Java by API/java.util/TreeMap — различия между версиями

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Версия 17:43, 31 мая 2010

new TreeMap < K, V > ()

  
/**
 *Output: 
 D: 99.22
 A: 3434.34
 C: 1378.0
 B: 123.22
 E: -19.08
 B"s new balance: 1123.22
 */
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;
public class MainClass {
  public static void main(String args[]) {
    TreeMap<String, Double> tm = new TreeMap<String, Double>();
    tm.put("A", new Double(3434.34));
    tm.put("B", new Double(123.22));
    tm.put("C", new Double(1378.00));
    tm.put("D", new Double(99.22));
    tm.put("E", new Double(-19.08));
    Set<Map.Entry<String, Double>> set = tm.entrySet();
    for (Map.Entry<String, Double> me : set) {
      System.out.print(me.getKey() + ": ");
      System.out.println(me.getValue());
    }
    System.out.println();
    double balance = tm.get("B");
    tm.put("B", balance + 1000);
    System.out.println("B"s new balance: " + tm.get("B"));
  }
}





TreeMap: entrySet()

  
/**
 *Output: 
 D: 99.22
 A: 3434.34
 C: 1378.0
 B: 123.22
 E: -19.08
 B"s new balance: 1123.22
 */
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;
public class MainClass {
  public static void main(String args[]) {
    TreeMap<String, Double> tm = new TreeMap<String, Double>();
    tm.put("A", new Double(3434.34));
    tm.put("B", new Double(123.22));
    tm.put("C", new Double(1378.00));
    tm.put("D", new Double(99.22));
    tm.put("E", new Double(-19.08));
    Set<Map.Entry<String, Double>> set = tm.entrySet();
    for (Map.Entry<String, Double> me : set) {
      System.out.print(me.getKey() + ": ");
      System.out.println(me.getValue());
    }
    System.out.println();
    double balance = tm.get("B");
    tm.put("B", balance + 1000);
    System.out.println("B"s new balance: " + tm.get("B"));
  }
}





TreeMap: firstKey()

  
/*
 Output:
Virginia, New York, Massachusetts
 * */
import java.util.TreeMap;
public class MainClass {
  public static void main(String args[]) {
    TreeMap map = new TreeMap();
    map.put("Virginia", "Richmond");
    map.put("Massachusetts", "Boston");
    map.put("New York", "Albany");
    map.put("Maryland", "Annapolis");
    if (!map.isEmpty()) {
      Object last = map.lastKey();
      boolean first = true;
      do {
        if (!first) {
          System.out.print(", ");
        }
        System.out.print(last);
        last = map.headMap(last).lastKey();
        first = false;
      } while (last != map.firstKey());
      System.out.println();
    }
  }
}





TreeMap: get(K k)

  
/**
 *Output: 
 D: 99.22
 A: 3434.34
 C: 1378.0
 B: 123.22
 E: -19.08
 B"s new balance: 1123.22
 */
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;
public class MainClass {
  public static void main(String args[]) {
    TreeMap<String, Double> tm = new TreeMap<String, Double>();
    tm.put("A", new Double(3434.34));
    tm.put("B", new Double(123.22));
    tm.put("C", new Double(1378.00));
    tm.put("D", new Double(99.22));
    tm.put("E", new Double(-19.08));
    Set<Map.Entry<String, Double>> set = tm.entrySet();
    for (Map.Entry<String, Double> me : set) {
      System.out.print(me.getKey() + ": ");
      System.out.println(me.getValue());
    }
    System.out.println();
    double balance = tm.get("B");
    tm.put("B", balance + 1000);
    System.out.println("B"s new balance: " + tm.get("B"));
  }
}





TreeMap: headMap(K toKey)

  
/*
 Output:
Virginia, New York, Massachusetts
 * */
import java.util.TreeMap;
public class MainClass {
  public static void main(String args[]) {
    TreeMap map = new TreeMap();
    map.put("Virginia", "Richmond");
    map.put("Massachusetts", "Boston");
    map.put("New York", "Albany");
    map.put("Maryland", "Annapolis");
    if (!map.isEmpty()) {
      Object last = map.lastKey();
      boolean first = true;
      do {
        if (!first) {
          System.out.print(", ");
        }
        System.out.print(last);
        last = map.headMap(last).lastKey();
        first = false;
      } while (last != map.firstKey());
      System.out.println();
    }
  }
}





TreeMap: headMap(K toKey, boolean inclusive)

  
import java.util.TreeMap;
public class Main {
  public static void main(String[] a) {
    TreeMap<String,String> map = new TreeMap<String,String>();
    map.put("key1", "value1");
    map.put("key2", "value2");
    map.put("key3", "value3");
    if (!map.isEmpty()) {
      String last = map.lastKey();
      boolean first = true;
      do {
        if (!first) {
          System.out.print(", ");
        }
        System.out.print(last);
        last = map.headMap(last, true).lastKey();
        first = false;
      } while (last != map.firstKey());
      System.out.println();
    }
  }
}





TreeMap: higherKey(K key)

  

import java.util.TreeMap;
public class Main {
  public static void main(String[] args) {
    TreeMap<Integer, Product> db = new TreeMap<Integer, Product>();
    db.put(1000, new Product("D", 350));
    db.put(1011, new Product("p", 15.75));
    db.put(1102, new Product("M", 8.50));
    db.put(2023, new Product("A", 150));
    db.put(2034, new Product("T", 9.99));
    System.out.println(db.subMap(1000, 1999) + "\n");
    System.out.println(db.tailMap(1011) + "\n");
    System.out.println(db.headMap(2023));
    System.out.println("First key higher than 2034: " + db.higherKey(2034));
    System.out.println("First key lower than 2034: " + db.lowerKey(2034));
  }
}
class Product {
  String desc;
  double price;
  Product(String desc, double price) {
    this.desc = desc;
    this.price = price;
  }
  public String toString() {
    return "Description=" + desc + ", Price=" + price;
  }
}





TreeMap: lastKey()

  
/*
 Output:
Virginia, New York, Massachusetts
 * */
import java.util.TreeMap;
public class MainClass {
  public static void main(String args[]) {
    TreeMap map = new TreeMap();
    map.put("Virginia", "Richmond");
    map.put("Massachusetts", "Boston");
    map.put("New York", "Albany");
    map.put("Maryland", "Annapolis");
    if (!map.isEmpty()) {
      Object last = map.lastKey();
      boolean first = true;
      do {
        if (!first) {
          System.out.print(", ");
        }
        System.out.print(last);
        last = map.headMap(last).lastKey();
        first = false;
      } while (last != map.firstKey());
      System.out.println();
    }
  }
}





TreeMap: lowerKey(K key)

  

import java.util.TreeMap;
public class Main {
  public static void main(String[] args) {
    TreeMap<Integer, Product> db = new TreeMap<Integer, Product>();
    db.put(1000, new Product("D", 350));
    db.put(1011, new Product("p", 15.75));
    db.put(1102, new Product("M", 8.50));
    db.put(2023, new Product("A", 150));
    db.put(2034, new Product("T", 9.99));
    System.out.println(db.subMap(1000, 1999) + "\n");
    System.out.println(db.tailMap(1011) + "\n");
    System.out.println(db.headMap(2023));
    System.out.println("First key higher than 2034: " + db.higherKey(2034));
    System.out.println("First key lower than 2034: " + db.lowerKey(2034));
  }
}
class Product {
  String desc;
  double price;
  Product(String desc, double price) {
    this.desc = desc;
    this.price = price;
  }
  public String toString() {
    return "Description=" + desc + ", Price=" + price;
  }
}





TreeMap: put(K k, V v)

  
/**
 *Output: 
 D: 99.22
 A: 3434.34
 C: 1378.0
 B: 123.22
 E: -19.08
 B"s new balance: 1123.22
 */
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;
public class MainClass {
  public static void main(String args[]) {
    TreeMap<String, Double> tm = new TreeMap<String, Double>();
    tm.put("A", new Double(3434.34));
    tm.put("B", new Double(123.22));
    tm.put("C", new Double(1378.00));
    tm.put("D", new Double(99.22));
    tm.put("E", new Double(-19.08));
    Set<Map.Entry<String, Double>> set = tm.entrySet();
    for (Map.Entry<String, Double> me : set) {
      System.out.print(me.getKey() + ": ");
      System.out.println(me.getValue());
    }
    System.out.println();
    double balance = tm.get("B");
    tm.put("B", balance + 1000);
    System.out.println("B"s new balance: " + tm.get("B"));
  }
}





TreeMap: size()

 
import java.util.TreeMap;
public class Main {
  public static void main(String[] args) {
    TreeMap<String,String> treeMap = new TreeMap<String,String>();
    treeMap.put("1", "One");
    treeMap.put("2", "Two");
    treeMap.put("3", "Three");
    treeMap.clear();
    System.out.println(treeMap.size());
  }
}





TreeMap: subMap(K fromKey, K toKey)

  

import java.util.TreeMap;
public class Main {
  public static void main(String[] args) {
    TreeMap<Integer, Product> db = new TreeMap<Integer, Product>();
    db.put(1000, new Product("D", 350));
    db.put(1011, new Product("p", 15.75));
    db.put(1102, new Product("M", 8.50));
    db.put(2023, new Product("A", 150));
    db.put(2034, new Product("T", 9.99));
    System.out.println(db.subMap(1000, 1999) + "\n");
    System.out.println(db.tailMap(1011) + "\n");
    System.out.println(db.headMap(2023));
    System.out.println("First key higher than 2034: " + db.higherKey(2034));
    System.out.println("First key lower than 2034: " + db.lowerKey(2034));
  }
}
class Product {
  String desc;
  double price;
  Product(String desc, double price) {
    this.desc = desc;
    this.price = price;
  }
  public String toString() {
    return "Description=" + desc + ", Price=" + price;
  }
}





TreeMap: tailMap(T fromKey)

  

import java.util.TreeMap;
public class Main {
  public static void main(String[] args) {
    TreeMap<Integer, Product> db = new TreeMap<Integer, Product>();
    db.put(1000, new Product("D", 350));
    db.put(1011, new Product("p", 15.75));
    db.put(1102, new Product("M", 8.50));
    db.put(2023, new Product("A", 150));
    db.put(2034, new Product("T", 9.99));
    System.out.println(db.subMap(1000, 1999) + "\n");
    System.out.println(db.tailMap(1011) + "\n");
    System.out.println(db.headMap(2023));
    System.out.println("First key higher than 2034: " + db.higherKey(2034));
    System.out.println("First key lower than 2034: " + db.lowerKey(2034));
  }
}
class Product {
  String desc;
  double price;
  Product(String desc, double price) {
    this.desc = desc;
    this.price = price;
  }
  public String toString() {
    return "Description=" + desc + ", Price=" + price;
  }
}





TreeMap: values()

 
import java.util.Collection;
import java.util.Iterator;
import java.util.TreeMap;
public class Main {
  public static void main(String[] args) {
    TreeMap<String, String> treeMap = new TreeMap<String,String>();
    treeMap.put("1", "One");
    treeMap.put("2", "Two");
    treeMap.put("3", "Three");
    Collection c = treeMap.values();
    Iterator itr = c.iterator();
    while (itr.hasNext()){
      System.out.println(itr.next());
    }
  }
}


Источник — «http://jexp.ru/index.php?title=Java_by_API/java.util/TreeMap&oldid=94»