org.datavec.local.transforms.misc.SequenceWritablesToStringFunction Maven / Gradle / Ivy
/*-
* * Copyright 2016 Skymind, Inc.
* *
* * Licensed under the Apache License, Version 2.0 (the "License");
* * you may not use this file except in compliance with the License.
* * You may obtain a copy of the License at
* *
* * http://www.apache.org/licenses/LICENSE-2.0
* *
* * Unless required by applicable law or agreed to in writing, software
* * distributed under the License is distributed on an "AS IS" BASIS,
* * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* * See the License for the specific language governing permissions and
* * limitations under the License.
*/
package org.datavec.local.transforms.misc;
import lombok.AllArgsConstructor;
import org.datavec.api.writable.Writable;
import org.nd4j.linalg.function.Function;
import java.util.List;
/**
* Simple function to map sequence examples to a String format (such as CSV)
* with given quote around the string value if it contains the delimiter.
*
* @author Alex Black
*/
@AllArgsConstructor
public class SequenceWritablesToStringFunction implements Function>, String> {
public static final String DEFAULT_DELIMITER = ",";
public static final String DEFAULT_TIME_STEP_DELIMITER = "\n";
private final String delimiter;
private final String timeStepDelimiter;
private final String quote;
/**
* Function with default delimiters ("," and "\n")
*/
public SequenceWritablesToStringFunction() {
this(DEFAULT_DELIMITER);
}
/**
* function with default delimiter ("\n") between time steps
* @param delim Delimiter between values within a single time step
*/
public SequenceWritablesToStringFunction(String delim) {
this(delim, DEFAULT_TIME_STEP_DELIMITER, null);
}
/**
*
* @param delim The delimiter between column values in a single time step (for example, ",")
* @param timeStepDelimiter The delimiter between time steps (for example, "\n")
*/
public SequenceWritablesToStringFunction(String delim, String timeStepDelimiter) {
this(delim, timeStepDelimiter, null);
}
@Override
public String apply(List> c) {
StringBuilder sb = new StringBuilder();
boolean firstLine = true;
for (List timeStep : c) {
if (!firstLine) {
sb.append(timeStepDelimiter);
}
WritablesToStringFunction.append(timeStep, sb, delimiter, quote);
firstLine = false;
}
return sb.toString();
}
}