Read ARFF

Synopsis

This operator is used for reading an ARFF file.

Description

This operator can read ARFF (Attribute-Relation File Format) files known from the machine learning library Weka. An ARFF file is an ASCII text file that describes a list of instances sharing a set of attributes. ARFF files were developed by the Machine Learning Project at the Department of Computer Science of The University of Waikato for use with the Weka machine learning software. Please study the attachedExample Processfor understanding the basics and structure of the ARFF file format. Please note that when an ARFF file is written, the roles of the attributes are not stored. Similarly when an ARFF file is read, the roles of all the attributes are set to regular.

Input

file

An ARFF file is expected as a file object which can be created with other operators with file output ports like the Read File operator.

Output

output

This port delivers the ARFF file in tabular form along with the meta data. This output is similar to the output of the Retrieve operator.

Parameters

Data file

The path of the ARFF file is specified here. It can be selected using thechoose a filebutton.

Encoding

This is an expert parameter. A long list of encoding is provided; users can select any of them.

Read not matching values as missings

This is an expert parameter. If this parameter is set to true, values that do not match with the expected value type are considered as missing values and are replaced by '?'. For example if 'abc' is written in an integer column, it will be treated as a missing value. Question mark (?) in ARFF file is also read as missing value.

小数的性格cter

This character is used as the decimal character.

Grouped digits

This parameter decides whether grouped digits should be parsed or not. If this parameter is set to true, thegrouping characterparameter should be specified.

Grouping character

This parameter is available only when thegrouped digitsparameter is set to true.This character is used as the grouping character. If it is found between numbers, the numbers are combined and this character is ignored. For example if "22-14" is present in the ARFF file and "-" is set asgrouping character, then "2214" will be stored.

Infinity string

This parameter can be set to parse a specific infinity representation (e.g. "Infinity"). If it is not set, the local specific infinity representation will be used.