Groovy - Map put(Object key, Object value) method

---

---

Description

Groovy Map put(Object key, Object value) method 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.

Syntax

public Object put(Object key, Object value)

Parameters

• key − The key to be put in the map.

• value − The associated value for the key.

Return Value

The returned key-value pair which is inserted.

Example - Adding key-value pair to a Map of String and String

Following is an example of the usage of this method −

main.groovy

// define a map
def map = ["TopicName" : "Maps", "TopicDescription" : "Methods in Maps"] 

// add a new key-value pair
map.put("TopicID","1");
println(map); 

Output

When we run the above program, we will get the following result −

[TopicName:Maps, TopicDescription:Methods in Maps, TopicID:1]

Example - Adding key-value pair to a Map of Integer and String

Following is an example of the usage of this method −

main.groovy

// define a map
def map = [1 : "Apple", 2 : "Banana"] 

// add a new key-value pair
map.put(3,"Mango");
println(map); 

Output

When we run the above program, we will get the following result −

[1:Apple, 2:Banana, 3:Mango]

Example - Adding key-value pair to a Map of Integer and Object

Following is an example of the usage of this method −

main.groovy

// define a map
def map = [1 : new Student(1, "Julie"), 2 : new Student(2, "Robert")] 

// add a new key-value pair
map.put(3,new Student(3, "Adam"));
println(map); 

class Student{
   int rollNo
   String name

   Student(int rollNo, String name){
      this.rollNo = rollNo
      this.name = name
   }

   @Override
   public boolean equals(Object obj) {
      Student s = (Student)obj
      return this.rollNo == s.rollNo && this.name.equalsIgnoreCase(s.name)
   }
   
   @Override
   public String toString() {
      return "[ " + this.rollNo + ", " + this.name + " ]"
   }
}

Output

When we run the above program, we will get the following result −

[1:[ 1, Julie ], 2:[ 2, Robert ], 3:[ 3, Adam ]]