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Iterate Through a HashMap

In a HashMap, we can

  1. iterate through its keys
  2. iterate through its values
  3. iterate through its keys/values

Iterating Using the forEach loop.


\begin{lstlisting} import java.util.HashMap; import java.util.Map.Entry; \par cl... ...()) { System.out.print(value); System.out.print('', ''); } } \end{lstlisting}

Output


\begin{lstlisting} HashMap : { One =1 , Two =2 , Three =3} Entries : One =1 , Two =2 , Three =3 Keys : One , Two , Three , Values : 1, 2, ,3, \end{lstlisting}

In the above program, note that we have imported the java.util.Map.Entry package. Here, Map.Entry is the nested class of the Map interface. This nested class returns a view (elements) of the map. It is also possible to iterate a HashMap using the iterator() method. In order to use this method, we must import the java.util.Iterator package.


\begin{lstlisting} import java.util.HashMap; import java.util.Iterator; import j... ...out.print( iterate3.next()); System.out.print('', ''); } } } \end{lstlisting}

Output


\begin{lstlisting} HashMap : { One =1 , Two =2 , Three =3} Entries : One =1 , Two =2 , Three =3 Keys : One , Two , Three , Values : 1, 2, 3, \end{lstlisting}

In the above program, note that we have imported the java.util.Map.Entry package. Here, Map.Entry is the nested class of the Map interface. This nested class returns a view (elements) of the map.