/// <summary>
/// Initializes a new <see cref="ArffAttribute"/> instance with the specified name and attribute type.
/// </summary>
/// <param name="name">The name of the attribute to create.</param>
/// <param name="type">The type of the attribute to create.</param>
/// <exception cref="ArgumentNullException"/>
public ArffAttribute(string name, ArffAttributeType type)
{
if (name == null)
{
throw new ArgumentNullException(nameof(name));
}
if (type == null)
{
throw new ArgumentNullException(nameof(type));
}
Name = name;
Type = type;
}
private object ParseValue(string value, bool quoted, ArffAttributeType attributeType)
{
if (!quoted && value == "?")
{
return(null);
}
if (attributeType == ArffAttributeType.Numeric)
{
if (!double.TryParse(value, NumberStyles.Float, CultureInfo.InvariantCulture, out double d))
{
throw new InvalidDataException($"Unrecognized data value: \"{value}\"");
}
return(d);
}
else if (attributeType == ArffAttributeType.String)
{
return(value);
}
else if (attributeType is ArffNominalAttribute nominalAttribute)
{
int index = nominalAttribute.Values.IndexOf(value);
if (index == -1)
{
throw new InvalidDataException($"Unrecognized data value: \"{value}\"");
}
return(index);
}
else if (attributeType is ArffDateAttribute dateAttribute)
{
if (!DateTime.TryParseExact(value, dateAttribute.DateFormat, CultureInfo.InvariantCulture, DateTimeStyles.NoCurrentDateDefault, out DateTime d))
{
throw new InvalidDataException($"Unrecognized data value: \"{value}\"");
}
return(d);
}
else if (attributeType is ArffRelationalAttribute relationalAttribute)
{
List <object[]> relationalInstances = new List <object[]>();
using (StringReader stringReader = new StringReader(value))
while (true)
{
// weights for relational instances are currently discarded
object[] instance = ReadInstance(out double?instanceWeight, relationalAttribute.ChildAttributes, stringReader);
if (instance == null)
{
break;
}
relationalInstances.Add(instance);
}
return(relationalInstances.ToArray());
}
else
{
throw new ArgumentException("Unsupported ArffAttributeType.", nameof(attributeType));
}
}
private ArffAttribute ReadAttribute()
{
string attributeName = ReadToken(endOfLine: false);
string typeString = ReadToken(endOfLine: false, quoting: false);
ArffAttributeType attributeType;
if (string.Equals(typeString, "numeric", StringComparison.OrdinalIgnoreCase) ||
string.Equals(typeString, "integer", StringComparison.OrdinalIgnoreCase) ||
string.Equals(typeString, "real", StringComparison.OrdinalIgnoreCase))
{
attributeType = ArffAttributeType.Numeric;
ReadToken(endOfLine: true);
}
else if (string.Equals(typeString, "string", StringComparison.OrdinalIgnoreCase))
{
attributeType = ArffAttributeType.String;
ReadToken(endOfLine: true);
}
else if (string.Equals(typeString, "date", StringComparison.OrdinalIgnoreCase))
{
string dateFormat = ReadToken();
if (dateFormat == null)
{
attributeType = ArffAttributeType.Date();
}
else
{
attributeType = ArffAttributeType.Date(dateFormat);
ReadToken(endOfLine: true);
}
}
else if (typeString == "{")
{
List <string> nominalValues = new List <string>();
while (true)
{
string value = ReadToken(out bool quoted, endOfLine: false);
if (!quoted && value == "}")
{
break;
}
else if (!quoted && value == ",")
{
continue;
}
else
{
nominalValues.Add(value);
}
}
attributeType = ArffAttributeType.Nominal(nominalValues);
ReadToken(endOfLine: true);
}
else if (string.Equals(typeString, "relational", StringComparison.OrdinalIgnoreCase))
{
ReadToken(endOfLine: true);
List <ArffAttribute> childAttributes = new List <ArffAttribute>();
while (true)
{
string token = ReadToken(skipEndOfLine: true, endOfLine: false, quoting: false);
if (string.Equals(token, "@attribute", StringComparison.OrdinalIgnoreCase))
{
ArffAttribute attribute = ReadAttribute();
childAttributes.Add(attribute);
}
else if (string.Equals(token, "@end", StringComparison.OrdinalIgnoreCase))
{
ReadToken(expectedToken: attributeName, endOfLine: false);
ReadToken(endOfLine: true);
break;
}
else
{
throw new InvalidDataException($"Unexpected token \"{token}\". Expected \"@attribute\" or \"@end\".");
}
}
attributeType = ArffAttributeType.Relational(childAttributes);
}
else
{
throw new InvalidDataException($"Unexpected token \"{typeString}\". Expected attribute type.");
}
return(new ArffAttribute(attributeName, attributeType));
}
