Golang : Copy map(hash table) example
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]
See also : Golang : Extract or copy items from map based on value
By Adam Ng
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