Iterating through a HashMap
15,841
The errors you are getting are due to:
You did not import
java.util.Iterator
HashMap.Entry
is a private inner class. You should useMap.Entry
Also you should, as templatetypedef says, use the generic version of Iterator, or use a for-each construct.
ADDENDUM
Here is some actual code, demonstrating both approaches:
import java.util.Map;
import java.util.HashMap;
import java.util.Iterator;
public class MapExample {
public static void main(String[] args) {
Map<String, Integer> m = new HashMap<String, Integer>();
m.put("One", 1);
m.put("Two", 2);
m.put("Three", 3);
// Using a for-each
for (Map.Entry<String, Integer> e: m.entrySet()) {
System.out.println(e.getKey() + " => " + e.getValue());
}
// Using an iterator
Iterator<Map.Entry<String, Integer>> it = m.entrySet().iterator();
while (it.hasNext()) {
Map.Entry e = (Map.Entry<String, Integer>)it.next();
System.out.println(e.getKey() + " => " + e.getValue());
}
}
}
Author by
Travis
Updated on June 05, 2022Comments
-
Travis almost 2 years
Okay so i'm currently working on a searching method, the terms searched are ran through the database and the matching products are added to a hashMap with 2 Integer fields.
then after the hashmap is made, the items are to be shown, however i'm having trouble getting the hashmap to print out the details
here's my code
public HashMap<Integer, Integer> bankSearch = new HashMap<Integer, Integer>();
and the use
Iterator it = bankSearch.entrySet().iterator(); while (it.hasNext()) { HashMap.Entry pairs = (HashMap.Entry)it.next(); System.out.println(pairs.getKey() + " = " + pairs.getValue()); if (bankItemsN[i] > 254) { outStream.writeByte(255); outStream.writeDWord_v2(pairs.getValue()); } else { outStream.writeByte(pairs.getValue()); // amount } if (bankItemsN[i] < 1) { bankItems[i] = 0; } outStream.writeWordBigEndianA(pairs.getKey()); // itemID }
current errors
.\src\client.java:75: cannot find symbol symbol : class Iterator location: class client Iterator it = bankSearch.entrySet().iterator(); ^ .\src\client.java:77: java.util.HashMap.Entry is not public in java.util.HashMap ; cannot be accessed from outside package HashMap.Entry pairs = (HashMap.Entry)it.next(); ^ .\src\client.java:77: java.util.HashMap.Entry is not public in java.util.HashMap ; cannot be accessed from outside package HashMap.Entry pairs = (HashMap.Entry)it.next(); ^ 3 errors Press any key to continue . . .