src/time/example_test.go

// Copyright 2011 The Go Authors.  All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package time_test

import (
	"fmt"
	"time"
)

func expensiveCall() {}

func ExampleDuration() {
	t0 := time.Now()
	expensiveCall()
	t1 := time.Now()
	fmt.Printf("The call took %v to run.\n", t1.Sub(t0))
}

var c chan int

func handle(int) {}

func ExampleAfter() {
	select {
	case m := <-c:
		handle(m)
	case <-time.After(5 * time.Minute):
		fmt.Println("timed out")
	}
}

func ExampleSleep() {
	time.Sleep(100 * time.Millisecond)
}

func statusUpdate() string { return "" }

func ExampleTick() {
	c := time.Tick(1 * time.Minute)
	for now := range c {
		fmt.Printf("%v %s\n", now, statusUpdate())
	}
}

func ExampleMonth() {
	_, month, day := time.Now().Date()
	if month == time.November && day == 10 {
		fmt.Println("Happy Go day!")
	}
}

func ExampleDate() {
	t := time.Date(2009, time.November, 10, 23, 0, 0, 0, time.UTC)
	fmt.Printf("Go launched at %s\n", t.Local())
	// Output: Go launched at 2009-11-10 15:00:00 -0800 PST
}

func ExampleTime_Format() {
	// layout shows by example how the reference time should be represented.
	const layout = "Jan 2, 2006 at 3:04pm (MST)"
	t := time.Date(2009, time.November, 10, 15, 0, 0, 0, time.Local)
	fmt.Println(t.Format(layout))
	fmt.Println(t.UTC().Format(layout))
	// Output:
	// Nov 10, 2009 at 3:00pm (PST)
	// Nov 10, 2009 at 11:00pm (UTC)
}

func ExampleParse() {
	// longForm shows by example how the reference time would be represented in
	// the desired layout.
	const longForm = "Jan 2, 2006 at 3:04pm (MST)"
	t, _ := time.Parse(longForm, "Feb 3, 2013 at 7:54pm (PST)")
	fmt.Println(t)

	// shortForm is another way the reference time would be represented
	// in the desired layout; it has no time zone present.
	// Note: without explicit zone, returns time in UTC.
	const shortForm = "2006-Jan-02"
	t, _ = time.Parse(shortForm, "2013-Feb-03")
	fmt.Println(t)

	// Output:
	// 2013-02-03 19:54:00 -0800 PST
	// 2013-02-03 00:00:00 +0000 UTC
}

func ExampleParseInLocation() {
	loc, _ := time.LoadLocation("Europe/Berlin")

	const longForm = "Jan 2, 2006 at 3:04pm (MST)"
	t, _ := time.ParseInLocation(longForm, "Jul 9, 2012 at 5:02am (CEST)", loc)
	fmt.Println(t)

	// Note: without explicit zone, returns time in given location.
	const shortForm = "2006-Jan-02"
	t, _ = time.ParseInLocation(shortForm, "2012-Jul-09", loc)
	fmt.Println(t)

	// Output:
	// 2012-07-09 05:02:00 +0200 CEST
	// 2012-07-09 00:00:00 +0200 CEST
}

func ExampleTime_Round() {
	t := time.Date(0, 0, 0, 12, 15, 30, 918273645, time.UTC)
	round := []time.Duration{
		time.Nanosecond,
		time.Microsecond,
		time.Millisecond,
		time.Second,
		2 * time.Second,
		time.Minute,
		10 * time.Minute,
		time.Hour,
	}

	for _, d := range round {
		fmt.Printf("t.Round(%6s) = %s\n", d, t.Round(d).Format("15:04:05.999999999"))
	}
	// Output:
	// t.Round(   1ns) = 12:15:30.918273645
	// t.Round(   1µs) = 12:15:30.918274
	// t.Round(   1ms) = 12:15:30.918
	// t.Round(    1s) = 12:15:31
	// t.Round(    2s) = 12:15:30
	// t.Round(  1m0s) = 12:16:00
	// t.Round( 10m0s) = 12:20:00
	// t.Round(1h0m0s) = 12:00:00
}

func ExampleTime_Truncate() {
	t, _ := time.Parse("2006 Jan 02 15:04:05", "2012 Dec 07 12:15:30.918273645")
	trunc := []time.Duration{
		time.Nanosecond,
		time.Microsecond,
		time.Millisecond,
		time.Second,
		2 * time.Second,
		time.Minute,
		10 * time.Minute,
		time.Hour,
	}

	for _, d := range trunc {
		fmt.Printf("t.Truncate(%6s) = %s\n", d, t.Truncate(d).Format("15:04:05.999999999"))
	}

	// Output:
	// t.Truncate(   1ns) = 12:15:30.918273645
	// t.Truncate(   1µs) = 12:15:30.918273
	// t.Truncate(   1ms) = 12:15:30.918
	// t.Truncate(    1s) = 12:15:30
	// t.Truncate(    2s) = 12:15:30
	// t.Truncate(  1m0s) = 12:15:00
	// t.Truncate( 10m0s) = 12:10:00
	// t.Truncate(1h0m0s) = 12:00:00
}