Sort (strings)

[csharpula csharp]

Hello,
What is the best way to sort strings by lentgh in .NET 2.o
?

What is the best way to implement it?
Thank u!

 

[Marc Gravell]

In 2.0 you can use the List<T>.Sort(Comparison<T>) overload:

List<string> list = new List<string>();
list.Add("abc");
list.Add("abcde");
list.Add("ab");

list.Sort(delegate(string x, string y)
{ return x.Length.CompareTo(y.Length); }
);

foreach (string s in list)
{
Console.WriteLine(s);
}

The alternative would be to write a class that implements
IComparer<string> - but the above is a lot easier ;-p
For reference, 3.5 (and LINQ) has a lot of support for ordering based
on projections (such as s => s.Length) - but if you have a C# 3
compiler you can still use this with .NET 2.0 via LINQBridge - then it
is as simple as:

foreach (string s in list.OrderBy(s=>s.Length))
{
Console.WriteLine(s);
}

http://www.albahari.com/nutshell/linqbridge.html

Marc

 

[Chris Dunaway]

In 2.0 you can use the List<T>.Sort(Comparison<T>) overload:

foreach (string s in list.OrderBy(s=>s.Length))
{
Console.WriteLine(s);
}

Hi Marc,

Am I correct in assuming that if you have multiple strings with the
same length, there is no guarantee as to the order of strings with the
same length?

In other words, if I have the strings:

ab
abcde
abc
abccd
abdc

Will abccd be sorted before abcde every time? Or does it depend on
their original order in the list?

Thanks,

Chris

 

[Marc Gravell]

You've quoted from 2 different examples there, and the behavior is
different... taking them separately:

In 2.0 you can use the List<T>.Sort(Comparison<T>) overload:

List<T> performs an unbalanced sort; there is no specific order to things
that match. You can add extra sorts, but short of introducing a row-index
(separately) there is no way of doing a balanced (matches listed in original
order) sort.

foreach (string s in list.OrderBy(s=>s.Length))

This is LINQ-to-Objects, which performs balanced sorts; so the order will
depend on the original order in the list. Obviously, if the LINQ query is
going to a different provider (LINQ-to-Foo), then it will be
provider-specific. If you want it sorted alphabetically, then you can append
a .ThenBy(), or use the alternative query langauge syntax.

Marc