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Jul 13, 2023 · How to iterate any Map in Java. There are generally five ways of iterating over a Map in Java. In this article, we will discuss all of them and also look at their advantages and disadvantages. First of all, we cannot iterate a Map directly using iterators, because Map are not Collection.
How to iterate Map in Java. In Java, iteration over Map can be done in various ways. Remember that we cannot iterate over map directly using iterators, because Map interface is not the part of Collection. All maps in Java implements Map interface. There are following types of maps in Java: HashMap; TreeMap; LinkedHashMap
The official way to do this is to call map.entrySet(), which returns a set of Map.Entry, each of which contains a key and a value ( entry.getKey() and entry.getValue() ). In an idiosyncratic implementation, it might make some difference whether you use map.keySet(), map.entrySet() or something else.
Jul 1, 2009 · If you need only keys or values from the map, you can iterate over keySet or values instead of entrySet. System.out.println("Key = " + key); System.out.println("Value = " + value); This method gives a slight performance advantage over entrySet iteration (about 10% faster) and is more clean.
Jan 8, 2024 · Overview. In this quick tutorial, we’ll look at the different ways of iterating through the entries of a Map in Java. Simply put, we can extract the contents of a Map using entrySet (), keySet (), or values (). Since these are all sets, similar iteration principles apply to all of them. Let’s have a closer look at a few of these. Further reading:
May 24, 2019 · A Quick Guide to How To Iterate Map in Java. Iterating Through HashMap in Java 8 forEach(Stream API - Lamda Expression) With Example Programs and Explained in Different Ways.
Feb 25, 2009 · 2 Answers. Sorted by: 89. Assuming K is your key type and V is your value type: for (Map.Entry<K,V> entry : map.entrySet()) { K key = entry.getKey(); V value = entry.getValue(); // do stuff. } This version works with every Java version that supports generic (i.e. Java 5 and up).
Oct 3, 2023 · Java introduces three distinct collection view methods for map traversal: entrySet (): Procures a collection perspective of a map with elements hailing from the Map.Entry class. Using entry.getKey () retrieves the key, while entry.getValue () fetches the corresponding value; keySet (): Acquires all keys within a map, presenting them as a Set;
Jul 19, 2022 · What are some common ways to iterate a Map in Java? Though there are many ways to traverse a map. However, we will focus on the most efficient and simple ways. The ForEach Loop method. The Iterators method. Please find the implementation of both methods below. Using the Foreach Loop method. Example. import java.util.Map; import java.util.HashMap;
Apr 6, 2021 · There are different ways to iterate a map in java. java.util.Map is an interface. There are various implementations of Map such as HashMap, TreeMap, LinkedHashMap. All the methods outlined in this article can be used for iterating over any of these types. Method 1: forEach () java map.
