Golang : Copy map(hash table) example



Tags : golang copy-map

Problem:

You have a map and you want to copy the elements to another map. How to do that ?

Solution:

Use for loop to iterate over the original map and assign the items/elements to a new map.

For example:

 package main

 import (
 "fmt"
 )

 func main() {

 originalMap := map[int]string{
 1: "A",
 2: "B",
 3: "C",
 }

 copiedMap := map[int]string{}

 fmt.Println("BEFORE : ")
 fmt.Println("Original Map : ", originalMap)
 fmt.Println("Copied Map : ", copiedMap)

 // copy map by assigning elements to new map
 for key, value := range originalMap {
 copiedMap[key] = value
 }

 // NOTES : Golang map(hash table) elements does not have order

 fmt.Println("--------------")
 fmt.Println("AFTER : ")

 fmt.Println("Original Map : ", originalMap)
 fmt.Println("Copied Map : ", copiedMap)
 }

Sample outputs:

BEFORE :

Original Map : map[1:A 2:B 3:C]

Copied Map : map[]

AFTER :

Original Map : map[2:B 3:C 1:A]

Copied Map : map[3:C 1:A 2:B] // map does not have order


BEFORE :

Original Map : map[1:A 2:B 3:C]

Copied Map : map[]

AFTER :

Original Map : map[2:B 3:C 1:A]

Copied Map : map[1:A 2:B 3:C]

Affiliate :

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  See also : Golang : Extract or copy items from map based on value



Tags : golang copy-map

By Adam Ng

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