smile.io

Class Arff

java.lang.Object

smile.io.Arff

All Implemented Interfaces:

java.lang.AutoCloseable

public class Arff
extends java.lang.Object
implements java.lang.AutoCloseable

Weka ARFF (attribute relation file format) is an ASCII text file format that is essentially a CSV file with a header that describes the meta-data. ARFF was developed for use in the Weka machine learning software.

A dataset is firstly described, beginning with the name of the dataset (or the relation in ARFF terminology). Each of the variables (or attribute in ARFF terminology) used to describe the observations is then identified, together with their data type, each definition on a single line. The actual observations are then listed, each on a single line, with fields separated by commas, much like a CSV file.

Missing values in an ARFF dataset are identified using the question mark '?'.

Comments can be included in the file, introduced at the beginning of a line with a '%', whereby the remainder of the line is ignored.

A significant advantage of the ARFF data file over the CSV data file is the meta data information.

Also, the ability to include comments ensure we can record extra information about the data set, including how it was derived, where it came from, and how it might be cited.

Constructor Summary

Constructors

Constructor and Description
Arff(java.nio.file.Path path) Constructor.
Arff(java.nio.file.Path path, java.nio.charset.Charset charset) Constructor.
Arff(java.io.Reader reader) Constructor.
Arff(java.lang.String path) Constructor.
Arff(java.lang.String path, java.nio.charset.Charset charset) Constructor.

Method Summary

Modifier and Type	Method and Description
void	close()
java.lang.String	name() Returns the name of relation.
smile.data.DataFrame	read() Reads all the records.
smile.data.DataFrame	read(int limit) Reads a limited number of records.
smile.data.type.StructType	schema() Returns the attribute set of given stream.
static void	write(smile.data.DataFrame df, java.nio.file.Path path, java.lang.String relation) Writes the data frame to an ARFF file.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Arff

public Arff(java.lang.String path)
     throws java.io.IOException,
            java.text.ParseException,
            java.net.URISyntaxException

Constructor.

Throws:

java.io.IOException

java.text.ParseException

java.net.URISyntaxException

Arff

public Arff(java.lang.String path,
            java.nio.charset.Charset charset)
     throws java.io.IOException,
            java.text.ParseException,
            java.net.URISyntaxException

Constructor.

Throws:

java.io.IOException

java.text.ParseException

java.net.URISyntaxException

Arff

public Arff(java.nio.file.Path path)
     throws java.io.IOException,
            java.text.ParseException

Constructor.

Throws:

java.io.IOException

java.text.ParseException

Arff

public Arff(java.nio.file.Path path,
            java.nio.charset.Charset charset)
     throws java.io.IOException,
            java.text.ParseException

Constructor.

Throws:

java.io.IOException

java.text.ParseException

Arff

public Arff(java.io.Reader reader)
     throws java.io.IOException,
            java.text.ParseException

Constructor.

Throws:

java.io.IOException

java.text.ParseException

Method Detail

close

public void close()
           throws java.io.IOException

Specified by:

close in interface java.lang.AutoCloseable

Throws:

java.io.IOException

name

public java.lang.String name()

Returns the name of relation.

schema

public smile.data.type.StructType schema()

Returns the attribute set of given stream.

read

public smile.data.DataFrame read()
                          throws java.io.IOException,
                                 java.text.ParseException

Reads all the records.

Throws:

java.io.IOException

java.text.ParseException

read

public smile.data.DataFrame read(int limit)
                          throws java.io.IOException,
                                 java.text.ParseException

Reads a limited number of records.

Parameters:

limit - reads a limited number of records.

Throws:

java.io.IOException

java.text.ParseException

write

public static void write(smile.data.DataFrame df,
                         java.nio.file.Path path,
                         java.lang.String relation)
                  throws java.io.IOException

Writes the data frame to an ARFF file.

Parameters:

df - the data frame.

path - the file path.

relation - the relation name of ARFF.

Throws:

java.io.IOException