result;
                }
            }
            return s1Length - s2Length;
        }
    }

这样调用：

test.sort(new AlphaNumericComparer());

//RESULT
Hello1 
Hello2 
Hello3 
Hello10 
Hello11 
Hello20 
Hello100 
Welcome0 
Welcome2 
World 
World3 

Array.sort版本：

创建类：

public class AlphaNumericComparer : 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)
        {
            var ch1 = s1[marker1];
            var ch2 = s2[marker2];

            // Some buffers we can build up characters in for each chunk.
            var space1 = new char[len1];
            var loc1 = 0;
            var space2 = new char[len2];
            var 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.
            var str1 = new string(space1);
            var str2 = new string(space2);

            var result = 0;

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

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

Call like so:

This time test is an array instead of a list.
Array.sort(test, new AlphaNumericComparer())

Answer 3

您可以将 LINQ 与正则表达式结合使用，以确保仅使用出现在字符串末尾的数字进行二级排序

test
  .Select(t => new{match = Regex.Match(t, @"\d+$"), val = t})
  .Select(x => new{sortVal = x.match.Success
                                ?int.Parse(x.match.Value)
                                :-1,
                   val = x.val})
  .OrderBy(x => x.val)
  .ThenBy(x => x.sortVal)
  .Select(x => x.val)
  .ToList()