Mega Code Archive
Map techniques
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import java.util.Collection;
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;
public class Main {
public static void main(String args[]) {
Map<String, Integer> atomNums = new TreeMap<String, Integer>();
atomNums.put("A", 1);
atomNums.put("B", 2);
atomNums.put("C", 3);
atomNums.put("D", 4);
atomNums.put("E", 5);
atomNums.put("F", 6);
System.out.println("The map contains these " + atomNums.size() + " entries:");
Set<Map.Entry<String, Integer>> set = atomNums.entrySet();
for (Map.Entry<String, Integer> me : set) {
System.out.print(me.getKey() + ", Atomic Number: ");
System.out.println(me.getValue());
}
TreeMap<String, Integer> atomNums2 = new TreeMap<String, Integer>();
atomNums2.put("Q", 30);
atomNums2.put("W", 82);
atomNums.putAll(atomNums2);
set = atomNums.entrySet();
System.out.println("The map now contains these " + atomNums.size() + " entries:");
for (Map.Entry<String, Integer> me : set) {
System.out.print(me.getKey() + ", Atomic Number: ");
System.out.println(me.getValue());
}
if (atomNums.containsKey("A"))
System.out.println("A has an atomic number of " + atomNums.get("A"));
if (atomNums.containsValue(82))
System.out.println("The atomic number 82 is in the map.");
System.out.println();
if (atomNums.remove("A") != null)
System.out.println("A has been removed.\n");
else
System.out.println("Entry not found.\n");
Set<String> keys = atomNums.keySet();
for (String str : keys)
System.out.println(str + " ");
Collection<Integer> vals = atomNums.values();
for (Integer n : vals)
System.out.println(n + " ");
atomNums.clear();
if (atomNums.isEmpty())
System.out.println("The map is now empty.");
}
}
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