Examples with BitmapBackedSelection tech.tablesaw.selection.BitmapBackedSelection used on opensource projects

Example 36 with BitmapBackedSelection

use of tech.tablesaw.selection.BitmapBackedSelection in project symja_android_library by axkr.

the class Rows method tail.

public static void tail(int rowsToInclude, Table oldTable, Table newTable) {
    int oldTableSize = oldTable.rowCount();
    int start = oldTableSize - rowsToInclude;
    Selection rows = new BitmapBackedSelection(rowsToInclude);
    for (int i = start; i < oldTableSize; i++) {
        rows.add(i);
    }
    copyRowsToTable(rows, oldTable, newTable);
}

Example 37 with BitmapBackedSelection

use of tech.tablesaw.selection.BitmapBackedSelection in project symja_android_library by axkr.

the class StandardTableSliceGroup method splitOn.

/**
 * Splits the sourceTable table into sub-tables, grouping on the columns whose names are given in
 * splitColumnNames
 */
private void splitOn(String... splitColumnNames) {
    Map<ByteArray, Selection> selectionMap = new LinkedHashMap<>();
    Map<ByteArray, String> sliceNameMap = new HashMap<>();
    List<Column<?>> splitColumns = getSourceTable().columns(splitColumnNames);
    if (containsTextColumn(splitColumns)) {
        for (int i = 0; i < getSourceTable().rowCount(); i++) {
            ByteArrayList byteArrayList = new ByteArrayList();
            StringBuilder stringKey = new StringBuilder();
            int count = 0;
            for (Column<?> col : splitColumns) {
                stringKey.append(col.getString(i));
                if (count < splitColumns.size() - 1) {
                    stringKey.append(SPLIT_STRING);
                }
                byteArrayList.addElements(byteArrayList.size(), col.asBytes(i));
                count++;
            }
            // Add to the matching selection.
            ByteArray byteArray = new ByteArray(byteArrayList.toByteArray());
            Selection selection = selectionMap.getOrDefault(byteArray, new BitmapBackedSelection());
            selection.add(i);
            selectionMap.put(byteArray, selection);
            sliceNameMap.put(byteArray, stringKey.toString());
        }
    } else {
        // handle the case where split is on non-text-columns
        int byteSize = getByteSize(splitColumns);
        for (int i = 0; i < getSourceTable().rowCount(); i++) {
            StringBuilder stringKey = new StringBuilder();
            ByteBuffer byteBuffer = ByteBuffer.allocate(byteSize);
            int count = 0;
            for (Column<?> col : splitColumns) {
                stringKey.append(col.getString(i));
                if (count < splitColumns.size() - 1) {
                    stringKey.append(SPLIT_STRING);
                }
                byteBuffer.put(col.asBytes(i));
                count++;
            }
            // Add to the matching selection.
            ByteArray byteArray = new ByteArray(byteBuffer.array());
            Selection selection = selectionMap.getOrDefault(byteArray, new BitmapBackedSelection());
            selection.add(i);
            selectionMap.put(byteArray, selection);
            sliceNameMap.put(byteArray, stringKey.toString());
        }
    }
    // Construct slices for all the values in our maps
    for (Entry<ByteArray, Selection> entry : selectionMap.entrySet()) {
        TableSlice slice = new TableSlice(getSourceTable(), entry.getValue());
        slice.setName(sliceNameMap.get(entry.getKey()));
        addSlice(slice);
    }
}

Example 38 with BitmapBackedSelection

use of tech.tablesaw.selection.BitmapBackedSelection in project symja_android_library by axkr.

the class RollingColumn method calc.

@SuppressWarnings({ "unchecked" })
public <INCOL extends Column<?>, OUT> Column<?> calc(AggregateFunction<INCOL, OUT> function) {
    // TODO: the subset operation copies the array. creating a view would likely be more efficient
    Column<?> result = function.returnType().create(generateNewColumnName(function));
    for (int i = 0; i < window - 1; i++) {
        result.appendMissing();
    }
    for (int origColIndex = 0; origColIndex < column.size() - window + 1; origColIndex++) {
        Selection selection = new BitmapBackedSelection();
        selection.addRange(origColIndex, origColIndex + window);
        INCOL subsetCol = (INCOL) column.subset(selection.toArray());
        OUT answer = function.summarize(subsetCol);
        if (answer instanceof Number) {
            Number number = (Number) answer;
            ((DoubleColumn) result).append(number.doubleValue());
        } else {
            result.appendObj(answer);
        }
    }
    return result;
}

Example 39 with BitmapBackedSelection

use of tech.tablesaw.selection.BitmapBackedSelection in project symja_android_library by axkr.

the class Table method dropWhere.

public Table dropWhere(Selection selection) {
    Selection opposite = new BitmapBackedSelection();
    opposite.addRange(0, rowCount());
    opposite.andNot(selection);
    Table newTable = this.emptyCopy(opposite.size());
    Rows.copyRowsToTable(opposite, this, newTable);
    return newTable;
}

Example 40 with BitmapBackedSelection

use of tech.tablesaw.selection.BitmapBackedSelection in project symja_android_library by axkr.

the class Table method sampleSplit.

/**
 * Splits the table into two, randomly assigning records to each according to the proportion given
 * in trainingProportion
 *
 * @param table1Proportion The proportion to go in the first table
 * @return An array two tables, with the first table having the proportion specified in the method
 *     parameter, and the second table having the balance of the rows
 */
public Table[] sampleSplit(double table1Proportion) {
    Table[] tables = new Table[2];
    int table1Count = (int) Math.round(rowCount() * table1Proportion);
    Selection table2Selection = new BitmapBackedSelection();
    for (int i = 0; i < rowCount(); i++) {
        table2Selection.add(i);
    }
    Selection table1Selection = new BitmapBackedSelection();
    Selection table1Records = selectNRowsAtRandom(table1Count, rowCount());
    for (int table1Record : table1Records) {
        table1Selection.add(table1Record);
    }
    table2Selection.andNot(table1Selection);
    tables[0] = where(table1Selection);
    tables[1] = where(table2Selection);
    return tables;
}