public static T RandomSingle <T>(this BaseCombinatoric <T> source)
{
var count = source.LongCount;
if (count == 0L)
{
throw new InvalidOperationException("source contains no element");
}
return(source.ElementAt(MathExt.Random.NextLong(count)));
}
public static T RandomSingleOrDefault <T>(this BaseCombinatoric <T> source)
{
var count = source.LongCount;
if (count == 0L)
{
return(default(T));
}
return(source.ElementAt(MathExt.Random.NextLong(count)));
}
