tech.tablesaw.api.TextColumn 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.api;
import com.google.common.base.Preconditions;
import com.google.common.collect.Lists;
import it.unimi.dsi.fastutil.ints.IntComparator;
import tech.tablesaw.columns.AbstractColumn;
import tech.tablesaw.columns.AbstractColumnParser;
import tech.tablesaw.columns.Column;
import tech.tablesaw.columns.strings.StringColumnFormatter;
import tech.tablesaw.columns.strings.StringFilters;
import tech.tablesaw.columns.strings.StringMapFunctions;
import tech.tablesaw.columns.strings.StringReduceUtils;
import tech.tablesaw.columns.strings.TextColumnType;
import tech.tablesaw.selection.BitmapBackedSelection;
import tech.tablesaw.selection.Selection;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Comparator;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
/**
* A column that contains String values. They are assumed to be free-form text. For categorical data, use stringColumn
*
* This is the default column type for SQL longvarchar and longnvarchar types
*
* Because the MISSING_VALUE for this column type is an empty string, there is little or no need for special handling
* of missing values in this class's methods.
*/
public class TextColumn extends AbstractColumn
implements CategoricalColumn, StringFilters, StringMapFunctions, StringReduceUtils {
// holds each element in the column.
private List values;
private StringColumnFormatter printFormatter = new StringColumnFormatter();
private final IntComparator rowComparator = (i, i1) -> {
String f1 = get(i);
String f2 = get(i1);
return f1.compareTo(f2);
};
private final Comparator descendingStringComparator = Comparator.reverseOrder();
private TextColumn(String name, List strings) {
super(TextColumnType.instance(), name);
values = new ArrayList<>(strings.size());
for (String string : strings) {
append(string);
}
}
private TextColumn(String name) {
super(TextColumnType.instance(), name);
values = new ArrayList<>(DEFAULT_ARRAY_SIZE);
}
private TextColumn(String name, String[] strings) {
super(TextColumnType.instance(), name);
values = new ArrayList<>(strings.length);
for (String string : strings) {
append(string);
}
}
public static boolean valueIsMissing(String string) {
return TextColumnType.missingValueIndicator().equals(string);
}
@Override
public TextColumn appendMissing() {
append(TextColumnType.missingValueIndicator());
return this;
}
public static TextColumn create(String name) {
return new TextColumn(name);
}
public static TextColumn create(String name, String[] strings) {
return new TextColumn(name, strings);
}
public static TextColumn create(String name, List strings) {
return new TextColumn(name, strings);
}
public static TextColumn create(String name, int size) {
ArrayList strings = new ArrayList<>(size);
for (int i = 0; i < size; i++) {
strings.add(TextColumnType.missingValueIndicator());
}
return new TextColumn(name, strings);
}
@Override
public boolean isMissing(int rowNumber) {
return get(rowNumber).equals(TextColumnType.missingValueIndicator());
}
public void setPrintFormatter(StringColumnFormatter formatter) {
Preconditions.checkNotNull(formatter);
this.printFormatter = formatter;
}
public StringColumnFormatter getPrintFormatter() {
return printFormatter;
}
@Override
public String getString(int row) {
return printFormatter.format(get(row));
}
@Override
public String getUnformattedString(int row) {
return String.valueOf(get(row));
}
@Override
public TextColumn emptyCopy() {
return create(name());
}
@Override
public TextColumn emptyCopy(int rowSize) {
return create(name(), rowSize);
}
@Override
public void sortAscending() {
values.sort(String::compareTo);
}
@Override
public void sortDescending() {
values.sort(descendingStringComparator);
}
/**
* Returns the number of elements (a.k.a. rows or cells) in the column
*
* @return size as int
*/
@Override
public int size() {
return values.size();
}
/**
* Returns the value at rowIndex in this column. The index is zero-based.
*
* @param rowIndex index of the row
* @return value as String
* @throws IndexOutOfBoundsException if the given rowIndex is not in the column
*/
public String get(int rowIndex) {
return values.get(rowIndex);
}
/**
* Returns a List<String> representation of all the values in this column
*
* NOTE: Unless you really need a string consider using the column itself for large datasets as it uses much less memory
*
* @return values as a list of String.
*/
public List asList() {
return new ArrayList<>(values);
}
@Override
public Table summary() {
Table table = Table.create("Column: " + name());
StringColumn measure = StringColumn.create("Measure");
StringColumn value = StringColumn.create("Value");
table.addColumns(measure);
table.addColumns(value);
measure.append("Count");
value.append(String.valueOf(size()));
measure.append("Missing");
value.append(String.valueOf(countMissing()));
return table;
}
@Override
public void clear() {
values.clear();
}
public TextColumn lead(int n) {
TextColumn column = lag(-n);
column.setName(name() + " lead(" + n + ")");
return column;
}
public TextColumn lag(int n) {
TextColumn copy = emptyCopy();
copy.setName(name() + " lag(" + n + ")");
if (n >= 0) {
for (int m = 0; m < n; m++) {
copy.appendCell(TextColumnType.missingValueIndicator());
}
for (int i = 0; i < size(); i++) {
if (i + n >= size()) {
break;
}
copy.appendCell(get(i));
}
} else {
for (int i = -n; i < size(); i++) {
copy.appendCell(get(i));
}
for (int m = 0; m > n; m--) {
copy.appendCell(TextColumnType.missingValueIndicator());
}
}
return copy;
}
/**
* Conditionally update this column, replacing current values with newValue for all rows where the current value
* matches the selection criteria
*
* Examples:
* myCatColumn.set(myCatColumn.isEqualTo("Cat"), "Dog"); // no more cats
* myCatColumn.set(myCatColumn.valueIsMissing(), "Fox"); // no more missing values
*/
public TextColumn set(Selection rowSelection, String newValue) {
for (int row : rowSelection) {
set(row, newValue);
}
return this;
}
public TextColumn set(int rowIndex, String stringValue) {
String str = TextColumnType.missingValueIndicator();
if (stringValue != null) {
str = stringValue;
}
values.set(rowIndex, str);
return this;
}
@Override
public int countUnique() {
return asSet().size();
}
/**
* Returns the largest ("top") n values in the column
*
* @param n The maximum number of records to return. The actual number will be smaller if n is greater than the
* number of observations in the column
* @return A list, possibly empty, of the largest observations
*/
public List top(int n) {
List top = new ArrayList<>();
TextColumn copy = this.copy();
copy.sortDescending();
for (int i = 0; i < n; i++) {
top.add(copy.get(i));
}
return top;
}
/**
* Returns the smallest ("bottom") n values in the column
*
* @param n The maximum number of records to return. The actual number will be smaller if n is greater than the
* number of observations in the column
* @return A list, possibly empty, of the smallest n observations
*/
public List bottom(int n) {
List bottom = new ArrayList<>();
TextColumn copy = this.copy();
copy.sortAscending();
for (int i = 0; i < n; i++) {
bottom.add(copy.get(i));
}
return bottom;
}
/**
* Returns true if this column contains a cell with the given string, and false otherwise
*
* @param aString the value to look for
* @return true if contains, false otherwise
*/
public boolean contains(String aString) {
return values.contains(aString);
}
@Override
public Column setMissing(int i) {
return set(i, TextColumnType.missingValueIndicator());
}
/**
* Add all the strings in the list to this column
*
* @param stringValues a list of values
*/
public TextColumn addAll(List stringValues) {
for (String stringValue : stringValues) {
append(stringValue);
}
return this;
}
@Override
public TextColumn appendCell(String object) {
values.add(TextColumnType.DEFAULT_PARSER.parse(object));
return this;
}
@Override
public TextColumn appendCell(String object, AbstractColumnParser parser) {
return appendObj(parser.parse(object));
}
@Override
public IntComparator rowComparator() {
return rowComparator;
}
@Override
public boolean isEmpty() {
return values.isEmpty();
}
/**
* Returns a new Column containing all the unique values in this column
*
* @return a column with unique values.
*/
@Override
public TextColumn unique() {
List strings = new ArrayList<>(asSet());
return TextColumn.create(name() + " Unique values", strings);
}
public TextColumn where(Selection selection) {
return (TextColumn) subset(selection.toArray());
}
// TODO (lwhite): This could avoid the append and do a list copy
@Override
public TextColumn copy() {
TextColumn newCol = create(name(), size());
int r = 0;
for (String string : this) {
newCol.set(r, string);
r++;
}
return newCol;
}
@Override
public TextColumn append(Column column) {
Preconditions.checkArgument(column.type() == this.type());
TextColumn source = (TextColumn) column;
final int size = source.size();
for (int i = 0; i < size; i++) {
append(source.getString(i));
}
return this;
}
@Override
public Column append(Column column, int row) {
return append(column.getUnformattedString(row));
}
@Override
public Column set(int row, Column column, int sourceRow) {
return set(row, column.getUnformattedString(sourceRow));
}
/**
* Returns the count of missing values in this column
*/
@Override
public int countMissing() {
int count = 0;
for (int i = 0; i < size(); i++) {
if (TextColumnType.missingValueIndicator().equals(get(i))) {
count++;
}
}
return count;
}
@Override
public TextColumn removeMissing() {
TextColumn noMissing = emptyCopy();
Iterator iterator = iterator();
while(iterator.hasNext()) {
String v = iterator.next();
if (!valueIsMissing(v)) {
noMissing.append(v);
}
}
return noMissing;
}
@Override
public Iterator iterator() {
return values.iterator();
}
public Set asSet() {
return new HashSet<>(values);
}
@Override
public int byteSize() {
return type().byteSize();
}
/**
* Returns the contents of the cell at rowNumber as a byte[]
*/
@Override
public byte[] asBytes(int rowNumber) {
return new byte[0];
//TODO (lwhite): FIX ME: return ByteBuffer.allocate(byteSize()).putInt(getInt(rowNumber)).array();
}
/**
* Added for naming consistency with all other columns
*/
public TextColumn append(String value) {
appendCell(value);
return this;
}
@Override
public TextColumn appendObj(Object obj) {
if (obj == null) {
return appendMissing();
}
if (!(obj instanceof String)) {
throw new IllegalArgumentException("Cannot append " + obj.getClass().getName() + " to TextColumn");
}
return append((String) obj);
}
@Override
public Selection isIn(String... strings) {
List stringList = Lists.newArrayList(strings);
Selection results = new BitmapBackedSelection();
for (int i = 0; i < size(); i++) {
if (stringList.contains(values.get(i))) {
results.add(i);
}
}
return results;
}
@Override
public Selection isIn(Collection strings) {
List stringList = Lists.newArrayList(strings);
Selection results = new BitmapBackedSelection();
for (int i = 0; i < size(); i++) {
if (stringList.contains(values.get(i))) {
results.add(i);
}
}
return results;
}
@Override
public Selection isNotIn(String... strings) {
Selection results = new BitmapBackedSelection();
results.addRange(0, size());
results.andNot(isIn(strings));
return results;
}
@Override
public Selection isNotIn(Collection strings) {
Selection results = new BitmapBackedSelection();
results.addRange(0, size());
results.andNot(isIn(strings));
return results;
}
public int firstIndexOf(String value) {
return values.indexOf(value);
}
@Override
public String[] asObjectArray() {
final String[] output = new String[size()];
for (int i = 0; i < size(); i++) {
output[i] = get(i);
}
return output;
}
@Override
public StringColumn asStringColumn() {
StringColumn textColumn = StringColumn.create(name(), size());
for (int i = 0; i < size(); i++) {
textColumn.set(i, get(i));
}
return textColumn;
}
@Override
public int compare(String o1, String o2) {
return o1.compareTo(o2);
}
}