Nice String Extensions
Ya Wheel
I discovered 5 minutes ago, that all wheels, I gona tell you today, already succesfully invented. But my is the prettiest ))
"Repeat me 3 times".Repeat(3); // :P
I need this code for creating dynamic tree from dashes like this “-”.Repeat(level). Unfortunatelly I did’not saw this forum post 
with StringBuilder effecient version, and also special way for chars. Thats what I was really looking. My code unfortunatelly much less effecient, but what I invented is this cool design with extension method. Soo human.
string displayName = null; string email = "web@mail" displayName.Coalesce(Email); // what the result?
What this thing do! We all know about coalesce method in C# - “??”. But it checks for nulls and we need something like this big and also very human-named method IsNullOrEmpty! Yes, its one more wheel - herу is one of implementations, a coalesce methods for C# 2.0 or even 1.0. My use all new features of C# 3.0
Wheel Code
Here we go:
public static class StringExtension { public static string Repeat(this string template, int repeatTime) { if (template == null) return null; int length = template.Length * repeatTime; char[] all_array = new char[length]; for (int i = 0; i < length; i++) { all_array[i] = template[i % template.Length]; //i - (i / tl) * tl } return new string(all_array); } public static string Coalesce(this string template, params object[] list) { if (!string.IsNullOrEmpty(template)){ return template; } return ((string)(list.FirstOrDefault( item => item != null || (item is string && ((string)item) != string.Empty) ) ?? string.Empty)); } }
Add tests, if you like such stuff:
[TestClass()] public class StringTest { [TestMethod()] public void CoalesceTest() { string first = "First"; string second = "Second"; string nullValue = null; Assert.AreEqual(first, first.Coalesce(second)); Assert.AreEqual(second, nullValue.Coalesce(second)); Assert.AreEqual(second, "".Coalesce(second)); Assert.AreEqual(string.Empty, nullValue.Coalesce(nullValue)); Assert.AreEqual(string.Empty, nullValue.Coalesce()); } [TestMethod()] public void RepeatTest() { string nullValue = null; Assert.AreEqual("", "".Repeat(3)); Assert.AreEqual(null, nullValue.Repeat(3)); Assert.AreEqual("---", "-".Repeat(3)); } }
