Groovy - Map get(Object key) method

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Description

Groovy Map get(Object key) method looks up the key in this Map and return the corresponding value. If there is no entry in this Map for the key, then returns null.

Syntax

public Object get(Object key)

Parameters

key − the key to search for retrieval.

Return Value

The key-value pair or NULL if it does not exist.

Example - Getting Value based on key from 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"] 

// get the value if key is present
println(map.get("TopicName")) 
println(map.get("Topic"))

Output

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

Maps
null

Example - Getting Value based on key from 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"] 

// get the value if key is present
println(map.get(1)) 
println(map.get(3)) 

Output

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

Apple
null

Example - Getting Value based on key from 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")] 

// get the value if key is present
println(map.get(1))
println(map.get(3)) 

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, Julie ]
null