Sorting mixed numbers and strings

Use the other overload of OrderBy that takes an IComparer parameter.

You can then implement your own IComparer that uses int.TryParse to tell if it's a number or not.

Perhaps you could go with a more generic approach and use a natural sorting algorithm such as the C# implementation here.

Two ways come to mind, not sure which is more performant. Implement a custom IComparer:

class MyComparer : IComparer<string>
{
    public int Compare(string x, string y)
    {
        int xVal, yVal;
        var xIsVal = int.TryParse( x, out xVal );
        var yIsVal = int.TryParse( y, out yVal );

        if (xIsVal && yIsVal)   // both are numbers...
            return xVal.CompareTo(yVal);
        if (!xIsVal && !yIsVal) // both are strings...
            return x.CompareTo(y);
        if (xIsVal)             // x is a number, sort first
            return -1;
        return 1;               // x is a string, sort last
    }
}

var input = new[] {"a", "1", "10", "b", "2", "c"};
var e = input.OrderBy( s => s, new MyComparer() );

Or, split the sequence into numbers and non-numbers, then sort each subgroup, finally join the sorted results; something like:

var input = new[] {"a", "1", "10", "b", "2", "c"};

var result = input.Where( s => s.All( x => char.IsDigit( x ) ) )
                  .OrderBy( r => { int z; int.TryParse( r, out z ); return z; } )
                  .Union( input.Where( m => m.Any( x => !char.IsDigit( x ) ) )
                               .OrderBy( q => q ) );

I had a similar problem and landed here: sorting strings that have a numeric suffix as in the following example.

Original:

"Test2", "Test1", "Test10", "Test3", "Test20"

Default sort result:

"Test1", "Test10", "Test2", "Test20", "Test3"

Desired sort result:

"Test1", "Test2", "Test3, "Test10", "Test20"

I ended up using a custom Comparer:

public class NaturalComparer : IComparer
{

    public NaturalComparer()
    {
        _regex = new Regex("\\d+$", RegexOptions.IgnoreCase);
    }

    private Regex _regex;

    private string matchEvaluator(System.Text.RegularExpressions.Match m)
    {
        return Convert.ToInt32(m.Value).ToString("D10");
    }

    public int Compare(object x, object y)
    {
        x = _regex.Replace(x.ToString(), matchEvaluator);
        y = _regex.Replace(y.ToString(), matchEvaluator);

        return x.CompareTo(y);
    }
}   

Usage:

var input = new List<MyObject>(){...};
var sorted = input.OrderBy(o=>o.SomeStringMember, new NaturalComparer());

HTH ;o)