// 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))
}
func ExampleDuration_Round() {
d, err := time.ParseDuration("1h15m30.918273645s")
if err != nil {
panic(err)
}
round := []time.Duration{
time.Nanosecond,
time.Microsecond,
time.Millisecond,
time.Second,
2 * time.Second,
time.Minute,
10 * time.Minute,
time.Hour,
}
for _, r := range round {
fmt.Printf("d.Round(%6s) = %s\n", r, d.Round(r).String())
}
// Output:
// d.Round( 1ns) = 1h15m30.918273645s
// d.Round( 1µs) = 1h15m30.918274s
// d.Round( 1ms) = 1h15m30.918s
// d.Round( 1s) = 1h15m31s
// d.Round( 2s) = 1h15m30s
// d.Round( 1m0s) = 1h16m0s
// d.Round( 10m0s) = 1h20m0s
// d.Round(1h0m0s) = 1h0m0s
}
func ExampleDuration_String() {
t1 := time.Date(2016, time.August, 15, 0, 0, 0, 0, time.UTC)
t2 := time.Date(2017, time.February, 16, 0, 0, 0, 0, time.UTC)
fmt.Println(t2.Sub(t1).String())
// Output: 4440h0m0s
}
func ExampleDuration_Truncate() {
d, err := time.ParseDuration("1h15m30.918273645s")
if err != nil {
panic(err)
}
trunc := []time.Duration{
time.Nanosecond,
time.Microsecond,
time.Millisecond,
time.Second,
2 * time.Second,
time.Minute,
10 * time.Minute,
time.Hour,
}
for _, t := range trunc {
fmt.Printf("d.Truncate(%6s) = %s\n", t, d.Truncate(t).String())
}
// Output:
// d.Truncate( 1ns) = 1h15m30.918273645s
// d.Truncate( 1µs) = 1h15m30.918273s
// d.Truncate( 1ms) = 1h15m30.918s
// d.Truncate( 1s) = 1h15m30s
// d.Truncate( 2s) = 1h15m30s
// d.Truncate( 1m0s) = 1h15m0s
// d.Truncate( 10m0s) = 1h10m0s
// d.Truncate(1h0m0s) = 1h0m0s
}
func ExampleParseDuration() {
hours, _ := time.ParseDuration("10h")
complex, _ := time.ParseDuration("1h10m10s")
micro, _ := time.ParseDuration("1µs")
// The package also accepts the incorrect but common prefix u for micro.
micro2, _ := time.ParseDuration("1us")
fmt.Println(hours)
fmt.Println(complex)
fmt.Printf("There are %.0f seconds in %v.\n", complex.Seconds(), complex)
fmt.Printf("There are %d nanoseconds in %v.\n", micro.Nanoseconds(), micro)
fmt.Printf("There are %6.2e seconds in %v.\n", micro2.Seconds(), micro)
// Output:
// 10h0m0s
// 1h10m10s
// There are 4210 seconds in 1h10m10s.
// There are 1000 nanoseconds in 1µs.
// There are 1.00e-06 seconds in 1µs.
}
func ExampleDuration_Hours() {
h, _ := time.ParseDuration("4h30m")
fmt.Printf("I've got %.1f hours of work left.", h.Hours())
// Output: I've got 4.5 hours of work left.
}
func ExampleDuration_Minutes() {
m, _ := time.ParseDuration("1h30m")
fmt.Printf("The movie is %.0f minutes long.", m.Minutes())
// Output: The movie is 90 minutes long.
}
func ExampleDuration_Nanoseconds() {
u, _ := time.ParseDuration("1µs")
fmt.Printf("One microsecond is %d nanoseconds.\n", u.Nanoseconds())
// Output:
// One microsecond is 1000 nanoseconds.
}
func ExampleDuration_Seconds() {
m, _ := time.ParseDuration("1m30s")
fmt.Printf("Take off in t-%.0f seconds.", m.Seconds())
// Output: Take off in t-90 seconds.
}
var c chan int
func handle(int) {}
func ExampleAfter() {
select {
case m := <-c:
handle(m)
case <-time.After(10 * time.Second):
fmt.Println("timed out")
}
}
func ExampleSleep() {
time.Sleep(100 * time.Millisecond)
}
func statusUpdate() string { return "" }
func ExampleTick() {
c := time.Tick(5 * time.Second)
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 ExampleNewTicker() {
ticker := time.NewTicker(time.Second)
defer ticker.Stop()
done := make(chan bool)
go func() {
time.Sleep(10 * time.Second)
done <- true
}()
for {
select {
case <-done:
fmt.Println("Done!")
return
case t := <-ticker.C:
fmt.Println("Current time: ", t)
}
}
}
func ExampleTime_Format() {
// Parse a time value from a string in the standard Unix format.
t, err := time.Parse(time.UnixDate, "Sat Mar 7 11:06:39 PST 2015")
if err != nil { // Always check errors even if they should not happen.
panic(err)
}
// time.Time's Stringer method is useful without any format.
fmt.Println("default format:", t)
// Predefined constants in the package implement common layouts.
fmt.Println("Unix format:", t.Format(time.UnixDate))
// The time zone attached to the time value affects its output.
fmt.Println("Same, in UTC:", t.UTC().Format(time.UnixDate))
// The rest of this function demonstrates the properties of the
// layout string used in the format.
// The layout string used by the Parse function and Format method
// shows by example how the reference time should be represented.
// We stress that one must show how the reference time is formatted,
// not a time of the user's choosing. Thus each layout string is a
// representation of the time stamp,
// Jan 2 15:04:05 2006 MST
// An easy way to remember this value is that it holds, when presented
// in this order, the values (lined up with the elements above):
// 1 2 3 4 5 6 -7
// There are some wrinkles illustrated below.
// Most uses of Format and Parse use constant layout strings such as
// the ones defined in this package, but the interface is flexible,
// as these examples show.
// Define a helper function to make the examples' output look nice.
do := func(name, layout, want string) {
got := t.Format(layout)
if want != got {
fmt.Printf("error: for %q got %q; expected %q\n", layout, got, want)
return
}
fmt.Printf("%-15s %q gives %q\n", name, layout, got)
}
// Print a header in our output.
fmt.Printf("\nFormats:\n\n")
// A simple starter example.
do("Basic", "Mon Jan 2 15:04:05 MST 2006", "Sat Mar 7 11:06:39 PST 2015")
// For fixed-width printing of values, such as the date, that may be one or
// two characters (7 vs. 07), use an _ instead of a space in the layout string.
// Here we print just the day, which is 2 in our layout string and 7 in our
// value.
do("No pad", "<2>", "<7>")
// An underscore represents a space pad, if the date only has one digit.
do("Spaces", "<_2>", "< 7>")
// A "0" indicates zero padding for single-digit values.
do("Zeros", "<02>", "<07>")
// If the value is already the right width, padding is not used.
// For instance, the second (05 in the reference time) in our value is 39,
// so it doesn't need padding, but the minutes (04, 06) does.
do("Suppressed pad", "04:05", "06:39")
// The predefined constant Unix uses an underscore to pad the day.
// Compare with our simple starter example.
do("Unix", time.UnixDate, "Sat Mar 7 11:06:39 PST 2015")
// The hour of the reference time is 15, or 3PM. The layout can express
// it either way, and since our value is the morning we should see it as
// an AM time. We show both in one format string. Lower case too.
do("AM/PM", "3PM==3pm==15h", "11AM==11am==11h")
// When parsing, if the seconds value is followed by a decimal point
// and some digits, that is taken as a fraction of a second even if
// the layout string does not represent the fractional second.
// Here we add a fractional second to our time value used above.
t, err = time.Parse(time.UnixDate, "Sat Mar 7 11:06:39.1234 PST 2015")
if err != nil {
panic(err)
}
// It does not appear in the output if the layout string does not contain
// a representation of the fractional second.
do("No fraction", time.UnixDate, "Sat Mar 7 11:06:39 PST 2015")
// Fractional seconds can be printed by adding a run of 0s or 9s after
// a decimal point in the seconds value in the layout string.
// If the layout digits are 0s, the fractional second is of the specified
// width. Note that the output has a trailing zero.
do("0s for fraction", "15:04:05.00000", "11:06:39.12340")
// If the fraction in the layout is 9s, trailing zeros are dropped.
do("9s for fraction", "15:04:05.99999999", "11:06:39.1234")
// Output:
// default format: 2015-03-07 11:06:39 -0800 PST
// Unix format: Sat Mar 7 11:06:39 PST 2015
// Same, in UTC: Sat Mar 7 19:06:39 UTC 2015
//
// Formats:
//
// Basic "Mon Jan 2 15:04:05 MST 2006" gives "Sat Mar 7 11:06:39 PST 2015"
// No pad "<2>" gives "<7>"
// Spaces "<_2>" gives "< 7>"
// Zeros "<02>" gives "<07>"
// Suppressed pad "04:05" gives "06:39"
// Unix "Mon Jan _2 15:04:05 MST 2006" gives "Sat Mar 7 11:06:39 PST 2015"
// AM/PM "3PM==3pm==15h" gives "11AM==11am==11h"
// No fraction "Mon Jan _2 15:04:05 MST 2006" gives "Sat Mar 7 11:06:39 PST 2015"
// 0s for fraction "15:04:05.00000" gives "11:06:39.12340"
// 9s for fraction "15:04:05.99999999" gives "11:06:39.1234"
}
func ExampleParse() {
// See the example for Time.Format for a thorough description of how
// to define the layout string to parse a time.Time value; Parse and
// Format use the same model to describe their input and output.
// 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)
// Some valid layouts are invalid time values, due to format specifiers
// such as _ for space padding and Z for zone information.
// For example the RFC3339 layout 2006-01-02T15:04:05Z07:00
// contains both Z and a time zone offset in order to handle both valid options:
// 2006-01-02T15:04:05Z
// 2006-01-02T15:04:05+07:00
t, _ = time.Parse(time.RFC3339, "2006-01-02T15:04:05Z")
fmt.Println(t)
t, _ = time.Parse(time.RFC3339, "2006-01-02T15:04:05+07:00")
fmt.Println(t)
_, err := time.Parse(time.RFC3339, time.RFC3339)
fmt.Println("error", err) // Returns an error as the layout is not a valid time value
// Output:
// 2013-02-03 19:54:00 -0800 PST
// 2013-02-03 00:00:00 +0000 UTC
// 2006-01-02 15:04:05 +0000 UTC
// 2006-01-02 15:04:05 +0700 +0700
// error parsing time "2006-01-02T15:04:05Z07:00": extra text: 07:00
}
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_Unix() {
// 1 billion seconds of Unix, three ways.
fmt.Println(time.Unix(1e9, 0).UTC()) // 1e9 seconds
fmt.Println(time.Unix(0, 1e18).UTC()) // 1e18 nanoseconds
fmt.Println(time.Unix(2e9, -1e18).UTC()) // 2e9 seconds - 1e18 nanoseconds
t := time.Date(2001, time.September, 9, 1, 46, 40, 0, time.UTC)
fmt.Println(t.Unix()) // seconds since 1970
fmt.Println(t.UnixNano()) // nanoseconds since 1970
// Output:
// 2001-09-09 01:46:40 +0000 UTC
// 2001-09-09 01:46:40 +0000 UTC
// 2001-09-09 01:46:40 +0000 UTC
// 1000000000
// 1000000000000000000
}
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,
}
for _, d := range trunc {
fmt.Printf("t.Truncate(%5s) = %s\n", d, t.Truncate(d).Format("15:04:05.999999999"))
}
// To round to the last midnight in the local timezone, create a new Date.
midnight := time.Date(t.Year(), t.Month(), t.Day(), 0, 0, 0, 0, time.Local)
_ = midnight
// 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
}
func ExampleLoadLocation() {
location, err := time.LoadLocation("America/Los_Angeles")
if err != nil {
panic(err)
}
timeInUTC := time.Date(2018, 8, 30, 12, 0, 0, 0, time.UTC)
fmt.Println(timeInUTC.In(location))
// Output: 2018-08-30 05:00:00 -0700 PDT
}
func ExampleLocation() {
// China doesn't have daylight saving. It uses a fixed 8 hour offset from UTC.
secondsEastOfUTC := int((8 * time.Hour).Seconds())
beijing := time.FixedZone("Beijing Time", secondsEastOfUTC)
// If the system has a timezone database present, it's possible to load a location
// from that, e.g.:
// newYork, err := time.LoadLocation("America/New_York")
// Creating a time requires a location. Common locations are time.Local and time.UTC.
timeInUTC := time.Date(2009, 1, 1, 12, 0, 0, 0, time.UTC)
sameTimeInBeijing := time.Date(2009, 1, 1, 20, 0, 0, 0, beijing)
// Although the UTC clock time is 1200 and the Beijing clock time is 2000, Beijing is
// 8 hours ahead so the two dates actually represent the same instant.
timesAreEqual := timeInUTC.Equal(sameTimeInBeijing)
fmt.Println(timesAreEqual)
// Output:
// true
}
func ExampleTime_Add() {
start := time.Date(2009, 1, 1, 12, 0, 0, 0, time.UTC)
afterTenSeconds := start.Add(time.Second * 10)
afterTenMinutes := start.Add(time.Minute * 10)
afterTenHours := start.Add(time.Hour * 10)
afterTenDays := start.Add(time.Hour * 24 * 10)
fmt.Printf("start = %v\n", start)
fmt.Printf("start.Add(time.Second * 10) = %v\n", afterTenSeconds)
fmt.Printf("start.Add(time.Minute * 10) = %v\n", afterTenMinutes)
fmt.Printf("start.Add(time.Hour * 10) = %v\n", afterTenHours)
fmt.Printf("start.Add(time.Hour * 24 * 10) = %v\n", afterTenDays)
// Output:
// start = 2009-01-01 12:00:00 +0000 UTC
// start.Add(time.Second * 10) = 2009-01-01 12:00:10 +0000 UTC
// start.Add(time.Minute * 10) = 2009-01-01 12:10:00 +0000 UTC
// start.Add(time.Hour * 10) = 2009-01-01 22:00:00 +0000 UTC
// start.Add(time.Hour * 24 * 10) = 2009-01-11 12:00:00 +0000 UTC
}
func ExampleTime_AddDate() {
start := time.Date(2009, 1, 1, 0, 0, 0, 0, time.UTC)
oneDayLater := start.AddDate(0, 0, 1)
oneMonthLater := start.AddDate(0, 1, 0)
oneYearLater := start.AddDate(1, 0, 0)
fmt.Printf("oneDayLater: start.AddDate(0, 0, 1) = %v\n", oneDayLater)
fmt.Printf("oneMonthLater: start.AddDate(0, 1, 0) = %v\n", oneMonthLater)
fmt.Printf("oneYearLater: start.AddDate(1, 0, 0) = %v\n", oneYearLater)
// Output:
// oneDayLater: start.AddDate(0, 0, 1) = 2009-01-02 00:00:00 +0000 UTC
// oneMonthLater: start.AddDate(0, 1, 0) = 2009-02-01 00:00:00 +0000 UTC
// oneYearLater: start.AddDate(1, 0, 0) = 2010-01-01 00:00:00 +0000 UTC
}
func ExampleTime_After() {
year2000 := time.Date(2000, 1, 1, 0, 0, 0, 0, time.UTC)
year3000 := time.Date(3000, 1, 1, 0, 0, 0, 0, time.UTC)
isYear3000AfterYear2000 := year3000.After(year2000) // True
isYear2000AfterYear3000 := year2000.After(year3000) // False
fmt.Printf("year3000.After(year2000) = %v\n", isYear3000AfterYear2000)
fmt.Printf("year2000.After(year3000) = %v\n", isYear2000AfterYear3000)
// Output:
// year3000.After(year2000) = true
// year2000.After(year3000) = false
}
func ExampleTime_Before() {
year2000 := time.Date(2000, 1, 1, 0, 0, 0, 0, time.UTC)
year3000 := time.Date(3000, 1, 1, 0, 0, 0, 0, time.UTC)
isYear2000BeforeYear3000 := year2000.Before(year3000) // True
isYear3000BeforeYear2000 := year3000.Before(year2000) // False
fmt.Printf("year2000.Before(year3000) = %v\n", isYear2000BeforeYear3000)
fmt.Printf("year3000.Before(year2000) = %v\n", isYear3000BeforeYear2000)
// Output:
// year2000.Before(year3000) = true
// year3000.Before(year2000) = false
}
func ExampleTime_Date() {
d := time.Date(2000, 2, 1, 12, 30, 0, 0, time.UTC)
year, month, day := d.Date()
fmt.Printf("year = %v\n", year)
fmt.Printf("month = %v\n", month)
fmt.Printf("day = %v\n", day)
// Output:
// year = 2000
// month = February
// day = 1
}
func ExampleTime_Day() {
d := time.Date(2000, 2, 1, 12, 30, 0, 0, time.UTC)
day := d.Day()
fmt.Printf("day = %v\n", day)
// Output:
// day = 1
}
func ExampleTime_Equal() {
secondsEastOfUTC := int((8 * time.Hour).Seconds())
beijing := time.FixedZone("Beijing Time", secondsEastOfUTC)
// Unlike the equal operator, Equal is aware that d1 and d2 are the
// same instant but in different time zones.
d1 := time.Date(2000, 2, 1, 12, 30, 0, 0, time.UTC)
d2 := time.Date(2000, 2, 1, 20, 30, 0, 0, beijing)
datesEqualUsingEqualOperator := d1 == d2
datesEqualUsingFunction := d1.Equal(d2)
fmt.Printf("datesEqualUsingEqualOperator = %v\n", datesEqualUsingEqualOperator)
fmt.Printf("datesEqualUsingFunction = %v\n", datesEqualUsingFunction)
// Output:
// datesEqualUsingEqualOperator = false
// datesEqualUsingFunction = true
}
func ExampleTime_String() {
timeWithNanoseconds := time.Date(2000, 2, 1, 12, 13, 14, 15, time.UTC)
withNanoseconds := timeWithNanoseconds.String()
timeWithoutNanoseconds := time.Date(2000, 2, 1, 12, 13, 14, 0, time.UTC)
withoutNanoseconds := timeWithoutNanoseconds.String()
fmt.Printf("withNanoseconds = %v\n", string(withNanoseconds))
fmt.Printf("withoutNanoseconds = %v\n", string(withoutNanoseconds))
// Output:
// withNanoseconds = 2000-02-01 12:13:14.000000015 +0000 UTC
// withoutNanoseconds = 2000-02-01 12:13:14 +0000 UTC
}
func ExampleTime_Sub() {
start := time.Date(2000, 1, 1, 0, 0, 0, 0, time.UTC)
end := time.Date(2000, 1, 1, 12, 0, 0, 0, time.UTC)
difference := end.Sub(start)
fmt.Printf("difference = %v\n", difference)
// Output:
// difference = 12h0m0s
}
func ExampleTime_AppendFormat() {
t := time.Date(2017, time.November, 4, 11, 0, 0, 0, time.UTC)
text := []byte("Time: ")
text = t.AppendFormat(text, time.Kitchen)
fmt.Println(string(text))
// Output:
// Time: 11:00AM
}
func ExampleFixedZone() {
loc := time.FixedZone("UTC-8", -8*60*60)
t := time.Date(2009, time.November, 10, 23, 0, 0, 0, loc)
fmt.Println("The time is:", t.Format(time.RFC822))
// Output: The time is: 10 Nov 09 23:00 UTC-8
}
|
