问题
I'm trying to sort an array of numbers that are strings and I'd like them to sort numerically.
The catch is that I cannot convert the numbers into int.
Here is the code:
string[] things= new string[] { "105", "101", "102", "103", "90" };
foreach (var thing in things.OrderBy(x => x))
{
Console.WriteLine(thing);
}
output: 101, 102, 103, 105, 90
I'd like: 90, 101, 102, 103, 105
EDIT: The output can't be 090, 101, 102...
Updated the code sample to say "things" instead of "sizes". The array can be something like this:
string[] things= new string[] { "paul", "bob", "lauren", "007", "90" };
That means it needs to be sorted alphabetically and by number:
007, 90, bob, lauren, paul
回答1:
Pass a custom comparer into OrderBy. Enumerable.OrderBy will let you specify any comparer you like.
This is one way to do that:
void Main()
{
string[] things = new string[] { "paul", "bob", "lauren", "007", "90", "101"};
foreach (var thing in things.OrderBy(x => x, new SemiNumericComparer()))
{
Console.WriteLine(thing);
}
}
public class SemiNumericComparer: IComparer<string>
{
/// <summary>
/// Method to determine if a string is a number
/// </summary>
/// <param name="value">String to test</param>
/// <returns>True if numeric</returns>
public static bool IsNumeric(string value)
{
return int.TryParse(value, out _);
}
/// <inheritdoc />
public int Compare(string s1, string s2)
{
const int S1GreaterThanS2 = 1;
const int S2GreaterThanS1 = -1;
var IsNumeric1 = IsNumeric(s1);
var IsNumeric2 = IsNumeric(s2);
if (IsNumeric1 && IsNumeric2)
{
var i1 = Convert.ToInt32(s1);
var i2 = Convert.ToInt32(s2);
if (i1 > i2)
{
return S1GreaterThanS2;
}
if (i1 < i2)
{
return S2GreaterThanS1;
}
return 0;
}
if (IsNumeric1)
{
return S2GreaterThanS1;
}
if (IsNumeric2)
{
return S1GreaterThanS2;
}
return string.Compare(s1, s2, true, CultureInfo.InvariantCulture);
}
}
回答2:
Just pad with zeroes to the same length:
int maxlen = sizes.Max(x => x.Length);
sizes.OrderBy(x => x.PadLeft(maxlen, '0'));
回答3:
And, how about this ...
string[] sizes = new string[] { "105", "101", "102", "103", "90" };
var size = from x in sizes
orderby x.Length, x
select x;
foreach (var p in size)
{
Console.WriteLine(p);
}
回答4:
Value is a string
List = List.OrderBy(c => c.Value.Length).ThenBy(c => c.Value).ToList();
Works
回答5:
There is a native function in windows StrCmpLogicalW that will compare in strings numbers as numbers instead of letters. It is easy to make a comparer that calls out to that function and uses it for it's comparisons.
public class StrCmpLogicalComparer : Comparer<string>
{
[DllImport("Shlwapi.dll", CharSet = CharSet.Unicode)]
private static extern int StrCmpLogicalW(string x, string y);
public override int Compare(string x, string y)
{
return StrCmpLogicalW(x, y);
}
}
It even works on strings that have both text and numbers. Here is a example program that will show the diffrence between the default sort and the StrCmpLogicalW sort
class Program
{
static void Main()
{
List<string> items = new List<string>()
{
"Example1.txt", "Example2.txt", "Example3.txt", "Example4.txt", "Example5.txt", "Example6.txt", "Example7.txt", "Example8.txt", "Example9.txt", "Example10.txt",
"Example11.txt", "Example12.txt", "Example13.txt", "Example14.txt", "Example15.txt", "Example16.txt", "Example17.txt", "Example18.txt", "Example19.txt", "Example20.txt"
};
items.Sort();
foreach (var item in items)
{
Console.WriteLine(item);
}
Console.WriteLine();
items.Sort(new StrCmpLogicalComparer());
foreach (var item in items)
{
Console.WriteLine(item);
}
Console.ReadLine();
}
}
which outputs
Example1.txt
Example10.txt
Example11.txt
Example12.txt
Example13.txt
Example14.txt
Example15.txt
Example16.txt
Example17.txt
Example18.txt
Example19.txt
Example2.txt
Example20.txt
Example3.txt
Example4.txt
Example5.txt
Example6.txt
Example7.txt
Example8.txt
Example9.txt
Example1.txt
Example2.txt
Example3.txt
Example4.txt
Example5.txt
Example6.txt
Example7.txt
Example8.txt
Example9.txt
Example10.txt
Example11.txt
Example12.txt
Example13.txt
Example14.txt
Example15.txt
Example16.txt
Example17.txt
Example18.txt
Example19.txt
Example20.txt
回答6:
try this
sizes.OrderBy(x => Convert.ToInt32(x)).ToList<string>();
Note: this will helpful when all are string convertable to int.....
回答7:
You say you cannot convert the numbers into int because the array can contain elements that cannot be converted to int, but there is no harm in trying:
string[] things = new string[] { "105", "101", "102", "103", "90", "paul", "bob", "lauren", "007", "90" };
Array.Sort(things, CompareThings);
foreach (var thing in things)
Debug.WriteLine(thing);
Then compare like this:
private static int CompareThings(string x, string y)
{
int intX, intY;
if (int.TryParse(x, out intX) && int.TryParse(y, out intY))
return intX.CompareTo(intY);
return x.CompareTo(y);
}
Output: 007, 90, 90, 101, 102, 103, 105, bob, lauren, paul
回答8:
I guess this will be much more good if it has some numeric in the string. Hope it will help.
PS:I'm not sure about performance or complicated string values but it worked good something like this:
lorem ipsum
lorem ipsum 1
lorem ipsum 2
lorem ipsum 3
...
lorem ipsum 20
lorem ipsum 21
public class SemiNumericComparer : IComparer<string>
{
public int Compare(string s1, string s2)
{
int s1r, s2r;
var s1n = IsNumeric(s1, out s1r);
var s2n = IsNumeric(s2, out s2r);
if (s1n && s2n) return s1r - s2r;
else if (s1n) return -1;
else if (s2n) return 1;
var num1 = Regex.Match(s1, @"\d+$");
var num2 = Regex.Match(s2, @"\d+$");
var onlyString1 = s1.Remove(num1.Index, num1.Length);
var onlyString2 = s2.Remove(num2.Index, num2.Length);
if (onlyString1 == onlyString2)
{
if (num1.Success && num2.Success) return Convert.ToInt32(num1.Value) - Convert.ToInt32(num2.Value);
else if (num1.Success) return 1;
else if (num2.Success) return -1;
}
return string.Compare(s1, s2, true);
}
public bool IsNumeric(string value, out int result)
{
return int.TryParse(value, out result);
}
}
回答9:
This seems a weird request and deserves a weird solution:
string[] sizes = new string[] { "105", "101", "102", "103", "90" };
foreach (var size in sizes.OrderBy(x => {
double sum = 0;
int position = 0;
foreach (char c in x.ToCharArray().Reverse()) {
sum += (c - 48) * (int)(Math.Pow(10,position));
position++;
}
return sum;
}))
{
Console.WriteLine(size);
}
回答10:
This site discusses alphanumeric sorting and will sort the numbers in a logical sense instead of an ASCII sense. It also takes into account the alphas around it:
http://www.dotnetperls.com/alphanumeric-sorting
EXAMPLE:
- C:/TestB/333.jpg
- 11
- C:/TestB/33.jpg
- 1
- C:/TestA/111.jpg
- 111F
- C:/TestA/11.jpg
- 2
- C:/TestA/1.jpg
- 111D
- 22
- 111Z
- C:/TestB/03.jpg
- 1
- 2
- 11
- 22
- 111D
- 111F
- 111Z
- C:/TestA/1.jpg
- C:/TestA/11.jpg
- C:/TestA/111.jpg
- C:/TestB/03.jpg
- C:/TestB/33.jpg
- C:/TestB/333.jpg
The code is as follows:
class Program
{
static void Main(string[] args)
{
var arr = new string[]
{
"C:/TestB/333.jpg",
"11",
"C:/TestB/33.jpg",
"1",
"C:/TestA/111.jpg",
"111F",
"C:/TestA/11.jpg",
"2",
"C:/TestA/1.jpg",
"111D",
"22",
"111Z",
"C:/TestB/03.jpg"
};
Array.Sort(arr, new AlphaNumericComparer());
foreach(var e in arr) {
Console.WriteLine(e);
}
}
}
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)
{
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;
}
}
回答11:
The answer given by Jeff Paulsen is correct but the Comprarer can be much simplified to this:
public class SemiNumericComparer: IComparer<string>
{
public int Compare(string s1, string s2)
{
if (IsNumeric(s1) && IsNumeric(s2))
return Convert.ToInt32(s1) - Convert.ToInt32(s2)
if (IsNumeric(s1) && !IsNumeric(s2))
return -1;
if (!IsNumeric(s1) && IsNumeric(s2))
return 1;
return string.Compare(s1, s2, true);
}
public static bool IsNumeric(object value)
{
int result;
return Int32.TryParse(value, out result);
}
}
This works because the only thing that is checked for the result of the Comparer is if the result is larger, smaller or equal to zero. One can simply subtract the values from another and does not have to handle the return values.
Also the IsNumeric method should not have to use a try-block and can benefit from TryParse.
And for those who are not sure:
This Comparer will sort values so, that non numeric values are always appended to the end of the list. If one wants them at the beginning the second and third if block have to be swapped.
回答12:
Try this :
string[] things= new string[] { "105", "101", "102", "103", "90" };
int tmpNumber;
foreach (var thing in (things.Where(xx => int.TryParse(xx, out tmpNumber)).OrderBy(xx => int.Parse(xx))).Concat(things.Where(xx => !int.TryParse(xx, out tmpNumber)).OrderBy(xx => xx)))
{
Console.WriteLine(thing);
}
回答13:
public class NaturalSort: IComparer<string>
{
[DllImport("shlwapi.dll", CharSet = CharSet.Unicode)]
public static extern int StrCmpLogicalW(string x, string y);
public int Compare(string x, string y)
{
return StrCmpLogicalW(x, y);
}
}
arr = arr.OrderBy(x => x, new NaturalSort()).ToArray();
The reason I needed it was to get filed in a directory whose filenames started with a number:
public static FileInfo[] GetFiles(string path)
{
return new DirectoryInfo(path).GetFiles()
.OrderBy(x => x.Name, new NaturalSort())
.ToArray();
}
回答14:
Try this out..
string[] things = new string[] { "paul", "bob", "lauren", "007", "90", "-10" };
List<int> num = new List<int>();
List<string> str = new List<string>();
for (int i = 0; i < things.Count(); i++)
{
int result;
if (int.TryParse(things[i], out result))
{
num.Add(result);
}
else
{
str.Add(things[i]);
}
}
Now Sort the lists and merge them back...
var strsort = from s in str
orderby s.Length
select s;
var numsort = from n in num
orderby n
select n;
for (int i = 0; i < things.Count(); i++)
{
if(i < numsort.Count())
things[i] = numsort.ElementAt(i).ToString();
else
things[i] = strsort.ElementAt(i - numsort.Count());
}
I jsut tried to make a contribution in this interesting question...
回答15:
My preferred solution (if all strings are numeric only):
// Order by numerical order: (Assertion: all things are numeric strings only)
foreach (var thing in things.OrderBy(int.Parse))
{
Console.Writeline(thing);
}
回答16:
public class Test
{
public void TestMethod()
{
List<string> buyersList = new List<string>() { "5", "10", "1", "str", "3", "string" };
List<string> soretedBuyersList = null;
soretedBuyersList = new List<string>(SortedList(buyersList));
}
public List<string> SortedList(List<string> unsoredList)
{
return unsoredList.OrderBy(o => o, new SortNumericComparer()).ToList();
}
}
public class SortNumericComparer : IComparer<string>
{
public int Compare(string x, string y)
{
int xInt = 0;
int yInt = 0;
int result = -1;
if (!int.TryParse(x, out xInt))
{
result = 1;
}
if(int.TryParse(y, out yInt))
{
if(result == -1)
{
result = xInt - yInt;
}
}
else if(result == 1)
{
result = string.Compare(x, y, true);
}
return result;
}
}
回答17:
Expanding on Jeff Paulsen answer. I wanted to make sure it didn't matter how many number or char groups were in the strings:
public class SemiNumericComparer : IComparer<string>
{
public int Compare(string s1, string s2)
{
if (int.TryParse(s1, out var i1) && int.TryParse(s2, out var i2))
{
if (i1 > i2)
{
return 1;
}
if (i1 < i2)
{
return -1;
}
if (i1 == i2)
{
return 0;
}
}
var text1 = SplitCharsAndNums(s1);
var text2 = SplitCharsAndNums(s2);
if (text1.Length > 1 && text2.Length > 1)
{
for (var i = 0; i < Math.Max(text1.Length, text2.Length); i++)
{
if (text1[i] != null && text2[i] != null)
{
var pos = Compare(text1[i], text2[i]);
if (pos != 0)
{
return pos;
}
}
else
{
//text1[i] is null there for the string is shorter and comes before a longer string.
if (text1[i] == null)
{
return -1;
}
if (text2[i] == null)
{
return 1;
}
}
}
}
return string.Compare(s1, s2, true);
}
private string[] SplitCharsAndNums(string text)
{
var sb = new StringBuilder();
for (var i = 0; i < text.Length - 1; i++)
{
if ((!char.IsDigit(text[i]) && char.IsDigit(text[i + 1])) ||
(char.IsDigit(text[i]) && !char.IsDigit(text[i + 1])))
{
sb.Append(text[i]);
sb.Append(" ");
}
else
{
sb.Append(text[i]);
}
}
sb.Append(text[text.Length - 1]);
return sb.ToString().Split(' ');
}
}
I also took SplitCharsAndNums from an SO Page after amending it to deal with file names.
回答18:
Even though this is an old question, I'd like to give a solution:
string[] things= new string[] { "105", "101", "102", "103", "90" };
foreach (var thing in things.OrderBy(x => Int32.Parse(x) )
{
Console.WriteLine(thing);
}
Woha quite simple right? :D
回答19:
namespace X
{
public class Utils
{
public class StrCmpLogicalComparer : IComparer<Projects.Sample>
{
[DllImport("Shlwapi.dll", CharSet = CharSet.Unicode)]
private static extern int StrCmpLogicalW(string x, string y);
public int Compare(Projects.Sample x, Projects.Sample y)
{
string[] ls1 = x.sample_name.Split("_");
string[] ls2 = y.sample_name.Split("_");
string s1 = ls1[0];
string s2 = ls2[0];
return StrCmpLogicalW(s1, s2);
}
}
}
}
来源：https://stackoverflow.com/questions/6396378/how-do-i-sort-strings-alphabetically-while-accounting-for-value-when-a-string-is