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!!! Java Frequently Asked Questions !!!

How to retrieve a key and Value from a map ?

SCJP 1.5/1.6 Exam Kit

!!!Answer!!!- From Technical Expert

Map<String, Object> map = new HashMap<String, Object>();

for (String key : map.keySet()) {
Object value = map.get(key);
// ...
}

OR

class Test{

public static void main(String[] args) {
Map map = new HashMap();
map.put("man", "john");
map.put("woman", "jane");
System.out.println("Key for john is: " +
getKey(map, "john"));
}

private static String getKey(Map map, String value) {
for (Iterator i = map.keySet().iterator(); i.hasNext() {
String key = (String)i.next();
if (map.get(key).equals(value)) {
return key;
}
}
return "No value found";
}
}

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Answer : ??????????
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Answer : if u dint have answers why did u create questions and wasting time of people who r in search of answers
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Answer :

Answered By : satya Replied Date : Oct 21 2008
Answer : import java.util.Map;
import java.util.HashMap;
import java.util.Iterator;

class Test {

public static void main(String[] args) {

// put value
Map map = new HashMap();
map.put("man", "nick");
map.put("woman", "jane");


//retrive value

Iterator itr = map .keySet().iterator();
while(itr.hasNext()){
String key = (String)itr.next();
String value = (String)map .get(key);
System.out.println("key "+key+" value "+value);


}

}

Answered By : satya Replied Date : Oct 21 2008
Answer : import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

public class MapKeyValue {

public static void main(String[] args) {
Map map = new HashMap();
map.put("man", "nick");
map.put("woman", "jane");
Iterator iter = map.entrySet().iterator();
while(iter.hasNext()){
Map.Entry entry = (Map.Entry) iter.next();
String key = entry.getKey().toString();
String value = entry.getValue().toString();
System.out.println("Key: "+key+" *Value: "+value);
}


}

}

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