Commatizing numbers: Difference between revisions

=={{header|C#}}==

<lang csharp>

static string[] inputs = {

"pi=3.14159265358979323846264338327950288419716939937510582097494459231",

"The author has two Z$100000000000000 Zimbabwe notes (100 trillion).",

"\"-in Aus$+1411.8millions\"",

"===US$0017440 millions=== (in 2000 dollars)"

};

void Main()

{

inputs.Select(s => Commatize(s, 0, 3, ",")).Dump();

}

string Commatize(string text, int startPosition, int interval, string separator)

{

var matches = Regex.Matches(text.Substring(startPosition), "[0-9]*");

var x = matches.Cast<Match>().Select(match => Commatize(match, interval, separator, text)).ToList();

return string.Join("", x);

}

string Commatize(Match match, int interval, string separator, string original)

{

if (match.Length <= interval)

return original.Substring(match.Index,

match.Index == original.Length ? 0 : Math.Max(match.Length, 1));

return string.Join(separator, match.Value.Split(interval));

}

public static class Extension

{

public static string[] Split(this string source, int interval)

{

return SplitImpl(source, interval).ToArray();

}

static IEnumerable<string>SplitImpl(string source, int interval)

{

for (int i = 1; i < source.Length; i++)

{

if (i % interval != 0) continue;

yield return source.Substring(i - interval, interval);

}

}

}

</lang>