Groovy - Maps

A Map (also known as an associative array, dictionary, table, and hash) is an unordered collection of object references. The elements in a Map collection are accessed by a key value. The keys used in a Map can be of any class. When we insert into a Map collection, two values are required: the key and the value.
Following are some examples of maps −

• [‘TopicName’ : ‘Lists’, ‘TopicName’ : ‘Maps’] – Collections of key value pairs which has TopicName as the key and their respective values.
• [ : ] – An Empty map.

In this chapter, we will discuss the map methods available in Groovy.

S.No.	Methods & Description
1	containsKey() Does this Map contain this key?
2	get() Look up the key in this Map and return the corresponding value. If there is no entry in this Map for the key, then return null.
3	keySet() Obtain a Set of the keys in this Map.
4	put() Associates the specified value with the specified key in this Map. If this Map previously contained a mapping for this key, the old value is replaced by the specified value.
5	size() Returns the number of key-value mappings in this Map.
6	values() Returns a collection view of the values contained in this Map.