libgo/go/time/example_test.go

   1 // Copyright 2011 The Go Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style
   3 // license that can be found in the LICENSE file.
   4
   5 package time_test
   6
   7 import (
   8         "fmt"
   9         "time"
  10 )
  11
  12 func expensiveCall() {}
  13
  14 func ExampleDuration() {
  15         t0 := time.Now()
  16         expensiveCall()
  17         t1 := time.Now()
  18         fmt.Printf("The call took %v to run.\n", t1.Sub(t0))
  19 }
  20
  21 func ExampleDuration_Round() {
  22         d, err := time.ParseDuration("1h15m30.918273645s")
  23         if err != nil {
  24                 panic(err)
  25         }
  26
  27         round := []time.Duration{
  28                 time.Nanosecond,
  29                 time.Microsecond,
  30                 time.Millisecond,
  31                 time.Second,
  32                 2 * time.Second,
  33                 time.Minute,
  34                 10 * time.Minute,
  35                 time.Hour,
  36         }
  37
  38         for _, r := range round {
  39                 fmt.Printf("d.Round(%6s) = %s\n", r, d.Round(r).String())
  40         }
  41         // Output:
  42         // d.Round(   1ns) = 1h15m30.918273645s
  43         // d.Round(   1µs) = 1h15m30.918274s
  44         // d.Round(   1ms) = 1h15m30.918s
  45         // d.Round(    1s) = 1h15m31s
  46         // d.Round(    2s) = 1h15m30s
  47         // d.Round(  1m0s) = 1h16m0s
  48         // d.Round( 10m0s) = 1h20m0s
  49         // d.Round(1h0m0s) = 1h0m0s
  50 }
  51
  52 func ExampleDuration_String() {
  53         t1 := time.Date(2016, time.August, 15, 0, 0, 0, 0, time.UTC)
  54         t2 := time.Date(2017, time.February, 16, 0, 0, 0, 0, time.UTC)
  55         fmt.Println(t2.Sub(t1).String())
  56         // Output: 4440h0m0s
  57 }
  58
  59 func ExampleDuration_Truncate() {
  60         d, err := time.ParseDuration("1h15m30.918273645s")
  61         if err != nil {
  62                 panic(err)
  63         }
  64
  65         trunc := []time.Duration{
  66                 time.Nanosecond,
  67                 time.Microsecond,
  68                 time.Millisecond,
  69                 time.Second,
  70                 2 * time.Second,
  71                 time.Minute,
  72                 10 * time.Minute,
  73                 time.Hour,
  74         }
  75
  76         for _, t := range trunc {
  77                 fmt.Printf("t.Truncate(%6s) = %s\n", t, d.Truncate(t).String())
  78         }
  79         // Output:
  80         // t.Truncate(   1ns) = 1h15m30.918273645s
  81         // t.Truncate(   1µs) = 1h15m30.918273s
  82         // t.Truncate(   1ms) = 1h15m30.918s
  83         // t.Truncate(    1s) = 1h15m30s
  84         // t.Truncate(    2s) = 1h15m30s
  85         // t.Truncate(  1m0s) = 1h15m0s
  86         // t.Truncate( 10m0s) = 1h10m0s
  87         // t.Truncate(1h0m0s) = 1h0m0s
  88 }
  89
  90 func ExampleParseDuration() {
  91         hours, _ := time.ParseDuration("10h")
  92         complex, _ := time.ParseDuration("1h10m10s")
  93
  94         fmt.Println(hours)
  95         fmt.Println(complex)
  96         fmt.Printf("there are %.0f seconds in %v\n", complex.Seconds(), complex)
  97         // Output:
  98         // 10h0m0s
  99         // 1h10m10s
 100         // there are 4210 seconds in 1h10m10s
 101 }
 102
 103 func ExampleDuration_Hours() {
 104         h, _ := time.ParseDuration("4h30m")
 105         fmt.Printf("I've got %.1f hours of work left.", h.Hours())
 106         // Output: I've got 4.5 hours of work left.
 107 }
 108
 109 func ExampleDuration_Minutes() {
 110         m, _ := time.ParseDuration("1h30m")
 111         fmt.Printf("The movie is %.0f minutes long.", m.Minutes())
 112         // Output: The movie is 90 minutes long.
 113 }
 114
 115 func ExampleDuration_Nanoseconds() {
 116         ns, _ := time.ParseDuration("1000ns")
 117         fmt.Printf("one microsecond has %d nanoseconds.", ns.Nanoseconds())
 118         // Output: one microsecond has 1000 nanoseconds.
 119 }
 120
 121 func ExampleDuration_Seconds() {
 122         m, _ := time.ParseDuration("1m30s")
 123         fmt.Printf("take off in t-%.0f seconds.", m.Seconds())
 124         // Output: take off in t-90 seconds.
 125 }
 126
 127 var c chan int
 128
 129 func handle(int) {}
 130
 131 func ExampleAfter() {
 132         select {
 133         case m := <-c:
 134                 handle(m)
 135         case <-time.After(5 * time.Minute):
 136                 fmt.Println("timed out")
 137         }
 138 }
 139
 140 func ExampleSleep() {
 141         time.Sleep(100 * time.Millisecond)
 142 }
 143
 144 func statusUpdate() string { return "" }
 145
 146 func ExampleTick() {
 147         c := time.Tick(1 * time.Minute)
 148         for now := range c {
 149                 fmt.Printf("%v %s\n", now, statusUpdate())
 150         }
 151 }
 152
 153 func ExampleMonth() {
 154         _, month, day := time.Now().Date()
 155         if month == time.November && day == 10 {
 156                 fmt.Println("Happy Go day!")
 157         }
 158 }
 159
 160 func ExampleDate() {
 161         t := time.Date(2009, time.November, 10, 23, 0, 0, 0, time.UTC)
 162         fmt.Printf("Go launched at %s\n", t.Local())
 163         // Output: Go launched at 2009-11-10 15:00:00 -0800 PST
 164 }
 165
 166 func ExampleNewTicker() {
 167         ticker := time.NewTicker(time.Second)
 168         defer ticker.Stop()
 169         done := make(chan bool)
 170         go func() {
 171                 time.Sleep(10 * time.Second)
 172                 done <- true
 173         }()
 174         for {
 175                 select {
 176                 case <-done:
 177                         fmt.Println("Done!")
 178                         return
 179                 case t := <-ticker.C:
 180                         fmt.Println("Current time: ", t)
 181                 }
 182         }
 183 }
 184
 185 func ExampleTime_Format() {
 186         // Parse a time value from a string in the standard Unix format.
 187         t, err := time.Parse(time.UnixDate, "Sat Mar  7 11:06:39 PST 2015")
 188         if err != nil { // Always check errors even if they should not happen.
 189                 panic(err)
 190         }
 191
 192         // time.Time's Stringer method is useful without any format.
 193         fmt.Println("default format:", t)
 194
 195         // Predefined constants in the package implement common layouts.
 196         fmt.Println("Unix format:", t.Format(time.UnixDate))
 197
 198         // The time zone attached to the time value affects its output.
 199         fmt.Println("Same, in UTC:", t.UTC().Format(time.UnixDate))
 200
 201         // The rest of this function demonstrates the properties of the
 202         // layout string used in the format.
 203
 204         // The layout string used by the Parse function and Format method
 205         // shows by example how the reference time should be represented.
 206         // We stress that one must show how the reference time is formatted,
 207         // not a time of the user's choosing. Thus each layout string is a
 208         // representation of the time stamp,
 209         //      Jan 2 15:04:05 2006 MST
 210         // An easy way to remember this value is that it holds, when presented
 211         // in this order, the values (lined up with the elements above):
 212         //        1 2  3  4  5    6  -7
 213         // There are some wrinkles illustrated below.
 214
 215         // Most uses of Format and Parse use constant layout strings such as
 216         // the ones defined in this package, but the interface is flexible,
 217         // as these examples show.
 218
 219         // Define a helper function to make the examples' output look nice.
 220         do := func(name, layout, want string) {
 221                 got := t.Format(layout)
 222                 if want != got {
 223                         fmt.Printf("error: for %q got %q; expected %q\n", layout, got, want)
 224                         return
 225                 }
 226                 fmt.Printf("%-15s %q gives %q\n", name, layout, got)
 227         }
 228
 229         // Print a header in our output.
 230         fmt.Printf("\nFormats:\n\n")
 231
 232         // A simple starter example.
 233         do("Basic", "Mon Jan 2 15:04:05 MST 2006", "Sat Mar 7 11:06:39 PST 2015")
 234
 235         // For fixed-width printing of values, such as the date, that may be one or
 236         // two characters (7 vs. 07), use an _ instead of a space in the layout string.
 237         // Here we print just the day, which is 2 in our layout string and 7 in our
 238         // value.
 239         do("No pad", "<2>", "<7>")
 240
 241         // An underscore represents a space pad, if the date only has one digit.
 242         do("Spaces", "<_2>", "< 7>")
 243
 244         // A "0" indicates zero padding for single-digit values.
 245         do("Zeros", "<02>", "<07>")
 246
 247         // If the value is already the right width, padding is not used.
 248         // For instance, the second (05 in the reference time) in our value is 39,
 249         // so it doesn't need padding, but the minutes (04, 06) does.
 250         do("Suppressed pad", "04:05", "06:39")
 251
 252         // The predefined constant Unix uses an underscore to pad the day.
 253         // Compare with our simple starter example.
 254         do("Unix", time.UnixDate, "Sat Mar  7 11:06:39 PST 2015")
 255
 256         // The hour of the reference time is 15, or 3PM. The layout can express
 257         // it either way, and since our value is the morning we should see it as
 258         // an AM time. We show both in one format string. Lower case too.
 259         do("AM/PM", "3PM==3pm==15h", "11AM==11am==11h")
 260
 261         // When parsing, if the seconds value is followed by a decimal point
 262         // and some digits, that is taken as a fraction of a second even if
 263         // the layout string does not represent the fractional second.
 264         // Here we add a fractional second to our time value used above.
 265         t, err = time.Parse(time.UnixDate, "Sat Mar  7 11:06:39.1234 PST 2015")
 266         if err != nil {
 267                 panic(err)
 268         }
 269         // It does not appear in the output if the layout string does not contain
 270         // a representation of the fractional second.
 271         do("No fraction", time.UnixDate, "Sat Mar  7 11:06:39 PST 2015")
 272
 273         // Fractional seconds can be printed by adding a run of 0s or 9s after
 274         // a decimal point in the seconds value in the layout string.
 275         // If the layout digits are 0s, the fractional second is of the specified
 276         // width. Note that the output has a trailing zero.
 277         do("0s for fraction", "15:04:05.00000", "11:06:39.12340")
 278
 279         // If the fraction in the layout is 9s, trailing zeros are dropped.
 280         do("9s for fraction", "15:04:05.99999999", "11:06:39.1234")
 281
 282         // Output:
 283         // default format: 2015-03-07 11:06:39 -0800 PST
 284         // Unix format: Sat Mar  7 11:06:39 PST 2015
 285         // Same, in UTC: Sat Mar  7 19:06:39 UTC 2015
 286         //
 287         // Formats:
 288         //
 289         // Basic           "Mon Jan 2 15:04:05 MST 2006" gives "Sat Mar 7 11:06:39 PST 2015"
 290         // No pad          "<2>" gives "<7>"
 291         // Spaces          "<_2>" gives "< 7>"
 292         // Zeros           "<02>" gives "<07>"
 293         // Suppressed pad  "04:05" gives "06:39"
 294         // Unix            "Mon Jan _2 15:04:05 MST 2006" gives "Sat Mar  7 11:06:39 PST 2015"
 295         // AM/PM           "3PM==3pm==15h" gives "11AM==11am==11h"
 296         // No fraction     "Mon Jan _2 15:04:05 MST 2006" gives "Sat Mar  7 11:06:39 PST 2015"
 297         // 0s for fraction "15:04:05.00000" gives "11:06:39.12340"
 298         // 9s for fraction "15:04:05.99999999" gives "11:06:39.1234"
 299
 300 }
 301
 302 func ExampleParse() {
 303         // See the example for Time.Format for a thorough description of how
 304         // to define the layout string to parse a time.Time value; Parse and
 305         // Format use the same model to describe their input and output.
 306
 307         // longForm shows by example how the reference time would be represented in
 308         // the desired layout.
 309         const longForm = "Jan 2, 2006 at 3:04pm (MST)"
 310         t, _ := time.Parse(longForm, "Feb 3, 2013 at 7:54pm (PST)")
 311         fmt.Println(t)
 312
 313         // shortForm is another way the reference time would be represented
 314         // in the desired layout; it has no time zone present.
 315         // Note: without explicit zone, returns time in UTC.
 316         const shortForm = "2006-Jan-02"
 317         t, _ = time.Parse(shortForm, "2013-Feb-03")
 318         fmt.Println(t)
 319
 320         // Some valid layouts are invalid time values, due to format specifiers
 321         // such as _ for space padding and Z for zone information.
 322         // For example the RFC3339 layout 2006-01-02T15:04:05Z07:00
 323         // contains both Z and a time zone offset in order to handle both valid options:
 324         // 2006-01-02T15:04:05Z
 325         // 2006-01-02T15:04:05+07:00
 326         t, _ = time.Parse(time.RFC3339, "2006-01-02T15:04:05Z")
 327         fmt.Println(t)
 328         t, _ = time.Parse(time.RFC3339, "2006-01-02T15:04:05+07:00")
 329         fmt.Println(t)
 330         _, err := time.Parse(time.RFC3339, time.RFC3339)
 331         fmt.Println("error", err) // Returns an error as the layout is not a valid time value
 332
 333         // Output:
 334         // 2013-02-03 19:54:00 -0800 PST
 335         // 2013-02-03 00:00:00 +0000 UTC
 336         // 2006-01-02 15:04:05 +0000 UTC
 337         // 2006-01-02 15:04:05 +0700 +0700
 338         // error parsing time "2006-01-02T15:04:05Z07:00": extra text: 07:00
 339 }
 340
 341 func ExampleParseInLocation() {
 342         loc, _ := time.LoadLocation("Europe/Berlin")
 343
 344         const longForm = "Jan 2, 2006 at 3:04pm (MST)"
 345         t, _ := time.ParseInLocation(longForm, "Jul 9, 2012 at 5:02am (CEST)", loc)
 346         fmt.Println(t)
 347
 348         // Note: without explicit zone, returns time in given location.
 349         const shortForm = "2006-Jan-02"
 350         t, _ = time.ParseInLocation(shortForm, "2012-Jul-09", loc)
 351         fmt.Println(t)
 352
 353         // Output:
 354         // 2012-07-09 05:02:00 +0200 CEST
 355         // 2012-07-09 00:00:00 +0200 CEST
 356 }
 357
 358 func ExampleTime_Unix() {
 359         // 1 billion seconds of Unix, three ways.
 360         fmt.Println(time.Unix(1e9, 0).UTC())     // 1e9 seconds
 361         fmt.Println(time.Unix(0, 1e18).UTC())    // 1e18 nanoseconds
 362         fmt.Println(time.Unix(2e9, -1e18).UTC()) // 2e9 seconds - 1e18 nanoseconds
 363
 364         t := time.Date(2001, time.September, 9, 1, 46, 40, 0, time.UTC)
 365         fmt.Println(t.Unix())     // seconds since 1970
 366         fmt.Println(t.UnixNano()) // nanoseconds since 1970
 367
 368         // Output:
 369         // 2001-09-09 01:46:40 +0000 UTC
 370         // 2001-09-09 01:46:40 +0000 UTC
 371         // 2001-09-09 01:46:40 +0000 UTC
 372         // 1000000000
 373         // 1000000000000000000
 374 }
 375
 376 func ExampleTime_Round() {
 377         t := time.Date(0, 0, 0, 12, 15, 30, 918273645, time.UTC)
 378         round := []time.Duration{
 379                 time.Nanosecond,
 380                 time.Microsecond,
 381                 time.Millisecond,
 382                 time.Second,
 383                 2 * time.Second,
 384                 time.Minute,
 385                 10 * time.Minute,
 386                 time.Hour,
 387         }
 388
 389         for _, d := range round {
 390                 fmt.Printf("t.Round(%6s) = %s\n", d, t.Round(d).Format("15:04:05.999999999"))
 391         }
 392         // Output:
 393         // t.Round(   1ns) = 12:15:30.918273645
 394         // t.Round(   1µs) = 12:15:30.918274
 395         // t.Round(   1ms) = 12:15:30.918
 396         // t.Round(    1s) = 12:15:31
 397         // t.Round(    2s) = 12:15:30
 398         // t.Round(  1m0s) = 12:16:00
 399         // t.Round( 10m0s) = 12:20:00
 400         // t.Round(1h0m0s) = 12:00:00
 401 }
 402
 403 func ExampleTime_Truncate() {
 404         t, _ := time.Parse("2006 Jan 02 15:04:05", "2012 Dec 07 12:15:30.918273645")
 405         trunc := []time.Duration{
 406                 time.Nanosecond,
 407                 time.Microsecond,
 408                 time.Millisecond,
 409                 time.Second,
 410                 2 * time.Second,
 411                 time.Minute,
 412                 10 * time.Minute,
 413         }
 414
 415         for _, d := range trunc {
 416                 fmt.Printf("t.Truncate(%5s) = %s\n", d, t.Truncate(d).Format("15:04:05.999999999"))
 417         }
 418         // To round to the last midnight in the local timezone, create a new Date.
 419         midnight := time.Date(t.Year(), t.Month(), t.Day(), 0, 0, 0, 0, time.Local)
 420         _ = midnight
 421
 422         // Output:
 423         // t.Truncate(  1ns) = 12:15:30.918273645
 424         // t.Truncate(  1µs) = 12:15:30.918273
 425         // t.Truncate(  1ms) = 12:15:30.918
 426         // t.Truncate(   1s) = 12:15:30
 427         // t.Truncate(   2s) = 12:15:30
 428         // t.Truncate( 1m0s) = 12:15:00
 429         // t.Truncate(10m0s) = 12:10:00
 430 }
 431
 432 func ExampleLocation() {
 433         // China doesn't have daylight saving. It uses a fixed 8 hour offset from UTC.
 434         secondsEastOfUTC := int((8 * time.Hour).Seconds())
 435         beijing := time.FixedZone("Beijing Time", secondsEastOfUTC)
 436
 437         // If the system has a timezone database present, it's possible to load a location
 438         // from that, e.g.:
 439         //    newYork, err := time.LoadLocation("America/New_York")
 440
 441         // Creating a time requires a location. Common locations are time.Local and time.UTC.
 442         timeInUTC := time.Date(2009, 1, 1, 12, 0, 0, 0, time.UTC)
 443         sameTimeInBeijing := time.Date(2009, 1, 1, 20, 0, 0, 0, beijing)
 444
 445         // Although the UTC clock time is 1200 and the Beijing clock time is 2000, Beijing is
 446         // 8 hours ahead so the two dates actually represent the same instant.
 447         timesAreEqual := timeInUTC.Equal(sameTimeInBeijing)
 448         fmt.Println(timesAreEqual)
 449
 450         // Output:
 451         // true
 452 }
 453
 454 func ExampleTime_Add() {
 455         start := time.Date(2009, 1, 1, 12, 0, 0, 0, time.UTC)
 456         afterTenSeconds := start.Add(time.Second * 10)
 457         afterTenMinutes := start.Add(time.Minute * 10)
 458         afterTenHours := start.Add(time.Hour * 10)
 459         afterTenDays := start.Add(time.Hour * 24 * 10)
 460
 461         fmt.Printf("start = %v\n", start)
 462         fmt.Printf("start.Add(time.Second * 10) = %v\n", afterTenSeconds)
 463         fmt.Printf("start.Add(time.Minute * 10) = %v\n", afterTenMinutes)
 464         fmt.Printf("start.Add(time.Hour * 10) = %v\n", afterTenHours)
 465         fmt.Printf("start.Add(time.Hour * 24 * 10) = %v\n", afterTenDays)
 466
 467         // Output:
 468         // start = 2009-01-01 12:00:00 +0000 UTC
 469         // start.Add(time.Second * 10) = 2009-01-01 12:00:10 +0000 UTC
 470         // start.Add(time.Minute * 10) = 2009-01-01 12:10:00 +0000 UTC
 471         // start.Add(time.Hour * 10) = 2009-01-01 22:00:00 +0000 UTC
 472         // start.Add(time.Hour * 24 * 10) = 2009-01-11 12:00:00 +0000 UTC
 473 }
 474
 475 func ExampleTime_AddDate() {
 476         start := time.Date(2009, 1, 1, 0, 0, 0, 0, time.UTC)
 477         oneDayLater := start.AddDate(0, 0, 1)
 478         oneMonthLater := start.AddDate(0, 1, 0)
 479         oneYearLater := start.AddDate(1, 0, 0)
 480
 481         fmt.Printf("oneDayLater: start.AddDate(0, 0, 1) = %v\n", oneDayLater)
 482         fmt.Printf("oneMonthLater: start.AddDate(0, 1, 0) = %v\n", oneMonthLater)
 483         fmt.Printf("oneYearLater: start.AddDate(1, 0, 0) = %v\n", oneYearLater)
 484
 485         // Output:
 486         // oneDayLater: start.AddDate(0, 0, 1) = 2009-01-02 00:00:00 +0000 UTC
 487         // oneMonthLater: start.AddDate(0, 1, 0) = 2009-02-01 00:00:00 +0000 UTC
 488         // oneYearLater: start.AddDate(1, 0, 0) = 2010-01-01 00:00:00 +0000 UTC
 489 }
 490
 491 func ExampleTime_After() {
 492         year2000 := time.Date(2000, 1, 1, 0, 0, 0, 0, time.UTC)
 493         year3000 := time.Date(3000, 1, 1, 0, 0, 0, 0, time.UTC)
 494
 495         isYear3000AfterYear2000 := year3000.After(year2000) // True
 496         isYear2000AfterYear3000 := year2000.After(year3000) // False
 497
 498         fmt.Printf("year3000.After(year2000) = %v\n", isYear3000AfterYear2000)
 499         fmt.Printf("year2000.After(year3000) = %v\n", isYear2000AfterYear3000)
 500
 501         // Output:
 502         // year3000.After(year2000) = true
 503         // year2000.After(year3000) = false
 504 }
 505
 506 func ExampleTime_Before() {
 507         year2000 := time.Date(2000, 1, 1, 0, 0, 0, 0, time.UTC)
 508         year3000 := time.Date(3000, 1, 1, 0, 0, 0, 0, time.UTC)
 509
 510         isYear2000BeforeYear3000 := year2000.Before(year3000) // True
 511         isYear3000BeforeYear2000 := year3000.Before(year2000) // False
 512
 513         fmt.Printf("year2000.Before(year3000) = %v\n", isYear2000BeforeYear3000)
 514         fmt.Printf("year3000.Before(year2000) = %v\n", isYear3000BeforeYear2000)
 515
 516         // Output:
 517         // year2000.Before(year3000) = true
 518         // year3000.Before(year2000) = false
 519 }
 520
 521 func ExampleTime_Date() {
 522         d := time.Date(2000, 2, 1, 12, 30, 0, 0, time.UTC)
 523         year, month, day := d.Date()
 524
 525         fmt.Printf("year = %v\n", year)
 526         fmt.Printf("month = %v\n", month)
 527         fmt.Printf("day = %v\n", day)
 528
 529         // Output:
 530         // year = 2000
 531         // month = February
 532         // day = 1
 533 }
 534
 535 func ExampleTime_Day() {
 536         d := time.Date(2000, 2, 1, 12, 30, 0, 0, time.UTC)
 537         day := d.Day()
 538
 539         fmt.Printf("day = %v\n", day)
 540
 541         // Output:
 542         // day = 1
 543 }
 544
 545 func ExampleTime_Equal() {
 546         secondsEastOfUTC := int((8 * time.Hour).Seconds())
 547         beijing := time.FixedZone("Beijing Time", secondsEastOfUTC)
 548
 549         // Unlike the equal operator, Equal is aware that d1 and d2 are the
 550         // same instant but in different time zones.
 551         d1 := time.Date(2000, 2, 1, 12, 30, 0, 0, time.UTC)
 552         d2 := time.Date(2000, 2, 1, 20, 30, 0, 0, beijing)
 553
 554         datesEqualUsingEqualOperator := d1 == d2
 555         datesEqualUsingFunction := d1.Equal(d2)
 556
 557         fmt.Printf("datesEqualUsingEqualOperator = %v\n", datesEqualUsingEqualOperator)
 558         fmt.Printf("datesEqualUsingFunction = %v\n", datesEqualUsingFunction)
 559
 560         // Output:
 561         // datesEqualUsingEqualOperator = false
 562         // datesEqualUsingFunction = true
 563 }
 564
 565 func ExampleTime_String() {
 566         timeWithNanoseconds := time.Date(2000, 2, 1, 12, 13, 14, 15, time.UTC)
 567         withNanoseconds := timeWithNanoseconds.String()
 568
 569         timeWithoutNanoseconds := time.Date(2000, 2, 1, 12, 13, 14, 0, time.UTC)
 570         withoutNanoseconds := timeWithoutNanoseconds.String()
 571
 572         fmt.Printf("withNanoseconds = %v\n", string(withNanoseconds))
 573         fmt.Printf("withoutNanoseconds = %v\n", string(withoutNanoseconds))
 574
 575         // Output:
 576         // withNanoseconds = 2000-02-01 12:13:14.000000015 +0000 UTC
 577         // withoutNanoseconds = 2000-02-01 12:13:14 +0000 UTC
 578 }
 579
 580 func ExampleTime_Sub() {
 581         start := time.Date(2000, 1, 1, 0, 0, 0, 0, time.UTC)
 582         end := time.Date(2000, 1, 1, 12, 0, 0, 0, time.UTC)
 583
 584         difference := end.Sub(start)
 585         fmt.Printf("difference = %v\n", difference)
 586
 587         // Output:
 588         // difference = 12h0m0s
 589 }
 590
 591 func ExampleTime_AppendFormat() {
 592         t := time.Date(2017, time.November, 4, 11, 0, 0, 0, time.UTC)
 593         text := []byte("Time: ")
 594
 595         text = t.AppendFormat(text, time.Kitchen)
 596         fmt.Println(string(text))
 597
 598         // Output:
 599         // Time: 11:00AM
 600 }