private static int FindLengthOfArray(string fieldName, string[] columns)
{
var length = 0;
for (var i = 0; i < columns.Length; ++i)
{
var pattern = @"\b" + fieldName + @"_(\d*)\b";
if (Regex.IsMatch(columns[i], pattern))
{
++length;
}
}
return length;
}