GoLang Map - Update and Delete Items

In this tutorial, we will learn how to update and delete elements from a Map along with the working examples of it.

We can update values and delete items in Map based on the key in Go language.

Map will store the key-value pair type of data.

Map Updating Items

In GO language, we can update values using the key.

Syntax:

map[key]=value

Example 1:

Let us create a map named manager with 2 key-value pairs and update values.

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package main
import ("fmt")
   
func main() {
    // Create an empty map such that key stores string type values, 
    //value stores integer type values and add 2 key-value pairs.
	var manager = map[string]int{"Sravan":23,"Anil":35}

	// Display the map
	fmt.Println("Actual map: ",manager)      
	
// Update Sravan Age to 34
manager["Sravan"]=34

// Update Anil Age to 21
manager["Anil"]=21

	// Display the map
	fmt.Println("Final map: ",manager)   
}

Output:

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Actual map:  map[Anil:35 Sravan:23]
Final map:  map[Sravan:34 Anil:21]

Explanation for the above output:

We have updated value of Sravan to 34 and Anil to 21.

Example 2:

Let us create a map named fruits with 5 key-value pairs and update some of them.

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package main
import ("fmt")
   
func main() {
    // Create an empty map such that key and valuestores string type // values and add 5 key-value pairs.
	var fruits = map[string]string{"apple":"guntur","guava":"nepal","banana":"guntur","grapes":"hyd","papayya":"hyd"}

	// Display the map
	fmt.Println("Actual Map: ",fruits)      
	
	// update value of apple to japan
	fruits["apple"]="japan"
	
		// update value of apple to usa
	fruits["papayya"]="usa"
	
	// Display the map
	fmt.Println("Final Map: ",fruits)   
}

Output:

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Actual Map:  map[guava:nepal banana:guntur grapes:hyd papayya:hyd apple:guntur]
Final Map:  map[apple:japan guava:nepal banana:guntur grapes:hyd papayya:usa]

Explanation for the above output:

We have updated apple's value to "japan" and papayya's value to "usa".

Map Delete Items

We can delete the items by using the key.

Syntax:

delete(map_name,key)

Parameters:

It takes two parameters.

1. map_name is the name of the map.
2. key is the key present in the map to be deleted.

Example 1:

Let us create a map named manager with 2 key-value pairs and delete one of them.

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package main

import (
	"fmt"
)

func main() {
	// Create an empty map such that key stores string type values,
	//value stores integer type values and add 2 key-value pairs.
	var manager = map[string]int{"Sravan": 23, "Anil": 35}

	// Display the map
	fmt.Println("Actual map: ", manager)

	// Delete "Sravan"
	delete(manager, "Sravan")

	// Display the map
	fmt.Println("Final map: ", manager)
}

Output:

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Actual map:  map[Anil:35 Sravan:23]
Final map:  map[Anil:35]

Explanation for the above output:

We can see that Item-"Sravan" is deleted from the manager map.

Example 2:

Let us create a map named fruits with 5 key-value pairs and delete some of them.

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package main

import (
	"fmt"
)

func main() {
	// Create an empty map such that key and valuestores string type // values and add 5 key-value pairs.
	var fruits = map[string]string{"apple": "guntur", "guava": "nepal", "banana": "guntur", "grapes": "hyd", "papayya": "hyd"}

	// Display the map
	fmt.Println("Actual Map: ", fruits)

	// delete apple
	delete(fruits, "apple")

	// delete guava
	delete(fruits, "guava")

	// Display the map
	fmt.Println("Final Map: ", fruits)
}

Output:

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Actual Map:  map[apple:guntur banana:guntur grapes:hyd guava:nepal papayya:hyd]
Final Map:  map[banana:guntur grapes:hyd papayya:hyd]

Explanation for the above output:

After removing the items "apple" and "guava", there are only 3 items in the fruits map.

Conclusion

Now we know how to update and delete values in a Golang Map data structure and understood the implementation with working examples.