HashMap

A HashMap is a data structure that implements an associative array or dictionary. It is an abstract data type that maps keys to values. In a hash table, the keys are hashed into a number of buckets, and the values are stored in the corresponding buckets. This allows for fast lookups of values by key.

The HashMap class in Java provides a generic implementation of a hash table. The keys and values in a HashMap can be of any type, as long as they are comparable. The HashMap class also provides a number of methods for adding, removing, and iterating over the keys and values in the map.

Here is an example of how to create a HashMap in Java:

HashMap<String, Integer> numbers = new HashMap<>();

numbers.put("one", 1);

numbers.put("two", 2);

numbers.put("three", 3);

System.out.println(numbers.get("one")); // Prints 1

Here is an example of how to iterate over the keys and values in a HashMap in Java:

for (String key : numbers.keySet()) {

System.out.println(key + " = " + numbers.get(key));

}

This code will print the following output:

one = 1

two = 2

three = 3

HashMaps are a powerful data structure that can be used to store and retrieve data quickly and efficiently. They are often used in applications where it is necessary to quickly find a value given its key, such as in a search engine or a database.

#java #programming #coding #javascript #developer #python #webdeveloper #coder #code #software #javatutorial #javahelp #javajobs #javabeginner #javatips #javanews #javacommunity #javalove #javaisawesome #javaislife