Go Scrabble Score
Scrabble Score
in Go

Performance deep dive

In this approach, we'll find out how to most efficiently determine the Scrabble Score in Go.

The approaches page lists two idiomatic approaches to this exercise:

  1. Using map.
  2. Using a switch on runes.

For our performance investigation, we'll also include a third approach that uses a switch on strings.


To benchmark the approaches, we ran the following Benchmark code for each approach:

func BenchmarkScore(b *testing.B) {
	if testing.Short() {
		b.Skip("skipping benchmark in short mode.")
	for i := 0; i < b.N; i++ {
		for _, test := range scrabbleScoreTests {

and received the following results:

BenchmarkScore-12    	 1544814	       711.7 ns/op	       0 B/op	       0 allocs/op

switch on runes
BenchmarkScore-12    	 4171696	       242.1 ns/op	       0 B/op	       0 allocs/op

switch on strings
BenchmarkScore-12    	  413484	      2527 ns/op	    1088 B/op	      12 allocs/op

Generally, the fewer bytes allocated per op (B/op) the faster (i.e. the fewer ns/op) the implementation. More info on reading benchmarks can be found here.

Using switch on runes was about three times faster than the next fastest approach, which was using a map. Using a switch on each letter being a separate string was over ten times slower than switching on runes.

29th Nov 2023 · Found it useful?