Delete keys from a map in Go with delete()

The built-in delete(m, k) removes the entry for key k from map m. If k is absent, the call is a no-op—no panic. Other languages call similar structures dictionaries or hash maps; in Python the ideas overlap with a Python dictionary. For Go basics, read maps in Go.

Tested with Go 1.24 on Linux.

Delete without checking

package main

import "fmt"

func main() {
	studentsScore := map[string]int{
		"Anna": 5, "Bob": 9, "Clair": 8, "Daniel": 10,
	}
	fmt.Println(studentsScore)
	fmt.Println("Deleting Bob")
	delete(studentsScore, "Bob")
	fmt.Println("Deleting Eve (missing key)")
	delete(studentsScore, "Eve")
	fmt.Println(studentsScore)
}

You should see Bob removed and the map unchanged by the Eve delete beyond losing nothing.

Delete when the key exists

package main

import "fmt"

func deleteKey(m map[string]int, key string) {
	if _, ok := m[key]; ok {
		delete(m, key)
	} else {
		fmt.Println(key, "is not in the map")
	}
}

func main() {
	studentsScore := map[string]int{
		"Anna": 5, "Bob": 9, "Clair": 8, "Daniel": 10,
	}
	fmt.Println(studentsScore)
	deleteKey(studentsScore, "Bob")
	deleteKey(studentsScore, "Eve")
	fmt.Println(studentsScore)
}

You should see a line reporting Eve is not in the map, then the map without Bob.

Summary

To golang delete from map data, call delete(m, k); it is safe on missing keys. When you need explicit handling, gate the delete with the comma-ok read. Pair deletes with clear map semantics from your functions or methods so callers know whether absence is normal.

References

• Effective Go: maps