tech.tablesaw.table.StandardTableSliceGroup Maven / Gradle / Ivy
/*
* 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 tech.tablesaw.table;
import tech.tablesaw.api.CategoricalColumn;
import tech.tablesaw.api.Table;
import tech.tablesaw.columns.Column;
import tech.tablesaw.selection.BitmapBackedSelection;
import tech.tablesaw.selection.Selection;
import java.nio.ByteBuffer;
import java.util.Arrays;
import java.util.List;
/**
* A group of tables formed by performing splitting operations on an original table
*/
public class StandardTableSliceGroup extends TableSliceGroup {
private StandardTableSliceGroup(Table original, CategoricalColumn... columns) {
super(original, splitColumnNames(columns));
setSourceTable(getSourceTable().sortOn(getSplitColumnNames()));
splitOn(getSplitColumnNames());
}
private static String[] splitColumnNames(CategoricalColumn... columns) {
String[] splitColumnNames = new String[columns.length];
for (int i = 0; i < columns.length; i++) {
splitColumnNames[i] = columns[i].name();
}
return splitColumnNames;
}
/**
* Returns a viewGroup splitting the original table on the given columns.
* The named columns must be CategoricalColumns
*/
public static StandardTableSliceGroup create(Table original, String... columnsNames) {
List> columns = original.categoricalColumns(columnsNames);
return new StandardTableSliceGroup(original, columns.toArray(new CategoricalColumn[0]));
}
/**
* Returns a viewGroup splitting the original table on the given columns.
* The named columns must be CategoricalColumns
*/
public static StandardTableSliceGroup create(Table original, CategoricalColumn... columns) {
return new StandardTableSliceGroup(original, columns);
}
/**
* Splits the sourceTable table into sub-tables, grouping on the columns whose names are given in
* splitColumnNames
*/
private void splitOn(String... columnNames) {
List> columns = getSourceTable().columns(columnNames);
int byteSize = getByteSize(columns);
byte[] currentKey = null;
String currentStringKey = null;
TableSlice view;
Selection selection = new BitmapBackedSelection();
for (int row = 0; row < getSourceTable().rowCount(); row++) {
ByteBuffer byteBuffer = ByteBuffer.allocate(byteSize);
String newStringKey = "";
for (int col = 0; col < columnNames.length; col++) {
if (col > 0) {
newStringKey = newStringKey + SPLIT_STRING;
}
Column c = getSourceTable().column(columnNames[col]);
String groupKey = getSourceTable().getUnformatted(row, getSourceTable().columnIndex(c));
newStringKey = newStringKey + groupKey;
byteBuffer.put(c.asBytes(row));
}
byte[] newKey = byteBuffer.array();
if (row == 0) {
currentKey = newKey;
currentStringKey = newStringKey;
}
if (!Arrays.equals(newKey, currentKey)) {
currentKey = newKey;
view = new TableSlice(getSourceTable(), selection);
view.setName(currentStringKey);
currentStringKey = newStringKey;
addSlice(view);
selection = new BitmapBackedSelection();
selection.add(row);
} else {
selection.add(row);
}
}
if (!selection.isEmpty()) {
view = new TableSlice(getSourceTable(), selection);
view.setName(currentStringKey);
addSlice(view);
}
}
}