Performance deep dive

In this approach, we'll find out how to most efficiently determine the response for Bob in Go.

The approaches page lists three idiomatic approaches to this exercise:

1. Using if statements.
2. Using a switch statement.
3. Using an answer array.

Benchmarks

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

func BenchmarkHey(b *testing.B) {
	for i := 0; i < b.N; i++ {
		for _, tt := range testCases {
			Hey(tt.input)
		}
	}
}

and received the following results:

if statements
BenchmarkHey-12    	  624798	      1746 ns/op	     432 B/op	      12 allocs/op

switch statement
BenchmarkHey-12    	  617388	      1791 ns/op	     432 B/op	      12 allocs/op

answer array
BenchmarkHey-12    	  632600	      1819 ns/op	     432 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.

Benchmarks can vary between one run and another by as much as a hundred nanoseconds, so these values represent the fastest results from several runs.

The if statements approach gave the fastest result. The switch statement approach was the second-fastest. The answer array approach came in third. Since each approach sometimes gave results slower than the other approaches, which to use could be a matter of stylistic choice.