[go-nuts] Re: Best way to truncate a ridiculously long string in GO

[peterGo]

A benchmark;

https://play.golang.org/p/oUyeldDG5Q

$ cat strslice_test.go
package main

import (
    "strings"
    "testing"
)

var (
    s      = strings.Repeat("a very, very long string", 4096)
    prefix string
)

func BenchmarkNil(b *testing.B) {
    for i := 0; i < b.N; i++ {
        prefix = string(append([]byte(nil), s[:3]...))
    }
}

func BenchmarkLiteral(b *testing.B) {
    for i := 0; i < b.N; i++ {
        prefix = string(append([]byte{}, s[:3]...))
    }
}

func BenchmarkConvert(b *testing.B) {
    for i := 0; i < b.N; i++ {
        prefix = string([]byte(s[:3]))
    }
}

$ go test -run=! -bench=. -benchmem strslice_test.go
goos: linux
goarch: amd64
BenchmarkNil-4           10000000           174 ns/op          16 B/op    
       2 allocs/op
BenchmarkLiteral-4       10000000           174 ns/op          16 B/op    
       2 allocs/op
BenchmarkConvert-4       20000000            77.0 ns/op         3 B/op    
       1 allocs/op
PASS
ok      command-line-arguments    5.512s
$

Peter

On Tuesday, August 22, 2017 at 12:15:44 AM UTC-4, Tamás Gulácsi wrote:
>
> prefix := string([]byte(verylongstring[:3]))

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